Just got a pair of these to see what they're like.   First, straight out of my DAC (AMB gamma2) I was completely underwhelmed - "Bass? What bass?" I thought.   See, I'm so used to high impedance headphones I forgot the gamma2 is totally unsuitable for ~25 ohm headphones like these.   Out...

  Off-topic, but I'm just reading an article that made me think of this. Especially this bit:     http://www.innerfidelity.com/content/musings-headphone-amplifier-output-impedance   This confirms my thoughts on the HD800, that it loves very-low output impedance amps to get the most...

  Interesting. A damping factor of 1.09 is miserably low. I wonder if it sounds better to you because the flabbyness of the amp cancels out the precision of the headphones   Nice craftsmanship all the same.

The article is a getting on a bit now but I thought it was worth sharing again.   http://people.xiph.org/~xiphmont/demo/neil-young.html   Convincing arguments for 44.1/16 being sufficient---even optimal---for playback.

  AMB says one S22 per B22 board for speakers (regardless of 2 or 4 board).  Deviate from that and you'll be deviating from the official word.  Anyway, 50 W into 8 ohms would imply a current of over 6 A, which is going to dissipate far too much heat in the MOSFETs for the stock heatsinks.  You...

  No, you'd only get half the VA rating that way. You need to wire the primaries in parallel with 115 V across each.

DefQon is wrong in his assumption. Assuming you live somewhere with a 115 V mains supply you want to wire the primaries in parallel (BLU and VIO live, GRY and BRN neutral). Not 100% sure on the secondaries ...

  I've got used to that feeling - it's been about 20 months since I ordered the first parts

Quote:   You're right. Let's hope it's a typo.

Come on wakibaki you know the answer to this. It's 128 dB monophonic, but this is a balanced DAC chip. The opamp afterwards acts as an unbalanced-balanced converter, giving you better SNR than just taking half the output alone.  

I just posted these links in the other DIY DAC thread. Check out the AMB designs.   http://www.amb.org/audio/gamma2/ http://www.amb.org/audio/gamma1/

Can't believe nobody has suggested the AMB designs yet.   AMB γ2   AMB γ1   I've got a gamma 2 and it's brilliant, technically and acoustically. I bought mine assembled for $200 and don't plan to ever replace it.

I'm not an expert, but you could compare your implementation to the σ25 (which uses the similar LM78xx parts). In that design, there is a smoothing cap before the rectifier (0.1 uF), a bulk cap (1000 uF electrolytic) and a bypass cap (0.1 uF) at the input of the reg, and another decoupling cap...

Quote:   I'm surprised nobody picked you up on this. Care to elaborate?

Quote:   Totally fine. Either get a double pole double throw switch and switch both signal and grounds, or get a single pole double throw switch and only switch the signal line and tie the grounds together at the inputs (I'd probably do the latter).   Of course you can have more...

Quote:   RudeWolf said it all really. If you're patient, do all the research, and have reasonable skill at managing the project/soldering, you can tackle anything.   My first project was a B22, which I chose over the dyna- amps for exactly the reasons above: better documentation and...

Come on, it's easy. Take out the ground channel from the schematic so you're left with a bridged pair, and order two of them. If you can't figure this out maybe the B22 isn't for you.   Or just do what almost every other builder has done and stack them, e.g. johnwmclean's build...

Quote:   Did you get the sarcasm?

Quote:   You'd really have to ask the circuit designer. The parts are similar (the one you have looks like a beefier version) but it depends on how critical the performance of that part is in the circuit.   The only ways to know for sure are to 1. simulate the part in pspice or...

FYI tangent the first link on that page is dead (redirects to FS subforum).  

Quote:   This is pretty ghastly. Far far too much solder and possibly some cold joints. The principle of soldering is to heat the board and the lead simultaneously and apply solder to the interface AWAY from the iron, so that solder flows into the gap, bonding the part board together.  ...

Quote:   In the context of a cmoy it makes sense a the power supply is the limiting factor, but you're right it should be noted that a gain of 8 will probably cover every headphone (even power hungry ones like the HE-6).

Quote:   Good reply from Tangent.   1. I would add that you should choose the gain based on the max voltage from your source and the max voltage output of the amp. If you were to use a 9V cell for example and could get the opamp to go up to the rails the max output would be 3.18 Vrms...

Nice anecdote of subjective experience guiding scientific experiment.   I wonder though how exactly Bateman's results correlated with Hood's impressions? Did "goodness by ear" correspond monotonically with a single electrical parameter?

Shame the link is down. Why not just use step down audio transformers? They would have been much cheaper and probably higher quality.