Ampeg R-212R Reverberocket Repair - Part 2
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- Опубліковано 20 вер 2024
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Pappa needs a brand new camera and lens (don't tell the missus).
On this episode I go into details regarding the main fault and some other issues that required addressing while the amp was apart.
Be sure to check out the part 1 video for more super witty banter and some context on this video.
• Ampeg R-212R Reverbero...
#ampeg #reverberocket
Great attention to details. People in your area are so lucky to have you around.
I have a 100 watt version of this amp, and if I set volume to your settings I would never hear again. I can rarely get above #3 on master or main. It is blistering loud. But I love the beast.
I really like these amps. My go to since the 90s
Wow..! What a terrific job Brad...Love the walk thru and your quality tech workmanship, right down to cleaning the cabinet. Very few quality tech's like you around nowadays I'd say..Your dad must be proud..! Thanks for sharing all that knowledge, I'm learning all the time..Thanks..Ed..uk..😀
Thanks for watching, Ed.
Hell of a voice you've got on you there, mate!
Another great video, Brad!
Really digging the way you're uploading the videos in several parts.
Cheers from Brazil, champion!
Glad you like them!
Great video man, I've just been reunited with a 212 just like the one you have here after 15 years. Definitely got me thinking about what else might have issues, outside of tubes (which it definitely needs). It's a 93 or 94, I've had it since 2003 and it's seen a fair bit of action and while mostly it's been a studio piece, it did spend several months in a friend's barn. (Not like, a barn barn but a large steel sort of large shed/workshop/jam space sort of situation, next to his house.)
Anyway wanted to ask if there was any effective way of cleaning the pots without removing the entire chassis? I've got some Deoxit and I reckon I can get the knobs off but a full teardown is likely beyond my skills. Can i just spray a little into each pot shaft and sort of work it in by twisting the knob?
Appreciate your hard work man, great stuff. Cheers
Sounds pretty good ! And your playing doesn’t suck 👍
That's the best compliment I've received all year!
Fastest hands ever. Amp sounds really good.
Hey Brad, I've got a totally different question and subject. Like most techs I have disassembled and repaired a fair number of single-wafer mono potentiometers, and there are dozens of videos online about how to do this, but I have yet to see any videos showing how to disassemble and reassemble a *stereo* potentiometer with a single common shaft that turns two wiper elements simultaneously! You're the only guitar amp guy I watch on a regular basis who also works on a fair bit of vintage stereo equipment, or pro audio mixers and processors that are stereo and therefore contain stereo pots. Replacement pots are rarely available in a form that will match the variety of pots found in most vintage stereo equipment (with the correct size threaded bushing, matching pin-outs, correct shaft length, diameter and splicing etc); and Stereo potentiometers are usually held together with a divot or peened area at the rear of the shaft that would have to be ground off in order to get the pot apart. And then, how would you fasten it all back together? I'd love to see somebody try this on UA-cam.
Iworked on a Yamaha CR-840 receiver recently that had an intermittent bass control, which was unique because it had shorting switches built into it that literally shorted the elements out of circuit when the pot was set to the 12 o'clock or flat position! If I tapped or wiggled the knob when it was set to the 12 o'clock position, the channel outputs would fluctuate and change, particularly on one channel. Tried squirting ordinary control cleaner into it, but it was mostly sealed and had a wrap of clear tape around the body of the pot to block off most of the openings. I finally removed it with great difficulty from the receiver and peeled the tape off to expose a couple of slots, and squirted it with a can of old, special, vintage contact cleaner that is mildly abrasive, somewhat thick and creamy, and unfortunately no longer available. This worked (the resistance of the pot sections literally goes to 0 ohms when it's set to the 12 o'clock flat position!) but our last can of that special cleaner is almost empty and we haven't been able to find any more. If I had to try and take that pot apart to fix it I don't know what I would do. I could probably grind off the divot/peened rivet on the back of the shaft and get the pot apart, but then would I be able to fasten the whole thing back together?.
Note too that all traditional pots use LUBE, any contact cleaner removes this and at times its required. Nye corp for example sells several types. Sadly "truly sealed" pots (RV4 or some variation) don't seem to be the answer as I think even Aiken Amps has abandoned them (PEC)
@@tedmich , intermittent pots aren't necessarily due to poor contact between the wiper "finger" and the carbon element but instead between the rear of the wiper assembly and the metal slip ring commutator that connects to the middle solder terminal of the pot.
@@tedmich no manufacturer ever tells you what type of lubrication is factory provided inside the pots, and some appear to use a different lube between the shaft and bushing compared to the lube on the wiper and resistive element.
Hello mate. I'll maybe do a video on that, should a suitable pot present itself in the future.
A few more Yamaha CA-series integrated amps just came in, so possibly one of them might be a contender, though I must admit, I hope not. Dismantling pots can be a bit of a hit/miss affair.
Often it's not the wafer or it's contact which is to blame, but the commutator ring for the middle pin - wiper connection. The metal becomes tarnished and normal cleaning cycles do not resolve it. The Mesa Boogie pots are the worst culprits, as they're built in a very old fashioned way and the shafts are plastic (of course they are, it's a Mesa!).
@@BradsGuitarGarage , I've dismantled numerous single-section (mono) pots for cleaning and repair, and a number of slide faders too; I've even repaired faders in Bang and Olafsen hifi gear where the wiper fingers had broken free of the moving nylon parts and had to be glued and heat fused back into place. I've even disassmbled and cleaned digital potentiometers (the ones with miniature pie-plate segments) with a pencil eraser, lubing them with silicone before reassembling; but I've never disassembled a ganged, stereo, dual potentiometer because although I could grind the back end off of the shaft to take it apart I'm not sure how I'd hold it all back together afterwards. I did a bunch of looking online and the closest thing to this I came across was a guy repairing a dissimilar dual potentiometer for a piece of Tectronix test equipment that actually had a broken inner shaft (the skinnier one) and he machined a new replacement shaft pin for it. That's a little bit beyond my capabilities!! Anyway, be careful with the controls and switches on that old Yamaha gear, and the same thing applies to Pioneer and Sansui in Samsung and Trio/Kenwood and all the rest. You never know when you're gonna come across a part that's so unusual that you would never be able to find a replacement except by pulling one from another junker unit. A worn-out or damaged volume control that has a loudness tap at a specified resistance point can also be extremely problematic to replace.
BTW, I actually put an Alps "blue velvet" style pot in that Yamaha CR-840 I mentioned (it was pretty easy because the pot was separately mounted, not soldered to the main PCB), and the pot we had in stock did have a loudness tap but it wasn't necessary for that circuit. Be aware that some of the "blue velvet" Alps pots my boss bought off of ebay and various sources are either factory-seconds/rejects and well out of tolerance, or possibly counterfeit, because the measured value is significantly different than the stated value on the pot. We have several pots marked 100k that measured 80k, and 50K pots that measured 40k; I haven't yet tried sweeping those through their rotation with ohmeters connected to both sections of the pot simultaneously to see if they track well or not.....
sigh - its all about knobs, sliders and bottom end here...
Nice educational explanation in the middle, keep it up! (fnarfnar)
Told ya I was spending too much time watching your handiwork 😂. Just glad it's not a Marshall as I'm selling a 1984 JCM800 for a mate, but haven't got the cab to test it out. Went inside to take some gut shots for the sale and nearly wept as I saw melted leads, massive blobs of solder and a nice big burn mark on a resistor thanks to the last tech who was inside it 😩. Wish we had some good techs round these parts!
Nice job! Poor Ampeg got shuttled pillar to post by about a zillion buy -outs, nice to see one clean up well. I just bought an Ampeg 412 set up with 2001 Vintage 30's, only $175 USD. Maybe buy a looper pedal and have the exact same playing each time (ideally with some improvisation once in a while!)
Yes, I was thinking about the looper pedal thing, but my mate from Fluid Audio Group has a cool handheld test oscillator which has the capability of storing .mp3 files for looping to test PA systems. Might be good to have some drum stuff and some full range music as well since I don't only work on guitar amps.
@@BradsGuitarGarage at one point Eminence had something similar online, each speaker with the exact same test conditions. It was very useful as speakers change your sound immensely but may have confused people.
I didn't know eminence did that, but I'm aware of Jensen's sound samples.
Nothing compared to standing in a room with the amp, though.
As such, my samples will only ever be a comparative example.
Hi Brad. maybe it would be safer to use a class x capacitor for the 47nf cap, you have ac voltage on this capacitor. Thanks for your videos !
Thanks for watching, mate!
The main reason x-class caps are required is for safety on the mains input.
Safety isn't the issue here as if the cap went short again, the fuse would prevent any further damage like it did here.
I think the main issue was poor quality of the factory capacitor.
I have a stupid question. How do you crimp the component leads to get the the same. Good video. Thanks
Are you talking about the lamp/LED?
A Pressmaster crimping gun with the appropriate die installed.
Thank you. Looks like a good crimp. I have always used the old style hand crimp. You got the amp sounding very good!
Thanks mate!
Sock it up X 2.... @10 :53 you say seaman? Lmfao hahahhahahha
Random question… thoughts on a Roland JC-40 as a pedal platform amp?
Pff, it's tiny. You'll only fit half a dozen pedals on that amp!
@@BradsGuitarGarage in your professional opinion if one wanted to go to a good solid state amp what would you suggest?
@@albertgutnick6979 So just a clean, single channel choocher? Or a multi channel? Head, combo or brick style?
@@BradsGuitarGarage clean single Chanel combo
@@albertgutnick6979 Power level?
First. sup?
You never forget your first. Lol!