The Amp Garage

jelle wrote: ↑Mon Nov 06, 2023 3:07 pm Glad you found it!!!

Thanks Jelle - I experimented a bit with the 390R vs. the 330R you provided in the NOS resistors. I preferred the 330R. Seemed to tame the presence so the change from 3 to 5 on the presence pot (thinking about clock hands) felt slightly more subtle.

Hey guys - I owe you an update - this is more than 2 years overdue. I haven't had a ton of time to dig into my amps over the preceding 2 years - mainly because of my 2 kids under four! But, I've finally swung back around to the #102 and figure out what was going on with my dang presence control. My ...

What is your expectation of the presence circuit? If you run the pot at 0 and then at 10, do you get enough effect? If not, changing the taper will not help. I was just curious if anyone has messed with it. Really don't have an expectation. Right now, I pretty much just leave it around "2", which i...

The presence control doesn't really do much until about 1 o'clock then you should be able to hear something move. Scott I agree! I never said that the entire range was inaudible? My point was the null point (mine! was 1 Gil's was 2) where it's most noticeable. I also never said? up too that point i...

The attached service bulletin "may" solve the vib tick... Sometimes a conductive fiber board is the culprit. See one fix in pic... Thanks for posting that! I went ahead and followed the service bulletin. The tick is about 80% gone I would say. Good enough for me to leave it alone. I can only really...

Very handsome amp. First time (maybe the only time) I ever saw one was about '66. Walked into a teen club with my date, trying to look cool. The out of town band was playing We Gotta Get Out Of This Place by the Animals. They had two blonde Showman stacks and a blond Bassman stack! I may have drool...

The attached service bulletin "may" solve the vib tick... Sometimes a conductive fiber board is the culprit. See one fix in pic... Thanks for posting that! I went ahead and followed the service bulletin. The tick is about 80% gone I would say. Good enough for me to leave it alone. I can only really...

Thanks again for your guys' help! So after messing with the bias for a while, I decided to look at the power tubes and one of them was not heating up at all - prior to that I couldn't get the amp biased very evenly (makes sense in retrospect). Now I've got it biased at 40mA and 47mA - I'm toying wit...

It’s an awfully bad idea to test and play an amp that hasn’t had its idle anode or cathode current checked. The HT voltage may be getting pulled down by a massive current draw from the power valves. The trem oscillator voltages require the footswitch plugging in an closing, otherwise both triode se...

Got some updates for you guys! I ended up getting some new parts in - I replaced on electrolytics in the entire amp. I replaced power tube grid stoppers and screen resistors. I also replaced a few of the resistors on the main board and the normal channel grid leak. See below photos. Upon going throu...

Yo, just to give you a heads up; years ago I scored a bunch of 10µF, 20µF, and 30µF high voltage film caps in ratings of both 500V and 700V. These were the Vishay MKP1848S series (designed with a low profile for tight spaces). I make scale vector images of all the components I use for layout purpos...

That photo of the amp box gives us a clue. That rectangular declivity in the bottom board was standard issue in the early 60's. I suspect your amp/cab combination is a "Frankenstein" - where someone mounted a newer chassis in an older box. No harm there, it's another adventure in the twisted histor...

That’s correct, and let’s deal with shorts if they happen. :D But if it did, the OT CT would be disconnected and power LBL reapplied to see if that stopped the bright bulb. So I got really antsy and had to go for it. I removed the valves and e-caps. The closest value fuse I had on hand was a 2-amp ...

....and a tube chart:

I've cleaned up the tolex a bit, but here are some pictures of the inside and out: IMG_5030.JPG IMG_5034.JPG IMG_5033.JPG IMG_5026.JPG IMG_5027.JPG IMG_5028.JPG IMG_5029.JPG IMG_20210309_201101643.jpg IMG_20210309_201032840_BURST000_COVER_TOP.jpg IMG_20210309_201025993.jpg