Seventh Circle Audio

Posted: **Tue Apr 29, 2008 1:46 am**

Anyone tried the SC10 Discrete Op-Amp in their A12 yet? I'm really curious to know what it sounds like? How the SC10 would change the sound? Cleaner perhaps?

I've read somebody comparing that Helios is like a Pacifica with balls so could the SC10 make the A12 sound somewhat similar to that of Helios type 69?

Thanks!

Posted: **Tue Apr 29, 2008 6:43 pm**

I ordered an SC10 and I should get it by friday. I've never experienced a helios pre, but I'll let you know how it differs from the SC25

Posted: **Wed Apr 30, 2008 9:11 pm**

cool I'd appreciate that.

Posted: **Thu May 01, 2008 10:51 am**

The SC10 has a simpler topology and less open-loop gain than the SC25. It also has a slower slew rate. Measurement-wise that means more distortion, especially as frequency increases. Sound-wise, I leave it to others to judge.

The Helios is a single-ended discrete circuit not unlike Neve and Trident A-Range, so any sonic similarities would probably have more to do with the transformers than the amplifier circuits.

Posted: **Fri May 30, 2008 6:59 am**

Is it ok to just swap straight the SC25 for SC10 in A12, like plug & play?

What is the proper working voltage for the SC10 Op-amp? Is it +/- 18V like SC25?

Posted: **Sun Jun 08, 2008 2:51 am**

The SC10 is happier with +/-24V rails.

Posted: **Mon Jun 09, 2008 11:43 am**

thanks I have to give it a try