Acrosound S1001

[Brice]

This preamp is odd.

The high level input goes straight to the tone circuit, then amplified/reversed.

So all the tone circuitry tend to pick up noise, which is amplified, instead of the classic design: 1st amplification, tone control (with loss), then re-amplification.
This design makes this preamp noisy.

And not using shielded wires makes matter worse. also some switches are soldered to the from panel. Not a great design IMO.

I made replica board but of course this did not solve anything.

I then started to change the circuit to a more classic preamp in simulation, but got side-tricked in the way.
That's as far as I went with it.

Brice.

 

[ramjet]

This preamp is odd.

The high level input goes straight to the tone circuit, then amplified/reversed.

So all the tone circuitry tend to pick up noise, which is amplified, instead of the classic design: 1st amplification, tone control (with loss), then re-amplification.
This design makes this preamp noisy.

And not using shielded wires makes matter worse. also some switches are soldered to the from panel. Not a great design IMO.

I made replica board but of course this did not solve anything.

I then started to change the circuit to a more classic preamp in simulation, but got side-tricked in the way.
That's as far as I went with it.

Brice.

My experience with the S1001 is different from yours. I never used it in it's original "as found state" as I rebuilt everything before use. Yes, no shielded wires, just like the Dynaco PAS, but I corrected that (same as I did in my PAS). My S1001 is not noisy but does have a low level hum, possibly due to the close quarters of the power supply to everything and it being tube rectified plus needing new electrolytics (rebuild was in 93'). I will fix all of the PS issues this time around (same as I did with my PAS with a solid state rectifier for the HV.

 

[pjrengineer]

I bought the one that multichamp built. He did a great job assembling it and I think it sounds quite nice. It’s being powered by the ULII amplifier through the octal socket. Credits to Brice on the help with the ULII. I just took out a fully restored Marantz 2275 which is about as good as it gets vintage for me and I do not want to put it back in the system if that tells you anything on the sound.