Search found 13281 matches

by martin manning
Mon May 27, 2024 10:22 am
Forum: Garage Talk
Topic: Anyone else having issues with the board?
Replies: 12
Views: 1920

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...
by martin manning
Sun May 26, 2024 9:30 pm
Forum: Garage Talk
Topic: He's no James brown
Replies: 3
Views: 127

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
by martin manning
Sun May 26, 2024 4:33 pm
Forum: Dumble Discussion
Topic: A SSS Build
Replies: 54
Views: 1937

Re: A SSS Build

GAStan wrote: Sat May 25, 2024 2:35 amThe bleeder is definitely a good idea.
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.
by martin manning
Sun May 26, 2024 12:21 pm
Forum: Dumble Files
Topic: ODS Eyelet Boards
Replies: 61
Views: 36030

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...
by martin manning
Sun May 26, 2024 10:32 am
Forum: Technical Discussion
Topic: LAR/MAR PPIMV bypass pop noise?
Replies: 7
Views: 246

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...
by martin manning
Sat May 25, 2024 9:49 am
Forum: Dumble Discussion
Topic: A SSS Build
Replies: 54
Views: 1937

Re: A SSS Build

GAStan wrote: Sat May 25, 2024 2:35 am The bleeder is definitely a good idea. The +170 volt caps were still at 50vdc after sitting overnight before I added it.
Credit Tony D for that idea.
by martin manning
Sat May 25, 2024 8:55 am
Forum: Dumble Discussion
Topic: The Much Anticipated (?) Bluesmaster Build Thread
Replies: 107
Views: 3547

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.
by martin manning
Fri May 24, 2024 3:54 pm
Forum: Dumble Discussion
Topic: A SSS Build
Replies: 54
Views: 1937

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.
by martin manning
Fri May 24, 2024 2:32 pm
Forum: Technical Discussion
Topic: Can I Parallel 2 Mosfets in VVR?
Replies: 38
Views: 1182

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 ...
by martin manning
Thu May 23, 2024 7:56 am
Forum: Dumble Discussion
Topic: A SSS Build
Replies: 54
Views: 1937

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...
by martin manning
Thu May 23, 2024 7:44 am
Forum: Technical Discussion
Topic: Can I Parallel 2 Mosfets in VVR?
Replies: 38
Views: 1182

Re: Can I Parallel 2 Mosfets in VVR?

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
Yes. The mechanisms of the heat transfer are different, but it’s the same concept.
by martin manning
Wed May 22, 2024 2:26 am
Forum: Dumble Discussion
Topic: A SSS Build
Replies: 54
Views: 1937

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...
by martin manning
Tue May 21, 2024 2:33 pm
Forum: Dumble Discussion
Topic: The Much Anticipated (?) Bluesmaster Build Thread
Replies: 107
Views: 3547

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.
by martin manning
Tue May 21, 2024 10:24 am
Forum: Dumble Discussion
Topic: A SSS Build
Replies: 54
Views: 1937

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...
by martin manning
Tue May 21, 2024 12:47 am
Forum: Dumble Discussion
Topic: 2nd Gen Build
Replies: 86
Views: 4038

Re: 2nd Gen Build

IMO it would be better if you could get it to cross zero.