badgerline wrote: ↑Thu Sep 06, 2018 5:14 pm
I just installed a 100pF snubber at the PI plates, then a 100pF from plate to ground at V1b and V2a (cold clipper). Each reduced hiss - together, it's almost non-existent. The one at the cold clipper also drastically improved the smoothness of transition into overdrive, which had been bothering me a bit.
I'm now so happy with the tone, feel, and low noise of the amp that I think I'll stop tweaking and maybe start playing guitar through it like a regular guy.
It took me a while the get curious about the TW family. Got very interested lately and decided to add the liverpool cold clipper stage on a fender deluxe reverb style amp. I landed at 0.005uF (tried 0.0015, 0.0025 and 0.0033 before) and 72K to ground with 100kb trimmer (tried 33k, 56k, 68k, 120k and 150k resistors before). I also added a 0.05uF coupling after the triode and 1M to ground to tame a touch of high end. I really like the AC30 style top end and the feeling of the notes under the fingers but the hiss (due to the amount of gain probably) Is a bummer. I have tried a 250pf and 500pf between plate (pin6) and cathde (pin8) but although it reduced some of the hiss, it took alway the high end feel. Also tried in parallel with the 1M a few caps to ground (from 15pF all the way to 0.0033uF, the latter being the only one that really got rid of the hiss made the amp sound like a guitar tone pot closed, very muffed).
I am curious to try the 100pF from plate to ground. Do you go from PIN 6 (or 1) to ground or from B+?
Check out the Dave Funk picture of the Liverpool he built when Ken Fischer was ill. It has a ten turn potion series with a cap. This is done to reduce gain, it also fattens up the tone of the amp.
Mark wrote: ↑Sun Oct 04, 2020 8:22 am
Check out the Dave Funk picture of the Liverpool he built when Ken Fischer was ill. It has a ten turn potion series with a cap. This is done to reduce gain, it also fattens up the tone of the amp.
Thanks for the tip Mark, looks like a cap between B+ and the plates and another across the cold clipper stage plate. Plus the ceramic in parallel with the orange drop. Any idea on the values of these 3 caps?
Sorry, I can’t remember the value of the cap, I think there is a thread here somewhere that discussed these values. It will be quite high, like 0.001uF to 0.005uF. I think I tried an 0.022uF at one stage.
Mark wrote: ↑Sun Oct 04, 2020 11:18 am
Sorry, I can’t remember the value of the cap, I think there is a thread here somewhere that discussed these values. It will be quite high, like 0.001uF to 0.005uF. I think I tried an 0.022uF at one stage.
Thanks Mark, I searched for Dave Funk and came across a lot of heated conversations lol. Then I searched for Malou but did not find what I was looking for.
Nevertheless I tried the .0015uF across the plates. Rolls off a lot of highs and makes the amp sound like a Marshal Plexi (rather than a Vox). I dig and will leave as it. Hiss is gone with so much treble roll off as well. Thanks for the tips.