Good class A headphone amp to build?

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Well in a reasonable price range, not too expensive and not too cheap. I'd not like a tube amp, for some reason I don't fancy them.

Turns out case is more expensive than actual amplifier itself :mad:
So that plays a part in the price range as well.

have you searched?
Yes I have, I've been looking at the lehmann linear amplifier, it would suite my needs the best (I think). I've read reviews and people say it's very natural sounding.

But here on diyaudio, there is some hate going on for this amp. For instance a few said sound quality is arguable and that they would keep their hands away from it on thread I started in solid state section yesterday: http://www.diyaudio.com/forums/solid-state/293145-lehmann-linear-case-drawings.html

I don't know what to believe or search for anymore. I have no knowledge when it comes to headphones amplifiers, do not know what's good and what's bad, unlike with large amps where I know what to look for, like knowing sound characteristics of a specific amplifier (like difference between krell ksa100 and accuphase p260 I currently own) etc.

So if you can say anything about this lehmann linear amp would be much of a help.
I've been looking at this complete kit, comes with a case and r core transformer as well: DIY Kit Class A Headphone Amplifier Preamp Base on Lehmann Amp L163 46 | eBay

Seems like an awesome deal, maybe even too good to be true. But then again, what do I know :rolleyes:

P.S. I'd also like some kind of headphones protection circuit in case if something were to go wrong :)
 
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Accuphasee, there is JLH headphone amplifier, class A, ~2watts, easy to built, plenty of kits on ebay, many threads here about it, some changes to be done to the circuit, great sounding, highly recommended (it has one cap in opposite polarity on the schematics, and it needs bigger heatsinks), it sounds great.

I myself am very fond of headphones and class A headphone amps...have been Sennheiser guy for years, till I got planar headphones, now I am planar fan. Last Xmass I treated myself to a pair. Since then I modified and build dozen of class A headphone amps. Me and friends had quite a few sessions till late hours (you can do it with headphones, not disturbing neighbors), comparing different headphone amps. My current favorite is 2 watt Class A Magnavox SE amp, to which I added resistor divider to run 50 ohm headphones. Next would be small chip amp LM1875 in transconductance current drive, then JLH, then 6L6 SE tube amp, then OTL with parallel 6SN7, then SE parallel 6H6P and on and on...
Tubes and headphones are a win win combination.
 
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+1 on JLH head phone amp. $20 can't beat the sound quality for the price. Very easy to build.

2016 NEW JLH HOOD1969 Class A Headphone Amplifier PRE AMP KIT DIY-in Headphone Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group

$_1.JPG


Need to add an $11 25va 15v toroidal trafo for the PS.

AN-0215 - 25VA 15V Transformer - AnTek Products Corp

Here it is installed in a small $5 craft box from Michaels's crafts store.

555993d1466516382-good-class-headphone-amp-build-jlh-headamp-completed.png
 

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You will be surprised, but the usual three-stage output follower, which operates in class AB, have only 0.02...0.03% distortion. For output voltage 4 V at a load of 32 ohms idle current of A class is equal to 60 mA. Increasing the idle current to improve the cascade to class And reduces these distortions are not much.

Cascades VAS working in class A. Much more distortion makes it VAS at least 0.2% for output stage with CB, a maximum of a few percent, for a cascade of CE. For the correction of the distortion VAS NFB should be as deep, as possible.
Unfortunately, the JLH circuit design may not give the desired depth of the NFB.
 
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You can try to do a Pass Ha. It's easy to do and it sound very well with the HD6x0. An EHHA is a good Amp too.

The best, If you can to do, IMO a Beta22 or dynalo/dynahi is the best option for a hd6x0
I was leaning to Beta22 after your reply until I saw the power supply section.
Why do I need a PSU board apart from a toroid transformer and the main boards? And if I were to proceed with this how many watts would I need?

Accuphasee, there is JLH headphone amplifier, class A, ~2watts, easy to built, plenty of kits on ebay, many threads here about it, some changes to be done to the circuit, great sounding, highly recommended (it has one cap in opposite polarity on the schematics, and it needs bigger heatsinks), it sounds great.

I myself am very fond of headphones and class A headphone amps...have been Sennheiser guy for years, till I got planar headphones, now I am planar fan. Last Xmass I treated myself to a pair. Since then I modified and build dozen of class A headphone amps. Me and friends had quite a few sessions till late hours (you can do it with headphones, not disturbing neighbors), comparing different headphone amps. My current favorite is 2 watt Class A Magnavox SE amp, to which I added resistor divider to run 50 ohm headphones. Next would be small chip amp LM1875 in transconductance current drive, then JLH, then 6L6 SE tube amp, then OTL with parallel 6SN7, then SE parallel 6H6P and on and on...
Tubes and headphones are a win win combination.

I am not sure on which JHL amp you meant, since I found one kit on ebay Dual Channel DIY Kit for JLH 1969 A Class A Amp Board Amplifier Parts | eBay

It's rated 10W per channel. Would that blow your headphones (or ears :D) ?
Isn't it way too much?

And would 30VA toroid be enough?

Planar headphones are electrostatic right? if so I never liked the sound oh electrostatic headphones (listened to stax) :p
They have weird sounding bass and need a lot of power, am I right?
 
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HD600 is 300 Ohms, 97 dB re 1 mW so 12 Vpk, 40 mA will hit 120 dB SPL

some single op amps will do this, more if paralleled like O2 or the old "A47" project amp
don't expect to use the data sheet max output currents - aim for using < 1/2 that for low distortion

Class A bias can be added to monolithic op amps with a external current source(or sink) tugging on the output

or by biasing the 2 op amps of the parallel schemes "against each other" to get push pull output - but I don't know of any kit/project amps that do it

using discrete outputs with+4 amp rated power transistors to drive 40mA peak "costs" in parasitics, "speed", short circuit failure current

the B22 is known to lunch its output Q when "hot plugging" the standard TRS connector - headphone amps need to be able to survive shorting the outputs to each other with signal present
 
the B22 is known to lunch its output Q when "hot plugging" the standard TRS connector - headphone amps need to be able to survive shorting the outputs to each other with signal present

Yes but only with the three channel versión (active ground). If you use a normal versión (two channel and passive ground) you have not problem. However I think that this is not a hadicap, you can use a 4 pin connector or turn off the amp.

Ok, is a Beta22 expensive? yes and is not perfect, but IMHO possibly you have one of the best headphone amps (tied with the Dynahi :rolleyes::rolleyes:).

Humbly, I know these amps and I know how the HD6X0 sounds with them.

If your budget is low, JLH is a good amp but the Lehmann clone is other interesting alternative too.
 
wrong, the TRS temporary short on insertion/removal is R,L channel-to-channel, not to gnd and does happen with 2-channel


"3-channel" is just wrong by itself - technically flawed arguments, waste of resource for worse result - a unfortunate headwize fad that I keep having to explain

the reasons given for "3-channel" don't hold up to engineering analysis or measurement

and particularly if you are willing to rewire to 4 pins, then going dual mono is cheaper, technically actually better


active splitting of a single supply does have its uses - "3-channel" however does it wrong with a single supply, is wrong when you have a perfectly fine dual supply with a "real ground"
 
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wrong, the TRS temporary short on insertion/removal is R,L channel-to-channel, not to gnd and does happen with 2-channel


"3-channel" is just wrong by itself - technically flawed arguments, waste of resource for worse result - a unfortunate headwize fad that I keep having to explain

the reasons given for "3-channel" don't hold up to engineering analysis or measurement

and particularly if you are willing to rewire to 4 pins, then going dual mono is cheaper, technically actually better


active splitting of a single supply does have its uses - "3-channel" however does it wrong with a single supply, is wrong when you have a perfectly fine dual supply with a "real ground"

Yes, you are right. I replied but I was thinking about this. Excuse me but I´am not sure if the two channel has this issue :cool:. However, the amp has no other fault and perfectly moves any headphone, regardless of their impedance... And most importantly, it sounds great
 
I am really leaning to beta22 now, since it's an extraordinary amplifier, but there is 1 problem in all this.

Where to get it from?

eBay

or

amb.org/audio

amb's admin said none of the eBay kits are trusted, genuine.

I'd buy it from amb.org/audio but they do not offer kits, which is a huge problem for me since those parts are not available to buy here in my country and shipping from websites like mouser is insane.

Can anyone confirm that eBay kits are good quality?
 
I was leaning to Beta22 after your reply until I saw the power supply section.
Why do I need a PSU board apart from a toroid transformer and the main boards? And if I were to proceed with this how many watts would I need?



I am not sure on which JHL amp you meant, since I found one kit on ebay Dual Channel DIY Kit for JLH 1969 A Class A Amp Board Amplifier Parts | eBay

It's rated 10W per channel. Would that blow your headphones (or ears :D) ?
Isn't it way too much?

And would 30VA toroid be enough?

Planar headphones are electrostatic right? if so I never liked the sound oh electrostatic headphones (listened to stax) :p
They have weird sounding bass and need a lot of power, am I right?

you are wrong in pretty much every account...
 
I am really leaning to beta22 now, since it's an extraordinary amplifier, but there is 1 problem in all this.

The only thing I find "extraordinary" about the Beta 22 is how extraordinarily overwrought it is. It was designed as nothing more than a numbers-chasing technical exercise with the prime directive being "throw in every trick in the book." It was completely designed in simulation software and Ti Kan only gave it a cursory listen just to make sure nothing was broken before calling it finished.

Ti Kan also popularized the extraordinarily stupid three channel "active ground" nonsense.

Ok. Rant over.

se
 
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