You need two speakers tripath amps are internally bridged so you cant bridge them yourself externally

Not sure fi this has been posted before sorry if it has.

http://www.storm-software.co.yu/diy/index.php?project=software

Thats completly fixed the preamp,to little capacitance between the virtual ground and 0v, sound great and totally stable at any gain setting.
I am so happy!!

The 100 watt class-D really gives this setup a hell of a kick. Utterly deafening in a flat, my neighbours must be getting a little annoyed. Thanks for all the input guys, even though this thread has turned into a bit of a monologue of late.

In DIY audio many people also sound they say great. I know many cases where people have used them for LM3886 and clss-D kits after using traditional transformer setups and got an improvemnt in performance. I have used them with some of the Tripath kits and they do seem to sound better than the traditional toroid/ diode setups.

The main advantage is that you can boost rather than just cut frequencies. This means a wider range of tones can be produced by the preamp, i cant think of any disadvantages.

My amp is still pumping at high gain levels. Could this be because i haven't got enough capacitance on the preamp board? i have eliminated the speakers, tried a hifi one and got the same effect, replaced the 25watts class-t with a 100 watt board. And removed the mixer amp temporarily. The only thing the same as the first test is the preamp so i guess this is where the issue originates. At the moment the virtual ground is only decoupled with 1uf and the 25v to gnd with 10uf? I think i might put some decent 100uf in both locactions to see what happens.

The boards from this site look very interesting and not difficult very difficult to implement.

http://www.profusionplc.com/pro/gex/prodGen.html?prdtyp=reverb#

I change input settign resistor int he second stage (r15) from 1m to 50k. This seems to have clear the sound up a lot, more test to follow tonight.

Well i guess that you get tone control on your amp??

And an active one will allow you to shape the sound more however i think that this cicuit as it stand doesnt give enough gain

Then i was thinking but this would mean that the second 11 x section from the initial design would be removed so i imagine i would have to stick this back on after the active tone. Does that make sense?

Right i was reading a section over on DIYaudio when a guy called minion posted an active tone control section. I thought this combined with the 2 stage preamp i was working on would probably work quite well.

This was my first thoughts on the idea

My amp setup uses a 100 watt class T amp and the TL071 based preamp many people here have help me with.

The issue is this, at high gain setting, i.e. when i want to play loud, the amp ocassionally gets stuck it a sort of weird feedback loop with the Bass driver pumping in and out slowly with no input from the guitar. Is that called motor-boating? Even totally dampening the strings doesnt stop it, the only way to control is it to either turn of the amp or cut the volume right down for a moment.

I was wondering what causes this and what could be done to reduce/eliminate it.

Any feedback(no pun intented!) greatfully recieved.

Phil

LJ King, i found that a couple of the pot were broken, replacing them fixed the issue, thanks a lot.

Well it is defientely connected, however i did have to bend some of the pins on the pot back into place after bending them 90 degrees back to wire point to point. This is probably the issue, i will check it out tonight.

Thanks a lot.

Oh also i set the input impedance of the first section to 1m, the second section is set the same. I imagine this isnt needed since the issue with the guitar pick has already been dealt with. What would a suitable value be for the second input impedance settign resistor? 100k?

Phil

Hello all,

I have been workign on my preamp again this weekend with less than stella results.
I wanted to change the setup so i had a fixed gain of 2 in the first section, then a volume pot and tone tones between it and the final fixed 11 x gain section. To this end i took the schematic from 'Tone stack generator' software and built this with a pot on the front for gain control.

I put this back in and the only thign that works is the volume/gain control none of the tone controls are doing anything.

Any ideas?