# Most powerful portable amp



## Rock Drummer

Want most power for Sennheiser HD650.  Future purchase will probably be Denon D-5000,Tesla T1,LCD-2.  I have narrowed it down to Headstage Arrow,RSA 71A,Lisa 3{L3},and Stepdance.  Battery life or size, is not a factor or price. I'm looking for highest sound quality and power to drive future high impedance phones. Not interested in balanced amp.   I've read posts that said the Stepdance had to be cranked up to 3O'Clock with HD650.  Any other portable more powerful?


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## Townyj

You cant go wrong with a Meier, great price and free delivery!  Jan is a great guy to deal with! I would probably pass on the Arrow as delivery/build times are insane unless you buy second hand. Havent had much to do with RSA or Lisa Amps.


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## ZARIM

Ibasso PB2, Lisa, E9, XM5 with BUF 634 634)))) and Stepdance.


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## GreenLeo

If size and battery life is not a factor and only SQ is important, I'd recommend Lisa.


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## Rock Drummer

Thanks for the replies so far but no one has mentioned The RSA SR71A -How does it compare with Stepdance?  Is Lisa3 available yet?


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## estreeter

The Lisa 3 has been available for several years - you just order one and wait in the queue. I suspect that you are referring to the 'L3', and I believe that is also available on the same basis.


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## GreenLeo

I haven't heard the SR71A.  My friend has heard the SR71, SR71A and Lisa and he thinks that SR71A is not in the same league as the other two.  It's unlikely that you can buy SR71 though and SR71 is another brick (I know you don't mind).
   
  Hope this helps.


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## wolfen68

The SR71 and SR71a are among the most powerful single ended portable amps ever made.  They have 18v available with their dual 9v batteries and they both sound great.  I trialed an HD650 from the SR71 and it did OK.  I spent more time with those amps with a K701 and they were very good for a transportable rig.


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## Vault101

Pb2, sr71b, stepdance.


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## jamato8

Quote: 





greenleo said:


> If size and battery life is not a factor and only SQ is important, I'd recommend Lisa.


 
  So you have compared all of those amps mentioned and the Lisa came out on top? How was it better than the others?


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## Uri Cohen

For some of those amps which ones are really portable that I can carry around with it while listening to music on my Minidisc?  I need something great that can match the RS-1is when I do my walks with them on.


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## KingStyles

i have only tried the lisa 3 when it comes to portable amps. I will say though it outperforms a lot of the small desktop amps and it powered my denons perfectly which most tube amps and small ss amps cant do.


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## estreeter

Is it just me, or are we back to the _elephant in the room_ here ? OK, I'm forced to use a large font with this:
   
*CAN SOMEONE PLEASE BUY THE PB2, THE SR71B, THE LISA (or L3) AND GIVE US A DETAILED COMPARISON OF THE 3 AMPS*
   
  We really don't care that your wallet will hate you - just take one for the team and win the undying admiration of your Head-Fi peers.  We already have Skylab's comparison of the L3/SR71B/Stepdance, and we know why iBasso's latest offerings werent included in his later reviews - we really cant ask any more of Rob, so clearly its time for someone else to step up to the sacrificial altar, er, plate. Even if it means going without food for a week or two, I really think the gear cred must be worth it 
   
  (For those thinking 'You first, estreeter ! You must think we are made of money !', ask yourself if this is *not* the aforementioned elephant in the room)


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## Rock Drummer

King Styles -Which Denons?  I can't decide D-5000 or D-7000.  I've read in some posts that the D-5000 out performs the 7000.


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## Croozer

The ibasso D6 looks to be a little powerhouse.


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## Jalo

D6 to PB2 is like 650mw to 2500 mw.


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## estreeter

Quote: 





jalo said:


> D6 to PB2 is like 650mw to 2500 mw.


 

 Agreed, but is that such a good deal for those of us restricted to SE sources and phones ? I dont need an integrated DAC, but I can understand why many would opt for the D6.
   
  Edit: sorry, you were referring to the previous 'powerhouse' post - agree that its a big difference in the numbers.


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## Canadian411

I've asked Ray Samuels regarding most powerful portable amp and he replied with Emmeline SR-71B.
   
  I have Beyerdynamic DT990 600ohm, I did not purchase any portable amp yet but I am considering. (no importance in order).
   
  1. iBasso PB2
  2. Ray Samuels Emmeline SR-71B (The Blackbird)
   
  Only thing that hesitating me to decide which one to due to no specs ! for example, output impedance.
   
  I might just ended up buying Woo 3 tube amp until someone or some company reveals the full spec.
   
  To be continue..


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## Jalo

FYI from PB2 manual:
   
   
  Specifications: 
  Power Source：Builtin 12.6V LiPolymer Battery Pack, or 
  16V External Power Supply 
  Frequency Response: 10Hz~150 KHz 0.5dB 
  Signal to Noise Ratio：115dB      
  Output power：Up to 2500mW+2500mW into 32Ω   
  Gain:  +6dB/ +12dB/ +20dB (Balanced Output) 
   0/ +6dB/ + 10dB (Single End Output) 
  Battery Life: >20 Hours  
  Battery Charge Time: 4 Hours 
  Recommended Headphone Impedance: 8~600I 
  Case dimension: 2.2W x 3.9L x 0.95H (inch) 
                55W x 1001L x 24H (mm) 
  Weight: 168g or 5.9oz


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## Canadian411

Oh great ! thanks Jalo.
   
  Do you know if SR-71B is recommended for 600 ohm cans ?


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## Jalo

I don't know specifically with regard to 600ohm cans, but it is known that it can drive the most difficulty cans like the ortho HE-6.  The HD 600/650 series are also known to be hard to drive and 71B can drive them very easily.  If you send your question to Ray, he is a very responsive guy and will definitely answer your question.  But the following is on his website.
   
  From RSA Website:
   
  There is no headphone ever made that SR-71B can’t drive with great authority & control. It will stand toe to toe with best balanced home amps out there. It can swing in balanced mode more than 26V p-p. SR-71B uses, custom designed for RSA, four Lithium Ion battery pack that when fully charged you have 16.8 volts DC. SR-71B can swing more than 12-14 volts p-p in single ended, making it excellent performer to drive HD 600/650.
   
  Personally, I am using a SR71B now and planning to but the PB2 also.  Good luck.


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## Skylab

The SR71B had no trouble driving the 600 ohm T1 very well.


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## Rock Drummer

Skylab I've been following your thread and your conclusion is that the Lisa L3 is your new reference portable amp supplanting the Stepdance but I don't think you explained which of the two is more powerful for hard to drive phones.  Your reply would really be appreciated since I am ready to purchase one of the two.  Also does the Lisa have better battery life than the Stepdance?


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## Golden Monkey

Two points regarding the Arrow:
  1) Robert's all caught up on back orders and getting ahead on builds, so wait time is less than two weeks now.
  2) Regarding power output...not sure exactly what this means, but "With an operation voltage of up to 12V and the best rail-to-rail operational amplifiers (AD 8397) the Arrow is able to drive any headphones <600 ohms with authority. ...The "Arrow" is the only headphone amp to use an automatic power adaptation. The battery voltage of 4V is boosted to a voltage just as high as needed--with a maximum voltage of 12V. ".
   
  And yes, I'm actually suprised at how well it drives HD650's.  Sounds better than my old LD MKV, and that wasn't portable.
   
  Not shilling them or anything, but after doing all my research it's the amp I went with.  It was the only amp that met all of my requirements (size/form factor, crossfeed, adjustible gain/impedance/bass boost, battery life, specific op-amp I was looking for, and price range).  under consideration were the Arrow, RSA P-51 Mustang, Meier Stepdance, and TTVJ Slim.
   
  NOTE:  Some folks have issues with Robert's past business practices, so I urge anyone to do some research before buying.  A lot of people are unaware of this, but a lot of them ARE and refuse to review Headstage amps. You're not going to find an unbiased review anywhere on Head-Fi that reviews all of the amps mentioned thus far (especially a Meier and Headstage).  For example, many Arrow reviewers have never tried a Stepdance, and likewise you won't find an Arrow review in any mega-review thread, but that doesn't mean either are "bad" amps or unworthy of consideration.  This isn't meant to be a condemnation of any amp, company, review, or anything like that, just a "disclosure statement", lol.


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## Canadian411

Quote: 





> The SR71B had no trouble driving the 600 ohm T1 very well.


 
   
  So I am still deciding in between, help me 
   
  Emmeline SR71-B or iBasso PB2.
   
  Do you actually have SR71B ? with 600 ohm headphones ? how's the sound ?
   
  Thanks in advance.


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## Skylab

Quote: 





rock drummer said:


> Skylab I've been following your thread and your conclusion is that the Lisa L3 is your new reference portable amp subplanting the Stepdance but I don't think you explained which of the two is more powerful for hard to drive phones.  Your reply would really be appreciated since I am ready to purchase one of the two.  Also does the Lisa have better battery life than the Stepdance?


 


  Again, that's not really an accurate summation you made.  Nowhere did I say the L3 is "my new reference", or is "supplanting the Stepdance",  The L3 does sound marginally better than the Stepdance in several ways, but for me, the size of the L3 is a dealbreaker for portable use, and so I am personally sticking with the Stepdance for my own use.  The L3 had better battery life than the Stepdance, yes.  I did not do a full drain cycle test so please don't ask me exactly how long each lasts.  And it's important to point out that the L3 is much bigger and heavier than the Stepdance.  Both of them were able to drive the T1 and the LCD-2 very well for Portables.


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## estreeter

Quote: 





skylab said:


> Nowhere did I say the L3 is "my new reference", or is "supplanting the Stepdance",


 

 I also found Rock Drummer's post a bit of a leap from what you had written, especially since you had made it clear that you were using the Stepdance but spending more of your time with your fullsize amps - thanks for the clarification, Rob.


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## zilch0md

Bumping this thread, I'd like to address the subject of how portable amps, when running on internal batteries, _*do not*_ enjoy a constant output power.
   
  First, let's have a look at the swing voltage specs for both the iBasso PB2 and the RSA SR-71B:
   
  Quoting iBasso's current web page for the PB2:


> 32V voltage swing, the highest voltage swing among portable Amplifiers


 
   
  Please note that iBasso is saying a 32V p-p swing is available with balanced output.  It's understood that if 32V is possible with balanced output, you would only enjoy a 16V p-p swing with single-ended output.
   
   Quoting RSA's current web page for the SR-71B:
   


> Making this portable balanced amp the most powerful Amp ever designed.
> 
> [snip]
> 
> ...


 
   
  Note that RSA is saying the SR-71B's voltage swing for single-ended output would be half (more than 13V) of balanced output (more than 26V).
   
  Going only on the voltage swing specs I've quoted, above, one might conclude that the PB2, with a voltage swing of "32V," is the clear winner vs. the SR-71B's "more than 26V."
   
  But consider this:  *The PB2's "32V" swing in balanced mode can only be enjoyed when the amp is connected to an external power source (either from an AC adapter or an external battery), that's supplying the maximum permissible 16 Volts DC.*  *The AC adapter that ships with the iBasso PB2 can supply 16VDC, but the PB2's internal, 3-cell Lithium-ion battery pack cannot.  *
   
  Lithium-ion cells have a nominal rating of 3.7V each, but they range between 3.0V, when fully discharged, to 4.2V when fully charged.  Thus, the PB2's internal Lithium-ion pack can deliver only 12.6 Volts when fully charged - that's 3 cells x 4.2 Volts per cell.
   
   Quoting iBasso's current PDF manual for the PB2:
   


> Power Source:  Built-in 12.6V Li-Polymer Battery Pack, or 16V External Power Supply


 
   
  If anyone can correct me, please do, but unless iBasso is using some sort of DC-DC converter to pump up the voltage from the internal battery (unlikely), this means that it's impossible for the PB2 to achieve a swing voltage of 32V during portable operation with the internal battery. (Note that the OP of this thread included the word "portable" in the title of his post.)  The only exception would be to carry an external battery pack during portable operation, that's capable of supplying the PB2 with the maximum permissible 16VDC.  
   
  But if you are relying only on the PB2's internal battery for portable operation, as the internal battery is used, the supply voltage that begins at 12.6V when fully charged, can fall as low as 9.0V (3.0 Volts x 3 cells), when it will be necessary to recharge the battery.  
   
*Thus, during portable operation with the internal battery, the PB2's swing voltage for balanced output will range from a maximum of 25.2V (when fully charged) all the way down to 18.0V, when the battery is depleted.  For single-ended use, the swing voltage will fall from 12.6V to 9.0V (fully charged internal battery vs. fully discharged).*
   
  So what does the SR-71B offer in terms of portable supply voltage?
   
   Quoting RSA's current web page for the SR-71B:
   


> SR-71B uses, custom designed for RSA, four [a four-cell] Lithium Ion battery pack that when fully charged you have 16.8 volts DC.


 
   
  When fully charged, a Lithium-ion cell yields 4.2 Volts.  Thus, a four-cell Lithium-ion pack will yield 16.8 Volts DC (4.2 Volts x 4 cells).
   
  This suggests that the SR-71B can enjoy a balanced mode swing voltage no greater than 33.6 Volts p-p, during portable operation on the fully-charged internal battery pack. Per my earlier quote, RSA only claims "more than 26V p-p" in balanced mode."     
   
  Given that the SR-71B's four-cell battery pack starts out at 16.8V when fully charged, vs. the iBasso's three-cell battery pack starting out at 12.6V, it looks to me as if RSA is being far more conservative than iBasso in claiming the SR-71B "can swing in balanced mode more than 26V p-p" vs. iBasso claiming the PB2 has "32V voltage swing."
   
  It's easier to see the ratios if you compare supply voltage to swing voltage p-p for single-ended output:
   
*SR-71B supply voltage (fully charged internal battery): 16.8V*
*SR-71B claimed single-ended swing voltage p-p:           13.0V   (This is credible, in my opinion, even when using the internal, 4-cell battery.)*
   
*PB2 supply voltage (fully charged internal battery):      12.6V*
*PB2 claimed single-ended swing voltage p-p:                16.0V   (This is incredible, in my opinion, except when using an external 16V supply.) *
   
  A single-ended swing voltage of 16.0V might be possible with a 16.0V external supply, but not with the 12.6V internal battery.
   
  So, which amp is more powerful?  It certainly varies with how you are powering the amp, but if you're talking about pure portable use, relying only on the internal Lithium-ion battery pack, I'd say the SR-71B wins, hands down, just for having a 16.8V, four-cell battery, vs. the PB2's 12.6V, three-cell battery.
   
  In conclusion, let me acknowledge that there are many factors one should consider in addition to an amp's power output, before making a purchase decision.  I also want to disclose that I very recently purchased an iBasso PB2, Toxic Cables' Silver Poison (balanced and terminated for LCD-2), and HiFlight's TopKit collection of opamps and buffers for the PB2.  (I'm still waiting for the cables.)  
   
  For portable operation, I intend to power the iBasso PB2, exclusively, with an Energizer XP8000 external lithium-ion battery pack in combination with an XPAL Willy WI15 inline voltage regulator cable.  I have no intention of using the PB2's (under-powered) internal battery for portable operation - not when the amp is capable of much better performance with a higher supply voltage.
   
   

   
  I've already tested this with the iBasso PB2 - it works fine, supplying a *constant*, regulated 15.11 VDC to the PB2, in portable operation.  Theoretically, this could yield swing voltages in balanced mode as high as 30.22 V p-p. (15.11V x 2 = 30.22V).  
   
*Don't miss the point that if you are using the internal battery of either the PB2 or the SR-71B, your swing voltages will decay as the battery pack goes from fully charged to fully discharged.*  Not so with the XP8000 + Willy WI15 inline voltage regulator cable.  The WI15 is fed a supply voltage from the XP8000 that starts out at 21.0V when the 5-cell pack is fully charged (4.2V x 5 cells = 21.0V), then decays to 15.0V, when the XP8000 is fully discharged (3.0V x 5 cells = 15V).  Throughout the entire discharge cycle, the WI15 delivers a *constant* 15 Volts (for a *constant* balanced-mode swing voltage of up to 30 Volts (vs. a decaying balanced mode swing voltage that ranges from 25.2V, when the internal battery is fully charged, to only 18.0V when depleted.)  The internal battery may offer convenience, but it kills performance.
   
  I'm now working on finding an external battery solution that can deliver the maximum permissible 16VDC to the PB2.
   
*Update:*  I've just discovered that XPAL makes a 16-Volt version of the 15-Volt voltage regulator cable that I had previously used with my Stepdance!  
   
  It's called the XPAL Willy Cable WI16  instead of WI15 (doh!)
   
  This will give me a constant, regulated 16VDC supply for portable operation of the PB2 with the XP8000.  And if the specs are true, I'll enjoy a constant 32V swing with balanced output, while portable.   Pulling the trigger, now!  
   
  Done!   And I found a better picture of it (then added comments):
   

   
  Joy!
   
  Mike


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## justin w.

Hi,
   
  In your analysis, you didn't take into account that amps of those voltages probably are using op-amps that do not swing rail-to-rail.  That's probably going to knock off several volts from the max power supply voltage.


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## DNZGamer

Just to chime in on the Arrow. The newest model of the Arrow 4G can drive HD650s easily into minispeaker volumes without any increase in gain settings. I can't compare the other amps.
   
  Since portability and price aren't a factor, it seems like the L3 is for you. I am assuming when you say portable, you mean transportable. 
   
  I've only tried the RSA Hornet with Grado headphones and I honestly felt that my Arrows were much better, mostly because of how well done the hardware EQ switches are on it. Other sonic differences on neutral settings were hard to perceive to my ears that I may as well have been making up the differences in my mind.


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## zilch0md

justin w. said:


> Hi,
> 
> In your analysis, you didn't take into account that amps of those voltages probably are using op-amps that do not swing rail-to-rail. That's probably going to knock off several volts from the max power supply voltage.




I hear you. That might explain why RSA (more conservatively?) claims a swing of 12 to 14V single-ended with the SR-71B (even though its 4-cell internal battery delivers up to 16.8V when fully charged). 

I really have no idea what inefficiencies are involved and I agree that we can't assume that single-ended swing will always equal the supply voltage, nor balanced swing twice the supply voltage, but there is at least a proportional relationship between the two, up to some finite limit set by the opamps in use as you've said, or some other limiting design factor. 

Still, with iBasso claiming a swing of 32V for balanced output, it seems certain they couldn't claim a higher figure with a maximum supply voltage of 16V. And there's no way the PB2 enjoys a swing of 32V balanced when using the fully charged three-cell 12.6V internal battery (where, at best, swing in balanced mode would be 25.2V, falling to 18.0V as the battery discharges.

What I take from all of this is that your supply voltage can make a BIG difference. There are several respected posters in the PB2 threads who have said PB2 performance is at its best when used with the 16V AC adapter. That's all I need to know to want a portable (transportable) 16V supply for the PB2 (i.e. XP8000 + WI16 regulator).

I've already reaped the benefits of this approach by powering the Meier Stepdance with its maximum permissible 15V supply voltage yielding much improved dynamics and bass control vs. using an internal 9V battery. A bunch of people have joined the 15V Stepdance cult. 

Convenience be gone - I want performance.


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## justin w.

i agree that voltage output is usually the limiting factor in performance of a portable amp, and it's rarely even an advertised spec.


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## zilch0md

Hi DNZGamer,

Actually, price is an issue for me! 

I went 18 months depriving myself of any upgrades before springing for the PB2 and balanced Silver Poisons, recently. The L3 and SR-71B were out of the question, for me. 

I'm not familiar with the Arrow offerings - Now I'm afraid of what I'll learn when I read up on them. 

Mike


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## Lorspeaker

O2................heard it for a few hours..., giant killer of a tiny amp...dunno much about it or how u are gonna get it...
  but from what i heard, i think its worth exploring.


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## DNZGamer

zilch0md said:


> Hi DNZGamer,
> Actually, price is an issue for me!
> I went 18 months depriving myself of any upgrades before springing for the PB2 and balanced Silver Poisons, recently. The L3 and SR-71B were out of the question, for me.
> I'm not familiar with the Arrow offerings - Now I'm afraid of what I'll learn when I read up on them.
> Mike


 
   
   
  Ah, well then the Arrow 4G is priced a bit under the RSA amps at $300 flat with shipping and tax included. I honestly did not find the flagship portable RSA amp all that impressive, especially for its size. 
   
  Not sure about what your budget is now but for $300, there is very little that could possibly trump the Headstage Arrow (this is my impression from reading a lot of reviews and comparisons before purchasing it myself). Depending on your cans, you may also really appreciate bass boost or treble boost or both. It is done extremely naturally and does not create distortion like other amps.
   
  Some of the most attractive features may be a bit irrelevant to you though. The 4G model can power a can like the HD650 for 30 hours or more and IEMs will go for up to 80 hours. It can charge and play at the same time so you can use it as your setup station. It automatically powers on and off according the the presence or absence of an input signal. The amp is really small and light, which I know you said wasn't a concern, but why have something bigger than it needs to be? I have no idea what RSA amps are packing in those boxes but the headstage offers just as much in a smaller form factor. 
   
  It has inputs on both ends of the device so when moving, you can plug them into the same side or when stationary, you can have the input coming from the opposite side of your output devices. The device itself also can power two channels at a time and can power two low impedance cans without even the slightest degradation. 
   
  Pretty much a neutral amp and will be passing your signal through with clarity, more power and body. Do not even concern yourself with it power wise. It will handle an HD650 easily and I even powered an HD800 to deafening volumes with the zero gain setting. Great amp to pass through a neutral signal and enhance the sound stage while adding power and body to your sound and has 3 settings for bass and treble if you want some more energy, some more body to the mid range or just want to enhance and pronounce a thumpin' beat. 
   
  Value wise, an amazing amp imo but I am sure there are plenty of people who will chime in with their own experiences. I've only used a few amps myself (Fiio e6, Fiio E11, Ray Samuels Hornet, RA-1 and the Headstage Arrow). Also there are people probably with much better trained ears who will probably tell you the differences between amps better than me.


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## zilch0md

Hey Justin,

It just occurred to me to ask you something that's a bit off topic but I'm dying to know: What benefit do buffers serve in an amp like the PB2? 

I'm asking because in his review of the PB2, Mike (Headphonia) wrote that replacing the PB2's buffers with the iBasso-supplied dummy buffers can actually improve SQ with some op-amps.

Thanks!

Mike

-----------------------------------------------------------------------------------------------------------------------------------------------

Update - an answer to my own question: (I know more than I did two months ago!) 

The buffer stage of a PB2 can be thought of as the current gain stage, where the L/R stage is the voltage gain stage. The "power" seen by the headphones is a product of both current gain and voltage gain. You can get to any particular number of Watts RMS per channel using a combination of low current and high voltage or by using a combination with low voltage and high current, but "power-hungry" planar headphones, like the HCE-6 or LCD-2 are current-hungry, not voltage-hungry, where "power-hungry" dynamic headphones, like the HD650, don't care so much whether the power comes from current gain vs. voltage gain. 

Thus, even though iBasso provides dummy buffers for use with the PB2, and even though you'll hear slightly greater detail and transparency when running the PB2 with dummy buffers, you'll be forfeiting a lot of current gain that could be had using something other than dummy buffers, but especially so with the likes of HA5002 buffers (each providing 200mA of output current) - available from Head-Fi member HiFlight, in his Topkit for PB2. 

More info regarding the PB2's "2500 mW" specification: The only way you're going to get anywhere near this is to supply the amp with 16V external power - either with the included AC adapter, an equivalent power supply, or with an external 16V battery pack, like the Energizer XP8000 with Willy Cable WI16 (a 16V inline voltage regulator cable that reduces the voltage from the XP8000's 19-21V output jack to a constant, regulated 16V.) The PB2's internal 12.6V battery (which drops to lower voltages during use) cannot drive any of the available op-amps/buffers at their rated maximum possible output voltages or currents. 

Currently, I'm using the PB2 with LT1678 op-amps, biased to Class A, and HA5002 buffers - all available with HiFlight's TopKit for PB2 - running balanced with Toxic Cables' Silver Poison to LCD-2 rev.1 - all of it powered by the XP8000 with WI16 cable. Amazing sound from a portable amp!





Mike


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## DNZGamer

Quote: 





lorspeaker said:


> O2................heard it for a few hours..., giant killer of a tiny amp...dunno much about it or how u are gonna get it...
> but from what i heard, i think its worth exploring.


 
   
  I just had a fellow head-fier tell me to build an amp a few weeks ago. Was tempting but the idea of building my own is still kind of intimidating.


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## zilch0md

lorspeaker said:


> O2................heard it for a few hours..., giant killer of a tiny amp...dunno much about it or how u are gonna get it...
> but from what i heard, i think its worth exploring.




Here it is, preassembled and ready for use: 

www.jdslabs.com/item.php?fetchitem=O2Full


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## zilch0md

Thanks DNZGamer! You've really whetted my appetite. I'll be searching for more reviews now.


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## proton007

Sorry to spoil the party guys, but there's no such thing as a 'more powerful' amp for a headphone. 
  A headphone will take whatever power it needs as long as the amp can supply it. Even if the amp is capable of 10x more, or 2x more, it doesn't make any difference.


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## DNZGamer

No problem. Just keep in mind the differences between each version. Apparently the 4Gs are a bit better amp wise compared to older models but I think the real difference will be the change in the EQ settings and battery life. Older models seem to have half the battery life of the 4G. 3G bass boost is I think 9dB and 9+9dB (huge bass boost!) where the 4G is 3dB and 9dB. The 3G also does not have a treble boost at all, which imo is a great feature, especially for a lot of the vocals. I almost have it permanently on when using the UM3x which is a bit treble light compared to how I like it. Some people just want bass though and if you are a bass head and want 18 dBs of bass boost then go with the older models.
  Quote: 





zilch0md said:


> Thanks DNZGamer! You've really whetted my appetite. I'll be searching for more reviews now.


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## justin w.

Quote: 





proton007 said:


> Sorry to spoil the party guys, but there's no such thing as a 'more powerful' amp for a headphone.
> A headphone will take whatever power it needs as long as the amp can supply it. Even if the amp is capable of 10x more, or 2x more, it doesn't make any difference.


 
   
  Most of these amps will start to have gobs of distortion if you get anywhere near their 'max power'


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## DNZGamer

Well that is because you are destroying your ears if you approach anything close to max volume on these amps... 50% volume, gain 1 on a headstage arrow for HD650 is enough.


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## zilch0md

proton007 said:


> Sorry to spoil the party guys, but there's no such thing as a 'more powerful' amp for a headphone.
> A headphone will take whatever power it needs as long as the amp can supply it. Even if the amp is capable of 10x more, or 2x more, it doesn't make any difference.




I get your point - a 100 Watt light bulb only pulls 100 Watts whether the circuit can support 1000 Watts or 10,000 Watts, but you made a conditional statement: "...as long as the amp can supply it." 

If a given amp cannot supply the power a given headphone demands, you'll need a "more powerful" amp. My iBasso PB2 is "more powerful" than the amp in my Sanza Clip when driving my LCD-2, but perhaps not when driving the earbuds that came with the Clip. Thus, there is such a thing as a "more powerful" amp for a headphone that demands more than what a "less powerful" amp can provide.

Party on! 



Mike


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## proton007

Quote: 





zilch0md said:


> I get your point - a 100 Watt light bulb only pulls 100 Watts whether the circuit can support 1000 Watts or 10,000 Watts, but you made a conditional statement: "...as long as the amp can supply it."
> If a given amp cannot supply the power a given headphone demands, you'll need a "more powerful" amp. My iBasso PB2 is "more powerful" than the amp in my Sanza Clip when driving my LCD-2, but perhaps not when driving the earbuds that came with the Clip. Thus, there is such a thing as a "more powerful" amp for a headphone that demands more than what a "less powerful" amp can provide.
> Party on!
> 
> Mike


 
   
  99% of the portable amps out there can easily work with headphones upto 600 Ohms. Plenty of power, no need to worry. If you have any doubts as to how much power you need, and you're not afraid of doing the calculations yourself, you can take a look at the thread link below. I've tried to consolidate these concepts.
  Take note that I said *amps* not portable media players. There's a reason pmp's use low impedance earphones.


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## liamstrain

ALO Continental claims 20 V P-P.


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## kellj

how about Larooco PRII ?


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## zilch0md

I've updated my earlier post in this thread - with information regarding the iBasso PB2's somewhat mythical 2500mw specification.
   
  http://www.head-fi.org/t/535497/most-powerful-portable-amp/30#post_8346448
   
  Mike


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## Chik0240

Dear all,
     I am currently running the ibasso pb2 with an onkyo se300 soundcard headphone out jack which provides internal amplification already, while using max output from the soundcard connecting to the PB2 (in stock buffer and opamp setting) using 3.5mm jack and then connecting the PB2 to hd650 using 3.5mm cables, the volume is loud enough with the volume dial on eleven o'clock position (~30-40% estimated), will using the included buffers to achieve the 2500mW power output help the sound quality? if not, will using dummy buffers to gain more details be better? 
   
  thanks


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## zilch0md

Hi Chik,
   
  Prior to spending any money on different op-amps for your PB2, I vigorously recommend that you get yourself a good USB DAC.  You will be amazed at how much better everything sounds when you bypass the sound card.  Using player software such as Foobar 2000 in combination with the WASAPI plugin can also bypass the operating system's handling of your sound - for a more direct path to the USB DAC.
   
  You are currently double-amping - simply amplifying the sound quality (or lack of sound quality) produced by your sound card.  Giving yourself more headroom by increasing the PB2's current or voltage will not fix what's wrong with your current setup.
   
  I know that the cost of a few op-amps might be more appealing than saving for a USB DAC, but  again, in my opinion, a DAC should be first on your shopping list.  
   
  The Stoner Acoustics UD100 costs about $60.00 with shipping.  It's got the same ESS9023 DAC chip found in the $280 Audioquest Dragonfly, with some major differences - the UD100 DAC does not include an analog volume control, but that's OK, since you would be using your PB2, rather than plugging headphones directly into the DAC, and the UD100's USB receiver chip can only handle redbook audio (44.1 kHz / 16-bit), where the Dragonfly's USB receiver chip can handle hi-rez files (i.e. 96/24).
   
  If you don't have any hi-rez files, the UD100 is a pretty good deal as your first USB DAC.   
   
  An equally affordable ESS9023 DAC that actually offers 96/24 capability is the HiFimeDIY Sabre USB DAC.
   
  These 9023 DACs will sound a little thin and lack warmth compared to some more expensive DACs (like the DACport LX), but they deliver plenty of detail, and you can "warm" them up with your PB2, by experimenting with op-amps, later.
   
  I hope I haven't been too forward in telling you how to spend your money, but feel free to solicit other opinions and enjoy the journey!


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## Chik0240

hi zilch,
     thanks for your advice! I will definitely go for a try for a usb dac! And in the meantime actually I rather enjoy the onkyo sound card's signature (when paired with the lower power requirement IEM like the UE900 with an 100Ohm adapter), just that I read here about the hd650 will need an good amp for the sound quality and the voltage swing/output current, so merely being curious will getting a higher current or to increase the voltage swing using the balanced cable will make it more lively  
   
  thanks so much
   
  Regards
  Chik


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## jamato8

Running the 650HD in balanced is the only way, IMO, to bring them to life. The PB2 or the Intruder will do that and the Intruder has a built in dac to take the signal from your USB source.


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## HKUSP

jamato8: How do you compare the HE-500 paired balance to the RSA SR-71B compared to the HE-500 paired to the Lyr?
   
  I just got my balanced Sunset cable and it made a huge difference going SE to balanced with the SR-71B. I don't know what the power specs are for the SR-71B, but I do remember reading that to get the full power of this amp, you need to run it balanced. My ears wholeheartedly agree, even if my brain can't confirm the numbers.


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## jamato8

Quote: 





hkusp said:


> jamato8: How do you compare the HE-500 paired balance to the RSA SR-71B compared to the HE-500 paired to the Lyr?
> 
> I just got my balanced Sunset cable and it made a huge difference going SE to balanced with the SR-71B. I don't know what the power specs are for the SR-71B, but I do remember reading that to get the full power of this amp, you need to run it balanced. My ears wholeheartedly agree, even if my brain can't confirm the numbers.


 

 They are different sounding but frankly, the 71b or the Intruder does so well with the HE500, I don't fire the Lyr up very often. Either balanced portable are like having a home amp.


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## HKUSP

Thanks for that feedback. I'm happy to know I can drain my wallet elsewhere...and I just did!


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## audiojun

Lifepo DAC & Quality Car amp + Car Battery + HE-6 = Sonic Bliss


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## HKUSP

Quote: 





audiojun said:


> Lifepo DAC & Quality Car amp + Car Battery + HE-6 = Sonic Bliss


 
  LOL, I can just see people's faces as I lug around a car battery in my "portable" setup! I have heard others saying good things about the Lifepo DAC, so that may be of interest. Thanks.


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## audiojun

someone asked for a powerful portable set up can 't go wrong with car amp lol. car amps generally outperform stand alone amps simply because of clean dc battery power and no need for ac dc transformer.


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## johnlittle879

For a high power amp thats reasonable try the Fiio E12 Mont Blanc , and its actually portable


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## Mooses9

for iem's most powerful amp ive used is the RSA SR71-B (intruder spec upgrade) However my fav amp that i feel is more than powerful any iem is the ibasso p4 warbler 600mw+600mw into 32 ohms IMO its stupid powerful, i get more than enough voume at 8-9 o clock if i want to be deaf 11 o clock is more than loud, of course i am running it on + gain for opamp stability benifits ect. but imo for just a amp the p4 is stupid powerful.....


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## zilch0md

Here's my "transportable" implementation of the *TBI Audio Millennia MG3*, which (on a 24V DC battery) can deliver 5.1 Watts rms into the 50-Ohm LCD-2...

http://www.head-fi.org/t/633511/pictures-of-your-portable-rig-part-xvi/7060_20#post_9857369



Mike


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