1965 Ampeg G-12 Gemini I TEARDOWN & SERVICE (Part 1) 

These amps take me back. They were omnipresent in the New York Studios in the 60s and 70s, these and Gemini IIs (with 15" speakers) and other Ampegs, probably because the company was in New Jersey. The ones from the New York Studios would have the New York Guitar Club stenciled to them, and replacing the power switch would've been a key. You'd pay into the club, and get a key. Running around New York with a big amp is a giant pain, and this was an early way to deal with it. By the time I was in the studio, the techs had bypassed the keys so anyone could turn them on, and many of them didn't sound that great (lack of maintenance probably). I was always a lot happier when I saw a Fender in the studio, and eventually I bought a Mesa Mark I and carted it around myself. But those amps actually have a great sound. The Gemini II had a treble boost switch and a switch on the Tremelo speed to really go fast. Thanks for this series.

I just pulled mine out of the pile to start the planning stage. 1965 - S/N 022047. This thing is gonna be a money pit. A previous owner lost / replaced all the knobs. =( It just goes down hill from there. :sigh: On the bright side at least Brad did a vid. Thank you, Brad!

I had a Gemini I and a Gemini II too, which both needed work when I copped them off the bay. Got them inexpensively on eBay about 15 years ago, planning to repair them myself, but health problems precluded that from happening - story of my life (and my lack of knowledge). So I sold them to a local amp tech (Arcane Amp Repair), who now charges $200 an hour to service amps in Portland (seriously). I also sold him a few other "projects" at the time, that I wish I'd kept. I was going to bail on Portland, and sold most of my stuff, but I'm still hear, trying to be a farmer and self-sufficient for a living. Mr. Guitologist and Uncle Doug have helped me to understand how tube amps work, not completely, but I'm getting there. It would be worth my money to send my amps to the Guitologist for servicing (I've got some interesting vintage amps), just to (hopefully) see him do a video fixing them - what a treat that would be! The local amp techs here mostly won't let you watch, because they don't want you to learn how easy it is, or be embarrassed about how much money they charge. IF you know what you're doing it's easy, like anything else I suppose.. There are some local amp techs here that will help teach me, but learning online like this is the best, because you can watch it repeatedly. Obviously thousands of other interested people agree with me, judging from the views here! I'm thankful to have found this channel, and a few others like it, but this is my favorite, and grateful to Brad for sharing his knowledge so generously (and I dig his guitar playing too - the clean stuff anyways)!

I enjoy your videos. I've been been collecting & repairing/rebuilding old Ampegs since 1972. They are normally built like tanks so it surprises me to see the filter caps flopping around like these were. I've never encountered that in my repairs but I do see a lot of shoddy repairs in the amps I work on. Whoever put the pieces of wood to hold that chassis in was a butcher, not an amp tech. Ampeg started in the 60's to "shock mount" their chassis using rubber pads or little rubber "donuts". Looks like somebody may have tried to jury rig this chassis to do something similar and it didn't work out. I also love it when they install a 3 prong power cord and don't remove the death cap. I have two Gemini's (a Gemini2 w/1x15 and a Gemini 20 w/2x10's. Both have polarity switches that weren't removed from the circuit nor was the death cap removed when the 3 prong cord was installed so if you flip that switch the wrong way it's a dead short to ground. You can't fix stupid I guess. Keep up the good work. BTW, that old amp faceplate you took off the back was obviously another amateur at work. The back cover should have foil shielding glued to it where it covers the open back of the chassis when the back cover is installed. It even has screws (clutch drive of course) to attach the back to the back of the chassis to seal the shielding up tight against the back chassis opening.

Man, everytime I watch your vids I wish I was back in Kentucky where all that cool gear is. This is like a gear desert here.

I have a Gemini VI that has issues.. You video helped a ton. Thanks

I just picked up an old ampeg rocketverb for 200 bucks at local flee market,,,works well but been serviced except the cab is rickety its got a perfect original speaker.i love the old stuff.

the phone number appears to be a cell phone. it went to generic voicemail. I didnt leave a message:)

The max position detent on the Trem Intensity activates the Ampeg "Stutter Effect". Max detent on the CH1 Treble is a Bright Switch.

I have one of these amps in my shop right now to service for a friend. I'm still trying to figure out how to remove the tube chassis from the wooden case. I was hoping your video would show me, but you merely confirmed that it's difficult and then skipped over how you did it! LOL! 🤣 I'll figure things out eventually. My friend's model appears to be about 6 to 12 months newer. Many things are the same, but a few small details are different. I guess that keeps things interesting... LOL!

Great video and nice clean work, the solder looks good... good to see the can was still good and not having to figure out an alt mounting plan for new caps. Does anyone make replacement cans? The amp sounds good on final test in part two!

Brad this video is very interesting! That faceplate came from an amp made by Eugene Andre. He was a designer with the Ampeg company. Go figure! Very little is known about him and his amps. And don't call me Shirley! Ha Ha! Why use a 7199 for phase inverter? Are those the same kind of tone sucking networks as Gibson used? They look similar. I noticed in the tremolo circuit, they used .05 uf caps for the oscillator instead of .01s or .02s. Would it change the freq. response? Will they work as long as they are the same value? Why did they not use a 12AT7 for the reverb driver? Why did they not use a transformer to couple the driver tube to the "echo" tank? Cost? I sound like a 4 year old. Daddy why this and Daddy why that? This is what 2 strong cups of coffee will do to you. Thank you so much for posting theses great videos! Thankz

love the old ampegs. they go for good $

Loved the simplicity of the tremelo rigg the light the guitoliguists joint..

Gene Andre had a shop in nyc -- I had an amp serviced there in the 80's -- he was a former Ampeg employee I believe -- Check out the secret switch on the trem for the after beat effect -- nice - Buzz Feiten told me he used a gemini on the full moon LP !

I made the mistake of selling that exact amp on eBay about 7 years ago with a broken top strap. I wonder if that could be the exact one I grew up with... anyway to find out where it came from? Paired it with a Norma electric acoustic guitar. Still have a few other jems my father passed down from the era. Thanks in advance! It would have sold from Milwaukee wi...

Ken Fisher ran the repair department at Ampeg and he hyped up quite a few returns to way better then new. Not saying this is one of his but that face plate might be something he would do

Those screws are called clutchhead screws GM used them on the older cars too around that time frame also. Oh tonight I found a Gemini 2 amp at the curb there was a car accident so I went a way I usually dont and saw the amp at the curb my luck or maybe my junk,LOL. Got home fuse was missing & put a fuse in it and the light came on switched the standby switch on and the fuse burned out. Took the back off and one speaker lead was broke.Its all complete except for the Ampeg logo and the handle is shot.Any free advice I have done some amp repair but not that much if you can help maybe a broken wire probably not but yours had one to the capacitor so maybe.The power tubes are metal 6L6S one RCA and one CBS I have only seen glass ones must be very very old tubes and also has the original 15 inch Jensen in it.So any advice should I put it back at the curb,LOLL I had a Gemini 2 when I was a kid.......................................Glenn P.

7591.... Same power tubes as the Cordovox thing I fixed up. My CV was really late... last of the Tube gen... 1971.

You're the man,as good if not better than Lee Jackson

Those caps that drive the reverb are usually huge value. I've seen them as high as 1uF on Magnatones. They go bad often. Snuggled up close to that huge resistor's heat probably isn't helping it any....but yea you can't use any old tank with those. The impedances have match on both ends...and you also have to make sure jacks are grounded correctly.

Hi, I’m curious about what’s going on with the electrolytics in your power section. I see 4 F&T’s there. My G-12 is also a late ‘65 and it has 70/40/40 in the can and a 20/20 on the chassis in one wrap. (Yours had 2 loosely mounted). But if you kept the can as-is, what are the 4 other F&Ts? Thanks!

the grey ampeg foot switch is worth and goes with the 60's ampeg reverberocket amp.. great reverb big spring can echo, great for guitar and accordion.

Maybe the Andre schematic exists somewhere? I shouldn't speak for anyone else, but I would be really interested in seeing a build series. Maybe that could be a future episode or episodes on your channel? Thanks for all your hard work bringing this to us, I look forward to seeing them

I know you don't custom build much stuff, I've spoken to "Doug" about this. Have you ever considered building a repro of the Butts "Echosonic"?

The little spring inside tie cabinet is probably to hold the foot switch like the metal strap in an old Gibson.

7591's are 19 watts. Very similar to a 6L6GB in performance with a 700vdc plate rating. Thank God JJ makes decent replacements. The 7199's on the other hand usually have to be replaced with a similar tube with an adapter or rewiring the socket. I love Ampeg amps but a full retube can cost more than what the amps are worth, especially the compactron 12 pin triple triodes. I don't know why you don't have more subscribers, your work on obscure and unpopular (but awesome) amps should draw in a larger crowd. You're the only one that does that!

You can get adapters to use a 7868 tube in place of a 7591.

You had me at surely! lol Just the way you said that made me laugh for 5 min. Please comment in Part 2, on what you find out about the amplifier that donated it's face, to hide inside the back of an Ampeg! I paused the video there to comment... Looks like a neat amplifier. I live in central jersey, not too far away from the old linden factory, but surprisingly you don't find a lot of Ampeg amplifiers around here. There aren't many pawn shops left either, but even 25yrs ago I only recall seeing a couple of em, but at the time I was only interested in Marshall's and Mesa Boogie's anyway. The schematic looks interesting, not really familiar with the 6cg7... I have a couple 7199 tubes in my Hammond H-112, I originally purchased that to gut for parts, but after hearing a few people frowning upon doing such things (you being one I believe), I decided to keep it and learn keyboards. I really enjoy amps that use tubes other than the typical 3-12AX7's pre-amp, 2-6V6 or 2-6L6 output layout, so I am excited to hear this one functioning again. Take care, Tom

haha! the Andre plate blew my mind

Teisco Del Rey All Tube Checkmate 25 w/ cabinet, original pioneer speaker $650 is this a good deal ? it works , all original , two prong plugs etc.

Skip the gazing to 16:00

Where do you find these old amps?

Seems I had a beautiful experience.of trying my microphone through all these beautiful amps... They just got sold like cheese burgers ...

The plate is from an Andre Universal 2 Amp, but what's interesting is that there are not many pictures of the full plate!! See: jedistar.com/andre-audio-2/

In this day of hand wired, boutique, one of a kind guitar amps, $750 is a reasonable price. I would much rather buy an amp from you, who would make sure it was in top notch condition, rather than someone who may try to sell you a false set of goods. Are you going to do a video on this amp! Do you have an email address? Thank you so much for sharing! Thankz

I see Ampeg didn't let the space race get away from their marketing department.

New subscriber here. Really interesting video.

Notification squad

I looked up Dalziel Rd on google earth and it's in a shabby old industrial park. It almost looks like some of the buildings there haven't been painted since that amp was built.

"don't call me Shirley"

Is that Gibson hawk for sale?

Here are the pot switches explained -- www.thegearpage.net/board/index.php?threads/ampeg-gemini-bright-and-trem-afterbeat-switches.1771922/

The only difference in channel 1 and 2 is that one has a 4M pot tied to a component labeled "m-1 *" ... that same jelly bean is over in the tremolo - must be the optoisolator? Just my 2c - those filter caps were disgusting. No strain relief!? Sheesh! Unbelievable...

clutch head screws

don't call me Shirley.

Same thing every time. What I want to know is how to get the chassis out of the cabinet. One frame it's in the cab, the next frame it's out. Thanks for nothing