Search found 1073 matches

by Charlie Wilson
Thu Mar 21, 2024 6:15 pm
Forum: Dumble Discussion
Topic: Choke Selection Question-Dumble Reverb
Replies: 15
Views: 655

Re: Choke Selection Question

... how much more current draw does the voltage doubler circuit put on the transformer? I'd say at least four times the DC current, but the waveform is spiky and will peak at a much higher value depending upon the DC resistance and reservoir capacitors. For this case I'm getting 65 mA peak and 25mA...
by Charlie Wilson
Mon Mar 18, 2024 2:09 am
Forum: Dumble Discussion
Topic: Choke Selection Question-Dumble Reverb
Replies: 15
Views: 655

Re: Choke Selection Question-Dumble Reverb

Hey look at that, thanks. The only thing that I wonder about is the 300VDC rating.
CW
by Charlie Wilson
Sun Mar 17, 2024 3:20 am
Forum: Dumble Discussion
Topic: Choke Selection Question-Dumble Reverb
Replies: 15
Views: 655

Re: Choke Selection Question-Dumble Reverb

Although not a choke question, another interesting thing about this device is the little Triad transformer used as the reverb driver. It is a S-13X which has a primary of 25k and a secondary of 3.2 ohms driven by a 5751 tube. So a mismatch with the 8 ohm input of the reverb pan. Not sure if he was t...
by Charlie Wilson
Sun Mar 17, 2024 1:46 am
Forum: Technical Discussion
Topic: Tweedle Dee PI - LNFB
Replies: 32
Views: 904

Re: Tweedle Dee LNFB

OK, so I am envious of being able to do all those calculations but did you, at some point, simply disconnect the LNFB and listen to the amp turned up? Do you hear a difference with it in and out of the circuit? If you don't hear a difference, then all the calculating may show why but if you do hear ...
by Charlie Wilson
Sat Mar 16, 2024 1:54 am
Forum: Dumble Discussion
Topic: C-lator hum
Replies: 170
Views: 2881

Re: C-lator hum

Are potentiometer casings referenced to ground?
CW
by Charlie Wilson
Thu Mar 14, 2024 7:14 pm
Forum: Dumble Discussion
Topic: Choke Selection Question-Dumble Reverb
Replies: 15
Views: 655

Re: Choke Selection Question

Thanks Martin.
CW
by Charlie Wilson
Thu Mar 14, 2024 2:39 am
Forum: Dumble Discussion
Topic: Choke Selection Question-Dumble Reverb
Replies: 15
Views: 655

Re: Choke Selection Question

Martin, the primary is 60 ohms and the secondary is 235.3 ohms. I wanted a transformer that would fit the existing cut out and I needed enough filament wind for 3 preamp tubes, so the 40 mA was as much as we could get for secondaries. Bill at Heyboer said he also beefed up the primary a bit. For a 6...
by Charlie Wilson
Wed Mar 13, 2024 2:56 am
Forum: Dumble Discussion
Topic: Choke Selection Question-Dumble Reverb
Replies: 15
Views: 655

Re: Choke Selection Question

Thanks guys. I can say that the device is a three tube stand alone reverb that Dumble did in the early eighties. It uses two 12ax7s and one 5751 as the reverb driver tube. The cut out for the power transformer is the venerable Triad R-2C, so 15mA DC. The hole spacing for the choke is 1 3/4", pretty ...
by Charlie Wilson
Tue Mar 12, 2024 2:08 am
Forum: Dumble Discussion
Topic: Dumbleator Filtering
Replies: 2
Views: 237

Re: Dumbleator Filtering

Thank you sir. Yeah I have built a few Dumbleators with the 47uf caps with good results. Not sure why I started to wonder about that other than seeing Brandons original post where he stated that they were 100uf. However, that post was almost 20 years ago. :D
CW
by Charlie Wilson
Tue Mar 12, 2024 1:23 am
Forum: Dumble Discussion
Topic: Choke Selection Question-Dumble Reverb
Replies: 15
Views: 655

Choke Selection Question-Dumble Reverb

Hello, I have a device that I am restoring and it was missing the power transformer and the choke. I sorted out the power transformer but I could use some help on selecting a choke. I have this in the Dumble section because it is a Dumble device but unfortunately I cannot share much more than that r...
by Charlie Wilson
Thu Mar 07, 2024 3:05 am
Forum: Dumble Discussion
Topic: Dumble ODS #22
Replies: 15
Views: 551

Re: Dumble ODS #22

The low plate classic was originally owned by Jackson Browne and lent to SRV.
CW
by Charlie Wilson
Sat Mar 02, 2024 4:32 am
Forum: Dumble Discussion
Topic: Dumbleator Filtering
Replies: 2
Views: 237

Dumbleator Filtering

Hello, I am going way back on this question. The main filtering everyone including myself seems to be using are the two 47uf in series per the schematic in the file section. However, I found a real early Brandon post where he stated that the first two caps were 100uf. So I am wondering, did we decid...
by Charlie Wilson
Fri Feb 16, 2024 2:02 am
Forum: Technical Discussion
Topic: New Astron caps?!?
Replies: 22
Views: 696

Re: New Astron caps?!?

If you want to spend a bunch of money and probably get a good sounding Astron style cap.
http://www.tweeddeluxe.com/recpro-capacitors.cfm
CW
by Charlie Wilson
Thu Oct 26, 2023 1:20 am
Forum: Fender Discussion
Topic: Current production Fender ‘65 Deluxe Reverb help
Replies: 4
Views: 10515

Re: Current production Fender ‘65 Deluxe Reverb help

So here is what is going on with this amplifier. Fender has made changes to the circuit that apparently the service department wasn't even aware of. One of the rectifier filament leads (yellow) goes to the tube socket the other (blue) goes to the circuit board. Between the rectifier filament lead an...
by Charlie Wilson
Mon Oct 16, 2023 11:16 pm
Forum: Dumble Discussion
Topic: 2nd gen chassis and pcb design?
Replies: 60
Views: 25296

Re: 2nd gen chassis and pcb design?

Yes, Overdrive Special is trademarked. As is Dumbleator and Overdrive Reverb. The trademarks are held by the Dumble estate.
CW