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How do you know it's the tank?
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04-17-2020 05:32 PM
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that's more likely a tube issue...than an actual spring issue...check your reverb send and recovery tubes V3 & V4..
Blackface model tube layout (Seen from behind, V1 is to the right side)
V1 12ax7 = Preamp normal channel
V2 12ax7 = Preamp vibrato channel
V3 12at7 = Reverb send
V4 12ax7 = 1/2 Reverb recovery and 1/2 gain stage for vibrato channel
V5 12ax7 = Vibrato
V6 12at7 = Phase inverter
V7 6L6 = Power tube #1
V8 6L6 = Power tube #2
V9 GZ34 = Rectifier tube
cheers
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Agreed NA, sounds like a bad preamp tube
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Hahhhhh...basic stuff. Clean the RCA jacks/plugs that connect the chassis to the reverb pan. They may be
ld, dirty, oxidized, broken, and just plain no good! Then, check the tube(s) for reverb send and return. (And their sockets) plus the pedal jacks. If not here, get a new pan, and while you're at it, get the 3 spring unit, for a more lush reverb, if you're into that sound. Otherwise a 2 spring is adequate.
Hope this helps.
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OK, am a step ahead of you guys, sort of.
I already figured out which tube does what and moved some things around...no difference there.
The reason I think it's the pan is because the tech did all the guts stuff - capacitors, etc. That should be all good. When I turn the reverb off, the amp doesn't make this sound at all, none - totally quiet. The second I turn the reverb on, it's there.
Also, when the reverb is on, and I tap the reverb pan, I get an extreme version of the noise I'm hearing. So, that's why I think it's the pan.
And another good point, I already did take the pan out, try to tighten the cables, etc. Is there a better way to clean the connections?
So...back to my original thing. Does it matter what kind of pan I get? This is like a $30 fix, right?
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Also, the cables could be a good guess...mine are OLD. If I am just going to replace the cables, which ones do I buy...generic RCA cables?
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Yes. Generic are fine. Make sure they are long enough - sounds obvious right? Not so. If you reverse the direction of the pan, you need longer cables. Why would you reverse the pan??? Because sometimes the new pan ( with a new cover) doesn't pop right in the same way ???? Then there is strapping the cables out of the way. Believe me, done this a few times.
Take the existing cables, gently pull them out and in a few times ( having fun ??) and maybe gently twist them in the sockets to get the contact surfaces clean. Should help but if there is noise or they short out, you know you need new cables. They DO NOT last forever, and your amp is old - but great no doubt.
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Sounds like a microphonic preamp tube.
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I appreciate it, guys. I think I am right, though, that it's the tank.
A really helpful guy, Frank, at Amp Repair Parts - Powered by Studio Sound Electronics had do the following...
"On the back panel of the amp, unplug the cable that goes to the jack labelled "Reverb Input". Leave the other cables connected. See if you still have the noise when you turn up the reverb control. If it is gone, the tank is not likely to be the problem.
If the noise is still there, unplug the cable that goes to the "Reverb Output" jack (keep track of which cable goes to which jack, since you now have two similar looking cables unplugged). That should kill the noise, and the tank is a very likely culprit.
If the noise, however, is still there with both cables unplugged - it's certainly not the tank - the tank is now completely disconnected."
When I unplugged the reverb input to the amp, the noise was there. When I unplugged the reverb output jack, no noise.
Also, how's this - I realized that it doesn't even matter what volume the amp's channel volume is on, could be 0, and the noise is still present with the tank attached.
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So, I bought a new tank, he told me which one to get. Hopefully that's the end of it. Will install in a few days.
Charlie
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‘66 vibrolux. Nice! Good luck with the reverb tank. I have that amp’s big brother (‘66 Super Reverb) and the only word I can come up with to describe it is ‘magical’. It sounds like heaven. These old amps are worth maintaining. Just something magical about the look, the sound, the glowing of tubes and even the smell of these magic old contraptions.
Roli
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I 100% agree. I love the look, the feel of the vacuum tubes glowing, the warmth, the machinery. Something totally alluring.
In my rock band too, always just loved the tube amps. Had a Marshall TSL 60 head...again, the tubes, there's a mystique...
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I couldn't quite follow the troubleshooting that's already been done, but I had a similar problem with a simple solution -- once I figured out what was wrong.
Originally Posted by crhyner
Crackling related to the reverb on an original Reverberocket.
Tried a bunch of things and spent a bunch of money. Eventually, I soldered in some new parts (following a recommendation from a guy on the internet) and, in the course of doing so, noticed that wiggling a certain wire reproduced the problem.
I followed the wire. What it turned out to be, making a long story short, is the little wings on the RCA jacks weren't making good contact with the reverb tank. The solution was bending them slightly with a pair of needlenose pliers.
Bear in mind, I had pressed them in to make sure they were seated tightly many times. They were pushed all the way in, but the little wings were not spread adequately.
That was all it was. Re-tubing, new parts etc etc, was all irrelevant. Ampeg built those amps like tanks. When something goes wrong, it is often something minor.
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Replacing a reverb tank is an easy job, but before doing that I'd unplug the RCA jacks and hit both male and female sides with Deoxit or QD electronics cleaner. Spittiness is often a result of crud build-up. Just spray all jack connections and work the jacks in, out, and rotating, and see if that doesn't fix the problem?
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Replaced the tank today, noise gone. Sounds perfect. The end!
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I have a BF ‘66 VR I’ve owned since 1979. For me it’s the perfect combination of weight, size, power and tone. There are some amps I like better for specific jobs, but for me there isn’t any amp that can do so many things so well.
A band would have to get really loud to overwhelm it. My experience is that you’re normally miked through a PA once you get to that volume.
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Originally Posted by NCjazzpicker
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