Transportable/battery-driven high-end amplifiers

[ValentinHogea]

After meticulous searches I don't seem to find a specific thread for this subject...
 
Background:
 

1. Most can agree that battery-powered electronics removes a lot of problems related PSU's in amplifiers.
2. Some of us still want to be able to move our rig. I know the majority doesn't... But some. [E.g. Audez'e demoed the closed back-prototype with a CLAS+Rx MkIII]
3. The power/sound in most mid-fi amplifiers isn't sufficient for a >1000$-headphone.

 
So... My wish is that we can join all the knowledge available regarding these amps (if there are any).
 

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Mid-price [400-1000 USD] amps not included; See the "Portable headphone amps" section of Head-Fi:

1. ALO Audio Rx Mk3-B - Price: 649 USD (US); Single-ended/Balanced
2. ALO Audio The Continental v2 - Price: 529 USD (US); Single-ended
3. ALO Audio The Pan-Am w/ Passport-battery-pack - Price: 699 USD (US); Single-ended
4. GoVibe Porta Tube/(+) - Price: 650/750 (+) USD (US); Single-ended

1. RSA SR-71A - Price: 450 USD (US); Single-ended
2. RSA SR-71B - Price: 650 USD (US); Single-ended/Balanced
3. RSA The Intruder - Price 700 USD (US); Single-ended/Balanced
4. Triad Audio L3 - Price: 800 USD (US); Single-ended
5. Vorzüge VorzAMP Pure/Duo - Price 430/520 USD (EU); Single-ended

 

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Red Wine Audio (RWA) Audez'e Edition
 
In short:
Balanced, Tube-DAC + Headphone amp (4-pin XLR), RCA Pre-out, 4 kg/9 lbs
 
Price:
4000 USD (US) w/o headphones directly from RWA.
4900 USD to 6225 USD (US) with LCD-2 or LCD-3 + ALO Audio-cable + custom carrying case from ALO Audio/Audez'e.
 
Details:
Red Wine Audio - Audez'e Edition - Official product webpage
 
More info and/or reviews:
InnerFidelity review
Head-Fi Skylab's review
Head-Fi Audez'e Edition System - Owner's Thread and Impressions
 
Pics:



 
Pics borrowed from RWA official site; permission obtained to use them in this thread
 

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Red Wine Audio (RWA) Corvinia
 
In short:
Headphone amp (1/4" TRS or 4-pin XLR), 2xRCA inputs, 2,7 kg/6 lbs
 
Price:
1000/1500 USD (US) Single-ended/Balanced (+100 USD, optional 12Vdc output jack)
 
Details:
Red Wine Audio - Corvinia - Official product webpage
 
More info and/or reviews:
CNET/Steve Guttenberg review
 
 
Pics:
 


 
Pics borrowed from RWA official site; permission obtained to use them in this thread
 

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Red Wine Audio (RWA) Isabellina HPA LFP-V Edition
 
In short:
Headphone amp (1/4" TRS or 4-pin XLR) + DAC, RCA Pre-out, 3,5 kg/8 lbs
 
Price:
2500 USD/3000 USD (US) Single-ended/Balanced (+500 USD Isabellina Pro DAC; +100 USD, optional 12Vdc output jack)
 
Details:
Red Wine Audio - Isabellina HPA LFP-V - Official product webpage
 
More info and/or reviews:
CNET/Steve Guttenberg review
SoundStage review (older non-LFP-V-version)
Head-Fi Skylab's review
Head-Fi librarian's review
Head-Fi Toob-Toob's review
 
Pics:


 
Pics borrowed from RWA official site; permission obtained to use them in this thread
 

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M2TECH Vaughan
 
In short:
32bit/384kHz DAC-section, Pre-amp, Headphone amp (1/4" TRS), 10 kg/22 lbs
 
Price:
7999 USD (US)
5995 EUR (EU)
 
Details:
M2TECH - Vaughan - Official product webpage
M2TECH - Vaughan - User manual
 
More info and/or reviews:
Head-Fi rudi0504's review
Dé Durob Audio blog mini-review
 
Pics:


 
Pics borrowed from De Durob Audio Blog
 

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[librarian]

I know only of Red Wine Audio...My own review of Isabellina HPA LFP-V Edition is here:
 
http://www.head-fi.org/t/634885/isabellina-hpa-lfp-v-edition-review-and-listening-impressions

 

[obobskivich]

The Koss E/90 (it comes with the ESP/950 headphones, and in theory can drive STAX headphones with an adapter (from the Koss d-sub to the STAX tube plug)) can run on a battery pack (I forget if it's C or D cell batteries). There's also a STAX amplifier that can do the same, SRD-7Pro or something like that (it's old, you'd have to find it used). AFAIK there is no way to get the E/90 separate from Koss though - you gotta buy the whole set, and the ESP/950 headphones themselves aren't exactly portable (fully open and all).

As far as driving dynamic headphones - I got nothing. But will add that any "desktop" unit that takes DC power (and includes an outboard wall-pack) can be rigged up to a battery pack along the lines of the E/90, depending on how many watts it wants to take in will dictate life. It won't look pretty or be light-weight, but it would be feasible for a "transportable" setup (again, like the E/90).

EDIT -

Someone will probably know more about this than I do (in fact, I guarantee you someone will!) - but aren't there balanced and portable amps from RSA and a few other places that are really stellar performers? For example, I found this one with a quick search:
http://www.raysamuelsaudio.com/products/intruder (I know nothing about this, it's what the Duck gave me).

 

[rudi0504]

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http://www.head-fi.org/t/614399/new-high-end-m2tech-vaughan-3-in-1-dac-head-amp-pre-amp-just-arrived-yesterday

 

[ValentinHogea]

Quote:

Someone will probably know more about this than I do (in fact, I guarantee you someone will!) - but aren't there balanced and portable amps from RSA and a few other places that are really stellar performers? For example, I found this one with a quick search:
http://www.raysamuelsaudio.com/products/intruder (I know nothing about this, it's what the Duck gave me).

IMHO... I don't consider ALO Audio/RSA-amps to have the performance I'm striving to discuss in this thread. They're good. Especially Pan Am pairs well with Audez'e-phones. But still a bit left compared to big desktop-amps.
Regarding battery-powering amplifiers. That could be an interesting, but since most desktop-amps that fit the performance-level have an IEC-connector (with a built-in PSU) it becomes a bit tricker.
 
You have some excellent points though!

 

[ValentinHogea]

I wanted to inform that I'll update the introductory post with the suggestions that come in (and relevant links to threads etc.).
 

 

[obobskivich]

IMHO... I don't consider ALO Audio/RSA-amps to have the performance I'm striving to discuss in this thread. They're good. Especially Pan Am pairs well with Audez'e-phones. But still a bit left compared to big desktop-amps.

Admittedly I don't follow portable amps that closely, because I tend to use open headphones at home, so it's not something I worry about. I just remembered a discussion a while ago about non-standard connectors starting to appear for balanced drive on portable amps, and that's what the Duck gave me when looking for "portable balanced headphone amplifiers" - I want to say there's another company beyond ALO and RSA that does a battery powered balanced amp too.

The other thing I'd consider, unless you're trying to take something like an HE-6 or K1000 out on the road, most higher-end closed headphones that provide serious isolation (like the Signature Pro, Edition 8, T5p, or AH-D7100) are also usually very easily driven (there seems to be a genre for "high end, closed-back, portable, and iPod compatible" headphones starting to take shape) - so as long as your amplifier is "clean" (good channel tracking, low/no noise (remember, these are all generally very sensitive headphones!), etc) it shouldn't be an "out of power" issue. But if you want to truck your K1000 or HE-6 or whatever around with you, that's another story.

 

[MalVeauX]

Heya,
 
I toyed around with a GoVibe Porta Tube (battery powered portable tube amp).
 
Here's how I did for a portable setup:
 
GoVibe Porta Tube
Hifiman  HE-500
Pelican 1450 case
 

 
Check out the Vulcan+ from GoVibe. It does half a watt nearly.
 
Very best,

 

[ValentinHogea]

Quote:

Heya,
 
I toyed around with a GoVibe Porta Tube (battery powered portable tube amp).
 
Here's how I did for a portable setup:
 
GoVibe Porta Tube
Hifiman  HE-500
Pelican 1450 case
 
Check out the Vulcan+ from GoVibe. It does half a watt nearly.
 
Very best,

 
Hi MaLVeauX!
 
Thanks for your input. I've read a lot about the Porta Tube. It looks like a great amp. However I have both the Triad Audio L3 and ALO Audio Pan Am, both packing quite a different sound and probably constituting the largest/most expensive/most elaborate amplifiers that mot audiophile would still consider borderline-portable. My scope with this thread was to find the (un)known gems that pack serious power and sound quality, for driving open-back orthos (in my case primarly LCD-3, not considered a "portable headphone") in the way desktop amps can.
 
So I put a >1000 USD-figure as a minimum. I know, price doesn't always equate to quality... But since most <1000 USD-amps are discussed under "Portable headphone amplifiers" on the forum, having a thread under Summit-Fi for >1000 USD-amps seemed logical.
 
I've added the GoVibe Porta Tube+ to the intro-post.
 
All the best,
V

 

[kevin gilmore]

The new GSX and 4 x 5AH 12V gell cells certainly fits into the transportable
category.
 
Pretty much any home amp with an external power supply can be driven
by batteries.

 

[ValentinHogea]

Quote:

The new GSX and 4 x 5AH 12V gell cells certainly fits into the transportable
category.
 
Pretty much any home amp with an external power supply can be driven
by batteries.

Hi Kevin!
 
Do you mind telling a bit more about the "4x5Ah 12V gell cells"?

 

[kevin gilmore]

4 of these
http://www.mouser.com/ProductDetail/Power-Sonic/PS-1250F1/?qs=sGAEpiMZZMv8kklI404Qlaoeq7O50GWo
wired in series as +/-24V.  Probably a good idea to add +/-20V regulators to the output of the batteries.

 

[ValentinHogea]

Quote:

4 of these
http://www.mouser.com/ProductDetail/Power-Sonic/PS-1250F1/?qs=sGAEpiMZZMv8kklI404Qlaoeq7O50GWo
wired in series as +/-24V.  Probably a good idea to add +/-20V regulators to the output of the batteries.

So it would take some DIY to build an envelope/casing for the batteries and implement the charging input(s) and voltage output.
Hmm... Is there no pre-made solution? Battery-pack or similar? Otherwise, for my part it becomes too complicated and less transportable than a built-in battery.

 

[bmichels]

Very very interesting thread. Thanks a lot V[size=11.199999809265137px]alentinHogea[/size]
 
[size=11.199999809265137px]The most interesting of the list seems to be the RWA Audeze Edition, but it's 16/48 kHz limitation from USB is not very convenient since it need a USB-to-SPDIF adapter to get 24/192 kHz.   I sent a mail to RWA to see if they have a new "full 24/192 kHz version" planned...  Otherwise the RWA Corvina + a portable DAC may do the trick, but this becomes a 3 pieces solution (Source + dac + amp)[/size]
 
[size=11.199999809265137px]The very best solution could be a battery powered version of the Resonessence Invicta ( [/size]http://resonessencelabs.com/ ). It has all that is needed (Very modern DAC, Good 2xheadphones amp, small enclosure, and... can decode music directly from it's SD Card reader, so... no need for a source ! 

).  
 
This project will 'just" need to take the internal power supply out of the case and replace it by a rechargeable battery (thus, it will become transportable and... by having the "noisy" power supply away, this may even improve the S/N ratio when operated from the battery ... )
 
Will someone be willing to experimente ?  Or can to do it for me ?  

 

[goodvibes]

Nice thread but there's one supposition I don't agree with. Batteries bring their own issues so not better than a mains connected PS done right. Just different trade offs to work around. I guess we can't all agree.