Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: dpm309 on March 06, 2022, 11:57:04 am

Title: 5E3 Dumble Mods
Post by: dpm309 on March 06, 2022, 11:57:04 am

I am in the process of doing some Dumble mods to my 5E3. This was my first build and I have already added a PPI master volume and tied both channels together. Came across this site: https://robrobinette.com/Generic_Tube_Amp_Mods.htm#Dumble_Tweedle_Dee_Mods and the mods look fairly simple and inexpensive and can easily be reversed if needed. Ordered a GZ34 rectifier and some 33uf/450V filter caps. This is one of my favorite builds and I am always looking at ways to improve the tone. I'll report back after I finish the mods.DPM

Title: Re: 5E3 Dumble Mods
Post by: Keppy on March 06, 2022, 05:57:23 pm

Very cool, looking forward to your report!

Title: Re: 5E3 Dumble Mods
Post by: dpm309 on March 10, 2022, 04:40:31 pm

Just finished the mods and it sounds great. Tightened up the bottom end and gives the amp a sweeter tone. The GZ34 raised the plate voltages and B+ Voltages.V1:  P1 184vdc, P6 205vdc.  V2: P1 208vdc, P6 257vdc.  V3: P3 384vdc, P4 386vdc, P8 26vdc. V4: P3 387vdc, Pin 4 386vdc, P8 26vdc. B+1 392vdc, B+2 390vdc and B+3 306vdc.This was a fairly inexpensive mod (GZ34 and some caps and resistors) and I think it was well worth the time.

Title: Re: 5E3 Dumble Mods
Post by: Madjackhatter on March 13, 2022, 10:09:35 am

Two questions for you! I have built a few as well as having a real deal Tweed Deluxe in my stable. Big 5E3 fan...
Did the choppy break up in the PI clear up from the  local NFB loop on the PI socket along with the tail load zister change. ??? I have had a few other ways I addressed that but I'm very curious.
 Also did you use the 10k balance pot or skip it? That part of the Dumble 5E3 has always peaked my interest but is a skipped part of the mod a lot of times.