The Amp Garage

For an 18W amp in an aluminum (not steel!) chassis I'd just bolt to the chassis. Don't forget heatsink grease/paste or one of those fancy silicone pads. For a 50W amp I'd use a real adequate heatsink.

For a larger amp I'd just get an 18W amp.

If power handling is a worry and I'm worried about that MosFET, can I just add a second MosFET in parallel? I can't imagine a tube amp needing parallel MOSFETs for VVR. Thes devices are rated for high power/high current with proper heatsink. For example, the NTE2973 that is commonly seen in many VV...

My electrolytics are rated for 450V, but with a 5U4, my B+ nears 500V while warming up. Is this okay, or should I get higher rated caps? I would be nervous. I like to measure the AC voltage on pin 4 or 6 of the rectifier tube, multiply that number by 1.414, and chose filter caps with a voltage rati...

... and this I what I get when using my new favorites link. This is correct.

I can't get "Board index" or "New posts" to show any content. Only "Your Posts" and "Unread posts" work. I've tried deleting cookies, relaunch, restart; no luck. Safari browser. I have a similar issue. My MS Edge favorites link to the forum takes me directly to "Unread posts". About two weeks ago i...

johnnyreece wrote: ↑Tue May 07, 2024 1:47 pm My range is now (from memory) 2.6-4 Hz on slow, 3.9-9.6 Hz on fast.

That's a very useful frequency range.

That's the same schematic I have. All four pots in this snip are connected to ground. The 2.2K cathode resistor is also directly connected to ground. The 2.2K does not have to go through the bass pot to get to ground. Could it have been drawn more clearly? Absolutely. But that's not the Gibson way! ...

Phil_S wrote: ↑Mon May 06, 2024 7:42 pm You still have the bass pot grounded. That's a mistake. The bottom lug goes to the 2.2K and then the PI.

That's not what my schematics show. That 2.2K is the PI cathode resistor and it connects to ground. Same for the ga50 and ga50T. Has nothing to do with the bass pot.

will I need to mod the bias supply and, if so can I still get enough range to be able to return to 6L6 when wanted ? Also what If I connected a 8ohms load ? The SR sets the bias voltage to -52V. The DR sets the bias to -35V. If your bias pot can swing as low as -35V you're OK. Otherwise, a simple m...

Saywhat71 wrote: ↑Fri May 03, 2024 4:07 pm I just plugged a mixer into my light bulb limiter and the bulb lit up fast then faded. Is this normal?

Probably. But brightness is relative. All depends on the normal current draw of the device under test and the bulb wattage.

Lastly, I used the signal generator of an oscilloscope to send a sine wave thru the amp. I connected the scope to the grid of V1A (12ax7) and I get a normal sine wave. I turn on AC coupling and connect the scope to the Plate of VIA, I get a clipped sine wave. (photos attached). The clipped Sine wav...

Build something that uses the same output tubes as the donor amp.

hebaton wrote: ↑Tue Apr 30, 2024 9:59 pm THe amp I am looking at is a 1990 !

Why do you say it is a 1990? Fender was not making any Deluxe Reverbs at that time and the Reissue did not go into production until 1993.

hebaton wrote: ↑Tue Apr 30, 2024 9:59 pm THe amp I am looking at is a 1990 !
THe label inside ( tube complement ) says : Deluxe Reverb-Amp AB763

Show us what you are looking at. The AB763 Deluxe Reverb was only produced between 1963 and 1967!

https://ampwares.com/amplifiers/fender- ... xe-reverb/

I asked Bing Copilot, "When did Fender release the first 65 Deluxe Reverb reissue?"

Copilot replied, "Fender introduced the '65 Deluxe Reverb reissue in 1993."

The manual I posted was dated 1993.