Fender Super Reverb reissue

  • Thread starter Thread starter Seeker of Rock
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Seeker of Rock

Seeker of Rock

Let us be unburdened by that which has been ?
I heard a rattle in the upper left speaker when doing a scratch track the other day. I only hear it when it's close-mic'd. It wasn't a big deal to move the mic to another speaker, but I'm not looking forward to getting into this, which will likely involve removing the speaker and possibly repairing or replacing it in a worst-case scenario. On the plus side, it sounded like a metallic jingling, like maybe a nut or washer was loose somewhere.

Before I get into it, has anyone ever had a situation something like this, faulty speaker picked up through a mic?
 
I'm sure we've all been-there-done-that, but it could literally be anything, so a thorough investigation is necessary. It'll make it a Zen experience, and you'll learn your amplifier inside and out.
It could be a loose mounting screw, a loose piece of hardware, or even a tube shield or microphonic tube. The 'upper left' is the preamp tube section, so don't dismiss any possibility. The speakers Fender uses are robust enough that a blown speaker is not the likeliest culprit. Each speaker gets 10-watts at most, so a reissue P10R rated for 25-watts isn't getting a lot of work. However, sh*t happens, so again, go over everything.
 
It doesn't sound like a blown speaker, but you never know. I'm guessing a loose metal something somewhere. This will give me something to do while I have the Indy 500 on in the background.
 
Took the offending speaker off and found nothing too unusual, except for the little metal bracket that the speaker wires attach to that is riveted to the speaker frame was loose. I snugged it up with electrical tape and will test it to see if this is what is/was rattling.
 
Also check the tubes themselves - I have had on more than one occasion a tube rattle, which sounds much like metal "jingling" - this is not uncommon in combo amps, especially Fenders. The inside of one or more tubes will rattle and cause exactly what you are saying. The best way to troubleshoot is to find the "sweet spot" on the guitar (usually just a good bass-heavy single note will do it) and have a trusted friend gently try to dampen each tube with a the eraser end of a pencil. I have had this happen on a couple of Fender amps. Keep us posted!
 
You guys nailed it. It came down to Ch1 first gain stage preamp tube. Not even using Ch.1, but totally removed the tube and the jingling stopped. So I wonder if I need to look into these:
 

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Glad you found it! The tube dampers should help for sure. Unfortunately this is a slight drawback to the combo amps that we love where the tubes sit so close to the speaker. Not sure what brand of tubes are currently in the amp, but I will take a guess and say Groove Tubes. Though I really like these, they have done what we are talking about more than some others.
 
I'm also getting some distortion when I hit lower strings hard that seems to come and go sometimes, but now seems permanent. The amp has less than 80 hours on it, but I would suspect tubes causing this. It is stocked with Ruby power tubes, I forget the rectifier brand tube, and Fender branded GT for the smaller pres, reverb and trem. I have some spare '80s production GT 7025s with low miles on them, so I may do some swapping with the 12ax7 preamp tubes and see what I come up with.
 
Could possibly be tube related also, I think you are on the right track. Fender amps are great, but somewhat delicate at times (the never ones) - none the less, I still prefer them over everything else I have for tone, whatever style playing it may be.
 
I'm thinking it may be the rectifier tube causing the overload. It's only if I hit the low E hard, but it's something that the Super handles when it's running right (humbuckers hitting heavy) if I'm not above 4 or 5. In some troubleshooting I discovered it is not my pickup heights and not the particular guitar (tested two with it, confirmed neither pup was too close to the strings), not the cord (switched that out to make sure), not V1 or V2 12ax7 (swapped those with the older 7025s) those it is V1 that is a little jingly. The 7025s were in my Marshall during the '90s and they REALLY jingled when I put them in. I have a call in to my amp tech to see what he thinks it could be.

As a bonus, I have a Mullard Blackburn 12au7 I've had for a few years and am going to try that out in the V3 reverb slot just to see how it sounds.
 
Amp tech says the symptoms sound like the bias is off, but also spoke against rectifier tubes from a personal preference. He said to try one of these (solid state rectifier plug) and if I didn't like it, then replace the rectifier tube and he would re-bias if it still needs it.
 

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And the nos Blackburn 12au7 replacing the stock GT 12AT7 sounds alright. Less harsh and in your face. But I think I kind of like harsh and in your face reverb, so I may switch it back.
 
Absolutely positively hands down (for my taste) like the 12at7 in there (Groove Tubes for Fender). I'd like to hear something smoother like a Telefunken NOS 12at7, but that's getting a little limp-wristed. I like the in your face reverby reverb when I do something like surf, which Fender reissues and originals do very well. I think I'll find the post on the Tele site I read suggesting the 12au7 and call bullshit. Of course, different flavors for different people and all.
 
Absolutely the weird 'distortion' could be the bias being way too cold. Have it checked, and if your tech can, compare the idle current of each 6L6. Even if he is using a scope, one tube could be at say 40mA and the other at 30mA or 50mA, which isn't good. The tube shield may have a loose spring inside, or maybe it's the tube itself. I doubt that, as removing the shield made the rattle go away. One thing I have done, and I can't explain how it works, is put that one tube shield on the phase inverter tube, and the original phase inverter tube shield on V1. Even with microphonic tubes, I've put that tube in the Reverb or Tremolo oscillator, and everything was fine. Of course, this was on a gig and I had no spare tubes with me. Otherwise, try and do it 'right', and have a fresh tube/shield in there.
 
Thanks for the great info, man. I ordered a new rectifier tube that I'm going to try first since it seems like a voltage related issue. If that doesn't do it, I'm going to take it in to him for a bias check. I went with Sovtek on the rectifier to replace a Ruby branded Chinese 5ar4 in there now. I'm reading up on new production 6L6 tubes just in case rectifier or bias drift are not the problem.
 
It wasn't the rectifier. I'm hoping the bias just drifted or something simple like that, but but no more guessing: It is in at the tech.

His first criticism was that it has Fender branded Groove Tubes power tubes in it, but he's just an old school purist. Anyway, he's leaving it on for a few hours to reconfirm the first bias setting. Or something like that.
 
The bias was way off, the amp sounds WAY better, but still getting the low end farts using humbuckers and driving low E string hard: The ultimate test of clarity and it used to handle it.

Toobs. Power tubes I'm guessing so I have a new set on order and the tech will re-bias for free. The amp doesn't have a shitload of hours on it or anything, but I guess I have had it since 2004 and have gradually (maybe) racked up enough hours on it to wear the tubes out. Maybe.
 
Got it back last night, but haven't plugged it in to test the new tubes yet. Getting ready to, though. I really like that amp.
 
I guess I shouldn't be use these dead as fuck LaBella strings to test out the new tubes, but I did. Still getting a little low end vibration on the speakers, but it is probably the speakers at this point. I knew the tubes were going because I had some random unexplained cutouts and I could turn the master to 3+ in my little studio. Big time power restore. The amp has its wattage back and sounds fantastic, and no more "choking" feeling when I'm playing chords.

I will tell you this...the Super Reverb (and this one is a reissue with PCB, not AB763 point to point) is one of the coolest amps I've had the pleasure of owning, and I've owned a few. But greater than the sum of the parts is a Fender Tele or Strat through it. Absolute beautiful sound. Similar to a Gibson through a Marshall, something magic happens.
 
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