[Jalo]

D6 to PB2 is like 650mw to 2500 mw.

 

[estreeter]

Quote:

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.

 

[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..

 

[Jalo]

 
 
FYI from PB2 manual:
 
 
Specifications: 
Power Source：Builtin 12.6V LiPolymer 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  

 

[Canadian411]

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

 

[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.

 

[Skylab]

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

 

[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?

 

[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.

 

[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.

 

[Skylab]

Quote:

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.

 

[estreeter]

Quote:

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.

 

[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]
 
It can swing in balanced mode more than 26V p-p.
 
[snip]
 
SR-71B can swing more than 12-14 volts p-p in single ended.

 
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
 
 

 

[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.

 

[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.