SE amp power supply filtering 'bloom/note flipping/feedback'

[JD0x0]

I recently bumped the filter caps for the power tube screens and B+ and the amp seemed to loose a lot of bloom and sustaining feedback, in exchange, for a healthier sounding low end, sharper/faster attack. I thought class A amps didn't really sag, so what would explain the perceived change? My voltages appear to measure about the same. Would tighter filtering on the screens cause this?

I'm trying to find a compromise between the sustain/feedback and the tighter low end. I want to keep the cleaner, faster responding bass, without losing that feeling that your notes want to keep going, and get bigger after the attack. The amp seems to have lost that to a large degree, after I increased the filtering.

[Stevem]

Yup that's the way things go at times!

Order up a Groovetubes 6V6s in a number 1 or 2 rating , you will likely have to wait out a order period for these as most places only stock rating 5.

[rp]

I'm trying to find a compromise between the sustain/feedback and the tighter low end.

I don't think that tighter low end is ever going to happen, to me tight low end means punch, punch means moving a lot of air fast, you can make it faster but at 9Ws you're not going to move enough air. IMO you can chase your tail, or get to work on a bigger amp.

IME w/ tweed Champs they sound much better with lower filtering, really low like stock tweed. You get a fatter more 3D sound. Not sure Fender did that intentionally as in the BF Champs they upped the filtering a lot. But there's something to be said about loose filtering where tightening/focusing the sound is kind of pointless, if not detrimental as, again, the looseness helps it sound bigger. Sometimes shitty is good.

I've built a couple 5F1s stock, even played into 12"s and they don't hum, so no real need go up the filtering.

[JD0x0]

I'm trying to find a compromise between the sustain/feedback and the tighter low end.

I don't think that tighter low end is ever going to happen, to me tight low end means punch, punch means moving a lot of air fast, you can make it faster but at 9Ws you're not going to move enough air. IMO you can chase your tail, or get to work on a bigger amp.

IME w/ tweed Champs they sound much better with lower filtering, really low like stock tweed. You get a fatter more 3D sound. Not sure Fender did that intentionally as in the BF Champs they upped the filtering a lot. But there's something to be said about loose filtering where tightening/focusing the sound is kind of pointless, if not detrimental as, again, the looseness helps it sound bigger. Sometimes shitty is good.

I've built a couple 5F1s stock, even played into 12"s and they don't hum, so no real need go up the filtering.

I seem to have gotten the lows into a pretty good place, I'm using a 5881 output tube, BTW, and the amp can be pretty big and punchy through my 2x12 closed back, considering its singled ended, low wattage.

I have some lower value filter caps coming, but it's interesting looking at Dumble's mods which are more heavily filtered than Fender's stock designs, yet his amps sound huge.

I had doubled the C41 and C43 capacitance and I like the tighter feel to a degree, the low notes come out way cleaner and more defined, with the amp cranked. Maybe reducing the filtering on the screen will do the trick.

[pdf64]

Class of operation loses relevance when the power section is overdriven.
A class A tube may draw more or less current as signal rises towards and beyond that, which way it goes may be influenced by various factors, eg symmetry of the signal fed into it, bias point (eg hot, centre, cold), HT sag, bias shift, squish.
There's a heavy blanket of capacitance, especially on the screen grid node, which may act to keep the tube's operating point overly stable, rather than allow it breathe / stagger then recover when it's hit hard.

[JD0x0]

Dropping some of the filtering back down seemed to have helped. I added a choke to the amp and that ended up stiffening it up even more, so dropping the preamp and screen filtering seemed to bring it to a pretty happy place. The amp is still really tight, which I like, but it 'breathes' a little better, now.

[JD0x0]

Had my friend test the amp with his new pickups I installed. Gainy little bugger. We had the VVR dialed way back to keep the volume reasonable, and the camera mic from clipping.

We were getting killer tone going straight in, but for the video he's going through his M13 for compression and delay, for one part. Drive is all from the amp, though. Gain was about 3/4 of the way up and volume was set at about 50%

[Stevem]

Try out bypassing your main filter and your last filter one at a time with a .22 and a .022 cap both in parallel .

[JD0x0]

Try out bypassing your main filter and your last filter one at a time with a .22 and a .022 cap both in parallel .

I'll give that a try, though I'm not sure how profound the effect will be, I tried to spring for low ESR caps