layout differences

[phsyconoodler]

I was just looking over the D'Lite layout and the Ceriatone layouts and there are some differences.The D'Lite shows the left lug of the presence pot grounded and the Ceriatone is not.
Then the two 22meg resistors on V1b are in series with the cap and the ceriatone's are on either side of the cap.
These are quite a bit different in my book,and I was wondering which one is right?
I wired my presence like the D'Lite and it does indeed work,and my two 22megs are the same as the D'Lite and again they do work.
I could just try the other way and see how it sounds I suppose,but it would be nice to know which one is better.

[Normster]

The presence control wiring on the D'Lite was my "mis-interpretation" of the Hybrid-A schematic. It does work and does add its own character to the amp, but the Ceriatone wiring is the correct way for a Dumble. The D'Lite presence was, IMHO, a "happy accident." Try it both ways, but I think you'll find the Dumble method provides more available upper frequency cut.

The 22M resistors can be done either way, but I prefer running the cap directly to the plate and putting both resistors on the grid side. You might be able to hear the difference between the two methods, but it would be too subtle to worry about, IMO.

[Funkalicousgroove]

The "Correct" Implemintation of the 22M resistors is on either side of the cap.

[heisthl]

RE: LFB
Tone wise I can't hear a difference but the correct way lays out better if you're using a terminal strip at the rear of the tube, plate has22m to strip, .05 (or.047) is mounted on the strip, and 22m to grid.
The other way allows you to ground the loop so you can put it on a switch or relay. Grounding point "B" in the picture disables the loop:

[greiswig]

RE: LFB
Tone wise I can't hear a difference but the correct way lays out better if you're using a terminal strip at the rear of the tube, plate has22m to strip, .05 (or.047) is mounted on the strip, and 22m to grid.
The other way allows you to ground the loop so you can put it on a switch or relay. Grounding point "B" in the picture disables the loop:

heisthl, what is the difference between grounding that point and just creating an open between the cap and resistors? I did the latter on mine, and have a 3-way switch: open/44m/66m. It is a neat tone control, but the open position is probably several db hotter than the others.

[heisthl]

no pop and no volume change

[greiswig]

no pop and no volume change

I don't have a pop currently, but I was hoping you'd say that about the volume change. Thanks!

[Funkalicousgroove]

Here it is in #195

[Funkalicousgroove]

#124

[greiswig]

I'm sorry if this is hijacking the thread, but...

Other than the switching advantage that heisthl spoke of, what particular difference does it make whether the two resistors are on either side of the cap or on only one? Does isolating the cap on both sides really sound different?

[phsyconoodler]

I'm going to find out by trying it both ways on the next build.

Thanks for the info guys!

[rutledj]

Can someone clue me in as to what exactly this feedback network does tonewise. What would be the result of removing it?

Rut

[phsyconoodler]

It extends the clean range of the amp before it breaks up.And it makes the amp fart out less on lower notes.I have tried it an other makes and circuits and it does indeed extend the clean headroom.
It makes the sound 'tighter' and more focused.

[Andy Le Blanc]

it looks like an anode follower
havent tried one yet
but that looks like a usefull little thing