Preamp question and Active Tonestack problem

[ubaid88]

I didn't wanted to create separate thread for them. Anyway...
Firstly..
I need know that if i use stompbox as preamp directly to poweramp, should i add clean booster after stompbox? Clean booster between stompbox and poweramp? I mean stompbox are usually used before clean preamp but if it directly goes to power without clean preamp, then wat should i do?

Secondly...
Iam doing tests of active tonestack for dr boogey. I ripped Boss mt-2 tonestack for it. Dr boogey work great without active tonestack. But from active tonestack i hear nothing. It is not working at all.
Here is the schematic. If there is any problem, please point it out for me.



Thanks in advance. Sorry for bad my English and typos. If there is anything not clear i will try to explain it in a better way.

[PRR]

> if it directly goes to power without clean preamp, then wat should i do?

Guitar (and gitar-cord effects) work at 20mV-200mV. However a "hot" effect turned to the max may be outputting 1V.

Power amps need 1V-2V to get all the power you paid for.

So "somewhere" you need a gain of 50, adjustable downward as needed (at least to unity gain, and usually to zero so you can change cords silently).

Your proposed tone control has a minimum input impedance of 22K. This is lower than most guitars and guitar-effects want to drive well. You want some buffering.

Guitars and effects are so weak that you usually want to gain-up before you mess with tone. That's WHY we have preamps.

But you do not want "too much" gain before some form of volume control. Assume you should be able to take a 0.5V-1V input, without clipping. Figure the maximum output level of your amplifier and power supply. That's how much gain you may have before your first gain/volume knob.

Fender tube amp has 250V supply, can make 50V peak output, was designed to accept 1V peak input, so it has gain of 50 and then a volume control. Chip running on 9V battery can hardly make 4V peak, so may not have gain over 4 or 8 before a volume knob.

If this tone control runs on +/-15V, and maybe on 9V, it can generally drive a power amp directly IF you do not have the volume control where shown.

This may work:

[ubaid88]

Hey thank you very much Paul. I more than appreciate your help my friend.

I like add this that my version of dr boogey is tonestackless. I removed bmt tonestack and added lpf plus vol knob. So is this ok ?

[PRR]

I missed this.

> from active tonestack i hear nothing. It is not working at all.

The schematic is correct as drawn. If it is not working, use standard debugging techniques. There is a sticky-thread at the top of this forum section.

DC voltages: In this plan, pin 8 should be at B+, pin 4 should be at ground, and all other pins should be at half voltage.