[aos]

Actually my DAC uses the same amplifier topology as META42. There would be no point in getting separate META42 if you had my DAC, except if you want to add crossfeed.

META42 has the benefit of larger dedicated board however, while my amp is optimized for size. This allows them to use bigger capacitors, different types of pots, and current sources to bias opamps into class A, although for AD8610 that doesn't seem too important. In any case, META42 has potential to sound better and potential to do mods.

However, for the very best sound you'd want to make full dual mono ala Blockhead, and for that you need elaborate external power supplies (possibly more complex than the amp itself), and it wouldn't make sense to use single EL2001, you should parallel couple of them or use EL2008/2009, so that you can supply large current to the headphones. All that would raise price (and size) through the roof. If you optimize for size however you have to make compromises. After all, in my case amp AND dac fit on 3 by 3 inch PCB!

 

[eric343]

3x3"?! Damn, I'd seen pics but I didn't know it was so damn TINY! Add me to the list if you ever make them for other people...

 

[aos]

Quality Guru, Elna Cerafines are high end caps. The only caps that are considered better - and only by some - are Black Gate capacitors. In sizes we're talking about prices aren't much different, however Elnas would be cheaper since Eric was selling them at prices you won't find from big guys.

 

[eric343]

FYI, aos means Erix, not me.

 

[shorton]

Originally posted by Nezer:

"If I had the money I'd be tempted to ask you to build me one. Of course I would need a balanced source too...

I guess when you start getting to this level a $3500 amp doesnt seem that big of a deal when you're using a $5000 source. "



If we use an intergrated DAC, don't we negate the need for the $5000 source?

How about two DAC's with a split digital feed with the DAC phase inverted? Never mind, that would just give you dual mono.

OK, split DAC output using a Darlington pair or tube type push/pull circuit...Hum, I guess the tube aspect kinda kills the small and/or portable side of things. On the other hand, if you are going METABlock anyway, we aren't talking protable anyway are we?

Tubed - intergrated DAC - METABlock - Hummmmmmm.

Thanks for letting me think "out loud" and I also look forward to your coming critiques.

 

[Audio-Me]

I should be getting my META42 anyday now. If it turns out well, I may want to go to the extreme with dual mono META42s using two Elpac medical grade linear regulated PSUs, stepped attenuators, and any other upgrades like super premium resistors and what not (large single steel case to hold everything including the PSUs, plus nice stainless steel volume knob, and other kicks, hehe). If eric is willing, I'll probably commission him again. But if I can find a quality pcdp with linear antiskip that has digital out, I will be very interested in your PDAC. The pana570 while decent for a pcdp, is still not very good and I want as good portable sound as I can get. =\

 

[aos]

I think that is the size. It might be slightly bigger but it's less than 4 by 4. DAC itself is considerably bigger since it needs batteries. In latest version of board, half of the box is taken by batteries and other half by PCB. Size of Hammond box is 6.1 by 3.6 by 1.4 inches. I plan to order some boards no matter what although I'm still not sure if I'll get Thomas to make me a dozen or so DACs for sale...

Your board is much easier to play with though, mine is crammed and I'm forced to use small capacitors. I'll actually probably get one of yours to play with, I want to make an amp with my precious EL2009 and that one has weird package.

 

[aos]

By the way, as good as the portable DAC is, one can still do better. For strictly portable use it's great, but once you start talking ultimate with no size and power consumption limits, there are better chips out there not to mention better designs. For example, you could take two of CS43122, each dedicated to single channel so there's no crosstalk, separate discrete power supplies, discrete cascoded analog stage or even Kevin Gilmore's amp as analog stage, and with SACD input too. Preferably re-clocked data for ultralow jitter. Etc. Now that would be over the top.

 

[Nezer]

Quote:

Originally posted by aos By the way, as good as the portable DAC is, one can still do better. For strictly portable use it's great, but once you start talking ultimate with no size and power consumption limits, there are better chips out there not to mention better designs. For example, you could take two of CS43122, each dedicated to single channel so there's no crosstalk, separate discrete power supplies, discrete cascoded analog stage or even Kevin Gilmore's amp as analog stage, and with SACD input too. Preferably re-clocked data for ultralow jitter. Etc. Now that would be over the top.

*NOW* you're talking my language!! If I paid you $250USD/month how long till I pay you off for such a project?

 

[morsel]

Once the price of a headphone amp exceeds the cost of good traditional amplifiers, it seems to me that using a traditional amplifier with the speaker outs hooked up to a headphone jack would make more economic sense.

The META42 is not really designed for dual mono operation, perhaps if you are set on spending that much money, you would be better off getting a custom amp board, or one of the multikilobuck Headroom models. On the other hand, you may find you get what you are looking for just by piggybacking buffers and using the best components. The point of diminishing returns is near.

 

[Nezer]

Actually I was kidding...

But just because it was never designed for dual-mon operation doesn't mean it wouldn't work well in that config. After all, it's crazy ideas like this that lead to things like Headroom's Blockhead.

 

[The Quality Guru]

Quote:

Originally posted by morsel Once the price of a headphone amp exceeds the cost of good traditional amplifiers, it seems to me that using a traditional amplifier with the speaker outs hooked up to a headphone jack would make more economic sense.

I think Antique Sound Labs came out with something that worked to this extent, called the UHC Signature
( http://www.divertech.com/uhcsignature.html )

 

[qwerty870]

The neutrik 1/4 inch jacks (the ones used on the nicer Headroom amps) can be obtained from mouser electronics.


www.mouser.com

part # 568-NJ3FP6C

It costs $6.39 each.