Twin (Reverb- popping/ rustling: noises).

[Sea Chief]

Yes pull V3 out and see if noise persists. If the noise is just the same then that rules out the drive side including transformer, valve, valve socket etc.

Could it be that the noise is there without reverb but just not all that intrusive? Reverb does sort of amplify / emphasise pops due to the decay. One obscure source of this can be loose UK mains plug wiring securing brass screws. A 78 amp will surely have an ancient mains cable.

V3 pulling results just done/ above (I don't know the significance of them, so waiting on G1's response).

I'll certainly peep at my mains plug brass screws, & report back.


Thanks for your input. Capt

[Sea Chief]

mikeydee77 All 3 mini brass screws tight in the plug, & wires secure, fuse secure. Old fuse mind you.

Capt

[g1]

pulling V3 (with the reverb ftsw plug removed so I know it's in ON mode)... mild amp hum only.

Turn the Reverb knob from 1 to 8 like so, & no change at all. Nothing nasty. Quiet amp. Just the mild hum.

So the V3 drive side of the circuit seems to be responsible. Changing the eyelet board and all of it's components eliminates most of the circuitry as suspects.
The only things on the V3 side of the circuit that haven't been changed (that I can think of) are the V3 socket and the reverb drive transformer. I'm leaning toward the transformer.
As far as transformers go, they are not expensive.

[Chuck H]

So the V3 drive side of the circuit seems to be responsible. Changing the eyelet board and all of it's components eliminates most of the circuitry as suspects.
The only things on the V3 side of the circuit that haven't been changed (that I can think of) are the V3 socket and the reverb drive transformer. I'm leaning toward the transformer.
As far as transformers go, they are not expensive.

I know I brought it up, but... Sea Chief has had some success cleaning sockets bofore. Less so lately and I think he's cleaned them repeatedly. I still question the socket but in my own experience bad socket connections reveal themselves very apparently. You can wiggle the tube in the socket with the amp in operation and if the contacts are bad it should reveal itself. What's left after that is the reverb transformer.

My concern is that Sea Chief tends to be a little jumpy about initiating intermittent contact failure because it's loud and unnerving. So, Sea Chief, are yo up to it? Wiggle and thump on the reverb drive tube in it's socket and see if that does or doesn't make it misbehave...

[Sea Chief]

So the V3 drive side of the circuit seems to be responsible. Changing the eyelet board and all of it's components eliminates most of the circuitry as suspects.
The only things on the V3 side of the circuit that haven't been changed (that I can think of) are the V3 socket and the reverb drive transformer. I'm leaning toward the transformer.
As far as transformers go, they are not expensive.

Hi G1, ok this seems like progress to me. Thank goodness.

So of course first is to go at this socket, that ruling that out.

Great- yup I recall the xfmr is a small whatnot & not too dear.

Many thanks, SC

[Sea Chief]

I know I brought it up, but... Sea Chief has had some success cleaning sockets bofore. Less so lately and I think he's cleaned them repeatedly. I still question the socket but in my own experience bad socket connections reveal themselves very apparently. You can wiggle the tube in the socket with the amp in operation and if the contacts are bad it should reveal itself. What's left after that is the reverb transformer.

My concern is that Sea Chief tends to be a little jumpy about initiating intermittent contact failure because it's loud and unnerving. So, Sea Chief, are yo up to it? Wiggle and thump on the reverb drive tube in it's socket and see if that does or doesn't make it misbehave...

Kind of you again Chuck: yup it still unnerves me (I turn on with ear defenders, each time!).. but those nasty loud pops, are no more. Just mild & occasional pops, so I'll wiggle about. I do know that my Pro put in a new JJ at7 for me in V3, so the actual tube can be crossed off the culprit list I think.

This beast hasn't been good for my nerves at all, in fact I get anxious turning any gtr tube amp on now, even a diddy 5w.

Thanks SC

[mikeydee77]

Althiugh the 12at7 in V3 is new it could still be the cause, bad luck but not impossible. On an unknown amp it would be the first suspect. Do you have a sub available? Or you could swap it with the PI (if i am remembering the tube chart correctly and the PI is a at7).

[Sea Chief]

Althiugh the 12at7 in V3 is new it could still be the cause, bad luck but not impossible. On an unknown amp it would be the first suspect. Do you have a sub available? Or you could swap it with the PI (if i am remembering the tube chart correctly and the PI is a at7).

Well well. First I tried jiggling V3. Nothing changed.

Then very last resort, swapped the PI & V3 around. Noise gone. Awol.

Played for 20 mins in case I was going insane, or, deluding myself that it was quiet.. but stayed noise-free.

I'll monitor it, because I've had the noise come & go before, falsely indicating all was finally well.

But tentatively.. this is possibly fixed! (I may have swapped these two around previously- & left the "unknowingly-bad" 12at7, in V3: putting my Pro's new JJ intended for V3 in the PI spot).

Is this V3 'reverb tube' position then particularly sensitive to picking up any small tube-inadequacies then?

Really grateful chaps- an everything-crossed, Capt

[mikeydee77]

Sounds promising...

Have you also tried flipping it back to check fault reappears?

Reverb drivers do have to put up with a fairly high plate voltage and anecdotally I do recall swapping out quitr a few over the years. So maybe it is a harder life than most.

[Chuck H]

FWIW when I buy preamp tubes for a build I buy an extra one for every three just to cull the bad one. And sometimes I still find myself short. New doesn't mean good anymore WRT preamp tubes. I've heard new tubes make popping and futz noises during burn in often. I have had a couple that never stopped popping and futzing. This sounds like it may be the case with your tube.

[Sea Chief]

Sounds promising...

Have you also tried flipping it back to check fault reappears?

Reverb drivers do have to put up with a fairly high plate voltage and anecdotally I do recall swapping out quitr a few over the years. So maybe it is a harder life than most.

No. No way MikeyD. I'm not tempting fate by swapping around again!

I do get your point, so will monitor things, & hopefully you won't see another SC's noisy TR thread. Ever.

Great help, (particularly pdf64 who jumped over from Gear Page & led me through various things, to get to this point).

Thanks, SC

[Sea Chief]

FWIW when I buy preamp tubes for a build I buy an extra one for every three just to cull the bad one. And sometimes I still find myself short. New doesn't mean good anymore WRT preamp tubes. I've heard new tubes make popping and futz noises during burn in often. I have had a couple that never stopped popping and futzing. This sounds like it may be the case with your tube.

Aha. There's me just assuming a new tube is tested & checks out, & then sold, before numpties like me put them in sockets.

Let's hope this is it.

Thanks for -just- staying on board/ for your patience Chuck.

SC

[g1]

It's possible the noise might reappear at the PI spot, so keep an ear open. I think it would be less noticeable due to the different type of circuit, but it still could be there in the background.

[mikeydee77]

No. No way MikeyD. I'm not tempting fate by swapping around again!

Ha ha ... I know that feeling well.

[Sea Chief]

It's possible the noise might reappear at the PI spot, so keep an ear open. I think it would be less noticeable due to the different type of circuit, but it still could be there in the background.

Yup will do. But it seems happy enough in that PI spot, if it is a slightly bad tube. Amp's had another few runs, & as it is, it seems cured.

Bloody miracle if so. What a long road it's been! My goodness. It nearly went into the Ystwyth a few weeks ago. I'd had 100% enough.

Very grateful folks, SC