[sacd lover]

Quote:

Originally Posted by Frihed89 /img/forum/go_quote.gif And op amp output stages are "bad" because they aren't sexy? Don't sound good? Don't cost enough? I have seen op amp output stages that sound absolutely lovely in power amps.

Most people dont really understand the limitations of op amps and the fact you cant bias them in true class A for the best sound quality ..... or you would burn them up. Moreover, op amps require large amounts of negative feedback, and the unavoidable sonic penalties that come with negative feedback, to stabilize them to work properly in an audio circuit. But, op amps are probably better accepted here than in most other areas of high fidelity because of their necessity in most portable amp designs.

Op amps dont come close to the sound quality of a zero feedback, class A, discrete design from my experiences .... and yes I have compared the two many times in both headamp and cd player output stages. I get rid of op amps in the signal path whenever I can.

Op amps dont cost enough?

From the prices you see for some op amp based headamp designs they cost plenty .... sometimes more than competing discrete designs.

 

[jcn3]

definitely not digging the clear faceplate -- looks like a cobbled together prototype . . .

 

[jcx]

Quote:

Originally Posted by sacd lover /img/forum/go_quote.gif Most people dont really understand the limitations of op amps and the fact you cant bias them in true class A for the best sound quality ..... or you would burn them up.

not so fast there - Op Amps can be biased for Class A output operation as I've shown with my experimental prototype amp and I've shown several circuit options and calcs that the AD8397 should be fine for most headphones with good pwr plane heatsinking

see:

http://www.head-fi.org/forums/showth...12#post2276512

pics of my proto earlier in that thread, another circuit on 2nd page

 

[luvdunhill]

Quote:

Originally Posted by sacd lover /img/forum/go_quote.gif Most people dont really understand the limitations of op amps and the fact you cant bias them in true class A for the best sound quality .....

Earl:

Here's a great read on biasing op-amps into class A and a half-dozen ways to do it:

http://tangentsoft.net/audio/opamp-bias.html

 

[GlendaleViper]

I have to agree with some of the others on this one. Despite what the amp may be capable of from a sonic perspective, the casing on it looks very DIY. Whether the faceplates are made from bulletproof materials or diamond, it just doesn't look right.

Then again, I'm not a huge fan of the Singlepower aesthetics to begin with.

 

[mofonyx]

2 volume pots?

:\ wouldn't that be a bit difficult for equal volume control? Unless we're talking about stepped attenuators here :S

 

[sacd lover]

Quote:

Originally Posted by jcx /img/forum/go_quote.gif not so fast there - Op Amps can be biased for Class A output operation as I've shown with my experimental prototype amp and I've shown several circuit options and calcs that the AD8397 should be fine for most headphones with good pwr plane heatsinking see: http://www.head-fi.org/forums/showth...12#post2276512 pics of my proto earlier in that thread, another circuit on 2nd page

A Push/pull class A op amp circuit with some extreme heatsinking? Ok, but how many people build an op amp circuit that way. Most op amps with say 40 ma max outputs are run with a few ma bias .... which people incorrectly label class A operation when what you have is class A/B operation. Such designs just plain dont sound good to me.

 

[sacd lover]

Quote:

Originally Posted by mofonyx /img/forum/go_quote.gif 2 volume pots? :\ wouldn't that be a bit difficult for equal volume control? Unless we're talking about stepped attenuators here :S

Not sure, but I would like to try that out. I had a McCormack Micro preamp years ago that had dual pots. I didnt think it was hard to set but I remember that I was never sure I had it right. The idea I might not have the volume balanced was more troubling than any actual imbalance I heard while listening.

 

[jjhatfield]

Quote:

Originally Posted by GlendaleViper /img/forum/go_quote.gif I have to agree with some of the others on this one. Despite what the amp may be capable of from a sonic perspective, the casing on it looks very DIY. Whether the faceplates are made from bulletproof materials or diamond, it just doesn't look right. Then again, I'm not a huge fan of the Singlepower aesthetics to begin with.

I am a fan of SP aesthetics, everything from the old style toaster MPX3s to the (now) classic black cases. But these two new amps... I'm totally mystified.

 

[Superpredator]

The balanced version of this amp was on my radar big time and I think the price is appropriate. However, I totally thought the pictures were of a prototype. I was hoping for the classic SP look. I want it to quack like a duck and look like a duck.

 

[mofonyx]

Quote:

Originally Posted by sacd lover /img/forum/go_quote.gif Not sure, but I would like to try that out. I had a McCormack Micro preamp years ago that had dual pots. I didnt think it was hard to set but I remember that I was never sure I had it right. The idea I might not have the volume balanced was more troubling than any actual imbalance I heard while listening.

Exactly! You would never know unless they are stepped attenuators.

And imagine the fear in changing the volume!

:\ I'm sure more thought would be put into 2 seperate volume pots :S

 

[guzziguy]

I think that the Square Wave would look better if it were done like AMB's amps. The bottom, sides, front and back are solid and the top is clear. If you want solid front and rear, I'm sure that Mikhail can do it for you.

 

[Asr]

I just discovered that the mini-jack on the front panel is a second headphone output. However, large plugs don't fit into it - only my ATH-ES7 is able to plug into it.

 

[rgbyhkr]

I know it's unlikely, but is there any chance that the Square Wave or the new mini tube amp has enough output to power the K1000s? Thanks.

Jeff

 

[sacd lover]

Quote:

Originally Posted by rgbyhkr /img/forum/go_quote.gif I know it's unlikely, but is there any chance that the Square Wave or the new mini tube amp has enough output to power the K1000s? Thanks. Jeff

The Mini-Tube should have enough power.