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.
Search found 13274 matches
- Fri May 24, 2024 3:54 pm
- Forum: Dumble Discussion
- Topic: A SSS Build
- Replies: 51
- Views: 1528
- Fri May 24, 2024 2:32 pm
- Forum: Technical Discussion
- Topic: Can I Parallel 2 Mosfets in VVR?
- Replies: 38
- Views: 974
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: 51
- Views: 1528
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: 974
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
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Franco
- Wed May 22, 2024 2:26 am
- Forum: Dumble Discussion
- Topic: A SSS Build
- Replies: 51
- Views: 1528
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: 105
- Views: 3253
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: 51
- Views: 1528
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: 84
- Views: 3800
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: 105
- Views: 3253
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: 51
- Views: 1528
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.
- Mon May 20, 2024 3:51 pm
- Forum: Dumble Discussion
- Topic: A SSS Build
- Replies: 51
- Views: 1528
- Mon May 20, 2024 2:21 pm
- Forum: Dumble Discussion
- Topic: 2nd Gen Build
- Replies: 84
- Views: 3800
Re: 2nd Gen Build
That lead me to recall some prior discussions here that you are not really balancing the PI as much as the whole power amp. Is that a fair statement or am I misunderstanding? You are correct. The best approach is to arrange the power tubes to get the best DC balance, and then use the PI trimmer to ...
- Mon May 20, 2024 12:55 pm
- Forum: Dumble Discussion
- Topic: 2nd Gen Build
- Replies: 84
- Views: 3800
Re: 2nd Gen Build
I think with 51k/47k plate loads and 22k tail as shown in the 2nd Gen layout, a perfectly matched 12AT7 would have very nearly balanced outputs. Any particular tube might be off in either direction, so keeping the original offset in place with a +/- capability via the trimmer would be the way to go.
- Mon May 20, 2024 9:10 am
- Forum: Dumble Discussion
- Topic: The Much Anticipated (?) Bluesmaster Build Thread
- Replies: 105
- Views: 3253
Re: The Much Anticipated (?) Bluesmaster Build Thread
Frankly, I'm sick of this. If you don't believe it or refuse to try it, good for you, whatever... Marc clearly heard a difference, as have numerous other folks, I applaud him for trying it for himself and making up his own mind. I have never said that I don't believe it makes any difference (and I ...
- Mon May 20, 2024 8:46 am
- Forum: Dumble Discussion
- Topic: 2nd Gen Build
- Replies: 84
- Views: 3800
Re: 2nd Gen Build
While waiting on some parts to arrive I "balanced" the PI. Scare quotes because with the 5K trimmer I installed and the tubes in the amp, I could get close using the ampeg method but not all the way to a 0v offset. It settled around 1.7. I do have another 12AT7 and may try that to see if it gets me...