Tube Amp Archive

Can you achieve 10 volts to the speaker or a 8 ohm load like the schematic says should be able to be done?

Do you have a O-scope?

When you excite the piezo’s do you read any Voltage out of them? If any of the grounds for this circuit are landed on the hold down of any terminal strip that this amp is made with be sure to do a resistance check as many times the rivites that hold them to the chassis loosen up over the years and t...

You might be interested in looking at the schematic for a Univox U45B model which can be found on line. This uses the triode sections as a driver and a splitter. It runs on a little under 300 volts to the output tube plates. I have two of these amps and every one who plays it cranked is amazed at ho...

So it’s outputting a sound unrelated to the notes your .playing, besides distorting?

It may be time for all new power supply filters.

I would also check the two plate load resistors on V3, as one may be open or changed in value drastically.

These amps are also known for blown output transformers.

Forget the stock reverb! It’s like my Sears 1484 reverb tank with its ceramic phono cartridge at each end of what amounts to a back door return spring! Get yourself a SS reverb block that powers up with 5 volts if you want the verb to work. Just replace c21,24,25 and 26 and then with a good tube the...

I would go with the 10 watt Hammond 123DSE if you will someday run two in parallel.

You will probably be hearing more of the 12n then the 12q since the 12N is much more efficient then the 12q! Also while your out & about in there I would up that 5 watt cathode resistor to 7 watts, or maybe for 10 cents more and even better stability go for 10 watts. Gez, even a blk or silver fa...

It would be a interesting test out, but I think the electrons are traveling to short of a distance to be defected like they are in even a small length CRT in a scope. I would also think that if electron’s where being manipulated that it would be more likely below a certain level of V+ . Also let’s n...

Any Ot that works for 6v6 will work fine for a 6AQ5

Since that pot’s case is at ground then just land the shield there.

I also think I would try and use a pot with a nylon shaft, or atleast no full metal knob.

If this is to be a internal multi turn trim pot then disregard what I just posted.

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Parafeed?
Wait a minute now, unless there’s a internal issue with the OT there’s no dc on the secondary side of the OT anyway!

I recall playing thru this exact model amp when I was younger and fully recall being very unimpressed with it! In fact it did not even sound as good as my very beat up Deluxe with 6V6 tubes and only one speaker. It may not be true to the original, but I would leave that choke out! It’s a odd thing b...

A coworker a few weeks ago asked me what the heck could be happening with the bulb in his son’s pet snake tank burning out every 4 days, so I lent him my spare voltmeter to take home and check things out . It turns out he had 137 volts at his wall outlets!! I had him that very minute call his power ...

If there is a weight difference between the two and you would like the bottom end to hold together a tad better then how the original Fender one did then go for the one with more mass.