My duude! This is an awesome resource. The Thunderbolt is my fav amp and this info is awesome for me to maintain mine, myself. Thanks!

Paul great presentation!

Very nice work.

You have done an excellent job with all my amps..im stoked you have a show on YT

Lovely work and great explanation! Only thing I would have done differently is the line cord ground, it’s probably just fine how you did it, but generally electrical safety standards require a mechanical connection like a ring terminal bolted to the chassis (technically it should also be a welded stud so that the fastener can’t be loosened from the outside of the chassis).

Yeah! Nice Pat! Psyched to be here and learn from you. ❤

Great work!!

My first amp was a Harmony 420, I'm pretty sure it was the same as a Thunderbolt (Valco) I now have a 64 thunderbolt as well as a few more classics. I like the tube rectifier. Fazio sent me lol.....

Yer off to a heckuva good start with this beauty, Patrick. I follow you on IG and jumped over here to subscribe. Awesome vid!

Hell yeah! Finally a repair video for a cool amp. I love what this video is NOT. It’s not a Fender amp and you’re not some deep-voiced narcissist whining about crappy modern construction methods and poorly playing the same terrible Mike McCready lick over and over and over. Keep it up, this video was refreshing and your channel has a lot of potential. Subscribed. RAWK!

we love you, Pat!

Oh hey, that's kinda like my Silvertone 1483, also sold as a bass amp, same 15" Jensen, pair of 6L6s, solid state rectifiers, and also really bad as an actual bass amp 🤣 The cabinet on mine is crappy 1/2" chip board, which just kills the low end. Great video, I will definitely watch more!

Nice amp, great video. Good explanation, just enough tech and troubleshooting, repair and upgrade process. You have good presence on video too. Only criticism, dump the Hot Pockets and splurge on a Pepperoni pizza.

Good start. I love point-to-point wiring tube amps. The problem is, nobody makes tubes anymore (except outdated factories in Russia, China and the Czech Republic)…

Cool video man! do more

Great work Pat! Thank you and looking forward to more!

You are going to blow up. I can feel the winds under the wings of the algorhythm gusting away! Great video!

Well, it's getting noticed by some good names to notice. I'll subscribe. Now all I need is a qualified guitar amp tech in far Eastern North Carolina. Good luck.

Hey nice bench, good to see your shop on the KZfaq & the Internet pipes. Keep posting !!

Thanks for this !!!!!! have fun on KZfaq Too !!!!!!

Fazio electric sent me and i don't regret it. Great stuff!

Great video

I had no idea soldering irons could be so big! I feel like solder would melt just looking at it

Great video Pat! That Thunderbolt sounds awesome, now I want one 😂

Greetings from Spain! Loved the video, looking forward to more of these!

I actually drew the Harmony 420 schematic you're working from, so long ago I'd forgotten I did it! The amp on your bench is a little different from the one I worked on: at 10:42, note that the on-off switch is a DPDT switch that flips/reverses the polarity of the incoming AC wall current, which isn't safe and doesn't meet modern electrical code, so I assume you rewired it for straight on/off operation and removed the "death cap".

Killer video Pat, looking forward to more of these👍

Great vid. I have a 1966 supro Taurus bass amp, dual tube rectifier. Great stuff.

Very cool workshop!

Great video Pat :D can't wait until you create more content!!

Nice discreet repair. 👍

Great video, enjoyed the amp history and general overview , i have a 66 in black tolex i had modded for a transparent gain circuit put in and put the gain knob in one of the inputs so i didn't have to alter the chasis to accommodate also put a Celestion Fullback GV100 so i won't harm the original Jensen . All original inside and nothing replaced, is that bad ? Should some components be replaced? Enjoyed watching you work, sounds great !

I built one of these and made use of the unused triode. I put a cross line MV in it (250k A) too. Love it. WGS ceramic 75 watt. I used a 5u4 tho. Don’t use a bypass cap. That’s a no no in this amp. 😊Wow,the Classic tone TB otx looks identical to the one in this video.

Really enjoyed you explaining the schematic along with step by step of diagnosing the issues. Killer video dude! I have a Harmony 430 with the 6973 power tubes and tube harmonic trem. Reverb is awful and there is nowhere to hook up a better tank (tried my original Falcon tank outside the amp and it was beautiful Verb). Don’t think I can shield it and haven’t found a compatible small tank to make it shine. I believe I would have to alter the reverb circuit to make it sing and I haven’t those skills yet. Any tips of where I could go to understand that better? Haven’t seen much on that topic on the tube or forums.

Hey man! Great video, I’m now subscribed!

This is recorded on sticky tape and rust… This is recorded on sticky tape and rust… Well done sir!

Patrick, do you ever come across old amps that when you take the screws out the wood strips out or the chassis? What do you do to fix that if so? So glad you’re on KZfaq now. Been following you on instagram for a while. Cheers!

Nice! I'm about to start on an old Gretsch Twin from the same era, curious what I'll find inside!

Hey Pat have a question what do you use on a scratchy pots ? I used deoxit but then I noticed later that it only lasts for a little while then the scratchiness comes back. I also noticed that the pot moves a lot more freely then normal almost as if the lubrication or Grease that was inside the pot has washed away. What products do you use to clean a pot and lubricate it???🤔 Thanks for a great demonstration on explaining how tube amplifier functions in a circuit!👍

I dig it. Subscribed.

Does anyone know if a General Electric Model 103 tube radio is a good candidate for a guitar amp conversion... Thanks for the help

Have the "v logo tuxedo version"

interesting that the schematic shows a center tapped power transformer used with a bridge rectifier... is that a mistake, wouldn't it short out the 2ndary winding the way it's shown?

Where on Earth did you get a Rich's Auto Body tee shirt? Are you near Merced?