Metropoulos Forum

Hello, Amp techs!!!

I have a 2203 that I'd like to loosen up, and add some 'SAG' to. Is it the phase inverter cap that I want to lower the value of? The stock value is 50uF/50uF. I'd like to try a 32uF and maybe a 16uF.

Has anyone done this? What was the outcome?? What value did you use???

If it is indeed the phase inverter cap that I want to change, can someone validate its location for me?? I think I know, but I'd like to be certain.

Thanks in advance!!

You need resistance in the B+. If you want to mimic the tube rectifier so you need this resistor after the rectifier bridge. The current will flow trough the resistor and there will be the voltage drop across it and your B+ will be lower. It Will SAG!

Depends what you mean by sag (ie drop in voltage as the amp is pushed into saturation) or smoother feel.

Haze13 has fiven the votage tip

For smoother greasy feel (with risk of ghosting) leave the PI cap alone and drop the screens caps down to 32 or even 16 uF. This needs the screens cans replaced with two 32uF cans.

First wire only one half of each can in series 32+32 = 16uF this is ealiest SL spec, if that ghosts then try adding the second a half of each can with a jumper (Marshall used the leg of the 56k 2w bleeder for this). This will give 64+64 in series for 32uF screens. The Pi can effect is very subtle and 100uF seems to work fine.

16u on the screens, It'll feel saggy.

So, this would be the 50/50 cap that feeds the screens of the power tubes, correct??

Could I achieve the same affect by changing the screen resistors to a different value???

yep.....i always liked 100uf's for power, 16uf's for screens and 32's for pre-amp. AWESOME