# Multiple amps, one source.  Best solution?



## Edwood

I know alot of you have this delimna.

 I have an unbalanced source (RME digi96/8 PAD soundcard) that I want to use with two amps.

 What solution have you guys come up with? I realize that there are switch boxes out there, but they are mostly for switching sources. Can I use one in reverse?

 What's the best solution money can buy? (besides having two identical sources hooked up to each amp).

 -Ed


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## sacd lover

Get a pair of rca splitters. Your source then can feed two amps through the two female rca's on each output. These only cost about $6 each at Radioshack.


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## ooheadsoo

Hey Ed,

 Meier audio sells some RCA splitters that are meant to do this job. I haven't been able to find them anywhere else. It's under their cables section.

 Edit: Ok, I guess radio shack has them.


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## Edwood

Hmmm. I hope it doesn't degrade the signal. Well, I guess it's not much of a worry til I get high end IC's.

 -Ed


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## dd3mon

Quote:


 _Originally posted by Edwood _
*Hmmm. I hope it doesn't degrade the signal. Well, I guess it's not much of a worry til I get high end IC's.

 -Ed * 
 

Vampire brand splitters are confirmed by some very knowledgable members here to not affect signal quality at all. The ones at Meier audio look similar in construction to the more expensive Vampires. The only problem you could have is if one of your amps or your source had some strange input/output impedence characteristics that made it a 'difficult load' which would make both sourced hooked up at the same time degrade signal quality.

 I have both my MG Head and my NAD C320BEE integrated amp hooked up to the two outputs from my cdp at all times, and I can hear no difference between one or both hooked up. The two outputs on my player are simply split wires inside the case, exactly what an rca splitter would do.

 -dd3mon


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## Ebonyks

Would it degrade sound? Sure, but that's insignificant to all of the compromises that the average amp makes to meet production costs. Just get a pair of splitters, and stop thinking about it


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## ooheadsoo

Yeah, I had the term "vampire splitter" stuck in my head but I couldn't seem to find any. I don't think they will affect the sound either unless there's some weird mismatches going on between the two amps' inputs.


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## spaceman

Quote:


 _Originally posted by ooheadsoo _
*Yeah, I had the term "vampire splitter" stuck in my head but I couldn't seem to find any. * 
 

You can get them at Headroom. In fact, I just bought a pair. Montana to Maine......48 hours.


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## Ebonyks

I've compared the vampire ones to the ratshack ones, and they appear to be almost identical. If you want to spend an extra 25 dollars to give you peace of mind, go right ahead, but you're not looking at any real-world difference here


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## kartik

The headphile combo cable is an ideal option. It is actually 2 cables rolled into 1 1/2. The cable consists of two different cores with 2 pairs of connectors and separate insulation with one pair of shared connectors at the other end. You can choose whether you want identical cores (silver or copper) or different ones. I have this cable except, my source has two outputs driving one amp. IT would be no problem reversing the situation with 2 amps driven by one source.
www.headphile.com
 Another solution would be to use a preamp with two outputs between your CD player and amp. any concern you have about excessive signal loss in splitting would be allayed by that. My preamp actually has 2 always-on outputs in addition to headphone outputs.


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## BANGPOD

Ummm, how about inventing a pre-source? 
	

	
	
		
		

		
		
	


	




 BANGPOD


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## Edwood

Would splitting the signal have a significant attenuating effect (lower volume output) when connected to two amps?

 -Ed


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## gerG

Solution 1: sell me the Grace. Problem solved 
	

	
	
		
		

		
		
	


	




 ok, what sort of outputs come out of that card? Can you run a digital cable to the Grace and anaolg to the SAC at the same time?

 Option 3 is get a selector box (like the headroom unit) and hook it up in single source, multi out mode.

 Splitting the signal once is not really a problem. I prefer 1 to 2 cable over the splitter block just for mechanical reasons. RCA plugs are just too delicate, and those blocks provide lots of leverage.


 gerG


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## gerG

oh, I learned something new last night. Don't get the power supply of the SAC anywhere near a signal cable. It can produce hum in a fully balanced and shielded cable from a foot away!


 gerG


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## Edwood

Hmmm. I don't hear a hum in anything. I have the SAC brick less than a foot away from the Grace. (she's mine! all mine!!!) My crappy monster IC's are pretty close to the brick too. 

 I looked for that selector box on Headroom's site. Looks like they don't carry it anymore. I think I'll go for the vampire splitters for now. THe analog output is pretty strong from the RME PAD, so I can stand to lose a little volume if any. And getting better IC's is in order too. (Now I have to get two pairs. Ugh)

 I would go with one digital out to the Grace and analog to the SAC, but the RME PAD's analog output sounds better.

 -Ed


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## BANGPOD

Just skimmed the post so I don't know if this was mentioned:

http://www.headphile.com/

 (Combo Cable Series)

 One set is silver and the other set is copper.
 It is the closest to what you have mentioned with what I've seen.


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## kartik

Look a couple of posts above your post and you should see the headphile post. I'm not sure the signal attenuation will be that much of an issue. But you won't know unless you try it out. The headphile combos have a 15 day no questions asked return policy, so what have you got to lose?


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## Orpheus

well there are quite a few to match your pro grace.... here are some:

http://www.colemanaudio.com/product.html

http://www.furmansound.com/pro/srm-80a/srm-80a.htm

 and there are plenty more.

 but as you can tell... they will all be overkill for you. just get some splitters.


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## gerG

Found the solution:







 Be sure to let us know how the built in headphone amp sounds! 
	

	
	
		
		

		
		
	


	





 gerG


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## Orpheus

heh he.... how could i forget that one! 
	

	
	
		
		

		
		
	


	




 hmm.... it doesn't have meters though.... strange. welp... there you go.... 3 companies with very expensive monitor routers. take your pick....

 if you need surround volume capabilities, get ready to sell your car for the money!


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## Edwood

Quote:


 _Originally posted by gerG _
*Found the solution:

http://www.gracedesign.com/products/...04_closeup.jpg

 Be sure to let us know how the built in headphone amp sounds! 
	

	
	
		
		

		
		
	


	





 gerG * 
 

LOL! You guys are killin me. 
	

	
	
		
		

		
		
	


	




 It would match the 901 perfectly. Isn't the headphone amplifier section in the 904 the same as the 901, though?

 -Ed


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## tortie

I had a high quality switchbox (with cardas RCAs & NKK 4DPT switches plus a built-in Pinkfloyd Xfeed) made my someone here. It has 2 pairs of inputs and 2 pairs of outputs & 2 on-off-on switches. I have 2 sources & 2 amps and I can select which source will feed which amp or I can have both amps play from a single source at the same time. Its really the best hassle free solution if you have multiple components. 

 Here's the pic. Sorry for the amateur labels


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## gerG

According to a reputable source, the headphone stage in the 904 is the same as the 901, but the D/A is better. I will post his remarks if he gives permision. 

 Funny, my wallet just ran and hid...


 gerG


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## Orpheus

heh he... well, it's not just the headphone amp and DAC you're paying for... that 904 is packed with features that no sane audiophile would ever need. but heck.... if you wanna buy one, and sell it used for 1/3 the price, you got a buyer right here! it would fix quite nicely into my system.


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## gerG

"Sane Audiophile"????

 Aaaaahaahaahaahaaa.......

 Damn, that made me laugh so hard I damned near peed me kilt! btw, why don't we have an acronym for that? LSHIDNPMK!
 ok, nevermind, now I know.

 What is the basic purpose of these "monitor systems"? It looks suspiciously like a digital preamp to me. If it has a digital processor loop, I am doomed to be an owner. Given my history with audio gear, you will have to wait for me to die before I part with it 
	

	
	
		
		

		
		
	


	




 Now if I were a "crazy" audiophile I would be twisting their arm to build me a balanced output version 
	

	
	
		
		

		
		
	


	





 gerG


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## Orpheus

yeah.... that's basically what it does.

 right now many recording studios are switching over to DAW's or "digital audio workstations"... in other words, computers instead of mixing consoles. usually the mixing console would allow you to monitor various inputs and recording devices.... but the monitor section is usually the weakness of these DAW's. so, now they have all kinds of these "monitor devices." they really are quite like preamps since they provide volume control and that kind of stuff. but they allow you to monitor various inputs and usually allow you to route the signals to various outputs. also, most of them have very good meters for accurate monitoring...... that Grace is the exception, and i really don't know why it doesn't have meters. but, that Grace unit is special: it also provides 5.1 surround support........ and usually stuff that can do that is really dang expensive.

 anyway, yes, the Grace can be used as an ultra-high-performance preamp..... and i suppose if you got the money, you could make one really dang good sounding 5.1 music playback system.

 it's actually quite a deal.... $2500 buys you a 5.1 volume control, reference headphone outs, and a ultra-high resolution DAC/ADC (192khz/24bit). i'd get one if i had the money. again, the only minus is that it has no meters..... which is really weird.

 and yes, gerG, now i realize "sane audiophile" is quite a oxymoron. .......are any of us really sane?--at least i'm sane enough to admit my own insanity... i guess. heh he.


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## Edwood

I'm extremely pleased with the Grace 901 and SAC. They are perfect compliment to each other.

 My computer is just too damn far from the amps. I have too many monitors in the way to move the amps closer to the computer. Argh! 

 Now I need two pairs of long analog IC's. 
	

	
	
		
		

		
		
	


	




 I'm using a 1.5 meter IC to my computer, and I temporarily put it at my feet to move it closer to the amps. I'm going to have to move the computer back to it's location. I guess I'll have to get some cheap ass cables from Rat Shack in the mean time. 
	

	
	
		
		

		
		
	


	




 -Ed


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## Orpheus

(ed, you will have the IC's (1 pair only... i didn't realize you needed 2, and the parts already came in) ready by sunday. in the mean time, you can leave your mouth open and drool. i can't wait to see your ideas on my website too... 
	

	
	
		
		

		
		
	


	




 )


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## Edwood

Sweet. I can move my music computer into it's place, and finally fix my workstation. And then I can start drawing some cool stuff fer ya. I recently upgraded my workstation, and have been itching to fire it up. My server is awaiting a lobotomy too. But first things first.

 Sweet. I can't wait to meet everyone in person. This "Mini" Meet is gonna rock!

 -Ed


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## Orpheus

heh he...... you know, if you really want even MORE routing options for your setup, get this:

http://www.mackie.com/products/8bus/images/8Bus328.JPG

 it's what i use. now, if that's not overkill for your situation, i don't know what is!

 with one of these babies, and a custom wired patchbay, you pretty much can make any setup imaginable. you can hook up 32 CD/SACD/DVD-A players at the same time.... and you can control volumes of 5 different headphone amps at the same time at the outputs. even more if you use the aux and mix-b outputs.

 now, ...........of course... there are these:

http://www.solid-state-logic.com/mus...00k/xlpure.php

 THE fanciest super-duper-insane-no-holds-barred-biggest-and-baddest-"preamp" in the whole wide universe. each single "channel strip" on that sucker costs about five times as much as one Grace, i think.

 gerG, i know you want one... then you can control all your insane little projects from one room. think about it.... all your tv stuff, your outdoor setup, your headphone stuff.... whatever you got.... um, your webcam mics that you have in your bedroom....... ha ha (don't worry.... i got my own setup too which she doesn't know about. heh he). ....well, actually, probably not... cause you'd have to sell a pretty good size house to buy one of those. but heck, it looks big enough to make a roof for your sleeping bag......

 bet you your Grace headphone outs are better than the ones on that monster though.


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## rickcr42

if using splitters 

 be aware that driving multiple amps will mean each amp input impedance will be in parallel with each other and can , if low enough , cause high end attenuation or preceeding stage driving problems not to mention input interaction


 switch selection or active distribution amps will eliminate this


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## Orpheus

Quote:


 be aware that driving multiple amps will mean each amp input impedance will be in parallel with each other and can , if low enough , cause high end attenuation or preceeding stage driving problems not to mention input interaction 
 

 well, i usually only turn on only one amp at a time......... and thus you don't have to worry about this right?

 but even if you leave everything on, i haven't had a problem that way either. here at my place, i sometimes have signals split more than 4 ways via patchbay!!! and everything's on at the same time... and i never had an audible problem.

 however, that's with my pro stuff. with my audiophile tube preamp, if i split a signal into the Monarchy power amp i used to have, even with it turned off the sound gets distorted. and i don't mean subtly... i mean like a distortion guitar amp! it's really weird. so, no guarantees i guess.

 but i think it's pretty safe to assume you won't hear a difference with high-end solid-state sources/pre's.


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## rickcr42

Quote:


 well, i usually only turn on only one amp at a time......... and thus you don't have to worry about this right? 
 

does not matter

 anything connected is still presenting a load regardless of whether it is on or off

 the classic case is a tape recorder connected to the record out of a preamp

 even though off , the input impedance of the deck will be in parallel with the volume control of the preamp !

 if the "off" impedance of the recorder is low enough it can totally screw up the sound (I use record out mute switches on my DIY preamps)


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## Orpheus

hmm, i wasn't sure...

 thanks for letting me know!--never knew.

 however, i still never heard any difference at all, even with signals split more than 4 times off the outputs of my mixer going into various amps and stuff. not any difference at all to my ears.

 so, i dunno... maybe your equipment is more sensitive, or your ears are compared to mine. which one you think it is? 
	

	
	
		
		

		
			





 heh he...


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## rickcr42

Quote:


 so, i dunno... maybe your equipment is more sensitive, or your ears are compared to mine. which one you think it is? heh he... 
 







 I am sorta- kinda a control freak so i have a switch for muting/routing just about everything in my system (ok,everything)

 if all input impedances are high and the driving or source impedance low enough the parallel impedance result may also be high enough to cause no problems

 where you could get into trouble is if you are using say a tube preamp with a highish (in the K range) output and the overall impedance 'seen" by the preamp (the parallel impedances-2X10=5K resulting ) falls around 10K or lower you may experience a lower drive voltage and reduced highs

 always a crap shoot man but at least worht thinking about

 impedance man strikes again


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## spaceman

Quote:


 _Originally posted by rickcr42 _
*if using splitters 




 switch selection or active distribution amps will eliminate this * 
 

When you say switch selection, do you mean some form of A/B switch? If so, what would be the best type of switching unit to utilize with two amps on one source?


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## rickcr42

don't have the exact part number in front of me but C&K silver contact DPDT center off 

 Amp 1-MUTE-Amp 2

 for more than two outrputs a good rotary switch works and for some REAL control a 1-of-6 input select rotary to a 1-of-6 output rotary-----allows only one amp to be active at a time

 OR

 six dpdt input selectors with downstream priority (series) and six dpdt output selectors (parallel) can allow IF DESIRED any combination of amps-what i use mostly but have and use both types

 if there are issues with long cables or interaction i use an active buffer or transformer isolation stage 

 according to what jacks are used (24 in all) it can be either dirt cheap or very expensive but the level of control is nice to have


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## asdfeproiu9

I'm in a similar situation - I have two sources and one amplifier that I need to connect to. I'm still 'split' between a switchbox and the RCA splitters. This is because the purist in me resents the unnecessary connections/wiring in a switchbox, but the paranoid in me thinks the vampire splitters would degrade/distort the signal significantly and audibly. Also, I'm eventually going to change the amplifier into something with two inputs so I don't want to invest in a quality switchbox.

 Grossly simplified, sound card -> DAC -> Singlepower PPX3 and a modified Sony SACD/CD/DVD receiver -> Singlepower PPX3 are the two systems.

 Any suggestions?


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## spaceman

I was always led to believe that splitters were ok for connecting two amps to one source as long as only one amp is used at a time. I am curious as well about the switch box. Won't the extra wiring, etc interfere, to some degree, with the signal quality?


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## tortie

If your a purist, switchboxes are a no-no. But on my own personal experience, I cant hear any loss in sound quality. Although im sure there is some loss with the signal passing thru extra IC's & switches. IMO its a very minor trade off for the convenience you get. Personally, I dont want to go to the back & swap ICs every time I want to listen to another source or amp.


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## Edwood

I guess I will go for splitters, then. I don't run both amps at the same time, but they are powered on at the same time. 

 Splitters seems to be the best option as I wouldn't have to hit a switch or anything. 

 Would I have to turn off one amp when using the other one?
 Or is it OK, as long as I have the volume all the way down?
 Or do I have to turn the volume all the way down and *not* have any headphones plugged in?

 -Ed


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## ooheadsoo

If you have 2 sources and 1 amp, you need a switchbox. The voltage mismatch can potentially damage one of your sources. I tried using a splitter for that scenario once and whenever my cd player was turned on, I got severe distortion and practically no volume from my soundcard.


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## Orpheus

ooheadsoo, didn't you come to my house before?--you saw all the crazy wiring i had....... i really don't think it's a problem to use splitters with modern solid-state gear. i've never had problems using them.... and A LOT of my gear is split... as i said before, my monitor feeds are even split 4 times!

 i doubt you have to worry about damaging your equipment. and your CD player failing is probably a freak occurance.


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## gerG

Hey Dean, are you splitting balanced or unbalanced signals? No underlying point, just curious.

 gerG


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## Orpheus

both...

 i try to use balanced when i can, but unfortunately the monitor feeds off the mackie are unbalanced. not sure why they did it that way. i guess they assumed the the monitors would be wired shorter than everything else. i dunno.

 but anyway, i also had the main outputs split before, which were balanced. i also had other sources around here split, and many of those were balanced too. i dunno... i kinda forgot what is connected to what, cause it's really a pain to change wiring configurations--there are zillions of wires everywhere, and the big desk is not movable.

 and the splitting is done at a patchbay. the patchbay allows for what they call "half-normalized" wiring, which is with no patch plugged in, the signal goes to the designate output (the "normal" output), but with a patch, it turns off the normal and goes to the new connection. it also allows for splitting too. pretty cool. so, i don't have to reach in back of my furniture to change anything, as long as it's connected to the patchbay. that of course is the whole point of having one.

 but anyway, yes, i split both balanced and unbalanced sources at the patchbay. NEVER had any audible problems to speak of.

 as i said, the only problem i ever had was with an esoteric tube preamp... but never with normal "modern" solid-state gear.

 but luckily, it's not hard for me to just remove the splitting and repatch instead, which is kind like a switch in a way. but i'm gonna leave all the splits in place 'till i have a problem. 
	

	
	
		
		

		
		
	


	




 Greg, it's too bad you don't play anything. i think you would love the music making process. not only do you get to make the music you love, you also get to play with 10x the gear. heh he.


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## Edwood

I'm splitting one source to two amps right now.

 So, does it matter what's on and whether a headphone is plugged into both, as per my questions above?

 -Ed


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## Scrith

I'll soon be in the same situation...one source (E-MU 1212M) and two amps (Singlepower PPX3 and some Klipsch computer speakers).

 So...should I put a splitter between my source and the Singlepower Amp so I can listen to my speakers sometimes? Or am I better off with a switch? And are both solutions going to end up compomising the sound quality?


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