Tube Amp Archive

Yes correct. When the Mid Boost is engaged you should see zero ohms between those two points, indicating that the the relay has switched and the NO contacts are closed. If it doesn't switch, you could try swapping in one of the other relays. Still haven't had a chance to open up the amp to check. I...

Glad to hear it's (mostly) working out! You should hear a pretty big difference when the mid boost is engaged, so something is probably not right there. When you get a chance, see if you can confirm that the Mid Boost relay is switching when it's engaged by checking for continuity from common to th...

xtian wrote:Extra points for photos from the road. Rock on, mouseman!

I have an unfavorable endorsement deal that I'm trying to get out of, so I can't be caught on camera with a different amp just yet. Really silly, but over the years, I've discovered that I don't really like their products anymore.

Hi Everyone! The amp's mostly been holding up just fine. The footswitch for the middle boost malfunctions on occasion. I haven't had the time to swap wires with one of the other switches in the three-switch unit to ascertain that it is the switch itself that is faulty. Perhaps its the relay or somet...

Hey Chairman, looking at the chassis picture you posted earlier I can make out the number 22921 on the top of the reverb transformer. That tells me it is probably the standard Fender type which has an 8 ohm output. I suggest picking up a new reverb tank such as 9AB2A1B, which has 10 ohm input imped...

BTW, 9FB2A1C reverb unit has 1925 ohm input impedance. Is that the recommended part number? What is the output impedance of the reverb driver transformer you have in this amp? Leaving for the train now ... I brought some tools and my laptop. Will check RT output impedance later... Thanks so much fo...

Only one way to find out, but lots of combos are pretty tight. How are you going to mount this reverb tank in a combo cab? No noticeable increase in hum. Just hope it's not sucking any signal or tone. :-) I have some horizontal back boards that I could put the tank behind, but the tanks won't be fl...

The reverb tank is an antenna for the EM field from the PT, just like the OT is. Position the reverb tank while the amp is in operation. You will be able to hear the hum increase and decrease as you move the tank in relation to the PT. You made me think of something else. I made a mistake when buil...

Horizontal with connectors up. The site you linked has a nice write up in their tech section. If this is going in a head box, it should be mounted on the inside of the front panel, connectors on top. If it's not sitting in that orientation you might try proping it up that way. Does it matter if the...

martin manning wrote:The reverb unit will be built for a particular orientation, like horizontal or vertical, open side up or down. Do you Know the make and model?

https://www.amplifiedparts.com/products/P-RMOD-9FB2A1C

Seems like it's a type-9 tank and needs to go vertical with connectors up.

Bingo! The blue wire coming from the reverb recover stage is shown connected to the wrong side of the reverb level pot. Move it to the opposite side of the pot, to the lug nearest to the FX send jack. Yay! It works, but not perfectly yet, probably because I haven't installed the tank in a good spot...

THANK YOU for coming to my aid when I desperately needed help. Thank you for your patience with me. I know I am a noob, but I think I learn fast, once things are explained. As I explore the world of amp building and electronics, I hope someday to be able to help others in the same generous way you h...

martin manning wrote:Bingo! The blue wire coming from the reverb recover stage is shown connected to the wrong side of the reverb level pot. Move it to the opposite side of the pot, to the lug nearest to the FX send jack.

Wow! I'll go try that now!

xtian wrote:I am really impressed with the OP and TAG collaboration. Awesome job. Bookies had it at 10:1 against.

Then I wish I'd put some money in the pool too, haha!

I was thinking the same thing about everyone helping out! A kit purchased from a commercial site. OP joins up for what seems like the sole purpose of getting help he can't get from seller. Posters patiently get him near the finish line in record time. Many of these accomplished builders could be at...