100uF Capacitor for 12000 Phase Inverter

[shakti]

After some experimentation with mine, I ended up with 50uF (100+100) on the screeens as well. To my ears (and hands) you keep all that is cool about a 12-series - the greasy, gainy feel, and chugging, chirping bottom - but just gave it a touch more focus. It also works better with a Strat that way if you want to cover some Hendrix ground. Just a touch tighter. WIth 32uF PI and 32uF screens it was just a bit messy to my ears, although that was before I put a bright cap in there. Perhaps I would have thought differently about it with a bright cap, but I really like to tighten it up just a little bit.

[jnew]

I currently run 16uF's for the pre-amp, 16uF for the screen's, 50uF for the mains and 100uF for the PI.

[awangotango]

interesting...I'm using 16 for pre, 50 (two 100) for screen, 50uf for mains, and 50uf for PI, I will try to up that to 100, then maybe i can knock down the screens to 32......Yes that vol bright cap changes things alot of course, i never leave home without it. I don't know if it tightens the sound but it shifts the balance much more towards the top end that it may seem that way, and so it may affect the filtering in terms of what the ear finally hears as 'tight' and so you may be able to knock one of those filter stages down a notch. I've been likeing 16 or 32 in the pre section and low screens and am not feeling there is much mush other than a bit of musical 'give' that I need to have there. the low pre filtering gives the 'air' and the low screens 'the give'. I have not found much benefit from low MAins filtering and I have not messed with the PI enough to know exactly what it imparts so I will be varying this a bit soon. 100uf sure seems like too much but maybe not



So I 've been messing with 32 vs 100 uf in the PI and feel that the change makes itself most apparent at higher volumes. giving more squish and sag when using the 32. 100 is a bit too tight for my tastes it seems. I like the amp to slow down when I crank it up and the lower PI cap is part of this....so I'm back to '67/8 specs there

[plexified]

Very interesting for sure . I had a 12 series with a totally stock set up and with a Harry Kolbe mod that entailed high filtering and a voiced lead channel . After plugging into it a million times , I loved it for sure , but the kicker was his normal channel was said to be voiced like a bassman . I always scratched my head on that one . It sure did sound that way , I turned it up one day and was just floored . I said to myself , self , what does this thing sound like stock ? So I pulled out the pencil and paper and had drawn a schematic . Surgically removed the mod and put it in a zip loc bag . Put in nos and stock parts up to spec and fired her up on a 110 variac load . Boom . Still sounded just as good but she was back to a respectable stock set up . I dropped a whole lot of filtering in the pre amp and power amp , even diodes to keep the voltage pull from happening and it was nada in terms of the effect . It should have been a major difference , but it was not . My guess is that the transformer set has a lot to do with this model . A dull existence for a lack of better description . If it was a hi fi transformer set it would have been night and day . This just enforces my position on the 12 series transformers as having the goods so to speak . Now the power transformer might be the actual key here . Remember Ed had a later 69 output in his around 79 . Perhaps his original did not last the world tour and we have the comparison between VHI with the original , dirt and all , and the later Transformer from 69 that is bolder and a bit more clear without the top end and less splatter . I
I have said this for a while now , some eight years . Today , someone , someone will finally get it . To this point the best sounding amp I ever heard was Joe Taylors 69 super trem with German EL34's. Super Huge . My head was resonating . Can you imagine that , your head resonating ? My house was resonating . The two cabinets were a Marshall 1960A and an Ampeg V4 with Celestion G12M's all from the 60's . The cabs were dancing on the floor it was soooo cool . I had played several of my Marshalls at the same day to share with Joe and I was intending on buying his supa trem with wads of cash . When it was all said and done , I ended with the last rif from ATBL and we both shook our heads . No cash was exchanged , despite my virtual begging and the head went home with Joe . Then he entered the witness protection program and I cannot find him. This cat played for Alice Cooper , Lita Ford etc etc . Joe JOe , JOE ! call me you fucker . I want that amp !

[Jeremy1283]

I gave Jeremy a dual 50uF for his PI position and I think he only needed to only drill 1 extra mounting hole for it to work. No big deal IMO.

I don't really recall where I got them but I think I got them on e-bay back in like 07 or 08 for a Small Box 100 watt project.

i drilled two holes to make it even.. no biggy

[jnew]

It's the 100K resistor in the NFB loop, where the 100uF filtering comes in and works it magic. At least by my experience.

[stef]

I like: 50 mains, 32 screens, 32 preamp, 50 PI
47k/16 NFB

[jnew]

Yep, that works too. I don' know why but I've come to like the greasy, hairy looseness of the 100K in the NFB.

[Lbrown3743]

I changed mine from 32 to 100 and i like it. Sounds alot better.