I made a small tweak to the eyelet board .pdf on this. Increased the current limiter to 47R, and decreased the bleeder to 150k. Should have it drained in a minute or so.
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- Sun May 26, 2024 4:33 pm
- Forum: Dumble Discussion
- Topic: A SSS Build
- Replies: 53
- Views: 1796
- Sun May 26, 2024 12:21 pm
- Forum: Dumble Files
- Topic: ODS Eyelet Boards
- Replies: 61
- Views: 35884
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 so the positive and negative sides of the supply will have balanced current draw, and allows the voltages on both sides to drain in about ...
- Sun May 26, 2024 10:32 am
- Forum: Technical Discussion
- Topic: LAR/MAR PPIMV bypass pop noise?
- Replies: 6
- Views: 163
Re: LAR/MAR PPIMV bypass pop noise?
That isn’t going to work because the grid can’t be lifted from a 220k leak to a 2M2 leak resistor no matter what. It has to retain the 220k resistance whether it’s a parallel of the MV control or a fixed resistor. It’s going to pop loudly also because it’s an open circuit while the contact switches...
- Sat May 25, 2024 9:49 am
- Forum: Dumble Discussion
- Topic: A SSS Build
- Replies: 53
- Views: 1796
- Sat May 25, 2024 8:55 am
- Forum: Dumble Discussion
- Topic: The Much Anticipated (?) Bluesmaster Build Thread
- Replies: 107
- Views: 3475
Re: The Much Anticipated (?) Bluesmaster Build Thread
Looks great! Your questions and feedback have led to quite a few updates to the documentation, so there is some great synergy going on here.
- Fri May 24, 2024 3:54 pm
- Forum: Dumble Discussion
- Topic: A SSS Build
- Replies: 53
- Views: 1796
Re: A SSS Build
Hope that solves it!
The speaker output should be in phase with the PI input.
Yours will be the first with the new resistors added to the bipolar supply. I’ll be interested to hear how that works in hardware.
The speaker output should be in phase with the PI input.
Yours will be the first with the new resistors added to the bipolar supply. I’ll be interested to hear how that works in hardware.
- Fri May 24, 2024 2:32 pm
- Forum: Technical Discussion
- Topic: Can I Parallel 2 Mosfets in VVR?
- Replies: 38
- Views: 1098
Re: Can I Parallel 2 Mosfets in VVR?
I just found a really thorough introduction to Thermal Resistance and Heat Dissipation, and I wish I had found this a few years ago. basics_of_thermal_resistance_and_heat_dissipation_an-e.pdf If the Texas Instruments pdf above was too specific for your tastes, this Rohm Semiconductor lesson covers ...
- Thu May 23, 2024 7:56 am
- Forum: Dumble Discussion
- Topic: A SSS Build
- Replies: 53
- Views: 1796
Re: A SSS Build
Completed installation of bipolar power supply. Amp is now working again with better B+ and other voltages. Question: with the decreased voltage the bipolar supply provides V7 does this limit the clean headroom? Volume? Is there a noticeable tonal difference between the original and bipolar supplie...
- Thu May 23, 2024 7:44 am
- Forum: Technical Discussion
- Topic: Can I Parallel 2 Mosfets in VVR?
- Replies: 38
- Views: 1098
Re: Can I Parallel 2 Mosfets in VVR?
Yes. The mechanisms of the heat transfer are different, but it’s the same concept.Kagliostro wrote: ↑Tue May 21, 2024 7:17 pm Something like the dissipation of the single triode within the same envelope of a dual triode tube
ECC82.png
Franco
- Wed May 22, 2024 2:26 am
- Forum: Dumble Discussion
- Topic: A SSS Build
- Replies: 53
- Views: 1796
Re: A SSS Build
Once you have an arc occur there may be carbon tracking on the tube sockets which must be completely removed to prevent more arcing. If the socket material has been burned, replacing the socket may be necessary. So what caused the initial arcing? I think it was most likely an oscillation in the powe...
- Tue May 21, 2024 2:33 pm
- Forum: Dumble Discussion
- Topic: The Much Anticipated (?) Bluesmaster Build Thread
- Replies: 107
- Views: 3475
Re: The Much Anticipated (?) Bluesmaster Build Thread
A 1kV 10n cap across the standby might help with the pop and increase the life of the switch contacts.
The better way to shut down is to turn the AC off first. That way the power supply caps will drain through the still hot tubes.
The better way to shut down is to turn the AC off first. That way the power supply caps will drain through the still hot tubes.
- Tue May 21, 2024 10:24 am
- Forum: Dumble Discussion
- Topic: A SSS Build
- Replies: 53
- Views: 1796
Re: A SSS Build
102 amp is still on, Operate, idle-no input. Transformer is very warm, I can only keep my fingers on it for 2-3 seconds. Similar in temperature to SSS transformer. This is after nearly 4 hours operation. Would your SSS run 4h and be at a similar temperature? It has four more preamp tubes, so 1.2A m...
- Tue May 21, 2024 12:47 am
- Forum: Dumble Discussion
- Topic: 2nd Gen Build
- Replies: 86
- Views: 3955
Re: 2nd Gen Build
IMO it would be better if you could get it to cross zero.
- Mon May 20, 2024 10:33 pm
- Forum: Dumble Discussion
- Topic: The Much Anticipated (?) Bluesmaster Build Thread
- Replies: 107
- Views: 3475
Re: The Much Anticipated (?) Bluesmaster Build Thread
- The PAB isn’t quite as pronounced as my 102. Is this a function of the lift pot adjustment? Indeed. - I have the FET biased at a little over V1/Vdd=2 because of what I have on hand. If everything sounds good and there’s no noticeable voltage problems, how concerned should I be about finding the e...
- Mon May 20, 2024 5:42 pm
- Forum: Dumble Discussion
- Topic: A SSS Build
- Replies: 53
- Views: 1796
Re: A SSS Build
You could do a shorted turns test on the one you have. See https://ampgarage.com/forum/viewtopic.p ... 11#p445611
Or if you have a power meter you could try energizing the primary with everything disconnected.
Or if you have a power meter you could try energizing the primary with everything disconnected.