Can power supply filtering be overkill?

[Ripthorn]

So I am finishing my first build and trying to fix the hum that is in there and noticed that the dirty channel doesn't sound the way it did on the breadboard (submini tubes). It seems to lack some of the punch that it had on the breadboard. I am talking just the preamp (I have an effects send/preamp out that I am using right now). Then it occurred to me that the HT supply filtering might be a little much (after reading about how chokes are supposed to retain better tone). So I thought I would ask here.

My power supply filtering goes like this: PT - ss rectifier - 47u cap - 10H choke - 220u cap - 1k series resistor - 100u cap - 1k series resistor - 47u cap - preamp HT supply. Is it possible that all the caps after the choke are doing something to my tone? When the amp is on and there is no input or the guitar volume is all the way down, the thing is pretty darn silent, even the dirty channel only has a low level 120Hz hum.

So long and short, is it possible to have too much power supply filtering?

[Structo]

I think I would put the bigger cap (220uf) first in line and have the plates of the power tubes off that tap, then the choke and have the screens of of that.
Then your dropping resistor and the 47uf for the PI and so on.

Here is the pwr supply for a D'Lite.
I have successfully used this same design in several amps with just alterations to the dropping resistors to achieve the voltages I need.

Of course this shows two 100uf caps in series with the balancing resistors in parallel to them.
But just use your 220uf cap there with no balancing resistor.

The Choke mod there is just to substitute a resistor for the choke but that is where the choke should go in the chain.

Don't worry about the 220K resistor on the end, that is just to simulate the FET input on a Dumble type amp.

Hope this helps.

[BigFun3]

In a word: YES.

The PS contributes to the sound, feel and noise floor of an amp. "Over-filtered" PS circuits work well in some designs, but lose some of the interesting artifacts that makes creative ampsmanship a fun and musiccally satisfying (!!!) hobby. For example, I am very fond of pulling a little ripple into B+ when a hard transient is squirted through an amp...it creates this really neat phase-shift effect with a little "ghost-noting" trailing the transient that drops away as the note decays. Very cool in some builds and utterly disgusting in others.

Really depends on the intended goals. The super stiff supplies in some Dumble-like amps serve that platform very well!

Have fun, BF3

[Firestorm]

A lot of circuit diagrams show the power supply off to the side (or below) the main circuit. This (and the fact that a lot of us tend to think more in terms of voltage than current) makes it easy to forget that filter caps are actually in the signal path. Filter caps in preamp stages and the resistors connected to them form filters that provide a ground path for frequencies above the point set by the caps and resistors. The "rule" is larger filters first, then smaller filters as you go down the rail. Preamp filters can actually be very small because each prior stage of filtering reduces the ripple by several orders of magnitude.

[solderstain]

What I seem to be missing in your original post is whether the actual build is also being done with the same submini tubes as the breadboarded version. If so, then I'll toss in this thought... keeping in mind I've never done a build with submini tubes myself...

Looking at the filter caps you say you're using, it looks like that's a hell of a lot of filtering for something that I suspect has very little in the way of current requirements, compared to a 'big' amp. Going purely on gut instinct and my experience on amp with full-size tubes, my guess would be that your submini build is vastly over-filtered. I'd guess that the thing would sound very stiff with no 'feel'.

My $.02

[brewdude]

I seem to remember one of the very experienced well respected Dumble builders suggesting that a cap above 22uF on the PS node supplying the screen grids was detrimental to the tone and/or feel of the amp.

I have also read of people using much smaller caps for the pre-amp, say 8uF.