The Amp Garage

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...

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...

I don't know how similar the effect would be, but I'd guess that a JFET source follower would be a better bet.

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...

You're right, of course, he's no James Brown, but nobody is... https://www.youtube.com/watch?v=zieXmNwHGYA

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.

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...

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...

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.

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.

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.

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 ...

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...

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.

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...