#102 Started. Checking in

[ayan]

I pulled the 68pf cap off the master on Tuesday and also changed the bright switch to 220pf, and the amp still seems bright without the Dumbleator. I was hoping to be able to use some of the bright switching to help tone shape my sound, but I'm still finding that the amp sounds best without them engaged. With the Dumbleator the highs are more balanced.

You could do something to "darken" the amp a bit without anything plugged into the loop. For example, wire the FX loop this way:

1. From the wiper of the amp's master volume, run a wite to the FX loop send jack (Dumble DID NOT do this, if you look carefully as pictures of amps. *)

2. To achieve normal results if you ran the wire as explained above, you you run a wire from the FX loop send lead lug to the switched lug on the FX return jack. That way, with nothing in the loop, the FX return jack (= input to the PI) would received the same signal stemming from the Master volume wiper.

3. Rather than doing 2 above, you can connect a resistor from the FX loop send lead lug to the switch lug on the FX loop return lug. You can size the resistor by putting in a pot wired as a variable resistor and dialing it in to taste. The larger the resistor, the more the highs will be attenuated. Once you use the FX loop in the amp, the switch lug no longer plays a role and everything will be "back to normal."

(*) For some reason, Dumble seemed to always run the wiper of the master volume to the switch lug on the FX return jack and from there, run another wire to the FX send lead lug. One exception to this was 124, where Dumble ran the master volume wire to the FX return switch lug and from it ran a 250pF//220K network to the FX send jack, such that the sound sent to the Dumbleator would be slightly brighter than the sound of the amp without using the loop.

Cheers,

Gil

[10thTx]

I'll offer my two cents worth.

I don't build D clones, but do build D-style inspired amps such as this Tweed BluezMeister.

The "enchance" cap (indicated with red) smoothed out the highs in three different amps that I own. I did not eliminate the highs, but smoothed out the tone in the high frequency. In two of my amps, I found the "tamed" highs allowed more blooming to take place.

The enhance cap is a super simple mod you can carefully try with a cap and two insulated alligator clip wires.

The cap circled in blue is a smoothing cap design that we see on numerous amps. However, please note that it is after the .033 coupling caps instead of before them.

A guy on the Hoffman forum discovered placing this cap after the coupling caps did not mute and kill the tone compared to placing the caps before the coupling caps. I tried it both ways on one of my amps & the placement did make a difference. The amp sounded lifeless and muted with that cap prior to the coupling caps. The cap after helped smooth out the harshness in the high frequencies. I actually don't have this cap on the Tweed BluezMeister as it is not needed on this amp. I do use it on another amp.

My personal conclusion was that I did not need to "darken" the tone, I simply needed to smooth out the high frequencies. I called it an enhance cap because it seemed to enhance the blooming effect.

With respect, 10thtx

[Structo]

Do you also find that the "fizz" cap on the PI output works better after the coupling caps?

Most of the time it is placed between the plates and plate resistors.

[10thTx]

Do you also find that the "fizz" cap on the PI output works better after the coupling caps?

I am not sure I understand the question? The schematic reflects what worked best for me trying different arrangements of "smoothing" caps. I also tried some other ideas that are not on the schematic but didn't care for them. A cap (like the 22p) across the LTPI plates like on some Fenders, just muted the tone and left it lifeless to my ears.

The cap across the LTPI plate made the most significant improvement. I think the high end harshness may have been a subtle oscillation issue & that the "enhance" cap removing that allowed the blooming dynamic to be more pronounced. Just a guess on my part? I could not hear a loss to the high frequency, just a smoother tone to the high frequency.

With respect, 10thtx

[Structo]

Thanks for the clarification.

[amplifiednation]

These are interesting suggesions. Man there is a lot of ways to skin the treble cat! Thanks guys. The amp sounds killer...but I want more control.

[ayan]

Well, I understood you had said the amp was too bright without the Dumbleator, and I think what I suggested will address that without chaning the sound when the Dumbleator is used. If the amp is too bright always, then we're talking about something entirely different. The question would be if it's too bright in clean mode as well, which I would suspect is not the case. If you put a non-trivial cap across one of the PI plate load resistors as suggested, you probably will dull the clean sound a bit, in addition to "smooothing" the overdrive.

Gil

These are interesting suggesions. Man there is a lot of ways to skin the treble cat! Thanks guys. The amp sounds killer...but I want more control.