[m11a1]

Quote:

Originally Posted by oneplustwo /img/forum/go_quote.gif Looks nice! Nice photos as well. (I really should try harder in my build photos.) Welcome to the club... what's the next build?

Thanks! It was done with a point and shoot too.

I'm planning on building a Gamma2 next. Perhaps after that or concurrently, a MiniMax. I'm starting to really love the sound of vacuum tubes.

now I understand why people say that K701 sounds better with tubes.

 

[oneplustwo]

Quote:

Originally Posted by m11a1 /img/forum/go_quote.gif Thanks! It was done with a point and shoot too. I'm planning on building a Gamma2 next. Perhaps after that or concurrently, a MiniMax. I'm starting to really love the sound of vacuum tubes. now I understand why people say that K701 sounds better with tubes.

Some point and shoots are very capable these days.

Have fun with the gamma 2 and minimax. I've built both (and a bunch of other stuff in the last year... poor wallet) and thought they were both fun builds with great performance.

 

[linuxworks]

Quote:

Originally Posted by mugdecoffee /img/forum/go_quote.gif But all the power inputs are DC which should mean no hum no matter how close they are.

you'd think so; but its actually not true; hum happens even due to proximity of power lines near input lines. on this amp, it does.

can't say it enough, wire routing matters a LOT, here.

 

[wap32]

Quote:

Originally Posted by linuxworks /img/forum/go_quote.gif you'd think so; but its actually not true; hum happens even due to proximity of power lines near input lines. on this amp, it does. [...]

Could you elaborate on that?

You'd think that with a good enough psu, the DC lines would be clean enough that no (noticable) EMI would pass to the audio input.
Is it wrong to assume this?

Also, what makes the beta22 more susceptible to this?

I usually take great care when routing wires, and probably wouldn't put the DC lines that close, but I'm pretty curious as to why it would make such a difference in this case.

 

[tintin47]

^ I don't think it does make a difference in this case. Like I said, the amp is totally without hum. One case that you could make for keeping DC away from inputs would be the change in current in during peaks in the music while the amp is running. That could induce a magnetic field which could induce current in the signal wiring. I find it difficult to believe that would actually happen though.

^linuxworks, power lines are high voltage AC, so 60 hz hum would make sense. The hum that people always talk about is from the 55-60 hz AC oscillation.

 

[wap32]

Quote:

Originally Posted by tintin47 /img/forum/go_quote.gif [...] One case that you could make for keeping DC away from inputs would be the change in current in during peaks in the music while the amp is running. That could induce a magnetic field which could induce current in the signal wiring. I find it difficult to believe that would actually happen though. [...]

It is certainly plausible, but I'm guessing it would take a high current variation (could happen in a very high efficiency amp) to be heard on the input via induction.

I'm guessing in practice though, the most you'd have to worry would be EMI interference from the AC power lines not filtered by the PSU.

 

[Fitz]

Quote:

Originally Posted by linuxworks /img/forum/go_quote.gif you'd think so; but its actually not true; hum happens even due to proximity of power lines near input lines. on this amp, it does. can't say it enough, wire routing matters a LOT, here.

Wait, are you suggesting the Sigma22 has a significant amount of AC on its output, enough to even be picked up on the wiring before the volume pot?

 

[rille2]

I made a γ2 in XXL:

It's powered by a σ11. I also added a gain switch.



Also my Stax TransistorAmp is finished:

Its the amp from high-amp.de. But I made my own PCB layout.

 

[ShinyFalcon]

With that much space in your y2 you could bypass the 4.5V regulators and even experiment with output coupling caps!

 

[Spacehead]

There is my Tori Szekeres amplifier with mosfet buffered ground channel. Power supply is 7815 adjusted to 24VDC (from 37V). Regulator and mosfets need large heatsink to dissipate about 10 Watts.


But the sound is harsh, too agressive highs with OPA2107 op amps. And I get dc offset with some other op amps I tried. It needs AD8066 I guess.

Edit:

Sound got little softer when I changed the mosfet heatsink to a larger one. And ground channel op amp is now AD8599, left and right opa2107.

 

[MomijiTMO]

xD I love the space rille2.

 

[johnwmclean]

rille2, that’s great work and looks terrific, is the chassis for the stax amp custom?

 

[Listen2this1]

Rille2, That DAC looks amazing. Reminds me of a Bryston. Again, good Work on both.

 

[n_maher]

Quote:

Originally Posted by Fitz /img/forum/go_quote.gif Wait, are you suggesting the Sigma22 has a significant amount of AC on its output, enough to even be picked up on the wiring before the volume pot?

I'm with you on this, there's no way the routing of DC power lines near the signal is going to matter one bit unless something else is drastically wrong with the build.

 

[ix912]

I'm the TA for my electronic manufacturing lab, so I was bored...

DIY Scott Nixon DAC - Upgraded output caps (AudioCap Thetas + Black Gate NX's)

Flickr: ix912's Photostream