Search found 13292 matches
- Wed May 29, 2024 9:48 pm
- Forum: Dumble Discussion
- Topic: ODS Inspired Build; #102 Values with Buffered FX Loop
- Replies: 24
- Views: 1681
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: 418
Re: The balance trimmer this stranger
Franco, DC balance and AC balance are two different things. First, get the DC balance (idle bias current) 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 just means put the tube with the highe...
- Wed May 29, 2024 2:17 pm
- Forum: Technical Discussion
- Topic: Taming amp gain in single channel deluxe reverb build
- Replies: 71
- Views: 2885
- Wed May 29, 2024 1:52 pm
- Forum: Technical Discussion
- Topic: Taming amp gain in single channel deluxe reverb build
- Replies: 71
- Views: 2885
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: 71
- Views: 2885
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: 1619
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: 4669
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: 10
- Views: 201
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: 4669
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...
- Tue May 28, 2024 10:26 am
- Forum: Technical Discussion
- Topic: What do you think causes pins 2 and 3 to arc in octal sockets.
- Replies: 10
- Views: 201
Re: What do you think causes pins 2 and 3 to arc in octal sockets.
I was talking to someone on You Tube about the octal sockets burning between pins 2 and 3. His opinion was that it’s caused by flyback from a speaker connection going open circuit. I don’t know if I entirely believe this (of course I could be wrong) as it would be easier for the arc to go through a...
- Mon May 27, 2024 1:31 pm
- Forum: Technical Discussion
- Topic: Cathode follower for compression
- Replies: 19
- Views: 1619
Re: Cathode follower for compression
I don't know how similar the effect would be, but I'd guess that a JFET source follower would be a better bet.
- Mon May 27, 2024 10:22 am
- Forum: Garage Talk
- Topic: Anyone else having issues with the board?
- Replies: 17
- Views: 3237
Re: Anyone else having issues with the board?
Is anyone actively administering this forum at this point? I see two posts by a new user at the top of Technical Discussion and Garage Talk which appear to be AI-generated or something in that vein. I think those have been taken down now. If you spot something, it seems like the thing to do is clic...
- Sun May 26, 2024 9:30 pm
- Forum: Garage Talk
- Topic: He's no James brown
- Replies: 3
- Views: 185
Re: He's no James brown
You're right, of course, he's no James Brown, but nobody is... https://www.youtube.com/watch?v=zieXmNwHGYA
- Sun May 26, 2024 4:33 pm
- Forum: Dumble Discussion
- Topic: A SSS Build
- Replies: 54
- Views: 2307
- Sun May 26, 2024 12:21 pm
- Forum: Dumble Files
- Topic: ODS Eyelet Boards
- Replies: 61
- Views: 36487
Re: SSS Bipolar Supply Update
The SSS bipolar driver supply board in the first post has been updated again with some fine tuning. The bleeder resistor mentioned above has been reduced to 150k to balance the current draw on the positive and negative sides, and to allow the voltages on both sides to drain in about a minute after s...