Tube Amp Archive

https://vintagefenderamprepair.com/blogs/information/fender-date-codes If the page referenced is correct, the "OI" on the tubes charts would denote September 1965 I once knew what the "Production" # was but cant seem to find the info. But as Martin mentioned, look for the rubber-stamped code inside ...

I have added a fitted secondary plate on a few. Stiffens things up quite a bit.

As I mentioned to you in the other thread you posted on this, I built a (massive) bass amp for a friend and it is paired with two 15" TL606 Thiele cabs each loaded with Eminence 15" speakers. The amp has four 6550s running in ultralinear for about 140Wrms. The entire power supply is choke filtered ...

You might want to look into the fEARful bass cab plans that were/are out there, as those have an extended range as they include a mid driver. I was an early adopter of the TL cabs and gigged for decades (on bass) with a pair of TL606s, which I still have. I also used many TL806s for PA, monitors, et...

Forgot to mention that the Rigol also has VESA mounting points so you can mount it off the bench on an articulated TV mount.

Have you tried cleaning the boards and removing the wax. Lyle Caldwell claims it fixes the issue, though from my experience there was a slight amount of voltage conducting through the board. I had seen his videos & DID try cleaning, then deep cleaning, but no luck. They were really, really caked wi...

Rigol DHO804 you can unlock all the features with hack I was typing & looking for a pic, as nekors reply posted. I am fairly new to scopes myself & after some learning time with a borrowed 20yo scope, I bought a DHO804 last year. I think most of the new digital scopes have pretty similar capabiliti...

Those are pretty tricky, hadn't seen them before.

I have been generally switching over to radials, those offer one more option.

I have done the "heaters on a 6V battery" thing a few times at a similar point, chasing an issue.

It can potentially eliminate the heaters as the culprit.

I am following this out of interest, but I have no real knowledge of SS & while I understand the concept, I am at a loss to imagine the implementation (mostly).

Could you guys maybe rough-out a sketch of how something like this would work?

^^^ I had a couple of thoughts/questions after you made that same point in another thread a day or so ago. Wouldn't the issue be dependent on what is plugged into the FX loop? A piece of rack gear would probably prefer a low impedance signal but pedals are usually getting a direct signal from the in...

Very nice build.

Watched the video as well. I appreciated the thorough explanation & thinking behind the design (as well as the documentation)

I am dabbling in the same general area; lower wattage with less-typical tubes in a compact form-factor.

pdf64 wrote: ↑Tue Aug 26, 2025 2:22 pm Do you realise that a 250k send level pot totally negates the low output impedance of the preceding buffer?

That is an interesting point that I hadn't thought of.

This looks like a drop-in MOSFET conversion of the Dumbleator schematic (that has a 250K pot in that postition)

You might find this chart useful, if you don't already have it. Something I grabbed from somewhere.

That looks very nice. I had a nearly identical build that I made a head cab for, but I tried to put the reverb tank in the bottom of the same cab, in a separate compartment with shielding. But I could NOT get it quiet & ended up making it a combo to get the physical distance for the tank, away from ...