Quote from: J M Fahey on November 06, 2011, 04:20:37 PM
Hissssssssssssssssssssss ! or hummmmmmmmmmmmmmmmmmmmm ! or Bzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz ?
Not the same.
If it were a Power supply capacitor problem it would not change by touching the chassis.

When amp is normally on (no spare cable in effects loop) the sound is hiss (maybe buzz when volume is full but I can't try it now because kids are sleeping).

When I put the spare cable in effects loop (power amp in) the sound is Buzzz

No Humm, or if there is, the hiss and buzz are louder and humm can't be heard.

Quote from: J M Fahey on November 06, 2011, 03:10:17 PM
Don't think so; bad power supply caps (not too likely in a relatively new amp) would rather bring hum with them, or instability problems, not specifically hiss.
Do you still hear it if you plug a spare cable in the power amp in or loop return, killing the preamp?

If I put a cable in power amp in (effect loop return) there will be quite loud buzz. If I put the cable in Pre amp out (Send) there is this same hiss, and the turning channel volume increases the hiss.

Also noticed that when guitar cable is not connected, touching the chassis will decrease the hiss.

Hi!

I bought used tm6o and it has noticeable hiss even when all volumes are down. Does this mean that power supply electrolytics should be replaced?

Thanks!

Edit. The amp is older version. It has 2112-A speaker.

Ok. This was something I was looking for.

Well what kind of power transformer I should have? The lm3886 wants 18v+/18v-, the stompbox preamps want 9v and the 12au7 preamp wants that 100v and 6,3v for heaters.

Any tips how should I do it?

Jari

Hello!

This is my first post in this forum.

I've built few tube amps from kits and I have some understanding about how they work. Now I'm trying to learn something about ss amps and I'm building one with my son.

The idea of the amp we're building is like this:

two different preamps driving a stereo amp(lm3886). One is driving the left channel and other the right channel. The idea was that you could use one or two amps the same time using an a/b/y box. I have a 2 x 12" combo that I'll use with two different speakers, alnico and ceramic. And the two preamps would drive naturally separate speakers.

Ok.

Here is the question: If I use for example stompboxes from runoffgroove as preamps, do I need a voltage amp before the poweramp? If I do, what if I use a tube circuit here? Will it contribute tube(ish) sound to overall result?

Hopefully you will  understand my writing

Thanks,

Jari