# Review: cMoy Headphone Amp Bass BOOST Edition



## Katsukare

I received my cMoy Headphone Amp Bass Boost edition in the mail that I ordered last week from this auction, 
http://cgi.ebay.ca/cMoy-Amp-Headphon...QQcmdZViewItem






*Heres a small review on it. *

 The seller/creator, three3three3 (John Seaber) kept VERY good communication. He customized my amp with a volume control and a white led. He also tuned my amp so it was customized for my *Grado SR-60s*. 





 The packaging it came in was a bit flimsy but it was nicely wrapped in bubble wrap. 

 A few things I noticed when I was inspecting it, 

 Very nice workmanship, everything is intact and secure. Dim, yet bright white led, perfect so it doesn't blind or annoy you. Comes with a free 9v battery. 
 Nice soldering, and everything is heat-glued together. Very secure design. 
 Custom PCB board with Bass Boost and version number + creators email address for any technical support. 









 The sound quality is absolutely amazing with my Grado SR-60s. Crisp sound, custom volume knob works great, and the bass even without the bass boost is good! 






 When you turn the bass booost on the sound is 
	

	
	
		
		

		
		
	


	




 . The Bass is simply AMAZING. Low sexy bass that does not distort or cause noise at all! The bass is low but so nice that you can actually fall asleep to it. It is not annoying what-so-ever. I could listen to my cmoy for hours with bass boost on if I wanted to. 

 The lower end bass really stands out. It sounds simply amazing. It's like listening to music with subwoofers in your headphones! I am being dead serious. I have so much audio equipment at home and in my car and to be honest, this cMoy amp sounds just like as if I'm blasting my bassy music in my car. I love it! Bass is rich, crisp and clear! 
	

	
	
		
		

		
		
	


	




 Even with my garbage samsung mp3 player it produced nice rich bass and still kept it's mid and high treble. It was very nice. 

 I wish I had some testing equipment to show you, or you could listen to this. It sounds absolutely amazing. For the price of it, I would recommend it to anyone! 

 My dad, a former audiophile back in the day tried my amp and he was surprised by the sound quality and bass that this amp could produce!

 For the price, I'd say this is THE BEST cMOY AMP on ebay! The sound it produces is amazing! Would highly recommend it for anyone who uses Mp3 players! 

 For all you bass lovers, be sure to check this out! 

 Bottomline: Affordable, Amazing Sound Quality, Breathless low-end Bass, Crisp sound, and great workmanship. 

 Don't be scared to contact John, hes a great guy and he replied to questions at lightning speeds! 
 Highly recommended!

 5/5 Stars for Build Quality.
 5/5 Stars for Sound Quality.
 4/5 Stars for Price.

 Overall: 5/5 Stars!


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## luidge

Hummm something sound fishy here...


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## blackinches

luidge, that's one of my customers. I didn't ask him to review it, but am glad to see enthusiastic reception. Thanks, Kinky!


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## Katsukare

Check my ebay account. I am one of blackinches customers. Check three3three3's feedback, I'm pure legit. 
 I promised that I would write him a review on his cmoy, thus attracting more customers and allowing an honest audiophile's review of these cMoy amps on ebay.

 Anyone in toronto who wants to meet up and try the amp, by all means pm me.


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## Logistics

SAGE goes in the e-mail field.

 "Bass boost?" I'd like to hear how this was accomplished.


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## fordgtlover

How does the bass boost work?

 I've built a few CMoys and never really found them lacking in bass.


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## jilgiljongiljing

well if it works, gfu


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## SK138

Very nice pictures to OP
	

	
	
		
		

		
		
	


	




 I just ordered one. I had lot of amps in my time but I like the price of this cMoy and most of all the builder is very responsive (even after 2am in the morning). Good service (and responsiveness) goes a long way for me. 

 Once I get it, I will add my impression after few hundred hours of burn in.


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## Katsukare

Quote:


  Originally Posted by *SK138* /img/forum/go_quote.gif 
_Very nice pictures to OP
	

	
	
		
		

		
		
	


	




 I just ordered one. I had lot of amps in my time but I like the price of this cMoy and most of all the builder is very responsive (even after 2am in the morning). Good service (and responsiveness) goes a long way for me. 

 Once I get it, I will add my impression after few hundred hours of burn in._

 

Haha yeah man. John is the best at communication. Hes on till 2 am - 4am. 
 Great guy. Keep it up John! 

 Thanks for the comments on the pictures. They were just quick snaps, nothing serious. I have some more serious photography but i just wanted to show some poeple the detail of the amp.


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## SK138

If I like the sound signature, I will buy another amp from John and build me a "poor man's" cMoy balanced system with my VDA2/VAC1 DAC and two 24v DC battery system (with large power cap) 
	

	
	
		
		

		
		
	


	




 I just need to make the appropriate cables for VDA2 and Senn 580 & 650. It should be a fun system and fun project 
	

	
	
		
		

		
		
	


	





  Quote:


  Originally Posted by *Kinky* /img/forum/go_quote.gif 
_Haha yeah man. John is the best at communication. Hes on till 2 am - 4am. 
 Great guy. Keep it up John! 

 Thanks for the comments on the pictures. They were just quick snaps, nothing serious. I have some more serious photography but i just wanted to show some poeple the detail of the amp._


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## ADD

I always wonder where all the actual mints go with these things.


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## d-cee

cos to most people mint tins are semi-cool!

 unfortunately bland plastic hammond enclosures aren't

 on the practicality side of things though...


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## Ocelaris

I just got John's Cmoy Bass Boost clone today also, and it definetly is a major improvement over non-amped for my AKG K271. I seem to have a bit different layout, without the volume knob, enough room such that I can stick another 9v battery in series, which I'm going to attempt tomorrow. I bought it because of this thread specifically, thanks for sharing. 

 My first headphone amp, and it's hell of a bang for the buck, especially since the AKG K271 are power hungry, and a bit bass shy compared to others, my EQ on my Iriver H120 doesn't have enough oomph for my tastes, but this does the job perfect...


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## luidge

Sorry to have doubting you, it's just that you had a very low number of posts and that your review looked to me like a publicity. However i am happy to see that you love your amp and i hope you will keep on finding new tweaks and gear to upgrade your musical listening experience! Welcome aboard

 Luidge


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## mrarroyo

I was about to order one and finally try a Cmoy amp. Then I went to Ebay and read that it does not have a volume control, however on the pictures above you have one with a volume pot. What gives? can I purchase one w/ a volume pot? 

 Also I am not to interested in a gain switch provided the seller can set the gain at 3 out of the Cmoy. Is this doable? Thanks.


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## souperman

never mind.


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## blackinches

Quote:


  Originally Posted by *mrarroyo* /img/forum/go_quote.gif 
_I was about to order one and finally try a Cmoy amp. Then I went to Ebay and read that it does not have a volume control, however on the pictures above you have one with a volume pot. What gives? can I purchase one w/ a volume pot? 

 Also I am not to interested in a gain switch provided the seller can set the gain at 3 out of the Cmoy. Is this doable? Thanks._

 

The OP requested a volume control and paid extra for it. The PCB is not designed for a volume potentiometer and I do not stock the parts right now. I happened to have some extra knobs and pots from building my Mini3. I will release a newer PCB after I sell off the rest of these. It will add an optional volume control.


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## bonkon

No volume control? Is this supposed to be used with the headphone out instead of the line out? Wouldn't that be useless to the purpose of a headphone amp.


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## HeadphoneAddict

I have a short 8" extension with volume and a 30" with volume, so with one of those a person could use line-level outputs and control the volume with the cable.


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## Canuck57

Quote:


  Originally Posted by *ADD* /img/forum/go_quote.gif 
_I always wonder where all the actual mints go with these things._

 

Good one!!!!


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## oicdn

Quote:


  Originally Posted by *bonkon* /img/forum/go_quote.gif 
_No volume control? Is this supposed to be used with the headphone out instead of the line out? Wouldn't that be useless to the purpose of a headphone amp._

 

+1


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## Crossfeed

I got mine today. Shipping took less than a week 
	

	
	
		
		

		
		
	


	




. The build quality looks nice. One might wanna add some extra stuff to keep the battery in place.

 I thought of giving this amp to my girlfriend to be used with her laptop and Sennheiser HD595. The gain is customized for the HD595, but I decided to test it with my Ultrasone Proline 650, since the HD595 hasn't arrived yet. I assume that the gain setting would fit the Prolines good enough for testing.

 However, I was actually disappointed when I tried it on the laptop with my Prolines. The headphone out on laptop has some static noise that is almost not noticeable when connecting the phones directly. However, when using the amp the noise gets amplified and is really annoying when not playing music quite loud.

 So this amp is not any good with a headphone out that is just a little noisy since the amp doesn't have any volume controller. If the amp would have a volume control one could set the volume on the computer to about 80% and then the noise would be smaller in comparison to the music. (output = noice + music (assuming most of the noise is static))

 I compared Corda Move with this cMoy amp with the noisy laptop both connected to headphone out. With the Move the noise was just noticeable when not playing any music. I used about 80% of the headphone out volume and then controlling the volume on the Move.

 I also tried the amp with my main computer. It worked better with my old soundblaster live card. Not much noise at all. However, the volume was quite load with the master volume close to zero. To decrease the digital volume controls doesn't seem to be a good idea to me. Then sound quality could be reduced.

 The cMoy amp worked quite okay with my old Sony minidisc player. For some music it was an improvement over the directly using the headphone out. Music that was quite loud and compressed self sounded more flat when using the cMoy. I don't know if this could be caused by a digital volume control on the minidisc.

 I think I will try to find a separate volume control and try it again with the noisy laptop. If that doesn't work I guess I'll keep it for the coolness.


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## blackinches

Quote:


  Originally Posted by *bonkon* /img/forum/go_quote.gif 
_No volume control? Is this supposed to be used with the headphone out instead of the line out? Wouldn't that be useless to the purpose of a headphone amp._

 

Yes, it's for use with headphone output. The cMoy is targeted as an entry level amp and that's how most people want to hook it up anyway. It works great with MP3 players. It's even fine with computers as long as you turn the volume down and have a decent signal to begin with.

 I know a volume control is desirable (and mandatory for the higher quality line out signals), and will reduce hiss at low volumes, but as already mentioned, I will add a volume control soon.

  Quote:


  Originally Posted by *Crossfeed* /img/forum/go_quote.gif 
_I got mine today. Shipping took less than a week 
	

	
	
		
		

		
		
	


	




. The build quality looks nice. One might wanna add some extra stuff to keep the battery in place.

 . . . 

 I think I will try to find a separate volume control and try it again with the noisy laptop. If that doesn't work I guess I'll keep it for the coolness. 
	

	
	
		
		

		
		
	


	


_

 

I've since moved the padding for the battery and it now stays in place very tightly. Here's a quick shot:






 As for noisy laptop signals, you're right, a volume control would help. However, garbage in = garbage out. Even with a volume control, the sound quality and noise present with integrated sound cards is undesirable. I personally place higher priority on maximizing the sound quality of my source before I bother amplifying a signal. The cheapest source I listen to, besides my iPod, is a SB Audigy 2 ZS.

 I haven't tried it myself, but this Koss volume control may be what you need. Sennheiser also makes a nice control.


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## Chewy

Last week I got a cmoy bass boost from John and I'm very happy with it. The build quality is solid and the battery lasts longer than my total airhead. The sound is tight, clear and brings out the soundstage.

 The bass boast is great with my Shure E3C and iPod. Though, overkill with my AT A900 and HD600 which already have plenty of bass. I'm currently using them with my A900 and SB Audigy 2 and don't hear any hiss.


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## Crossfeed

Quote:


  Originally Posted by *blackinches* /img/forum/go_quote.gif 
_I've since moved the padding for the battery and it now stays in place very tightly. I'll edit this post later with a picture.

 As for noisy laptop signals, you're right, a volume control would help. However, garbage in = garbage out. Even with a volume control, the sound quality and noise present with integrated sound cards is undesirable. I personally place higher priority on maximizing the sound quality of my source before I bother amplifying a signal. The cheapest source I listen to, besides my iPod, is a SB Audigy 2 ZS._

 

You might want to add some protection above the large capacitor as well. I for some reason pressed lightly against the amps top while playing and that was kind of scaring 
	

	
	
		
		

		
		
	


	




.

 Yeah, I know the laptop as source sucks. However I think the sound card is good enough for the one that was supposed to use it 
	

	
	
		
		

		
		
	


	




. It sound quite okey when using my Prolines without amp except for playing really loud. I just want to add some extra power to be able to control the drivers better for a small cost. Not to amp the signal to play much louder...


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## blackinches

Quote:


  Originally Posted by *Crossfeed* /img/forum/go_quote.gif 
_You might want to add some protection above the large capacitor as well. I for some reason pressed lightly against the amps top while playing and that was kind of scaring 
	

	
	
		
		

		
		
	


	




.

 Yeah, I know the laptop as source sucks. However I think the sound card is good enough for the one that was supposed to use it 
	

	
	
		
		

		
		
	


	




. It sound quite okey when using my Prolines without amp except for playing really loud. I just want to add some extra power to be able to control the drivers better for a small cost. Not to amp the signal to play much louder..._

 

There is about 4mm clearance between the tallest capacitor and the lid in the current PCB. The board is also locked in place, so that should never happen again. And I leave my offer standing if you'd like a replacement.

 Also, due to the high number of requests generated by the images of Kinky's amp, I've revised the PCB to accommodate an Alps RK097 volume control:






 I will have a few of these boards in 2-4 weeks. Meanwhile, to save everyone time: Sorry, I cannot build any amps with a volume control until the new boards arrive. Patience, please


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## SK138

I got two "balanced" cMoys from John few days ago and "cooking" (burning in) well
	

	
	
		
		

		
		
	


	




 I did NOT want to have a volume pod for a balanced system. The volume is controlled by iTunes and it's working perfectly well. I will post pictures and some "review" after I get it burned in for few more days (~200 hours).


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## jgonino

Just ordered one of these with the dual gain switch. Should be here by wednesday.


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## jgonino

I just got this baby in the mail today, and I LOVE it!! The amp worked right out of the box, no problems what so ever. All the connections are tight, and both switches work properly. I have tried my dt770's, sr60's and my ksc75's with this amp, and I think the sr-60's sound the best. It sounds like an open dt770 with the bass boost on. I will add pictures later when I have the chance


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## SK138

This is NOT a formal review....because I know I suck at it
	

	
	
		
		

		
		
	


	




 Consider this to be my commentary, observation, opinion, desire to share information, and story of a personal eargasm based on two matched cMoy amps built by John Seaber in a balanced configuration. Before I publish this...I had to think carefully because I did not want to become a possible laughing stock here at Head-Fi or just keep it silent and enjoy my music. When a person finds a rare elation that many other can also potentially enjoy...one just can't keep it quiet.
	

	
	
		
		

		
		
	


	




 First of all, John Seaber (aka blackinches) is a top notch person with great product and one of the best service I have experienced here. The combination of great product and service (and responsiveness) goes a long way of earning my business. That's why he is building my next budget balanced rig: the balanced mini^3 
	

	
	
		
		

		
		
	


	




 Back to the amp....and my unorthodox configuration...

 SETUP: 
 When I first read this thread by Iron_Dreamer (http://www.head-fi.org/forums/showpo...&postcount=10), that motivated and inspired me to test an idea of going balanced with my Senn HD650 and HD580 cans using my CIAudio's VDA2 DAC with VAC power supply. 

 I ordered two matching cMoys from John without volume pod and with gain switch. He carefully matched the two cMoys with matching resistors so the cMoys sound identical as possible. Since my intent was to use this purely as desktop amp, I took the battery out and used an expensive 24vDC output ELPAC power supply.










 I connected a standard RCA to stereo mini cable from VDA2's right 0 and 180 phases and plug the mini stereo input plug to cMoy #1 (right side of headphone) and I repeated for the left 0 and 180 phase RCA from VDA2 to mini stereo input plug to cMoy #2 (left side of headphone). On the mini stereo plugs, the 0 phase was the tip of stereo plugs, 180 phase was the ring of stereo plugs, and ground was ground.










 I modded the RnB's Grace 52 Senn cable from single ended to balanced TRS format to match the above stereo plugs signal orientation, where the - (minus) pole is tip of the TRS plug and the + (plus) pole is ring of TRS plug, per right and left side. Therefore the tip of TRS = 0 phase and ring of TRS = 180 phase per right and left headphone.






 I plugged everything...double checked...triple checked...the connections. I turned off the bass boost on the cMoys. Set the amps to low gain. I lowered the volume on iTunes to lowest. I pressed to play Diana Krall's song, "Narrow Daylight".... I heard a loud POP and my drivers went dead.....JOKING;D

 INITIAL SOUND:
 When I gradually raised the volume on iTunes and heard Diana's song, "Narrow Daylight" for the first time on this setup, I thought the sound sucked. It was course, grainy, boomy, no soundstage, compressed sounding, piercing treble all over the spectrum,....I simply hated the sound. It wasn't even a decent music to me. I thought I wasted <$100 on amps, >$60 on ELPAC power source, and cut up a valuable RnB's Senn cable for nothing. I let it continue to play for few hours and heard little more on Diana's "`S Wonderful" and it sounded pretty good. The boomy bass tighten up and grainy sound was greatly gone. The soundstage returned little bit and compressed sounding was gone...and there were lots of details and channel separation. The first thing I noticed was the Senn650's dark veil sound was almost gone on the balanced configuration and it's the most powerful sound I have ever heard. The sound had potential so I let it sit and play music for almost 2 days straight without listening to it because I was too busy with work...and I had to tolerate my kids telling me I left the music on many times a day
	

	
	
		
		

		
		
	


	




 BACKGROUND:
 In this forum we read many people exclaiming, "OMG!!!", "eargasm" , "The best ever...", etc. when they are elated with quality of sound they never heard before. I rarely felt that way before with any of my amps from the past. I had many amps in the past. To list them, it goes something like this:

 Stainless Steel "Toaster" MPX3 6SN7 with SLAM Adapters
 Berning MicroZOLT (Sylvania Gold Brand 6201 & Russian 1960s 6SN7 tubes)
 Updated Xin Supermacro 3V6 to near IV (AD797 with Buffers Bypassed)
 Insanely modded X-CAN V2 (#1)
 Xin Supermacro LE (ST-WA)
 2005 MicroStack with Desktop Module (again)
 Ray Samuels XP-7 (AD797)
 MisterX XP Amp
 Xin Supermicro IV
 Rockhopper Audio's maxed out M^3 (Great amp!)
 Upgraded (silver wire / blackgate caps) Gilmore V2-SE
 Woo3 with enough NOS tubes to last until the next Ice Age
 Mapletree Ear Purist + HD
 Pinky modded X-CAN V2 (#2)
 X-CAN V3 (few days...modded X-CAN V2 was better)
 2000 Ok HP 100A hybrid Chinese amp
 Headamp AE-1
 Headamp Gilmore Lite V2 (twice)
 Ray Samuels SR-71
 Xin Supermini 3V3
 Modwright CIAudio's VHP-1/VAC-1
 Corda Aria
 2005 Headroom MicroStack with desktop module
 Zhaolu D2 with discrete head amp
 Shellbrook Super Mini Moy

 They all have one thing in common. They are all single ended. Out of them, the best sounding amps were my last two amps; microZOTL and Toaster MPX3. They made me think I would stop upgrading and gear swapping for good. Along comes Iron_Dreamer's comment about attaching two single ended amps to create a truly balanced system with VDA2 DAC absolutely intrigued me. I then began crudely test the idea by hooking up the ZOTL and MPX3 in a "balanced" configuration with hacked up stock Senn HD650 cable to make it balanced TRS format. After careful volume matching on two amps...it had potential and warranted a further practical research and experiment. I had made a promise to my wife that I will NOT keep more than two amps at a time so ZOTL or MPX3 had to go and stay around $1000 budget. I hated the idea of selling the ZOTL but I had to give it up and find it a very good home. I found a perfect home for it. Then I stumbled onto John's little bass boosted cMoy and that along with Iron_Dreamer's idea sparked this whole experimentation, revelation, eargasm, and "never go back to single ended system" mantra.

 BACK TO THE SOUND:
 After few days of burning in the cMoy amps...I didn't expect much as I was playing Diana's Live in Paris CD on iTunes. What can I say, the sound was amazing, powerful, the details, the channel separation was ....just WOW!! I had to look over to the two Altoids tin cans with rubber band strap on it and I just had to laugh out loud. This sound just can't be coming out of that!!! No way...no how!!! I compared the sound with MPX3 and the balanced cMoy and the balanced cMoy sound fuller, more organic, powerful, the bass went deeper, more detail, better channel separation, the treble energy was better than the MPX3 with vintage Sylvania 6SN7 and KenRad 6SN7 tubes, which was considered to be the best 6SN7 tubes for my old MPX3 6SN7 system. What is going on?!?! How can this be?! I am absolutely addicted to the balanced sound. I heard balanced rigs at the meets but never impressed me too much because the meetings are not the ideal environment to listen anything critically.

 Instead of questioning too much at my elation and eargasm, I immediately decided to sell the MPX3 to fund it towards purchase of a "real" balanced system....Headroom's Desktop Balanced with Home module and dedicated power supply. (I promised my wife I would not buy any more cans for 6 months..hehe) The bad news was I had to wait two weeks plus for Headroom goodies to be built and shipped to me. Few days later, I decided to take Iron_Dreamer's original idea of going with all CIAudio's "balanced" system with two VHP2 amps and VAC power supplies. I canceled the Headroom order. The VHP2s and VACs should be here very soon
	

	
	
		
		

		
		
	


	




 CONCLUSION...NO REVELATION:
 It's true...SennHD650 turns into a different creature with balanced configuration. The sound it produces is probably the best bang for the buck in any headphones costing below $1000. Match that value with John's two matching cMoys that cost less than $100, another $100 on decent cables and power supply for the cMoys and you got your self a great balanced system on the cheap as long as you have a balanced DAC and easily modded balanced Senn stock cable.










 When I get the VHP2s soon, I am planning to send out John's balanced cMoys to others who have VDA2 DAC and HD6** / HD580 so they can also contribute to "balanced system on a shoe string budget" opinion. I am NOT saying here that balanced cMoys can beat a $1000 balanced system or even a top notch single ended system. This information is to share a great idea inspired by Iron_Dreamer's and great product made by John Seaber (aka blackinches) in action at a great price/performance ratio. For me, I absolutely love the balanced sound...I can't go back to single ended
	

	
	
		
		

		
		
	


	




 Final thought...I just want to thank Iron_Dreamer for his spontaneous idea of going balanced with two single ended amps that inspired me and John's cmoy to make it all happen in the first place.

 Fiinally, Head-Fi's first story that's happy for your wallet
	

	
	
		
		

		
		
	


	




 Next stop... balanced custom mini^3


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## HeadphoneAddict

I bought one of these to play with, and got it yesterday.

 The sound is quite fun, adding punch to the ipod's output. It plays more than loud enough, without clipping. Bass boost is very smooth, with*OUT* unsightly coloration in the mid-bass. It is also very quiet, without background noise. Too quiet as a matter of fact for some (or many) audiophiles. 

 When listening to "Jazz at the pawnshop" at 192kbps on an 8gb Nano with my Ultrasone HFI 700 headphones, it sounds just like the recording was made in a studio. The problem is that it is a live recording made in a small club. With the Tomahawk Amp and the same source and headphones it sounds like a live recording. 

 With the cMoy the ambience/reverberation between notes or after the strike of the drums, etc... seems to be missing. Almost like the threshhold for letting quiet sounds and secondary harmonics pass through is set too high, i.e echo and resonance from the environment.

 I will let this burn-in once I am done burning-in my D1, and report back in a few weeks with changes and improvements that I hear with this issue. I may also try it using my H120 optical+D1 as the Transport/DAC, instead of with an ipod's built-in DAC.

 However, for casual listening with a nice set of headphones it will definitely rock out. It is a $39 amp that sounds like a $100 amp, and I have no regrets buying it as a spare. It should get better with time.

 The seller is also very good at communicating about your needs and accomodating those needs, or customizing as needed. I got a gain switch hidden internally, and the LED brightness custom tailored. All I need now is a AC-to-DC power supply and rechargable 9v and I'm all set to not have to buy 9v batteries.


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## HeadphoneAddict

Previously I complained about the ER6i earphones being harsh, and even shrill with piano notes, but with good detail and bass. Because of that I have burned in my ER6i for 86 hours so far (was told I don't have to) and as a result they are indeed less harsh and have more bass. Also, this is with the Shure Black Olive foamies installed instead of any of the flanged or foam tips that came with the ER6i.

 Since the ER6i actually seem smoother through the new iBasso amp than the Tomahawk, so I tried them with the new "un-broken-in" Altoids cMoy with bass boost. *The cMoy amp really seems to tame the ER6i and make them more enjoyable. 
	

	
	
		
		

		
			



* So, I am going to spend more time burning this cMoy sooner than later, and use it to sleep with music every night.

 I'll continue to test the ER6i and the cMoy as I go to bed each night. I have to because today I gave my E2c "sleeping phones" to my lawn guy since I discovered he was using sennheiser open ear buds to listen to music over the loud gas mower (okay, so he offered to cut my lawn 4 times for them). 

 So, I think this little cMoy is going to mature nicely. The guys at work already want one, because barfing $300-400 for a RSA amp isn't agreeable to their wallets. One of them also wants to trade his E3c for my E4c but that isn't gonna happen 
	

	
	
		
		

		
		
	


	




 He might not want mine after he tries his with a *c*Moy-*b*ass-*b*oost amp. We should just call these a C-B-B amp.


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## 1Time

I bought this cMoy on eBay today to use with my HD580 and Chaintech AV-710, plain with no LED for $45.95 shipped. I just wanted something cheap and the info in John's eBay listing intrigued me. Then I came to Head-Fi and reading this thread sold me.


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## 1Time

Quote:


  Originally Posted by *HeadphoneAddict* /img/forum/go_quote.gif 
_ We should just call these a C-B-B amp._

 

I suggest calling it a cMoyBB.


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## jewman

I'm thinking of buying this amp as my first headphone amp. I would be using it mostly with my UE SF3's and my h320. Should I buy it? Or should I save up some more dough and reach for the iBasso T2? If I should buy it, should I wait for the volume knob or not? I know it's a lot of questions, but I trust you guys can answer them all. Thanks!


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## 1Time

Quote:


  Originally Posted by *jewman* /img/forum/go_quote.gif 
_I'm thinking of buying this amp as my first headphone amp. I would be using it mostly with my UE SF3's and my h320. Should I buy it? Or should I save up some more dough and reach for the iBasso T2? If I should buy it, should I wait for the volume knob or not? I know it's a lot of questions, but I trust you guys can answer them all. Thanks! 
	

	
	
		
		

		
		
	


	


_

 

You should buy it now because 1) you can benefit from an amp now, and 2) the cMoyBB is selling at an introductory price. You should not wait for the volume knob since it is not needed.


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## SK138

Wait until I have my modded iGrado balanced with senn HD650 stock cable and it will be one of the most "happy for your wallet" gear around
	

	
	
		
		

		
		
	


	





  Quote:


  Originally Posted by *ampjoy* /img/forum/go_quote.gif 
_CMOY balanced... Kinky. 
	

	
	
		
		

		
		
	


	


_


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## HeadphoneAddict

I have to say I have over 24 hours of burn-in on the cMoyBassBoost and it is cleaning up very nicely! It doesn't sound anything like it did fresh out of the box. 

 Everything I listen to now has an improved sound-stage, the fine details that were being filtered out on the live jazz recording can NOW be heard, and the amp has plenty of power. 

 I have the optional switch that allows my Sennheisers to run more efficiently, and the other flip on the switch is the setting for my IEM's (just tell him what headphones you have when you order, and if you want the optional switch). If I play the PMX100 headphones with the IEM setting I can hear the amp running out of power - flip the switch and voila! it is clear as a bell. The IEM will play with either setting, but the Senn setting has less gain but also less hiss with the volume all the way down (maybe s/n ratio of at least 75-80db I'm guessing with the louder setting). The way I understand it, highly efficient headphones will show the hiss more but you can adjust the impedance (or gain I think) and that improves with a little less efficiency.

 I also picked up a power adapter at Radio Shack so that when I listen to it at home I don't have to run the batteries down, and the amp disconnects the battery when it is plugged into the wall. I tested the alkaline 9v battery after 24 hours of use and it still looks close to a full battery; so it seems to run so well off an Alkaline battery that it doesn't need a charging circuit. I'd bet the battery is good for 75-80 hours.

 It still isn't close to the RSA Tomahawk amp, but it is very impressive for the price.


----------



## HeadphoneAddict

Quote:


  Originally Posted by *SK138* /img/forum/go_quote.gif 
_Wait until I have my modded iGrado balanced with senn HD650 stock cable and it will be one of the most "happy for your wallet" gear around
	

	
	
		
		

		
		
	


	


_

 

WHY DIDN'T I THINK OF THAT! Then they'd sound better than my PMX100 with all kinds of music, not just Rock


----------



## MusicallySilent

Yea about your cmoy balanced... you make me so very tempted to make a mini3 or cmoy or pimeta in a good case with a good power supply so both are in one case and try to wire it for a single volume pot.


----------



## HeadphoneAddict

You know, I had skipped over SK138's balanced post because I am not interested in doing that right now.

 But, I went back and read it just now and realised that my posted observations on the sound quality and the progress or transformation over 48 hours are identical. It feels good to know my "ears to brain to mouth connection" in assessing sound works the same as with other people 
	

	
	
		
		

		
		
	


	




 It also serves to lend more credibility to his post about balanced cMoys, that he really isn't nuts but acted on a great idea!

 My observations are spread between three threads though - this one, the ER6i vs Super.fi 3 thread, and a new one I posted about head to head inexpensive altoids c;moy testing. I wish I could post the links here, but it is way too complicated on the Motorola Q smartphone, which with a 4GB SD card is now an excellent additional music source for me.


----------



## SK138

I should thank you for validating me. I was REALLY hesitant to post my findings about the balanced cMoy thinking I would be the laughing stock here at Head-Fi. I am not any "authority" when it comes to sound quality. I just know what makes me enjoy endless hours of music that I love. On that note, you did a super review
	

	
	
		
		

		
		
	


	





  Quote:


  Originally Posted by *HeadphoneAddict* /img/forum/go_quote.gif 
_You know, I had skipped over SK138's balanced post because I am not interested in doing that right now.

 But, I went back and read it just now and realised that my posted observations on the sound quality and the progress or transformation over 48 hours are identical. It feels good to know my "ears to brain to mouth connection" in assessing sound works the same as with other people 
	

	
	
		
		

		
		
	


	




 It also serves to lend more credibility to his post about balanced cMoys, that he really isn't nuts but acted on a great idea!

 My observations are spread between three threads though - this one, the ER6i vs Super.fi 3 thread, and a new one I posted about head to head inexpensive altoids c;moy testing. I wish I could post the links here, but it is way too complicated on the Motorola Q smartphone, which with a 4GB SD card is now an excellent additional music source for me._


----------



## blackinches

The first two prototype PCBs arrived today. I'll make some layout adjustments and have the final PCBs in under two weeks.

 However, I'm extraordinarily busy and one of the jacks I use is backordered until October. Thus, it may be a while before I can begin to sell these on eBay.


----------



## HeadphoneAddict

You might want to re-think the in/volume/out being that close together.

 Some people have 3.5mm plugs that are too fat to fit into those jacks!


----------



## 1Time

Quote:


  Originally Posted by *HeadphoneAddict* /img/forum/go_quote.gif 
_You might want to re-think the in/volume/out being that close together.

 Some people have 3.5mm plugs that are too fat to fit into those jacks!_

 

I have 2 different 3.5mm to 1/4" adapters, one round and the other hexagonal. I put one in the IN and the other in the OUT to check this, and my guess is there would be enough room for the volume. My cMoyBB has the bass boost toggle where the volume would be. Maybe blackinches didn't count on anyone using larger than ordinary adapters.


----------



## blackinches

Quote:


  Originally Posted by *HeadphoneAddict* /img/forum/go_quote.gif 
_You might want to re-think the in/volume/out being that close together.

 Some people have 3.5mm plugs that are too fat to fit into those jacks!_

 

Hence the layout adjustments I mentioned 
	

	
	
		
		

		
			





 The final PCBs will not be so cramped.

 Some of the components I use are backordered until October, so no more sales until then.


----------



## MuzlL0dr

Quote:


  Originally Posted by *blackinches* /img/forum/go_quote.gif 
_Some of the components I use are backordered until October, so no more sales until then._

 






 I just saw these for the first time a couple days ago, and *just* missed the last ones on ebay. Oh well. I'll be watching for your next iteration in October.


----------



## jewman

Okay, I just received my CmoyBB on Friday, and I can really tell that it helps out the low end on my UE Super.fi 3s, which really need help in the bass dept. It amplifies the hiss on my h320 to a fairly high level, so I used the included volume attenuator, which seemed to have solved the hiss problem, although I'm afraid I'm missing out on the real sound by using the attenuator. 

 I've been using the amp with a cheap Radioshack cable, so I'm wondering if using maybe a Cardas IC would lessen the hiss. Also, this amp seems to be well made. Nothing jiggles, the battery assembly looks very sturdy, overall a very solid product. So far, I'm very satisfied.

 P.S. The led is very bright. Don't stare directly into it for too long.


----------



## Chri5peed

Altoids has always been too close to Hemorrhoids for me.


----------



## 1Time

Quote:


  Originally Posted by *Chri5peed* /img/forum/go_quote.gif 
_Altoids has always been too close to Hemorrhoids for me._

 

That's strange. Most humanoids are more readily aware of the differences.


----------



## Chri5peed

Do you know what Hemorrhoids are?

 Bum grapes.


----------



## blackinches

Hehe, here's my dish of Altoids:





 I added as much space as I can between the RK097 and mini jacks and am now utilizing a ground plane. Prototype boards will arrive around the same time as I resume sales:


----------



## sbulack

I purchased a cMoyBB with a Volume Pot built from one of the earlier prototype boards, and it arrived on Friday. I've had it running on two 9V batteries in series and burning in since then. As the burn-in has progressed, the sound of the Bass Boost has become clearer, cleaner and more transparent, as has the sound of everything, as I would expect. I've got to say that the cleanness, openness, spaciousness and transparency of the sound has become a very real pleasure to listen to. At this point, the Bass Boost has become so clean and transparent that I've been leaving it on all the time for a fuller spectral sound and (not sure why) a deeper and more credible, coherent soundstage to my ear.

 I paid an additional $10 for the Volume Pot and, soundwise, this amp offers a really fine value. From operatic soprano to Joe Satriani (with Classic Rock, Trip-Hop, Fusion, Ambient/Techno electronica in between), the sound draws me right into the music with the performers, with loads of intimacy, expressive energy and a very credible sense of space and presence to my ear. The balance and synergy between the sonic facets of the cMoyBB make this one of those listening tools for which the whole is a good deal more than the sum of its parts.


----------



## Caribou679

Quote:


  Originally Posted by *sbulack* /img/forum/go_quote.gif 
_I purchased a cMoyBB with a Volume Pot built from one of the earlier prototype boards, and it arrived on Friday. I've had it running on two 9V batteries in series and burning in since then. As the burn-in has progressed, the sound of the Bass Boost has become clearer, cleaner and more transparent, as has the sound of everything, as I would expect. I've got to say that the cleanness, openness, spaciousness and transparency of the sound has become a very real pleasure to listen to. At this point, the Bass Boost has become so clean and transparent that I've been leaving it on all the time for a fuller spectral sound and (not sure why) a deeper and more credible, coherent soundstage to my ear.

 I paid an additional $10 for the Volume Pot and, soundwise, this amp offers a really fine value. From operatic soprano to Joe Satriani (with Classic Rock, Trip-Hop, Fusion, Ambient/Techno electronica in between), the sound draws me right into the music with the performers, with loads of intimacy, expressive energy and a very credible sense of space and presence to my ear. The balance and synergy between the sonic facets of the cMoyBB make this one of those listening tools for which the whole is a good deal more than the sum of its parts._

 


 Excuse my asking but: isn't burn-in usefull for lamps amp?

 I do not think that the condensers or resistors in the amp you have will change their characteristics in time or with use.
	

	
	
		
		

		
		
	


	




 Please let me know as I am still wondering about that. 
	

	
	
		
		

		
		
	


	




 Last week I received another brand of headphone amp and it sounds the same after 30 hours of use compared to when I received it.

 regards,


----------



## Baines93

i really dont know what to get?? royal penguin, or caffeine, or this or ?? (cant remember what else i was looking at, will edit)

 -= Matt =-


----------



## Baines93

OMG I read the whole thread now i have some time, and i really want one now, i think the bass boost will be good, as i isten to some bassy music too, sometimes.....I think i would have dual gain, for maybe oneday when i have some decent headphones, and low gain for my er6i's. i would hopefully have the Gain and bass boost switches inside the tin, and an OPA2227 (are they user replaceable on your amps??) i would have the plain tin......

 In october how much would the amp cost approximatley? (With the stuff i want) and the cheapest shipping to the UK.

 I need to save up the right ammount!

 Thanks in advance, please reply!

 -= Matt =-


----------



## Chri5peed

Quote:


  Originally Posted by *Caribou679* /img/forum/go_quote.gif 
_Excuse my asking but: isn't burn-in usefull for lamps amp?_

 

This is a sub-genre of the whole 'Burn-in' debate.


 Personally I'm a believer of it in moving things[HP drivers] but not in static things.


----------



## Caribou679

Quote:


  Originally Posted by *Chri5peed* /img/forum/go_quote.gif 
_This is a sub-genre of the whole 'Burn-in' debate.


 Personally I'm a believer of it in moving things[HP drivers] but not in static things._

 

I have read a thread at Head-Fi about the usefulness of burn-in in lamps amp. I only own "cmoy" type amps so I cannot voice in favor of lamps amp but for the solid state I do not perceive a difference in time and use.

 I fully agree with you as regard usefulness in mechanical parts, like headphones and earphones, where a coil is acting against a membrane or whatever...

 But if I smoke a few good ones I might think the former


----------



## HeadphoneAddict

I think you're gonna upset a few people about this.

 This particular CMoy bass boost does use a capacitor that might need burn-in or time to "form". The builder does say it will work well without a cap. On this particular amp I can say it has changed a little, acheiving a mildly to oderately improved soundstage vs new. I reported on this earlier.

 However, I can vouch for, affirm, or attest to the fact that my iBasso D1 and my PenguinAmp Royal have had even more significant changes as they put more hours on the clock, they use significantly bigger caps...


----------



## HeadphoneAddict

I think you're gonna upset a few people about this.

 This particular CMoy bass boost does use a capacitor that might need burn-in or time to "form". The builder does say it will work well without a cap. On this particular amp I can say it has changed a little, acheiving a mildly to oderately improved soundstage vs new. I reported on this earlier.

 However, I can vouch for, affirm, or attest to the fact that my iBasso D1 and my PenguinAmp Royal have had even more significant changes as they put more hours on the clock, they use significantly bigger caps...


----------



## Caribou679

Quote:


  Originally Posted by *HeadphoneAddict* /img/forum/go_quote.gif 
_I think you're gonna upset a few people about this.

 This particular CMoy bass boost does use a capacitor that might need burn-in or time to "form". The builder does say it will work well without a cap. On this particular amp I can say it has changed a little, acheiving a mildly to oderately improved soundstage vs new. I reported on this earlier.

 However, I can vouch for, affirm, or attest to the fact that my iBasso D1 and my PenguinAmp Royal have had even more significant changes as they put more hours on the clock, they use significantly bigger caps..._

 

My intention is not to upset people, but on a forum discussions can bring counter ideas.

 On the amps I am using I do not saw significant changes with burn-in. However with IEMs and headphones, yes I notice a noticeable/significant change for the better, so an improvement.

 Under better circumstances,and a more stable base, I will have a tubes amp and will be able to experience it myself.

 I am interested in getting this bass expanded amp to experiment the change in sound it brings.

 Currently using an amp with closed earphones,RP22, to listen to Beethoven's symps and Opeth growls!

 Anything that can help to improve these experiences is welcome...

 regards,


----------



## neogeosnk

Quote:


  Originally Posted by *sbulack* /img/forum/go_quote.gif 
_As the burn-in has progressed, the sound of the Bass Boost has become clearer, cleaner_

 

 How long do you guys burn in your cmoy amps for ? Real interested to see what the "standard" burn in time would be. I believe burn in for cmoy does have an effect btw. You're not crazy. Even solid state parts tend to settle, IMO.


----------



## HeadphoneAddict

I burned mine in as I used them - with the exception of my iBasso D1 which I ran for 250 hours with occasional checks on the sound, and the exception of my Tomahawk that had 700 hours on it when I got it.


----------



## sbulack

Quote:


  Originally Posted by *neogeosnk* /img/forum/go_quote.gif 
_How long do you guys burn in your cmoy amps for ? Real interested to see what the "standard" burn in time would be._

 

The improvements that I heard happened during the first 60 hours or so of use. Beyond that, I haven't heard any further development of the sound through it.

 What I very much enjoy about the sound through the cMoyBB is its cleanness, clarity/transparency, openness/spaciousness which I find to be very refreshing to my ear and my listening. I've got two home amps and a variety of portable amps (including the TTVJ Portable Millett Hybrid Amp), all of which I enjoy very much as listening instruments. The cMoyBB fills another, and valued/enjoyed, listening niche for me - through its high-quality simplicity - much like well-prepared sonic lemon ice.


----------



## Baines93

Blackinches, how are you doing building this newest batch? And what will the final price be?

 -= Matt =-


----------



## blackinches

Everything is on schedule. I have two v1.55 prototypes. The bass boost switch will now be wired separately from the PCB.







 I will have all the parts to resume sales in stock by Friday, October 5th (or possibly as soon as Monday the 1st). I am happy with the latest board, but before I release the final version I will be sending out one of the v1.55 amps for customer evaluation. I cannot add any more space between the jacks and volume knob and I want to make sure it is suitable from the customer's perspective. It's a definite improvement over the last version.

 I have not yet decided a final price. Because of the added volume knob, I am considering eliminating the option of dual gain. Most of my customers end up picking one gain and leaving their amps set to that option constantly. With the volume knob, the function is even more useless.

 Would anyone be interested in buying the bare PCBs and/or kits? While I enjoy doing this, demand is higher than one person can handle.


----------



## Baines93

I would definatley be interested in testing/evaluating one.... Depending on price, i would also be interested in making a kit..... I could have made a cmoy, but wanted bass boost, so yeah, a kit would be great, so long as it comes with everything, and depending on price of the kit vs profesionally made.....

 I would definatley be interested in testing/evaluating one though.... Let me know if i can please!

 I could give you some of my impressions on how it is to use, and how i think it sounds.....

 If you do let 2 people do some evaluations of the new board, Please can I be the first one on the list!

 -= Matt =-


----------



## blackinches

The first v1.55 amp has already been claimed and I will hold on to the other for my own analysis.

 However, I will have a used v1.50 available this week. PM me if you are interested.


----------



## HeadphoneAddict

Quote:


  Originally Posted by *blackinches* /img/forum/go_quote.gif 
_Everything is on schedule. I have two v1.55 prototypes. The bass boost switch will now be wired separately from the PCB.






 I will have all the parts to resume sales in stock by Friday, October 5th (or possibly as soon as Monday the 1st). I am happy with the latest board, but before I release the final version I will be sending out one of the v1.55 amps for customer evaluation. I cannot add any more space between the jacks and volume knob and I want to make sure it is suitable from the customer's perspective. It's a definite improvement over the last version.

 I have not yet decided a final price. Because of the added volume knob, I am considering eliminating the option of dual gain. Most of my customers end up picking one gain and leaving their amps set to that option constantly. With the volume knob, the function is even more useless.

 Would anyone be interested in buying the bare PCBs and/or kits? While I enjoy doing this, demand is higher than one person can handle._

 

In the non-volume control version I have found the gain switch to be very helpful switching between IEM's and Sennheiser headphones. It also helps reduce hiss with very efficient IEM's.

 So, basically you are looking for a partner to put together kits for you vs selling the amps as a kit? I wonder if I have enough time and energy (or skill) since I retired early on medical disability last month. I DO know a very skilled engineer, David, at www.proecm.com who may be interested.


----------



## blackinches

Quote:


  Originally Posted by *HeadphoneAddict* /img/forum/go_quote.gif 
_In the non-volume control version I have found the gain switch to be very helpful switching between IEM's and Sennheiser headphones. It also helps reduce hiss with very efficient IEM's._

 

Right, for the non-volume control edition, that is precisely why I offered the dual gain switch. 

 With a volume control, the signal is much easier to control. Mathematically, a single gain amp will indeed have a fixed gain if the input voltage is measured at the input capacitors. The actual input signal is the output signal of the audio source. In my opinion, this is a more appropriate theoretical reference point for calculating gain, since gain = Vout/Vin. The volume control changes the amplitude of Vin, thus, directly affecting gain.

 The dual gain switch in my amps changes the gain according to the following equation:

 Gain = Av = 1 + R4/(R3a+R3b)

 Clearly, the dual gain switch has an entirely different relation to the input signal. While it has a similar effect and could be used as an option to alter the rate at which the volume increases/decreases, I think it's best considered a $5 method of altering a variable that will already be controllable.
  Quote:


 So, basically you are looking for a partner to put together kits for you vs selling the amps as a kit? I wonder if I have enough time and energy (or skill) since I retired early on medical disability last month. I DO know a very skilled engineer, David, at www.proecm.com who may be interested. 
 

Thanks for the offer. Some of my engineering friends have offered to help assemble amps. Anyone who can solder should be able to assemble one. I'm mainly interested making my amp available to DIY'ers for two reasons:

 1) It will make the amp cheaper.

 2) I feel it is important to feed the DIY market to support engineering creativity and progress.


----------



## Baines93

EDIT:

 Oh, i didnt get it 
	

	
	
		
		

		
		
	


	




 Oh well....How much will the used one be? Does it have a volume control?


----------



## cchaeha

would these drive 250 ohms phones well?


----------



## blackinches

Quote:


  Originally Posted by *cchaeha* /img/forum/go_quote.gif 
_would these drive 250 ohms phones well?_

 

Yes, it should be no problem.


----------



## Schalldampfer

I might be interested in having one as a backup.

 If I specify it for my HD-650 and PROline 750 gain switch, default tin can, no light change, how much would it run me? And by when can it be shipped?


----------



## marshes

my dt770 80 ohms should be arriving friday, the same time hopefully blackinches gets all his parts for his amp. Wonderful timing, super excited to start my head fi journey. Hopefully once i have an abundance of money ill turn them into darths!

 Sent from my iphone!!


----------



## sharkz

Would these adequately power a pair of HD-580's? I have a pair of SR-60's right now, but will likely be adding a pair of HD-580's in the near future. I want something that will power both well from my Zen Vision M.


----------



## blackinches

My amps work well with HD-580's.

 Unless I am too busy, I will resume sales some time next week. Also, I may begin to sell bare PCBs in the coming weeks.


----------



## sharkz

Do they sound well with SR-60's too? If so, I will be in for one when they are ready.


----------



## Chewy

IMO, the bass boast works even better with Grados. The HD580 and HD600 go low enough and don't need more bass.


----------



## physh

I would be very interested in a kit.


----------



## willisv

I would also be interested in buying a kit.


----------



## blackinches

"sbulack" will be evaluating one of the two v1.55 amps early next week. If he agrees that the jack spacing is adequate, I will order final boards and make kits available around the week of Oct. 22-26.

 While v1.55 undergoes evaluation, I have one v1.50 prototype for sale.






 (v1.50 in back, v1.55G in front)


----------



## sharkz

Are these available yet? If not when will they be? And where can I pick one up from?


----------



## Ultimate157

Is it possible to get one of these with a 1/4" jack?


----------



## blackinches

It's possible if you bypass the automatic-on feature, but since wiring a 1/4" jack separately from the PCB will add minor inductance to the circuit, the theoretical benefit of avoiding a 1/4" to 1/8" adapter is likely defeated. So, I recommend sticking with the 1/8" jack and using an adapter.

  Quote:


  Originally Posted by *sharkz* /img/forum/go_quote.gif 
_Are these available yet? If not when will they be? And where can I pick one up from?_

 

I should have the new PCBs available in 2 weeks and will continue sales on eBay.


----------



## Caribou679

Hi!
 In this thread I posted a snide comment doubting the usefullness and validity of amp burn-in.

 Well I want to make my Mea Culpa (a formal acknowledgment of personal fault or error) on this matter.

 I have a Go Vibe 7 amp only since a few weeks and the thing sounds different now than during the first hours of use. I used it maybe 40-50 hours and it sounds alot better now! At first it was only loud. Now the sound is more clear and I hear alot of subtilities that were not present before.

 This under the same condition: Using the amp connected to the line out of a Cowon X5, with the volume knob of the amp at about 11 o'clock and listening to the same type of music through the same IEM and headphones.

 I do not want to steer this thread on the Go Vibe 7 but to state what I observed: The fact of the matter is that burn-in takes some time, even with an amp!

 Now I just received a Qables SilverCab Cowon iAudio X5 LOD and very curious of changes occuring...in time...

 regards,


----------



## HeadphoneAddict

Quote:


  Originally Posted by *Caribou679* /img/forum/go_quote.gif 
_Hi!
 In this thread I posted a snide comment doubting the usefullness and validity of amp burn-in.

 Well I want to make my Mea Culpa (a formal acknowledgment of personal fault or error) on this matter.

 I have a Go Vibe 7 amp only since a few weeks and the thing sounds different now than during the first hours of use. I used it maybe 40-50 hours and it sounds alot better now! At first it was only loud. Now the sound is more clear and I hear alot of subtilities that were not present before.

 This under the same condition: Using the amp connected to the line out of a Cowon X5, with the volume knob of the amp at about 11 o'clock and listening to the same type of music through the same IEM and headphones.

 I do not want to steer this thread on the Go Vibe 7 but to state what I observed: The fact of the matter is that burn-in takes some time, even with an amp!

 Now I just received a Qables SilverCab Cowon iAudio X5 LOD and very curious of changes occuring...in time...

 regards,_

 

ROTFLOL!! 
	

	
	
		
		

		
		
	


	




 Really, laughing. I knew this would happen, it's all good


----------



## Ranma13

Well, the concept is easy to understand. At some point the digital signal gets converted into an analog signal, and since electronic devices themselves are physical objects, the electrons and silicons within the electronic device will gradually affiliate themselves with a certain pattern.


----------



## blackinches

Quote:


  Originally Posted by *Ranma13* /img/forum/go_quote.gif 
_Well, the concept is easy to understand. At some point the digital signal gets converted into an analog signal, and since electronic devices themselves are physical objects, the electrons and silicons within the electronic device will gradually affiliate themselves with a certain pattern._

 

I have an idea that may give us a graphical view of the effect of burn in, but I don't have any burned in amps this week. I'll post some graphs after I've burned in some of the new amps.


----------



## sbulack

The second Volume Pot prototype (with more space between jacks and pot) has reached its SQ zenith at around 60 hours of use, this time with a higher quality IC - which now fits between the input jack and volume pot. Everything I've ever posted about the SQ of the cMoyBB is as true as ever, only better now than before through the use of better quality IC's. I must repeat that the cMoyBB, with the clean transparency, spacious openness and elegant simplicity of its sound, fills a needed and enjoyable niche as a listening instrument in the collection of home and portable amps I already use.


----------



## HeadphoneAddict

Looks like enough parts turned up for more old style amps...

http://cgi.ebay.com/cMoy-Amp-Headpho...QQcmdZViewItem


----------



## Ultimate157

Quote:


  Originally Posted by *HeadphoneAddict* /img/forum/go_quote.gif 
_Looks like enough parts turned up for more old style amps...

http://cgi.ebay.com/cMoy-Amp-Headpho...QQcmdZViewItem_

 

Make that one less


----------



## SpiderX1016

I was wondering, I have a Super.fi 3 and iPod Nano 2nd gen
 Is it worth it to get an amp? I ask because these amps are so cheap, it's tempting me but there aren't any on ebay that hes selling right now (Well I don't know because I see some Cmoy ones but I don't really trust them....)

 The bass is a little lacking on the super.fi...


----------



## jewman

Quote:


  Originally Posted by *SpiderX1016* /img/forum/go_quote.gif 
_I was wondering, I have a Super.fi 3 and iPod Nano 2nd gen
 Is it worth it to get an amp? I ask because these amps are so cheap, it's tempting me but there aren't any on ebay that hes selling right now (Well I don't know because I see some Cmoy ones but I don't really trust them....)

 The bass is a little lacking on the super.fi..._

 

I would say yes. I too have a set of SF3s, and this amp really helped to boost the bass and yet keep it detailed. This amp also helped the overall detail and separation of the music through my h320.


----------



## blackinches

I have just released the Bass Boost cMoy v2.00. eBay listings will come and go according to demand and my weekly schedule.

 Also, if anyone is interested, I am ready to offer bare PCBs (no kits yet).


----------



## kool bubba ice

I'm spreading the word on your amp at AVS.. The title of the thread is about gaming headphones. Theres over 500 replies.. I'm recommending a good headphone, the JVC 5.1 adapter & your amp for gaming & movie watching.. I had like 6-7 guys buy the JVC 5.1 adapter based on my recommendations. & I'm glad they like it.


----------



## TotalDistinction

Quote:


  Originally Posted by *kool bubba ice* /img/forum/go_quote.gif 
_I'm spreading the word on your amp at AVS.. The title of the thread is about gaming headphones. Theres over 500 replies.. I'm recommending a good headphone, the JVC 5.1 adapter & your amp for gaming & movie watching.. I had like 6-7 guys buy the JVC 5.1 adapter based on my recommendations. & I'm glad they like it.
	

	
	
		
		

		
		
	


	


_

 

I happen to be one of those folks that kool bubba ice recommended this amp to on AVS and just purchased one a few minutes ago on eBay. After reading this thread, I'm looking forward to experiencing this amp.

 Now for the slow wait for it to ship to Canada. 
	

	
	
		
		

		
		
	


	




 I can't wait.


----------



## TotalDistinction

As a portable amp, does this cmoy have enough juice to sufficiently power Senn HD600's at 300 ohms?


 P.S. The amp was shipped fast enough but I'm still waiting for it to arrive


----------



## kool bubba ice

Quote:


  Originally Posted by *TotalDistinction* /img/forum/go_quote.gif 
_As a portable amp, does this cmoy have enough juice to sufficiently power Senn HD600's at 300 ohms?


 P.S. The amp was shipped fast enough but I'm still waiting for it to arrive 
	

	
	
		
		

		
		
	


	


_

 

It will drive them 'ok'.. I'm sure they will arrive before Friday..


----------



## Katsukare

I haven't been on these forums for a long time, but I am glad your all enjoying the Amp. It's a great small amp for it's price. Hopefully John will have something new for us all later.


----------



## blackinches

Quote:


  Originally Posted by *Kinky* /img/forum/go_quote.gif 
_I haven't been on these forums for a long time, but I am glad your all enjoying the Amp. It's a great small amp for it's price. Hopefully John will have something new for us all later._

 

Version 2.00 is new enough, I think. 
	

	
	
		
		

		
		
	


	




 I am in the process of updating my site. cMoyBB v2.00 PCBs can now be purchased from www.jseaber.com/cMoy


----------



## BrinNutz

I just picked one of these amps up...

 Pairing it with some Audio Technica ATH-AD700's that will be arriving hopefully tomorrow!!


----------



## leo5111

i just got one from him good guy to deal with bass boost on turns my denon ah-c700,s into forget bass monsters bass GODZILLAS nice strong bass and he also has option you can put a pentomiter instead of bass on off switch so you can tune bass exactly to where you want it


----------



## shoejuice

ever wonder what he does with the mints? 
	

	
	
		
		

		
		
	


	




 W0QQitemZ130217809300QQihZ003QQcategoryZ38176QQssP ageNameZWDVWQQrdZ1QQcmdZViewItem


----------



## LostMoogle

Quote:


  Originally Posted by *leo5111* /img/forum/go_quote.gif 
_i just got one from him good guy to deal with bass boost on turns my denon ah-c700,s into forget bass monsters bass GODZILLAS nice strong bass and he also has option you can put a pentomiter instead of bass on off switch so you can tune bass exactly to where you want it 
	

	
	
		
		

		
		
	


	


_

 

Could you explain exactly how to do that or link me?


----------



## madnanny1

i have recently ordered a bsg h/phone amp am awaiting delivery,i live in england and delivery will not be until 14/09. i am eager to try this with my sony minidisc (portable) mzrh1/mznh1/mznh900 .i wonder how much improvement there will be


----------



## H-ermes

I have ordered one few days ago. 

 I really hope it will match my expectations... but before buying on eBay I could ask a LOT of questions to John who quickly and gently answered me. A good point before reviewing his amp...

 H.


----------



## H-ermes

Received few days ago. Here few comments. 

*
 How I listen music ?*

 I own an Iphone 3GS and I use Shure SE 530. It was my first valuable headphone and I really appreciate them. I'm looking for a new headphone, probably a Grado, but that is not the issue in this thread. 

 When I'm moving, I use Iphone with the Ipod fonction and I did install the spotify app on my Iphone. For that, I encoded all my CD collection (AAC 256 and/or Apple loseless format). 

 When I'm working, I use my laptop and the Spotify client.

*What I use to listen ?*

 I listen to a wide range of music. Bach, Daft Punk, Motown's stuff, funk and Jazz. I like to have a neutral sound, well balanced. 

*Why I needed an amp ?*

 After few weels of use, I found that my Iphone miss a little bit punch and power. It was like the sound was "blank". After reading a lot of reviews of head-fi, I've tought I may need an amp. But i would not spend at this time to much money on that. I found that topic and decided to give a try to it. 

 I've contacted John who kindly answered me before I bought his amp. He answered very qickly to all of my questions. I really appreciate that. After buying, he sent the amp qickly and I get it in a couple of days : that's fast for an onverseas transaction (I'm living in France). 

*Does it worth the price ?*

 Definetely yes. What I was looking for - a reacher / warmer sound - is there. The price was not overestimated nor the shipping costs (thanks for not asking 20 US $ like others John). 

 His amp is well done, I appreciate the retro design. It's simple, really easy to use. And it works perfectly. 

 I would recommend this amp to anybody looking for a better sound. I will update my comments after few weeks and maybe after buying a new HP.

 H.


----------



## Sadaiyappan

Just ordered mine.


----------



## Judge Buff

I just ordered one v2.2 from Mr. Seaber's JDS Labs site. It will be paired with my new 280 Pro that I'm cooking now. Pick me out a winner, John!


----------



## Sadaiyappan

I have both GRADO SR 60 and Sennheiser HD 428. I asked him to customize the gain for me for 32 ohm headphones, and I am using his amp but I don't notice any difference in sound. In some cases I notice very slight differences. So I think it must be my source. Am I right or wrong here? I am just using my laptop sound card which is Sigmatel HD audio. Its possible it will sound better after "burn in" so I'll see if the sound improves after some use.


----------



## Judge Buff

Quote:


  Originally Posted by *Judge Buff* /img/forum/go_quote.gif 
_I just ordered one v2.2 from Mr. Seaber's JDS Labs site. It will be paired with my new 280 Pro that I'm cooking now. Pick me out a winner, John!_

 

The 280s went back today due to the right side cutting off. Since the original deal I bought was finished on the 280s, I went with a good deal on Shure SRH440s. I hope this combo works okay!


----------



## pez

I have a cMoy v1.48 with Bass Boost and I use them with Grado SR60's. While the gain on low switch still gives me that fuzz, I can adjust the volume on my speakers and it works fine. The bass boost on mine gives the Grado's a completely FULL bottom end. It's nice because it doesn't just add a boomy bass, it actually provides it with a bottom end that seems much needed after switching back and forth.


----------



## stringgz301

Just finished my CMOYBB v2.02 and enjoying listening to it during burn-in. Has anyone tried different opamps in this? The standard one is OPA2227PA.

 Thanks


----------



## JayJay22

I'm looking into buying a CMOYBB 2.02. Will I need additional cables, or will the cord on my headphones be enough? Does it come with an 'input' cable?


----------



## Azi

I have had this Amp for a long time now, maybe a year or so. All i can say is "WOW!!!" Absolutley brilliant amp. I always use the Bass Boost feature and it sounds amazing. The Bass is soo Deep, tight and controlled. Unlike the EQ bass on my ipod touch. This sounds tight, fast and powerfull. This amp and
 the Triple.Fi10's; what a combo!
 Thank you J.Seaber


----------



## definitionz

Just tried out the cMoyBB v2.02 with my headphones, can't say I'm utterly impressed but it does redefine the bass. I listen to music with heavy bass (hardstyle, hard trance, hip hop), the SRH840's has neutral bass to start with. The sound distorts at higher volumes. I'm going to purchase some new headphones and I'll try them out again hopefully with some better results.


----------



## razorblader

I've been using the Cmoy 2.02 Bass boost version made by John Seaber for about two months now, mostly with my AKG 601 headphones, sources are the Iphone 3GS and the Cowon X5 (both on line out), LODS are Practical Devices and Canare cooper cable with Neutrik plug, the sound is very crisp and detailed, the bass boost really works wonders for the AKG 601's.

 Have also tried it with my Phonak Audéo PFE IEM's and they also work very nicely together, read good things about the amp but was still positively impressed by its performance.

 Really an excellent portable HP amp, it has enough Power to drive my AKG headphones without a problem and the soundstage is nicely layered.
 Highly recommended and honestly a bargain for the price.


----------



## rappsy

I have hd-580's and am interested in this amp. It will be my first, so thought I would get my feet wet with something at this price point that will drive the cans. Rock, Country, Show, Jazz and Blues, so I'm all over the place. 

 How does this compare with Headroom Airhead? I ask because as it is my first, literature gets me thinking and it has crossfeed, which sounds like it makes sense to me, but it may just be marketing. Build quality okay? I worry about the bass switch being so far out.

 Also, should I get it customized for this high imped phone, or leave it alone for when I get some other can?

 Opionions? 

 Thanks.

 Lenny...


----------



## razorblader

Quote:


  Originally Posted by *rappsy* /img/forum/go_quote.gif 
_Build quality okay? I worry about the bass switch being so far out.

 Also, should I get it customized for this high imped phone, or leave it alone for when I get some other can?

 Opionions? 

 Thanks.

 Lenny..._

 

Build quality is very good Lenny, the boost switch on mine is a small switch on the PCB inside the amp rather than the big, clunky switch on the older models.

 I would definitely recommend to contact John and ask about customising the amp for the phones you have in mind, he is very knowledgeable and will be able to answer your questions.

 Best have a look here: JDS Labs


----------



## rappsy

Thanks razorblader.

 I talked to him and bought it this morning. He was generous with his answers and I am really looking forward to getting it. I also am sending him a different flavor tin as I wanted Chocolate, and he will be doing it as soon it arrives.

 Thanks for the advice and Happy Holidays.


----------



## komebudu

Quote:


  Originally Posted by *razorblader* /img/forum/go_quote.gif 
_I've been using the Cmoy 2.02 Bass boost version made by John Seaber for about two months now, mostly with my AKG 601 headphones, sources are the Iphone 3GS and the Cowon X5 (both on line out), LODS are Practical Devices and Canare cooper cable with Neutrik plug, the sound is very crisp and detailed, the bass boost really works wonders for the AKG 601's.

 Have also tried it with my Phonak Audéo PFE IEM's and they also work very nicely together, read good things about the amp but was still positively impressed by its performance.

 Really an excellent portable HP amp, it has enough Power to drive my AKG headphones without a problem and the soundstage is nicely layered.
 Highly recommended and honestly a bargain for the price. 
	

	
	
		
		

		
			



_

 



 Razorblader,

 Thank you for your post.. Now i'm considering buying K702, driven by cMoyBB 2.02.... 
	

	
	
		
		

		
		
	


	




 Current rigs: Sony NW-A808, CX500, cMoyBB 2.02 (still at burning-in phase)...


----------



## razorblader

Quote:


  Originally Posted by *rappsy* /img/forum/go_quote.gif 
_Thanks razorblader.

 I talked to him and bought it this morning. He was generous with his answers and I am really looking forward to getting it. I also am sending him a different flavor tin as I wanted Chocolate, and he will be doing it as soon it arrives.

 Thanks for the advice and Happy Holidays._

 

The chocolate amp, sweet. 
	

	
	
		
		

		
		
	


	




 Have fun with your new amp and happy holidays (New Years still coming up ) to you too.


----------



## razorblader

Quote:


  Originally Posted by *komebudu* /img/forum/go_quote.gif 
_Razorblader,

 Thank you for your post.. Now i'm considering buying K702, driven by cMoyBB 2.02.... 
	

	
	
		
		

		
		
	


	




 Current rigs: Sony NW-A808, CX500, cMoyBB 2.02 (still at burning-in phase)..._

 

That should be a very nice combination indeed, would love to hear your impressions if you choose to go that route.


----------



## komebudu

I am no hardcore audiophile. I only wanted to share my experience…and MHO..

 After having burnt-in for more than 72 hours ( I used only 2 IKEA alkaline batteries J )… the sound was simply astounding…. Sara K’s ‘Brick House’… sounded more air that I didn’t realized before… more attack, more dynamic, crisper.. this amp added more detail… the instruments had more volume. I could clearly hear fingers plucked guitars, and her sublime voice rendered perfectly….and I didn’t now that Sara K breathe..! 
	

	
	
		
		

		
		
	


	




 Maybe there are people who doesn’t like ‘added’ detail in sound reproduction... me neither. But for this case, I made an exception because the ‘added’ detail was so natural and in a very pleasant way… even with humble CX500 which well known as a bit dry sounded, less energy in HF…and bass oriented phones (I exaggerated a little..  .. CX500 was good earphones actually, for the price off course) could sound quite analytical…I can’t imagine what this CmoyBB 2.02 could do for more decent cans…

 Soundstage wise, I could comment more since CX500 was not designed for that…I supposed… I still however heard larger soundstage even I could not detect precisely where the instruments/musicians were located. One of great example was Ray Browns’ Superbass – Sculler Blues… nice… very nice indeed…. 
	

	
	
		
		

		
		
	


	




 Bass boost? I only engaged this feature on certain music such pop, rock, electronic… but for jazz, classical or naturally well recorded acoustic musics, I disengaged it… it’s my preference after all… not because the bass is bloated or mudding other frequency spectrum… The bass boost rendered bass more impact, deeper… Only that I could not compare with other head-amp or cans… 


 The only complain … I didn’t know if it happened to anybody else… I just wanted to hear full impact from Kitaro’s Matsuri Live, I increased the volume up.. till my ear drums feels uncomfortable.. then I can hear distortion… something like crete signal or like the current was insufficient to deliver such full impact… I don’t know if perhaps it was due to the fact that CX500 has low impedance of 16 Ohms… Maybe Blackinches could give some comments…?


 When I returned to my Sony NW-A808 directly to CX500 without CmoyBB 2.02, it sounded raw…less juicy… a little bit dry…less organic… detail was less pronounced..I still could tweak by adjusting freq equalizer, quite impressive result but it seemed artificial now.. The magic was gone…! Maybe my NW-A808 had entrusted his new mate, CmoyBB to take over all music detailing job …
	

	
	
		
		

		
		
	


	




. Highly recommended ..!!!

 AKG… I’m coming….!!!!


----------



## razorblader

Thanks for your review komebudu, interesting to hear about what this amp can do with the CX500's. About the distortion on high volumes, I don't get that with my AKG phones and remember that you can power the amp with an external power supply with higher voltages than 9V as well.


----------



## BMH

I'm using a first generation iphone & Klipsch custom 2 earphones. Is this (or any) amp going to improve the quality of my hearing experience? 

 My biggest concern is that my iphone creates a bit of static, obviously only noticeable when no music is playing. Will this static become a problem when amplified?

 And finally: I saw a chinese seller on Ebay selling Cmoy's with build-in li-ion batteries. I like it's design & the rechargeable battery. But are they just as good as the other ones?


----------



## AcousticDreams

Quote:


  Originally Posted by *komebudu* /img/forum/go_quote.gif 
_The only complain … I didn’t know if it happened to anybody else… I just wanted to hear full impact from Kitaro’s Matsuri Live, I increased the volume up.. till my ear drums feels uncomfortable.. then I can hear distortion… something like crete signal or like the current was insufficient to deliver such full impact… I don’t know if perhaps it was due to the fact that CX500 has low impedance of 16 Ohms… Maybe Blackinches could give some comments…?_

 

This happens mostly when a low impedance HP is used under low voltage (< 9V) conditions. How razorblader has mentioned before, you can also connect a power-supply of 24V DC (100 mW - 1000 mW). It's hardly recommended to turn up the volume of your audio player to approximately 70%, so that the input for the amplifier is strong enough. The source volume should be set so the amplifier plays cleanly to slightly past half of its volume knob rotation. Use a line-out signal whenever possible, iPod line-output adapters can be also found online. A high voltage DC adapter can easily extend the dynamic range of the cMoyBB.

 What here also plays a role, is that the volume control on the cMoyBB affects the gain too. The higher the volume, the higher the gain. This is one of the reasons why the most HP's would work without customization.


----------



## lwells

I picked up one of these for kicks.

 I really have to say, it's quite a few steps ahead of the total Airhead (using a hp or line out).


----------



## komebudu

Quote:


  Originally Posted by *AcousticDreams* /img/forum/go_quote.gif 
_This happens mostly when a low impedance HP is used under low voltage (< 9V) conditions. How razorblader has mentioned before, you can also connect a power-supply of 24V DC (100 mW - 1000 mW). It's hardly recommended to turn up the volume of your audio player to approximately 70%, so that the input for the amplifier is strong enough. The source volume should be set so the amplifier plays cleanly to slightly past half of its volume knob rotation. Use a line-out signal whenever possible, iPod line-output adapters can be also found online. A high voltage DC adapter can easily extend the dynamic range of the cMoyBB.

 What here also plays a role, is that the volume control on the cMoyBB affects the gain too. The higher the volume, the higher the gain. This is one of the reasons why the most HP's would work without customization._

 

Thank you for the advice, AscousticDreams and Razorblader.

 I had purchased 12V (1000mA) DC supply adapter.... and just received K701 (not K702 as planned... ). The problem is still there. I had however send a S.O.S signal to Blackinches... hopefully he would solve as quickly as possible (I know he will...).

 Luckily my K701 is on burning-in treatment...


----------



## blackinches

Quote:


  Originally Posted by *komebudu* /img/forum/go_quote.gif 
_I increased the volume up.. till my ear drums feels uncomfortable.. then I can hear distortion… something like crete signal or like the current was insufficient to deliver such full impact…_

 

This is not a defect, per se. Remember, the cMoyBB is a cMoy with switchable bass boost and several power supply enhancements (a TLE2426 virtual ground instead of a resistor divider, decoupling capacitors, and a low impedance return plane). These features give the cMoyBB an edge over the base cMoy circuit, but it's still a cMoy.

 Assuming a stable amplifier such as the cMoyBB, distortion at "uncomfortable" volume levels can be the result of one (or several) of the following situations:

 1) Insufficient supply voltage. This can be expected when operating high impedance headphones at very high volumes with a 9V battery. When the volume is raised too high, the opamp is forced to clip the signal. Bass boost exasperates the problem by demanding an even stronger signal voltage. An 18-24V power adapter will significantly raise the positive and negative supply rails, therefore, the opamp can then produce higher voltage signals (i.e., louder music) before being driven into clipping.

 2) Insufficient current. Typical opamps supply 20-30mA current, which is generally enough to attain reasonably loud volumes. Efficient headphones will reach dangerously loud volume levels before consuming too much current. Even moderately inefficient headphones can reach high volumes without overloading a cMoy. However, it is unrealistic to expect 20mA to be enough to drive _all_ headphones at absurd volumes. Some headphones simply demand more current than a cMoy can provide; they may barely reach the maximum volume of an iPod. Nothing can be done about this in a cMoy, else it would not be called a cMoy.

 3) Physical limitations of the drivers. Every headphone driver (speaker cone) will reach a point where it cannot physically respond to the voltage received from the amplifier. Most commonly, this occurs when listening to strongly amplified bass. It is rare for a cMoy to overexert headphone drivers, but it can happen.


*komebudu*: You are exactly right, I suspect the amplifier is running out of current at those "uncomfortable" volume levels with your CX500's. At only 16 ohms, it's extremely unlikely that voltage is an issue. An 18V+ power adapter may help slightly with your AKG K-701's, but from my experience, they also need more current to achieve painful volumes (volume is quite subjective, though).

 For anyone new to the scene, it is important to understand the goals of headphone amplification. Refined sound quality is the chief concern! The ability to reach higher volumes comes secondary. 

 Some general advise: If you haven't acquired it already, spend some time reading about hearing loss and tinnitus. Most people here are well aware of this risk, but I always make a point to warn anyone who chooses to listen to loud music...

 Health risks aside, current limitations can only be overcome by adding a current buffering stage to the amplifier and its ground channel. As mentioned above, however, we're then talking about redesigning the cMoy.

 Happy New Year, everyone!

 --JDS


----------



## komebudu

Quote:


  Originally Posted by *blackinches* /img/forum/go_quote.gif 
_This is not a defect, per se. Remember, the cMoyBB is a cMoy with switchable bass boost and several power supply enhancements (a TLE2426 virtual ground instead of a resistor divider, decoupling capacitors, and a low impedance return plane). These features give the cMoyBB an edge over the base cMoy circuit, but it's still a cMoy.

 Assuming a stable amplifier such as the cMoyBB, distortion at "uncomfortable" volume levels can be the result of one (or several) of the following situations:

 1) Insufficient supply voltage. This can be expected when operating high impedance headphones at very high volumes with a 9V battery. When the volume is raised too high, the opamp is forced to clip the signal. Bass boost exasperates the problem by demanding an even stronger signal voltage. An 18-24V power adapter will significantly raise the positive and negative supply rails, therefore, the opamp can then produce higher voltage signals (i.e., louder music) before being driven into clipping.

 2) Insufficient current. Typical opamps supply 20-30mA current, which is generally enough to attain reasonably loud volumes. Efficient headphones will reach dangerously loud volume levels before consuming too much current. Even moderately inefficient headphones can reach high volumes without overloading a cMoy. However, it is unrealistic to expect 20mA to be enough to drive all headphones at absurd volumes. Some headphones simply demand more current than a cMoy can provide; they may barely reach the maximum volume of an iPod. Nothing can be done about this in a cMoy, else it would not be called a cMoy.

 3) Physical limitations of the drivers. Every headphone driver (speaker cone) will reach a point where it cannot physically respond to the voltage received from the amplifier. Most commonly, this occurs when listening to strongly amplified bass. It is rare for a cMoy to overexert headphone drivers, but it can happen.


*komebudu*: You are exactly right, I suspect the amplifier is running out of current at those "uncomfortable" volume levels with your CX500's. At only 16 ohms, it's extremely unlikely that voltage is an issue. An 18V+ power adapter may help slightly with your AKG K-701's, but from my experience, they also need more current to achieve painful volumes (volume is quite subjective, though).

 For anyone new to the scene, it is important to understand the goals of headphone amplification. Refined sound quality is the chief concern! The ability to reach higher volumes comes secondary. 

 Some general advise: If you haven't acquired it already, spend some time reading about hearing loss and tinnitus. Most people here are well aware of this risk, but I always make a point to warn anyone who chooses to listen to loud music...

 Health risks aside, current limitations can only be overcome by adding a current buffering stage to the amplifier and its ground channel. As mentioned above, however, we're then talking about redesigning the cMoy.

 Happy New Year, everyone!

 --JDS_

 

Hi Blackinches,

 Thanks for giving all those advice... at least least i know where i should go... before getting deaf... hi..hi..

 My next step... is to sell my K701... ha..ha..ha... just joking.. 

 Actually I will need to seek for new desktop headamp... while keeping CmoyBB for my daily portable purposes.. after all, it was designed for that, right......?

 Keep up creating good products, Blackinches….


----------



## MikeW

I recently built on of these little guys, was my first project (i've got a fair amount of soldering experience though). Went pretty quick, hardest part was the case. Fired up and worked the first time. I used the panasonic fm power supply cap, and the wima 1uf caps. I have a question though, I noticed with my recabled Koss KSC75, at moderate to high volume the amp starts to clip. Is this normal for a cmoy?

 edit: forgot to mention the gain is "8", I might be able to get to half volume on the pot /w maxed mp3 player volume before clipping.
 I've also got a spare AD743JN laying around, I wonder if this op-amp is compatible with this cmoy?


----------



## komebudu

well..well...

 Now i can live happily with my K701 driven by CmoyBB....ONLY when using 24V supply, and ONLY bass boost toggle switched off...otherwise, clipping is unavoidable. Off course i'm not going to push the little baby to clip whatsoever... but it drives K701 higher than comfortable sound level without distortion... it's very good indeed, knowing that how lazy K701 is.

 I prefer using my CX500 for rock music....for the moment...

 ps: K701 seems more sensitive after more than 320hrs burned-in... (or it is me who is less deaf than last two weeks...? )


----------



## TheRookie52

I just read the whole thread and Im bout to purchase may amp as soon as J. Seaber responds to this last question I had to ask him.


----------



## bolinao

I am thinking about buying a cMoy v2.02,i have a question though.
 Does the volume control just control the volume of the source device(ipod..etc) or does it actually add to the max volume of the source device,i find my ipod is not loud enough with some music,so am looking for something that will make the ipod louder...thanks


----------



## weibby

if you DIY you can play around with the gain to your preference.


----------



## bolinao

Quote:


  Originally Posted by *weibby* /img/forum/go_quote.gif 
_if you DIY you can play around with the gain to your preference._

 

So do you mean that it does increase the loudness of the max volume of my ipod ?,i have no technical knowledge,so am after something that is stock and will increase the max volume of ipod,i dont want to tinker with the amps default settings...thanks


----------



## flexium

it WILL increase the max volume. i.e. the max sound after amp is much louder than the max sound of just ipod. but i would caution that excessive exposure to loud sound can cause tinnitus. Tinnitus Causes, Symptoms, Diagnosis, Treatment, and Prevention Information on MedicineNet.com


----------



## flexium

Here is some questions Deep Funk asked me when he was deciding if he wants the amp. I figured other people might have the same questions so I decided to post it up. 

 regarding the sound signature would you say the latest cMoy adds more warmth, bass and sound stage?
_yes, especially on um3x. ad900 might be warm already. change is not obvious with it.
_

 Furthermore, does the bass sound defined and deep with the cMoy?
_yes actually it does and it extends deeper. sounds much better with cMoy than just straight out from headphone out. so improve both quantity and quality. you can hear how the bass sound and the tiny fluctuation of the bass guitar string. also true on the bass in orchestra(this is honestly what i feel. This is why i bought the cMoy in the first place)
_

 Does the bass invade the midrange?
_ad900, slightly. um3x, definitely not._

 The vocals and highs generally still sound true to the record through the cMoy and headphone?
_for ad900, definitely changes, if the song has both low and high. for um3x, definitely sounds true to me.
 for ad900 if the song only has vocal, then it is okay. only moves the voice slightly away from where it was.
 I think it changes the high more on classical music, i.e. violins. the violins moves to the back of the crowd, and the bass comes to the front of the crowd, ie you can clearly hear the bass plucking on their string.
 but on vocal(male and female) it is only a slight change. again, vocal moves back a little, and the bass comes a little forward.
*additonal note that i want to add is the change can be minimize by lower the volume control on the amp and increasing the dap's volume. the bass increase is definitely still there but the effect on high becomes smaller. that actually sounds like a very good solution to me.*_

*It may sound like it is all negative. But i am just focusing on the changes of high. On a lot of songs, you can definitely feel the difference in bass quantity and quality but little effect on the high and mids. honestly, on um3x, it sounds so good that i don't want to take them off and switch to ad900 for testing. If you are taking the amp on-the-go, this is probably a good solution to increase the bass on cold sounding IEM.*


----------



## Deep Funk

I got the cMoy V2.02 BB to work. It sounds sounds more fun with bass boost, without it still sounds good but less fun and less bassy. The music sounds better with bass boost, less neutral though. 
   
  My Fiio E5 is toast compared to the cMoy. Bass boost on the cMoy is addicting, especially with typical bassy music. For the moment I am a confirmed bass boost addict.


----------



## Deep Funk

I am keeping the cMoy on bass boost, it sounds so much better.


----------



## BlutoSlice

I seem to have problem with clipping, the source volume has to be quite low (<25%) otherwise it distorts (xonar DX or Mobile phone DAP). I dont have this issue with my e5 or bravo at same settings. Is my cmoybb faulty or am I expecting too much. I have replaced the battery and it still clips even with bass boost off. Has anynoe else experienced this?


----------



## bolinao

I have the same problem,mine distorts around 40% volume level.


----------



## Deep Funk

Which cMoy do you use? How long do you have the cMoy? How many hours of use for the cMoy?
   
  Just some questions. My cMoy BB V2.02 is quite new.


----------



## bolinao

for me i have cMoy BB V2.02,i have been using it for about 2 weeks and about 20 hours of use.I ma thinking of returning it for a refund,the distortion is pretty bad.


----------



## komebudu

Hi Bolinao...
   
  you are using CmoyBB to which HP..? Matbe it's due to the low impedance?


----------



## Deep Funk

Low impedance? Whatever it is check out the internals...


----------



## BlutoSlice

I have had mine (2.02) for a few weeks, about 5-8 hours use as I went back to my old amp. My cans are ultrasone HFI-780 32ohms  . I dont know if the recent batch is faulty as i cant imagine this is standard. Ill check with my senn 555 which are 50ohms to see if its a sensitivity thing


----------



## jseaber

[duplicate post]


----------



## jseaber

The behavior you and "bolinao" have described is definitely abnormal. A cMoy with a gain of 6 (default for the cMoyBB) should be capable of producing clean playback up to 60-75% of its volume knob rotation when paired with 64 ohm headphones and an iPod at maximum volume. Lower impedance, higher sensitivity headphones generally reach maximum playback volume sooner. However, JDS Labs adjusts the cMoyBB's gain according to customers' headphones, so this example should remain true for most cMoyBB owners.

 Regardless, a cMoy with a fresh battery should be quite capable of driving headphones to volume levels _at least _as loud as the portable audio player to which it is connected. Distortion should not occur from a source set above 25%.

 I will be examining bolinao's amplifier as soon as possible. Each cMoyBB is hand assembled and hand tested. Therefore, there are no bad batches. This issue is most likely caused by a blown IC. As to how such a defect could arise, that is a mystery at this point.

 Should anyone else encounter trouble, please do not hesitate to contact me.

 --JDS
  Quote: 





			
				BlutoSlice said:
			
		

> I have had mine (2.02) for a few weeks, about 5-8 hours use as I went back to my old amp. My cans are ultrasone HFI-780 32ohms  . I dont know if the recent batch is faulty as i cant imagine this is standard. Ill check with my senn 555 which are 50ohms to see if its a sensitivity thing


 
   
_*EDIT (June 7, 2010): *_ I personally tested bolinao's amplifier and can confirm that it was an isolated faulty unit. Although his description suggested a weak battery, results were inconclusive due to moderate shipping damage. The amplifier passed oscillation/FFT tests at low volumes. However, it was received with obvious physical damage to capacitor C1, component U2 (TLE2426CLP), and the opamp. This type of damage can occur for any of the reasons stated in the Instructions guide (including shipping damage). *A brand new cMoyBB would never make it past my workbench with such extensive flaws.* bolinao's amplifier is shown below to provide documentation of a bulging/blown capacitor (also notice the spots of capacitor acid scattered across the board). Any device with a blown capacitor should be returned for repairs.
   
  In conclusion: Be sure to follow the Instructions!


----------



## Sinty

i purchased a v2.2 on ebay today, cant wait to see how it works


----------



## beaglepower

I just got mine today. It shipped quick!
   
  This is my first amp so I can't say how it compares to other, but I have my paired with my Senn HD555s and the sound quality has improved greatly. The BB is an awesome feature.
   
  Ratatat has never sound better than now, in my case anyways.
   
  Thanks for the great product!


----------



## swbf2cheater

I'd like to point out the 2.02 BB cmoy is perhaps the best portable amp I've ever used.  I actually prefer it to the D3 Python.  
   
  It's got just the right amount of coloring and kick, the bass booster is pretty awesome.  I couldn't be happier.  Its one of the few buys I would recommend to anyone and that I am not at all dissatisfied with.  Amazing amp.  Got it in blue wintergreen


----------



## sluker

X2
  I bought this amp in January and have since then expanded my collection with an icon mobile, a D3, a Tomahawk and an Sflo2 (includes a built-in amp). Even though all of these are more expensive and supposedly higher quality amps I still use my BB especially with the AKG 701's (the base boost compensates for the lack of base) and the HD280's for which it seems this amp was designed for.
  My only gripe is that with todays air travel security I am hesitant to take this with me on the plane (I travel for work a fair bit) for fear of the plastic glove treatment


----------



## TheGame21x

Quote: 





swbf2cheater said:


> I'd like to point out the 2.02 BB cmoy is perhaps the best portable amp I've ever used.  I actually prefer it to the D3 Python.
> 
> It's got just the right amount of coloring and kick, the bass booster is pretty awesome.  I couldn't be happier.  Its one of the few buys I would recommend to anyone and that I am not at all dissatisfied with.  Amazing amp.  Got it in blue wintergreen


 
  Definitely agreed on all counts there. I love my CMoy BB.


----------



## KnightK

I built one myself by sourcing the parts and it was pretty fun to build. The final product was definitely worth it; I think it is the best bass boost under $100 that I have tried, ie bass seems pleasant and with minimal distortion. Plus, it just looks cool!


----------



## komebudu

Months ago I got problem with my CmoyBB...
   
  Then had sent the unit back to John Seaber for repair (I'm pure mechanical guy after all), with $6.50 additional cost...shipping and parts.
   
  The item had been repaired (Once received, John only took less 3 days to send it back to me..only the shipping time is sometimes very annoying, i would say) and i received it nearly a month later...  - Not your fault, John..
   
  I had explained him how the amp was used. Fortunately my CX500 weren't affected by the fact that i accidently common ground my NW-A808 external supply to CmoyBB..see further below    - Not your fault, John..
   
  Therefore, below are some observation and report by him:
   
  ------------------------------------------------------------------------------------------------------------------
  Diagnosis:
  Components U2, D2, and C1 damaged due to external electrical bridging of V- and Vgnd.
   
Cause:
Audio ground of the audio player shares ground with USB power supply ground. Charging of audio player via USD cable and common 22V adapter to headphone amplifier create an electrical connection between power supply ground and audio ground within CmoyBB.
   
Solution:
Disconnect CmoyBB power adapter before charging audio player from common USD charging cable.
   
Components repaired:
Replaced circuit board and ALL components. Amplifier optimized for AKG K701 headphones:
-Gain reduced from 6 to 4
-Rb changed from 24k to 16.2k
-C1 changed to Nichicon 470µF, KW series
-R2 and R4 changed to 1/8W parts
   
  ------------------------------------------------------------------------------------------------------------------------
   
   
  Nice..and when i received my CmoyBB..  the best thing was he included in the bubble pack 2 pcs opamps.. LMXXXX  and ADXXXX... allowing me to evaluate personally the sound by swapping those opamps.I think it was my best $6.50 spent so far... on top of that... he even supplied me another 9V battery - Totally not your fault, John..
   
  Now i love my CmoyBB better than ever. Paired with CX500 and newly received NE-6...make me happy again.... (NE-6 with OPA2227 is the way to go... IMO)
   
  Can't try with K701 yet, since it had been sent for repair, due to distorted sound on left channel. Yes..  K701 needs power...but hey, it's no harm to get Cmoy amplifier to drive it...as long as I'm happy. Did I mention that I'm poor...?
	

	
	
		
		

		
		
	


	



   
  I'm not promoting..  only to express my satisfaction how  sincere he is towards one of his customers.
   
  Highly recommended product, and service...
   
  Thank you John..!!! Maybe it's time for you to introduce us your another great product...
	

	
	
		
		

		
		
	


	



   
   
   
  (sorry for my substandard writing skill)


----------



## komebudu

My friend gave me his Octave's DAE-1 on loan, which hw didn't use it for a while. I never know this product before.. . http://octave-electronics.com/Products/dae.shtml from NW-A808 > DAE-1>CmoyBB>NE-6... and WOW!.. CmoyBB seems to be more powerful..less prone to clip.. even i only run with 9V battery.... and even the NE-6's 12 Ohms.....
   
  Can't wait to try it with K701...


----------



## substance90

Guys, would you recommend the cMoy v2.02 for AKG K271 MKII for usage with the headphone output of a notebook or do I need a DAC for this purpose? I`m just not happy enough with the bass of my cans.


----------



## komebudu

Quote: 





komebudu said:


> My friend gave me his Octave's DAE-1 on loan, which hw didn't use it for a while. I never know this product before.. . http://octave-electronics.com/Products/dae.shtml from NW-A808 > DAE-1>CmoyBB>NE-6... and WOW!.. CmoyBB seems to be more powerful..less prone to clip.. even i only run with 9V battery.... and even the NE-6's 12 Ohms.....
> 
> Can't wait to try it with K701...


 

 Got my K701 finally....
   
  The drive units had been changed to new pairs.. Technically..  it's brand new K701.
   
  The problem is that..i have to run the burn-in process again..   Alas !!  
   
  "Out of the box", combined with Toshiba DVD player, DAE-1 and modified CmoyBB 2.02..  K701 Wows! (i hope more WOW! prior to burn-in process)...  sweet and pleasant sounding. ..  very nice indeed, compared to previously, a slight trace of sibilance though. And now i can use Bass Boost at the CmoyBB.   This CmoyBB seems less tendency to clip after being optimized, as mentionned before. For normal or confortable listening level, i don't have any issue... because mainly i listen to classical, jazz and acoustic concert. My fav CD right now is Lara Fabian - En Toute Intimité... ahhh.... superb performance...great recording.
   
  Now I'm a happy man...  (until my head-fi desease re-occur, one day)


----------



## pekingduck

Ordered one today... Can't wait to compare it to the PA2V2


----------



## parked07

First off I apologize for bumping a somewhat old thread. I believe this is my first post on this board. I've been lurking for quite a while and decided to write in about my experience with this amp. I have decided to replace the stock OPA2227 with a AD823ANZ and have tried a AD712JNZ. I haven't read anything about amp rolling with this amp in particular so I'd like to share what I found if you guys don't mind 
   
  I use a pair of ATH-M50s with this amp. These sound great unamped but I was looking for something to help increase the sound stage and maybe give me a bit more kick and volume then what my Macbook and iPod can give me. 
   
  Out of the box this is a great amp. I've had it for about a year now and it has been great. It definitely grabs attention for it's design (but I would imagine the same is true for any CMoy) and the build quality is superb. Little things like the auto power off when the battery's unplugged, or the foam to help hold in the battery shows their attention to detail and knowledge of what matters to the customer. It's more than capable of driving my headphones and the OPA2227 sounds great. Very detailed (after burn in) and but it seemed to do nothing for my main problem with my M50s, which is the limited soundstage. They did have a somewhat neutral sound to them but I feel like the highs were kind of accentuated, and the low end was kind of lacking. After looking around on this forum I read some reviews of other amps and looked a lot into amp rolling. I had no prior experience with this kind of thing and so I emailed JDSLabs and like when I bought it, he got back to me within three hours. He gave me a lot of good reference links and recommended a few amps. Customer Service is amazing with this guy. It's unlike anything I've experienced from any other company. I'd buy fifty more amps just because of that. 
   
  I took advantage of the sample program with AD (which I feel kinda bad about) and got the amps very soon after. Rolling was a piece of cake because of the socketed amp and detailed instructions can be found on the JDSLabs website. 
   
  I'd like to talk about the 712 first. It is extremely crazy to me how revealing it is. I can hear members of the orchestra from The Parent Trap Suite (I'm completely aware at what a lame choice of music this is, but I have a thing for soundtracks and this suite always gets me nostalgic) breathing or flipping pages. Piano benches creak in Diana Krall's "Live In Paris" and I can hear the plucking stand out on both the guitar and the bass as well as audience members coughing, etc... The mids are just there and they seem right. The low end is AWESOME. But let me say that on both of the amps I tried, the bass boost is useless. Which I understand as I assume they have been tuned to the OPA2227. Regardless I don't even care as the sound from this amp was great. The highs were just so perfectly tuned it seemed like they had been made for my headphones. But alas, my soundstage problem had only been mildly helped, and at times the amp seemed unable to power the amp, as distortion occurred where I know the headphones could reach. On a side note I have tested these headphones using both a Samson Servo120 and a very old Sony MDR 4 track minidisc recorder and an EQ to see just what (or rather where) these headphones can reach. I know that I can buy a power adapter or wire in another battery but I'm only 17, my source of income is non existent and those adapters are wicked expensive. 
   
  Anyway I decided to switch to the AD823 and to prevent redundancy, I'll just say all of the revealingness of the 712 was there but with such a better texture (its smooth and responsive and able to keep up better with fast music. I'm not good at using descriptive adjectives and for that I apologize. Also it fixed my tight claustrophobic music with (YAY) an incredible soundstage. Everything has a place now. I listen to a lot of Owl City, Rocket to the Moon, Hawk Nelson and Diana Krall as well as some recordings I've done myself and one of my favorite pianists, Emile Pandolfi. Everything sounds stereo ya know? All the instruments have places and I can feel like I'm in the middle of the band. 
   
  I'm really sorry about the quality of this. I'm not nearly as good at reviewing as the other members on here. But I would like to say if you have this amp, try rolling the amp. It's an amazing difference. The amp out of the box is amazing, you won't regret it. But if you can find a way to get these amps, do it. It's awesome. Especially if you can get a power adapter because even the 823 seems thirsty once in a while. Also be aware the bass boost is not worth turning on anymore, which I'm more than fine with as they really helped bring out the bass in my M50s. 
   
  If your still reading and want to know more I'd be more than happy to post more. I just don't know what to post about  Thanks for reading though.
   
  P.S. If your reading this still Mr. John ever since I rolled this bad boy I seem to be having a problem with the VGround. I hear humming when I touch the input or the volume pot. Also the pot seems wicked dirty now. When I turn the knob it kinda crackles. Any suggestions?


----------



## komebudu

Hmm..  interesting.  
   
  John had also recommended me to try AD823 chip for K701...  which i didn't yet.  Perhaps should give a try.....
   
  thx P07


----------



## jseaber

Great info! Could you elaborate on what you mean by, "bass boost is not worth turning on anymore" with the other opamps? This is surely not true for everyone. The OPA2227 goes well with the default bass boost configuration, but it is purposefully tuned for a warm, powerful sound that can be overwhelming with certain opamp/headphone combinations. Some slight adjustments would restore the feature's impressiveness with your equipment.
   
  Regarding the humming after opamp rolling, have you tried reverting to the OPA2227? I have never known humming to be a problem. I can only suspect that a short has occurred, or the potentiometer has physically worn out. Slide a business card (or something equivalent) beneath the circuit board; this will ensure the board is isolated from the tin. If that doesn't help, send me an e-mail and we can get your potentiometer replaced.
   
  --JDS
   
  Quote: 





parked07 said:


> First off I apologize for bumping a somewhat old thread. I believe this is my first post on this board. I've been lurking for quite a while and decided to write in about my experience with this amp. I have decided to replace the stock OPA2227 with a AD823ANZ and have tried a AD712JNZ. I haven't read anything about amp rolling with this amp in particular so I'd like to share what I found if you guys don't mind
> 
> I use a pair of ATH-M50s with this amp. These sound great unamped but I was looking for something to help increase the sound stage and maybe give me a bit more kick and volume then what my Macbook and iPod can give me.
> 
> ...


----------



## parked07

Hey John thanks again and again for this amp. It's crazy to me how much of a difference it has made in my music. 
   
  When I say that the bass boost is not worth using with the other amps I mean (and this may be completely different with another amp, maybe with more power) that its so wide of a boost, in that with the 2227 it is a tight boost with a good punch to it, this sounds like someone just turned up the low mids to a point where it sounds hollow, and without any definition. This was the same with both amps, but less so with the 823. I plan on getting a power adapter later so I'll see if that helps. The new amps do seem to need a bit more juice to get them going. 
   
  Also the credit card did seem to help. The potentiometer (?) still seems a little fussy but I can live with that. I'm stoked with how this sounds. Thanks again man!


----------



## jseaber

Ah, that's the cutoff frequency of the bass boost. Swapping the stock 0.068uF Cb capacitors for 0.1uF parts will shift the curve down to your liking.


----------



## UltimateCrash

Hello all, I received a new cMoy 2.02 a few weeks ago as a gift from somebody and it's been working ok, except that I can't turn the volume knob up to the levels that I would like to before my headphones start cutting out ( The cutting out has gotten worse, I can barely turn the knob at all until it starts up again).  I'm using JVC HA-S700 headphones (32 Ohm impedance, one month old, and tested with other audio sources, so I think it's not the headphones) if that helps, but I myself do not know much about sound, so I don't know what the problem is really.  I went to your site Mr. Seaber and read that you can customize the amp to specific headphones, but is that what I need to get done?  Or are my headphones simply too weak? Or is my cMoy damaged somehow?  Thanks in advance to anyone who answers my questions, and pardon me if my question does not belong here.
   
  - Crash


----------



## jseaber

Yes, customization is strongly recommended for 32 ohm headphones and below. Low impedance headphones demand more current. If you've been pushing the amplifier into distortion for weeks on end, you've likely damaged the TLE2426 by continuously pulling more current than it can safely supply. Along with gain adjustment, I can also install a second TLE2426 to double the current supply.
   
*Note to all:* Please contact us directly via e-mail or through JDSLabs.com if you need help.
   
*Edit: *Several have asked about this modification. The cMoyBB is normally assembled with a single Texas Instruments TLE2426 "rail splitter". These chips have been used in CMoys since 1998 for their superior performance over resistive voltage dividers. The majority of CMoy users need just a single TLE2426, but in rare cases (very low impedance headphones played at very high volumes), more current is demanded than any CMoy can supply. Turning on bass boost exacerbates the problem by roughly doubling the current draw. In such cases, the cMoyBB can be modified to accomodate dual TLE2426 chips. This leads to higher current handling and therefore higher clean playback volumes. So why not always use dual TLE2426 chips? Four reasons:
   
  1) Most headphones above 32 ohms achieve very high volumes with less than 30mA (one TLE2426 is fine)
  2) Battery life is nearly cut in half with 2 chips
  3) Parts & assembly cost increase
  4) The listener risks hearing damage at those higher volumes!
   
  Therefore, *it is optimal to use a single TLE2426.*
   
  Quote: 





ultimatecrash said:


> Hello all, I received a new cMoy 2.02 a few weeks ago as a gift from somebody and it's been working ok, except that I can't turn the volume knob up to the levels that I would like to before my headphones start cutting out ( The cutting out has gotten worse, I can barely turn the knob at all until it starts up again).  I'm using JVC HA-S700 headphones (32 Ohm impedance, one month old, and tested with other audio sources, so I think it's not the headphones) if that helps, but I myself do not know much about sound, so I don't know what the problem is really.  I went to your site Mr. Seaber and read that you can customize the amp to specific headphones, but is that what I need to get done?  Or are my headphones simply too weak? Or is my cMoy damaged somehow?  Thanks in advance to anyone who answers my questions, and pardon me if my question does not belong here.
> 
> - Crash


----------



## UltimateCrash

Thanks a lot Mr. Seaber, I'll go ahead and do that.


----------



## gilency

Just purchased the PCB. I will be using it only with IEM's with an impedance of 56 ohm (ES3X) and would like to be able to control the volume better than my Headsix (which I believe has 5 or 6 db at low gain).
  Is 4X the lowest recommended gain?
  Also, the volume knob from digi-key is hard to find  anywhere else since I am not willing to pay 8.00 just for shipping for a 6.00 item. Any other options?
  Is the CUI 2.5mm Mono Jack needed? Mouser does not have an equivalent item.
  Thanks


----------



## jseaber

@gilency: Lower gains are fine. Try a gain of 2 (R3 = R4 = 10.2k). The DC jack can be omitted (see Modifications). Any volume knob with a 0.25" shaft diameter can be used. RadioShack sells several (since you're in the US), or you can search the DIY forums here for more recommendations.


----------



## gilency

Thanks.


----------



## gilency

Which opamp would you recommend to increase the soundstage of IEM's like the ES3X?


----------



## gilency

Just received all the components. John, I had to pay 3.00 extra for the PCB package (had incomplete postage). The PCB looks very nice, like much much better than the Banzai 2.0.
  Purchased 3 different opamps and will use a gain of 2 for my IEM's.
  DigiKey and Mouser delivered. Just need a better hole puncher.


----------



## jseaber

@gilency: No one has ever reported anything like that. Every single package from JDS Labs is manually weighed and processed by our local post office in Maryville, IL, USA (yes, despite their digitally prepared labels). Unless our post office made a mistake, there should never be additional postage due.
   
  E-mail me a photo of the package/bill and I will be glad to reimburse you for the $3.00 charge anyway.
  
  Quote: 





gilency said:


> Just received all the components. John, I had to pay 3.00 extra for the PCB package (had incomplete postage). The PCB looks very nice, like much much better than the Banzai 2.0.
> Purchased 3 different opamps and will use a gain of 2 for my IEM's.
> DigiKey and Mouser delivered. Just need a better hole puncher.


----------



## gilency

I am very happy with your PCB.  Much better quality than the Banzai v2.
  I should have kept the postage issue private. An issue not even worth mentioning regarding a very professional individual. My apologies.


----------



## gilency

I finished my cMoy BB tonight in a chocolate Altoids can. Looks and sounds pretty cool.
  My second cMoy, and the best.  I have several opamps to try but is 3 am and have to go to bed. DIY is exciting!
  I used a gain of 2 as suggested. Ideal for IEM's with better volume control.
  There is something unusual I don't understand though:
  a) with my iPod Classic, it sounds great either from the phone out or Lod.
  b) with my 5th gen iPod Nano it sounds great from the phone out, but no sound comes out when using the Lod. Not sure if this particular Lod does not work with 5th gen Nanos or not. Any other explanations?


----------



## komebudu

Again, my CmoyBB burnt due to mishandling with the DC supply.
   
  Sent to John for repair .... the job done was very fast...  without any additional cost requested... Thanks, John.
   
  Then  I had the idea to go further to put some muscle to this unit... John suggested to DIY by adding additional dual TLE2426  http://www.jdslabs.com/diy_mods.php .
   
  Equipped with AD823 chip, driving 12 Ohms NE-6 is such a breeze now...  no issue with clipping whatsoever...  Even with K701...  i can really push the volume LOUD ....  not only talking about quantity here...  the quality as well...  Awesome upgrade!!
   
  My Fav setup at this moment:
   
  NAD 502 CDP + DAE-1 (similar to MF X10D) + CmoyBB + NAD302 power amp section....  Sublime combination at very affordable price..!!!
   
  Again..  always impressed iwth the CmoyBB ability and excellent customer service by John.
   
  Cheers....


----------



## jseaber

Mishandling was by komebudu's young son, if I recall. 
	

	
	
		
		

		
			




    
  Quote:


komebudu said:


> *Again, my CmoyBB burnt due to mishandling with the DC supply.*
> 
> Sent to John for repair .... the job done was very fast...  without any additional cost requested... Thanks, John.
> 
> ...


----------



## komebudu

Yeah... John...  your memory is intact...


----------



## proedros

Hello mr Saber
   
  I am thinking of buying one of the 2.2 version i saw in your ebay page *to drive my re-252 and re-262 through a clip+*
   
  i wanted to ask if there is any modifications need to be done to your amp or it works fine as it comes ?
   
  I am a complete noob with amps but this looks like a good one for starters
   
  My only concern is , will it require anychanges or these 2 IEM's are fine for use with the 2.2. version ?
   
  Thank you
   
  (if anyone else can help me out , please chime in your 2 cents)


----------



## zachfeen

How much would a customized unit be with 2 chips?  I will be using Audio technica es7 32 ohm headphones


----------



## UltimateCrash

Mr. Seaber repaired my Mccoy very quickly and shipped it back to me very fast as well.  My headphones sound great with this awesome amp!  I am very pleased.
   
-Crash​


----------



## pov1

Quote: 





add said:


> I always wonder where all the actual mints go with these things.


 
  Some ones  getting pretty hefty ha ha !


----------



## UnityIsPower

Any plans for making it rechargeable? How about selling on Amazon?


----------



## TheOneInYellow

I would like to apologise to John Seaber, famed cMoy maker, Electrical Engineer, Chief Executive Officer and President of JDS Labs, Inc. (based in Illinois, Maryville, US), and a DIY enthusiast.
I am going to make no excuses, but here is the simple point; I let John down, twice, by not writing reviews for two amps I bought of him between 2008 and 2009 (cMoyBB v2.00 and a Custom cMoyBB v2.02). Rather than write a brand new review for either (since both are technically discontinued), I would like to write a report on how awesome John is, some of the messages and emails we sent to each other in purchasing/building cMoyBB amps, and my mini-review of the Custom cMoyBB v2.02 that I wrote to him but never published anywhere. There is a reason why I am resurrecting this thread, but that reason will become clear at the end, or you can just check out this topic.
   
So, lend me your ears (eyes) for a moment (*as a disclaimer, this is a potential TL;DR post*; if you have the strength to read it, then you are seriously awesome, but not as *AWESOME* as John ):
   
The first time I contacted him was in March 2008 when I was searching for an amplifier for my newly acquired Ultimate Ears Super.Fi 5 Pro’s and my Etymotic Research ER-6i’s; both items are now discontinued (and Jerry Harvey no longer works at UE and UE is owned by Logitech). At the time, he was still studying a degree in BSEE at Missouri S&T, and he operated a shop using eBay as a frontend.
After working through the Head-Fi.org forum, I had selected a few amps that I was considering to buy, but to keep things short, I went and opted for the cMoyBB v2.00 headphone amplifier from John. We exchanged messages between us using mainly the eBay messaging service, but some of this has been lost, and some are unnecessary for this thread
I promised to write a review of the amp on this forum (the one I am in right now), and I never, never did.
   
Fast forward just over a year later, to 6th July 2009. I re-contacted John again at the end of that Summer to inquire about his latest amp, the cMoyBB v2.02, but also to talk about my previous amp and, at the time, my new job.
First, my old cMoy v2.00. It was malfunctioning. Badly. For just under a year. Here is a quote, from me to John, when I wrote him an email describing the problem:
   
_“The problem is that: the input 3.5mm jack is not performing as it should, cuts out the left channel, introduces noise, lowers overall volume, does not provide a secure fit (an inserted TRS/3.5mm connector sometimes pops out during use)…_
   
_“I have looked at the differences of the socket on the PCB with my naked eye, and can see that whereas the output socket looks like it is double the size of the input socket. I assume that this was done for space. I also shone a light done the two sockets, and can clearly see that the internal parts of the connectors look different; the output socket has what looks like two prongs touching, whereas the input prongs hardly make contact. I presume that when I connect my cable in, the input connector prongs do not make a complete connection to the TRS jack, thus causing issues with sound.”_
   
I also wrote:
   
_“Rather than having this fixed, I would like a new amp, but for one very important change (beyond my suggestions for a possible custom built amp); I would like both I/O sockets to be of either higher quality, or that the sockets are more durable from stress (such as in my jean pockets or otherwise). At least so that this problem does not arise again._
_I can also salvage the old amp, and do some opamp rolling ”_
   
So, what about his latest (then) amp? I wanted a custom built amp, not the standard one he offered to customers. I went and wrote what I wanted in detail, and told him that I was pushed for time; my new job would start very soon (August), but I did *not* want to rush him. Of all the customisations I wanted, I especially wanted no more issues with cable connections (TRS contact issues) at all. (For the purposes of this post, I won't write what those inital customisations were, as it is irrelavnt).
He replied back, told me what was not possible, but offered many alternatives to really make a great amp. After some more exchanges, we agreed on what the build should be and the total cost via email. I paid him (via PayPal) and, seriously the best part, he actually built it quickly for me. To be clear, I spoke to him on the 6th July ’09, paid him on the 9th, and received a fully built Custom cMoy BB v2.02 on the 16th. A further note, I live in the UK. Yeah, _seriously_, I bet there are few people who could do this, and he really is awesome (will continue to say this, bear with it ).
   
This following is a list of what made my cMoyBB v2.02 a ‘custom build’ over the, at the time, standard (he actually wrote this on my paper order form when I received my jiffy-bag envelope parcel, so I will transcribe it word-for-word):
   

 Hand Selected Alps RK097 potentiometer
 330Ω DC coupling
 Gain = 4
 Premium nichion 470µF KW capacitor
 New Kyron STX-3100-9C output jack.
   
(He underlined the ‘9C’ part of the ‘STX-3100-9C’ output jack for emphasis on my order form).
Just to expand, the Gain is set at 3.3kΩ, and the Alps RK097 is a 10k potentiometer.
The amp would also uses the *Burr-Brown OPA2227PA* op-amp, which is such a beautiful OPAMP, *swoons*!
On that note, one or two of these modifications are mentioned on the JDSLabs.com DIY section, which talks about building your own cMoyBB v2.02 amp; take a look 
To make the whole affair sweater, in the original discussions he said not to use a particular OPAMP, the *LM4562NA*, as it causes interference with wireless access points, but he included it, for free, in case I ever wanted to use it. Unfortunately, I have never used it; it is still in the original anti static bag inside my (still kept) jiffy-bag envelope he used to send me my custom amp.
Before I go any further, his last email to me (20th July 2009), he asked me to say in my future review (I never wrote a review for either my amps...) that the _Kyron STX-3100-9C_ will be a standard part until mid-August 2009; obviously too late now, but at least it is mentioned.
   
When I received the new amp, I immediately compared it with my old one; to get the old one to work, I had to physically push the TRS connector of my interconnect cable to one side to make contact, but other than that, I was able to make some healthy observations. Rather than write this out again after two and a half years, I will post my mini-review that I sent him, now visible and open to the public. As another disclaimer, I was much younger then, so please ignore the biased, sometimes childish, and poor writing/reviewing skills:
   
---


Spoiler: Sent%20to%20John%20Seaber%20on%20Sunday%2C%2019%20July%202009%20%40%2008%3A09.



 
Sent to John Seaber on Sunday, 19 July 2009 @ 08:09.
   
/START
   
_"Hi John,

 I have finally received your amplifier on the 16th!
 Just looking at the internal restructuring of your Custom cMoyBB v2.02 circuit board against my old v2.00, and I am quite impressed at your handiwork! It seems that you have continually tried to improve on your older designs rather than re-hashing old ideas; something that I commend you for.

 I also had a look and identified the custom internal components; the 330Ω DC coupling value resistors and the Nichion 470uF "KW" capacitor are the most obvious changes, and both look well soldered (I actually like the look of them on this new circuit board rather than the v2.00 respective components). I am very, very pleased with the Alps RK097 10k potentiometer; the pot is simply incredible over the old amp's pot. I love the movement of the pot; it is just so much more responsive than the v2.00. I like the smooth, but resistive/solid turn of the pot, which feels very reliable, far exceeding the older amp. More importantly, the volume is better controlled with this amp, very accurate over the v2.00. I also like that the volume knob of the potentiometer is not too close to the lid of the amp, which makes turning the pot more comfortable, and looks better (does not have an 'angled' look like my v2.00).
 There are major design improvements I find with this custom v2.02 amp over the old v2.00 amp. The potentiometer and input/output jack’s re-placement make it easier to use cables and I have a more accessible pot (rather than thumbing between my cables trying to use the v2.00 pot). The internal bass boost switch is a smart idea, giving the amp a more discrete look, and better allows for better fit in my pockets. Although a bass boost potentiometer would have been nice, in reality, the internal switch is a far more convenient option and is less susceptible to environmental changes, such as the rubbing of my amp/iPod in my pockets (unlike the v2.00). The threaded Kyron STX-3100-9C jacks look superb against the older jacks from the v2.00, and give a more, secure fit when I use my 3.5mm connectors. Indeed, your cut holes are far better than the v2.00!
 This custom cMoyBB v2.02 amp simply looks more professional than the old v2.00 amp.

 So, after enjoying the look and build of your amp, what do I think of the sonic quality? Absolutely stunning!
 As a stress test, I performed an A/B test between your custom cMoyBB v2.02 and the cMoyBB v2.00 amplifiers, using my iPod Classic 160GB as the source. This was connected to my NuForce Icon amplifier (with the stock 23W PSU), and I played lossless music to first my JohnBlue AudioArt JB3 loudspeakers.
 It was obvious that the two amps had very different SQ. I could play my music at a higher volume on the custom cMoyBB v2.02 than the old cMoyBB v2.00. Also, the bass is far more controlled with the new custom v2.02 amp when I switch on the bass boost switch. I can actually go louder overall with the BB switch on without bass distortion, something the old amp cannot achieve. The increased volume is not what I intended as being important, just the fact that the custom v2.02 is more powerful and more refined in dynamics and soundstage than the old v2.00 amp, and can achieve this at both lower and higher volumes. Overall, very impressive!
 Now, onto a harsher test; the same setup, but using my 'AKG K 701' circumaural headphones instead of my loudspeakers.
 These headphones are super accurate, very precise, and have amazing imaging coupled with breathtaking soundstage. So how did the custom v2.02 fare in this test? Fairly well, I would say, but it brought down the overall finesse of the K 701, simply because this cMoy amp cannot give enough [head] room for the headphones to breathe; the K 701 are extremely hard to drive, so even when I used the v2.02 as a preamp before the signal is passed to my main amp, the headphones suffered from detail and soundstage. Indeed, they felt like I was using in-ear monitors (IEM), albeit an awesome beast compared to my two IEM's. I tested before and after the BB switch and it helped bring out the best bass of the K 701, but at a loss of fine detail in the other frequencies. Nevertheless, I still enjoyed this setup, and I am impressed that custom cMoyBB v2.02 performed so well.
 I tried using just the iPod, cMoy v2.02 and my K 701, but this was not a good combination. The bass boost needed to be on for the K 701 to actually present the music well in the lower frequencies, but there was not enough power from both the v2.02 and the iPod to really allow the K 701's to work at their best in all the frequencies and both soundstage/imaging suffered. I believe the iPod is the first, main cause of this issue. Yet, again I am surprised at how the custom cMoyBB v2.02 can perform so well on the AKG K 701, there are not many amps, let alone portable amps, that can at least drive and play music on these headphones, and play at least somewhat well (I still enjoyed listening to this setup, just that it does not beat my soundcard and amp).

 Finally, I have used your amp for its intended purpose, portable headphone amp. I have used both my Etymotic Research ER-6i isolator and Ultimate Ears Super.Fi 5 Pro IEM's with the custom cMoyBB v2.02 and my iPod; absolutely superb!
 Playing music like this is fantastic, the ER-6i's gains new life when I use your amp, and are stunning with the BB switched on. The Super.Fi 5 Pro's are extremely soulful and have a 'live' like sound to them with the v2.02, and the BB switched on gives me the impression that I am at a live gig! I enjoy (and missed) using your amps and this new amp simply blows my old v2.00 away into the nether regions. The soundstage and imaging from your amp is amazing and very enjoyable.

 My custom cMoyBB v2.02 amp is clearly ahead of my old v2.00 in SQ, it is far clearer and causes less clipping on my audio gear when I increase the volume; the amount of headroom from your amp is stunning.

 I will publish this mini-review, with much refinement, in the future on Head-Fi.org, as I am away with a new job. I shall road test the custom cMoy BB v2.02 and report on changes of the amp and my listening experiances later.

 Thank you John for making this amp, I am extremely pleased, and I cannot wait to see how you progress in the world of cMoyBB!

 Kind regards

 [Contact Information and name redacted]

 ^_^_
   
_(P.S I apologise for some of this email if there is any illegibility and/or repetition)_
_(P.P.S. feels good to update my audio signature  )_
   
_---

 Desktop Audio Rig:_

 _PC (Vista SP2 with ASIO4All drivers) playing MP3 [Lame], High Resolution WAV or AIFF, FLAC or ALAC/Apple Lossless via Foobar2K/Songbird/iTunes respectively;_
 _Asus Xonar D2X PCI-E soundcard;_
 _Zu Audio Zu Cable Pivot™ (Mk2) Miniphone > RCA Cable (1.0 m) [stereo miniphone connector (3.5 mm) > RCA / RCA with 8" leadout]_
 _NuForce Icon Desktop Amplifier/DAC/Pre-Amp/Headphone Amp;_
 _JohnBlue AudioArt JB3 loudspeakers or AKG Acoustics K 701 circumaural headphones._
   
_Portable Audio Rig:_

 _Apple iPod 6G 160GB;_
 _Audio Line Out (ALOaudio.com) iPod Female Connector;_
 _ALOaudio.com JenaLabs Jena Wire Jumbo Cryo 3.5mm Mini to Mini (4 inch cable, 6 inch tip to tip) cable;_
 _JDS Labs (John Seaber, www.jseaber.com) custom cMoy v2.02 Bass Boost (via internal switch) headphone amplifier with Texas Instruments Burr-Brown OPA2227PA op-amp. This amp is custom built with the following changes: gain selection at 4 (3.3kΩ), Nichion 470uF "KW" electrolytic capacitors, 330Ω DC coupling value resistors instead of Vishay/BC 1uF Metallised Polyester Film Capacitor or WIMA 1.0uF Polyester Film Capacitors, Kyron STX-3100-9C (threaded) input/output jacks, and a hand selected Alps RK097 10k potentiometer;_
 _Ultimate Ears Super.Fi 5 Pro canalphones;_
 _Etymotic Research Inc. ER-6i isolator canalphones."_
   
/END
   


 ---
   
He wrote back, in his last email to me, the following reply:
   
---


Spoiler: Received%20from%20John%20Seaber%20on%20Monday%2C%2020%20July%202009%20%40%2004%3A10



 
Received from John Seaber on Monday, 20 July 2009 @ 04:10
   
/START
   
_[NAME REDACTED],_
   
_Thanks for your thorough and praiseful remarks! If I had the time, I’d give a more thorough response. Again, I truly appreciate your feedback. Customer responses such as yours are the reason I continue running JDS Labs._
   
_One thing: If you mention the STX-3100-9C in your “future” Head-Fi review, please remember to note that this will be the standard part by mid-August 2009._
   
_Best regards,_
   
_John Seaber_
_www.cMoyBB.com_
   
/END
   


 ---
   
   
Since that time, near the end of 2009, I lost one of the Super.Fi 5 Pro earpieces, which left me devastated, but also my entire lossy collection of music (13,000+ tracks) became corrupt on my PC, leaving my 6th Gen iPod Classic 160GB (2007 edition) the only place where they now exist; it also had some 3,000 lossless FLAC files, but not my entire collection. My FLAC/Apple Lossless stuff on my PC was fine, but I have (still) never updated my iPod since. My lossless collection has since grown, and I use Spotify Premium for lossy music playback, but I hardly ever use my portable rig except long car journeys.
In some ways, my initial rigs, as outlined in the first email written above, has not changed much, save for using foobar2k almost exclusively for all music using WASAPI mode and other tidbits.
   
Now that you may or may not have read that report, here is why I am posting this after a long time.
I am in the market for a new amp, simply because I just bought an Ultimate Ears Triple.Fi 10 Pro IEM from Amazon.co.uk Boxing Day Deals (still going) for _£109.99_, which I have mentioned in various, many topics, including my own.
Unfortunately, when I received my IEM’s early in the morning of the 31st Dec 2011, I had received a *defective*, D.O.A IEM. I have described it here (and again in a follow-up post) and here if you are interested, but please read the rest of both topics; I am receiving a new replacement this week or next Monday (6th - 9th Jan 2012) from Amazon, so all is good; their customer service is brilliant.
   
At the moment, I don’t have a huge amount to spend, so my budget is small, but I decided to do one of three things, either: get a professional portable amp, continue to enjoy my still working Custom cMoyBB v2.02 amp, or invest in a customised Rechargeable, 2x9 batteries *cMoyBB v2.03*.
I have decided to go for the former option, but pre-order and buy the c421 Headphone Amplifier from John (get the amp now with 2nd batch faceplates, and get the new, 3rd batch faceplates in February). After much research, he still comes up top for amazing quality amps at very budget prices.
This gives me room to possibly order a set of custom mould ear sleeves (tips) for my Triple.Fi 10’s later this month, since I have been entertaining this idea for a while now. ACS Communications Solutions (alternate site) are pretty famous in the UK for making ear moulds for Etymotic, but they do make ear moulds for other earphones (*ACS UK Custom Fit Earphone Sleeves*). I have three places where I can get this (*HiFiHeadphones.co.uk*, *iHeadphones.co.uk*, or *BootsHearingCare.com*), so there is no rush and I can mull over which would give me the best to purchase from.
I can also invest in a nice new line-out-dock (LOD). Indeed, I  am thinking getting Moon-Audio.com’s *Silver Dragon V1 LOD Cable*  or *Silver Dragon V3 LOD Cable*, but this depends on what cash I have remaining.
Finally, I am interested in purchasing the *FiiO RC-UE1 Replacement Cable for Ultimate Ears IEM’s* from HiFiHeadphones.co.uk, but this is more of an afterthought. Plus, there is no memory wire in these cables, which I like, and due to the weight and the little fact that I wear spectacles, I will need to do further thinking and research before I shell out money for it.
   
I will be making this order very soon, but first, I need to send some…emails...to John Seaber; I will make an apology to him for not writing any reviews all those years ago, and then ask him some (lots of) questions about the C421.
   
I will update the following thread, and create a separate one to review the C421 Amplifier (depending on the conversation between John and myself via email), and thank you to anyone who read the entire post. I think you may be crazy, but I guess if your already a Head-Fi member...


----------



## labman

Hope you guys don't mind me bumping the thread. I was debating between keeping my fiiO 5 or getting the FiiO 6 or 11 after research I decided to order a Cmoy with the AD823 and bass boost from hpa_labs at $45 hopefully I didn't make a mistake. I'm not a Audiophile by any means just a good music fan boy.


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## Puffery

The JDS cmoy I use generally provides more raw power then my portable player for my HD25s, depends on the headphones you will be using them with.


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## H20Fidelity

I ordered a V2.03 rechargeable CmoyBB today from JDSLabs through John, really great service, he was prompt to reply to my emails when I wanted to make an order correction as it's going to be customized for my triple-fi 10 and other IEM's 32 ohms and under. Cant wait to try it after all the rave reviews I've been reading! This amp sounds perfect for my applications and portable needs!  Price seems really resanable too. Shipping to Australia was next to nothing compared to other purchases I've made.

 I'll report back when it arrives!


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## HiFiGuy528

Is the sound neutral or does it add flavor? Is there any noise like hiss? I saw one that uses TWO 9v batteries for an "audiophile" grade Cmoy. Is that hot air?


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## Katsukare

Those wondering if I am still around, yes I am and till today it is still one of my most favourite cMoy amps.
  However I did order a new unit, after my first great one that I gave to my uncle.
  The only thing I was not too happy about was that John only gave me a tiny tiny discount. 
  Otherwise? Same old, solid product. Be sure to keep your 9V's fresh otherwise the bass tends to distort once your low on battery.


----------

