Please help..My Traynor is squealing!

[Toneblenders]

I was wondering if you someone could help me with my Traynor amplifier. It is a YGL-3A model. It’s like a Fender Twin.Not sure of the age. My guess would be late 60's early 70's? It has the flip-top lid. The serial number is 2100965. The problem is when I turn the reverb past 2 it lets out a high pitched squeal. I was told by a tech that it is because the reverb tube (6BQ5) is missing the tube shield. I haven’t been able to find a tube shield that will fit. Do they make tube shields for these tubes? The guy I bought it from said that it never had one. Do they need them, or do you think it could be just a bad tube? I have switched out all of the preamp tubes for good ones and I just put in a new matched set of Ruby 6L6's.

Thanks in advance for any help

Bob

[SatelliteAmps]

If you are getting that much squeal, it might be a microphonic tube, or something else wrong with that part of the circuit.

The shields can be found. You might have to get one from an antique radio shop to get the right size, if a standard one won't fit.

[donnyjaguar]

I do believe its a 1965 model by the last two digits in the s/n. I think it would be a good idea to overhaul the amplifier myself as there are a number of things that can cause this.

[Ronsonic]

I doubt the tube shield is the issue. 6BQ5 would be the driver tube, it's a power tube, same as an EL84. I've never seen a shield that would fit and that circuit shouldn't have any tendency to oscillate. If it does, there's another problem - bad tube or other faulty component in that circuit.

Is the squeal caused by the reverb springs feeding back? Remove the reverb pan from the cabinet, just set it on something behind the amp. Are the cables to and from clean and solid. How about the connections within the pan. In an amp that old there are any number of potential problems. Aged, failing decoupling caps; leaky coupling caps; shorty, leaky cathode bypass caps - noticing a theme :) Resistors could have drifted, the reverb recovery tube could be flaking.

I'd suggest trying the simple stuff here - isolate the pan, clean and check cabling - and if no joy get a tech who's a little more enthused about tracking this down.

[SatelliteAmps]

There are tube shields that fit that size tube. They are available, but again, probably not the issue.

[Toneblenders]

Sorry guys. I didn't realise I got replies on this. I thought I would get notification of replies by email.:huh Thanks for all your replies!

I found out that the replacement reverb tank that the previous owner put in is not the correct one. It is accutronics model# 4FB3D1B and model# 4FB2B1C is the right one. The main difference being that the input is not grounded as it should be. I’ve switched out all the tubes except for the 6bq5 which I don’t have an extra one for. It sounds like it may be a grounding problem because if I turn the reverb up just below squealing it will squeal when anything gets placed near the input side of the reverb pan. And I looked inside the pan and everything looks normal.

Any suggestions on how I can make this reverb unit work?

[zzmoore]

We have that head also, they are a nice sounding, versatile amp, with trem and reverb. I would definitely try a new EL84. I have never seen a shield for that tube. I have always seen the retainer that slips over the top of the glass. Anyway, as others have already said, I am sure it is of no consequence. Have you contacted Acutronics? They have pretty good customer service, and also it has always seemed to me that new reverb tanks are pretty cheap.
Good Luck

[SatelliteAmps]

The impedance difference is going to also be an issue. I would just order the correct tank. They aren't expensive, and it beats fighting to make that one work.

[Toneblenders]

Thanks for all your help on this. I fixed the problem with help from Henry at Red Plate Amps.:) All I had to do is run a ground wire from the ground on the input rca jack on the reverb tank to the reverb tank itself.