Search found 13298 matches
- Sun Jun 02, 2024 7:24 pm
- Forum: Technical Discussion
- Topic: Tremolo Changes after EL84 to 6V6 Swap
- Replies: 7
- Views: 276
Re: Tremolo Changes after EL84 to 6V6 Swap
Not sure what the amplitude coming out of the 8038 will be, but guessing 10V p-p I would try something like this. It should get the positive swing up to ~0V at max intensity. The right side is 6G9-B Tremolux.
- Sun Jun 02, 2024 5:54 pm
- Forum: Technical Discussion
- Topic: OT mounted to speaker
- Replies: 8
- Views: 256
Re: OT mounted to speaker
It was very common on radios, which usually had a low-power single-ended audio output stage. My best guess is that it was done to save chassis space for other things. Did I win?
- Sun Jun 02, 2024 11:51 am
- Forum: Technical Discussion
- Topic: What do you think causes pins 2 and 3 to arc in octal sockets.
- Replies: 21
- Views: 490
Re: What do you think causes pins 2 and 3 to arc in octal sockets.
I always connect a load when the output tubes are installed. If an oscillation starts, the amp will create its own signal.
- Fri May 31, 2024 12:51 am
- Forum: Dumble Discussion
- Topic: Starting a 100 Watt #124 Build
- Replies: 4
- Views: 244
Re: Starting a 100 Watt #124 Build
Could anyone guide me to a good source for the 300uF 350V electrolytic capacitors, as well as the 2kL pot for the presence control? As suggested above, 330u snap-in caps are readily available, and it’s easy to convert the all-axial cap board to all- or part-radial. For the presence pot, a 5k with a...
- Thu May 30, 2024 3:36 pm
- Forum: Technical Discussion
- Topic: Taming amp gain in single channel deluxe reverb build
- Replies: 78
- Views: 3312
- Thu May 30, 2024 1:41 pm
- Forum: Technical Discussion
- Topic: Taming amp gain in single channel deluxe reverb build
- Replies: 78
- Views: 3312
Re: Taming amp gain in single channel deluxe reverb build
I don’t have my notes in front of me(on tour) but the 6v6s were right at 420 and all of the preamps were pretty much right in spec with the deluxe schematic. So thinking 185-190 on v1, etc. Nothing much higher or lower than spec. My bias was taken off the hv winding and I implemented Merlin’s bias ...
- Wed May 29, 2024 9:48 pm
- Forum: Dumble Discussion
- Topic: ODS Inspired Build; #102 Values with Buffered FX Loop
- Replies: 24
- Views: 1877
Re: ODS Inspired Build; #102 Values with Buffered FX Loop
Jumpering across the 2k2 between B+2/4 gives 280/285 close enough to what 102 has (and highest I can get). I understand this combines the two power stages and puts the filtering caps in parallel. Is this going to cause any adverse affects? Any reason not to replace this 2k2 with a wire? If you do t...
- Wed May 29, 2024 9:05 pm
- Forum: Dumble Discussion
- Topic: The balance trimmer this stranger
- Replies: 8
- Views: 524
Re: The balance trimmer this stranger
Franco, DC balance and AC balance are two different things. First, get the DC balance (idle bias current) on each side of the power stage to match as closely as possible. Use matched tubes and/or swap pairs from side to side for the best balance. With four power tubes, this means placing the tube wi...
- Wed May 29, 2024 2:17 pm
- Forum: Technical Discussion
- Topic: Taming amp gain in single channel deluxe reverb build
- Replies: 78
- Views: 3312
- Wed May 29, 2024 1:52 pm
- Forum: Technical Discussion
- Topic: Taming amp gain in single channel deluxe reverb build
- Replies: 78
- Views: 3312
Re: Taming amp gain in single channel deluxe reverb build
Ok, cool. I'll fix up the schematic based on the above.
- Wed May 29, 2024 1:35 pm
- Forum: Technical Discussion
- Topic: Taming amp gain in single channel deluxe reverb build
- Replies: 78
- Views: 3312
Re: Taming amp gain in single channel deluxe reverb build
I was thinking the same thing... I read through the thread and tried to capture the changes in the attached.
(updated)
(updated)
- Tue May 28, 2024 10:18 pm
- Forum: Technical Discussion
- Topic: Cathode follower for compression
- Replies: 19
- Views: 1676
Re: Cathode follower for compression
But JFETs lack an equivalent to a triode’s grid current, which IIRC is supposed to play a significant role in the DCCF’s compression effect.
- Tue May 28, 2024 12:19 pm
- Forum: Dumble Discussion
- Topic: 2nd Gen Build
- Replies: 95
- Views: 4989
Re: 2nd Gen Build
Thanks for the run down on using the ratio pot. I recall HAD saying in some article or interview that the Ratio control was a great feature on the ODS. Must have been shortly after its introduction. I may give the scope a try again before boxing up the amp. I remember when I built the #102, that I c...
- Tue May 28, 2024 11:53 am
- Forum: Technical Discussion
- Topic: What do you think causes pins 2 and 3 to arc in octal sockets.
- Replies: 21
- Views: 490
Re: What do you think causes pins 2 and 3 to arc in octal sockets.
How is this flyback voltage generated. The individual claimed it was from an open circuit on the secondary. I had heard people claim an open circuit secondary leads to shorted turns because the insulation is damaged, but I haven’t heard it affecting the parts in primary. Given that the amp in quest...
- Tue May 28, 2024 11:03 am
- Forum: Dumble Discussion
- Topic: 2nd Gen Build
- Replies: 95
- Views: 4989
Re: 2nd Gen Build
Very nice! If you find that you are using one setting for the Ratio control, you could replace it with a fixed divider, but I'm interested to hear how you are using it. IMO the ODS was a continuously evolving concept, with the changes HAD made over the generations being improvements. For the PI bala...