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This page calls out voltages for 16 and 4: www.geofex.com/ampdbug/outtrans.htm The windings only shorting under higher volumes and when warm doesn't sound likely to me.

I chose 3.25 volts in order to follow the procedure outlined here: www.geofex.com/ampdbug/outtrans.htm I also had concerns about the voltage I would see on the primary if I went with a higher voltage on the secondary.

Yes, but what's the goal? If you want to push the internal speaker and an external speaker at the same time, you would need to swap the internal to get the right ohm load with an external. If you just want to use an external cab without driving the internal speaker, you can disconnect the internal speaker and use the 1/4" output that drives it.

@@TheBrothaAB what is the ohm load on the internal speaker?

@@huanton2many 8 ohms

@@TheBrothaAB I see. Then the external and internal speaker should be 16ohm each to match the amp. Which in return means that the amp would be mismatched when played without an external cab.

I get parts from CE Distribution. I keep CTS pots on hand, and I have some up for sale on eBay. 100k = www.ebay.com/itm/276434513577 10k = www.ebay.com/itm/276434514072 1M = www.ebay.com/itm/275476444534 250k = www.ebay.com/itm/275204308255

With that amp, I would start by pulling all the tubes and testing them. I would also power the amp on, tubeless, through a light bulb limiter. I'd also check the diodes in the power supply. You don't really need to pull the power transformer to test it.

Thank ya!

Thank you!

Thank ya!

Excited!

Thank ya!

Not sure if he knows it either!

Glad to hear it! Thank ya!

Thank you!

Sorry, we don't re-tolex. I'm available to work on it. Send me an email at ABToneGroup@gmail.com.

@@TheBrothaAB Great. Thank you! Do you know anyone who does tolex?

Thank ya!

Thanks!

Thank ya! One of my favorites for sure.

i heard it just fine

I respectfully do not agree with you.

Seems like a lot of work to me.

Found the problem, broken tubes

I am not usually a fan of the silverface twins. I think they maybe do one sound well and the rest seems to come up short.

Thank you! I stumbled across LJW in the Heartworn Highways documentary. The day Spotify finally put up - and kept up - all of his recorded music was a good one.

@@TheBrothaAB I created a Blaze Foley channel on Pandora. oohoopie river bottom land played on that channel, it lead me to heart worn highway. More and more of his songs began adding to the pandora channel.

@@TheBrothaAB do you give lessons online?

@@Mendedsticks Sorry, I do not. I just have too many projects ongoing right now.

@@TheBrothaAB if you ever find time to do a LJW tutorial series, that would be awesome.

It's hard to diagnose something in a comment section, but a bad preamp tube can cause the issue you're describing. The first step is to swap the two preamp tubes with each other. This is really just to see if you get a change. If you experience a change, we can be pretty sure that the issue is preamp tube related. If you have some spare preamp tubes, or if you want to upgrade the them to something like Groove Tubes - go ahead and change them for some new ones. If that doesn't fix your issue, take it to a qualified tech because the next step would be to open it up.

thank you i am testing tubes for microphonics first and replace tube that is not sounding right if that does not work then I will take it in to professional I appreciate you answering me.

@@jamesklucky777 You're welcome! Keep us updated when the problem is solved.

@@jamesklucky777 do you solve the problem? I have the same on my pro junior 3

@@dar6497 it was the pre amp tubes that needed to be replaced!!! works great now

My dream is to have a camera angle directly above, looking down on the bench. I'm hoping in my next video I can make that happen.

They really are a bargain. Just picked up a 72 for $600. I mean wtf. New Made in China crap is 2.5x that much! GL finding a 1972 guitar for $600!

@@cgavin1 exactly!

Bought a silverface bassman last year for cheap... it's become one of the best guitar amps I ever had. So easy to work on and tweak. The only complaint I could summon up is that the chassis nuts aren't welded in place.

@@kbkman7742 All the ones I've had have been welded on. I guess over the years that really annoyed a lot of people to the extent it was a common mod. Hehe.

@@kbkman7742 , clean, rough up and degrease the metal around the mounting holes, and clean/rough-up the nuts, and glue the nuts in place with JB Weld epoxy (the slow-cure type, not JB QwikWeld). If you prep the metal well and have good gluing skills, the nuts will stay in place and won't spin when you tighten or loosen the chassis-mounting bolts. I recommend you lightly lube a quad of matching-thread bolts and put them in the nuts to keep the glue from infiltrating the threads while the glue sets.

I'm no fan of lead free solder by any means, but I've never zeroed in on it as the culprit for the issues that these amps (and the entire Hot Rod series) have with the tube PCB. I'll have to do some more research!

Thanks for the info on the Nationals! Can you speak to their quality at all? I wish I knew the history of this amp and where it picked up just one. I'm aware that 12AT7s in Twins are used for the reverb driver and phase inverter. V6 is the PI, and I pulled a 12AT7 from that position. Someone probably moved the 12AT7 reverb driver (V3) to another position to limp the amp along.

I have seen some nationals imported to Australia. Marked made in hungary but I think they rebranded from all over the place

@@TheBrothaAB , "National" tubes in a *red* box, and with the same logo in red on the tubes themselves, could have been made just about anywhere ---- they didn't make tubes, they merely re-branded them. Country of origin was shall we say "fluid", subject to change, and they may have sometimes changed the printing on the tube to say " Made in Great Britain" or "Made in Germany" to fool people into thinking they were "Mullard" or Telefunken" tubes. Sometimes the tubes were indeed high-quality American or European, but they could also be quality-control rejects, or electronics surplus, but they also rebranded some Japanese tubes as well. Originally, there was a company called National that made radio tubes going back to the late 20's and early 1930's (01A's, 2A3's and 45's and the like) and they made lots of tubes for the military during WWII, but eventually the name got bought and sold a couple of times. Not sure if it was ever the "same" company but there was a National Electronics company that was at one point owned by Richardson Electronics, who made high-quality transmitting tubes, but nothing you'd see in a guitar amp....