Rocker 30 power tube / socket issue?

[Ridgeback65]

Greetings from a new member. I've been lurking for quite a while and gotten a lot of great information here.

Anyway, I'm experiencing this sporadic / intermittent sound loss that sounds kinda like when you have a bad guitar cord and the signal pops in and out as you shake it. I suspect it to be one of the tubes. Indeed, when I tap on the power tubes with a pencil eraser the sound really pops on one of them.

Thoughts? Microphonic? It doesn't sound squeely. The sound is great for a few seconds and then it pops out, then it's back for 10 seconds, etc. Do I need to retension the tube sockets? If so, best left to a tech?

Also, if I replace these tubes will it need to be rebiased? I think somewhere I read that this amp is auto-bias. Is that correct?

[BrianPhase90]

Yes, the Rocker 30 is self-biasing. I would start with the most simple solution and work forward. Try a tube change, if that doesn't work I would start looking for broken solder joints and loose connections. Or just get it into your tech if you arent comfortable poking around inside your amp..

[Upstate]

First thing....

on the top of the chassis, where the tube sockets are, there is no chance of getting zapped, at least under most conditions, so,...

next... with the tubes in the sockets, the one that is making noise, when the amp is ON, just wiggle the tube in the socket, like you are going to remove it, circular motion, etc. Does it make the same noise??? Try not to jiggle the tube, only move it in the socket.
If the noise is there, it could be the soldering on the back of that socket, as stated by BrianPhase. If it does NOT make that noise,.. try just switching the tubes you already have to other sockets. If the noise follows the tube and the original socket is quiet, then it is the tube.
If the amp has not had the power tubes replaced in quite some time you should do that first, before taking it to a tech,... less money spent is better.
It is not an issue about the bias, and you should have much better sound with new tubes. If you STILL get the same sound when the new tubes are in, it is most likely the socket, and it should then go to a tech, or someone who knows the guts of the amp,...

DEADLY VOLTAGES IN THERE, so do not mess with it underneath unless you know what you are doing.

Good luck!!

S

[Ridgeback65]

Hey Brian and Upstate,

Thanks for the replies. I tried that tube movement technique to see if it follows the tube or stays in the original socket and it's not the tube. It stays with the socket.

So you guys are thinking that it must be a bad solder issue as opposed to a stretched-out pin retainer not making good contact?

If it's a solder problem, how hard is it for a tech to repair? I know it wouldn't be a big deal with a hand-wired amp, but looking through the socket I can see a circuit board right underneath!

-S

[Upstate]

Sometimes depending on how often the tubes have been changed, the sockets do have an issue with making contact with the tubes pins,... as often as not, it is that different tube makers do not have a 'standard' size for the pins,... sometimes the pins are slightly smaller than the previous tube that was in that socket,... so, my advice, before using any soldering at all would be to readjust ther sockets size, or at least the size of the holes the pins go into,... but be aware the voltages stay in the caps, and you can still get zapped even if the amp is unplugged and off. so if you do not know or feel comfortable doing anything to the underside of your amp, take it to a tech.

That being said, the above advice would be my first shot at a fix,.... no money spent etc....

I have just put a small drop of solder in the pin hole to make it smaller, inserting the tube as quickly as possible so as not to have the hole entirely blocked, just made slightly smaller,.... if this or just squeezing the sockets pin holes works, then I would maybe think of it as a temporary fix, and ask a tech to look into replacing the socket in question...

If on the other hand that method does not result in a fix, then it would be the soldering as a next choice3. as the tubes are removed, and replaced, the entire socket is flexed slightly while the process happens. This results in soldered joints being stressed a bit, and ultimately they will need attention, all that is usually necessary is to reheat each joint to let the existing solder re seat itself and that is all it takes,.. usually not necessary to add any more solder, only a bit of flux to make what is there flow nicely.
Again, if you are not comfortable doing that, take it to a tech.

Good luck and make some good noise will ya!!!

S

[Upstate]

Sometimes depending on how often the tubes have been changed, the sockets do have an issue with making contact with the tubes pins,... as often as not, it is that different tube makers do not have a 'standard' size for the pins,... sometimes the pins are slightly smaller than the previous tube that was in that socket,... so, my advice, before using any soldering at all would be to readjust ther sockets size, or at least the size of the holes the pins go into,... but be aware the voltages stay in the caps, and you can still get zapped even if the amp is unplugged and off. so if you do not know or feel comfortable doing anything to the underside of your amp, take it to a tech.

That being said, the above advice would be my first shot at a fix,.... no money spent etc....

I have just put a small drop of solder in the pin hole to make it smaller, inserting the tube as quickly as possible so as not to have the hole entirely blocked, just made slightly smaller,.... if this or just squeezing the sockets pin holes works, then I would maybe think of it as a temporary fix, and ask a tech to look into replacing the socket in question...

If on the other hand that method does not result in a fix, then it would be the soldering as a next choice. as the tubes are removed, and replaced, the entire socket is flexed slightly while the process happens. This results in soldered joints being stressed a bit, and ultimately they will need attention, all that is usually necessary is to reheat each joint to let the existing solder re-seat itself and that is all it takes,.. usually not necessary to add any more solder, only a bit of flux to make what is there flow nicely.
Again, if you are not comfortable doing that, take it to a tech.

Good luck and make some good noise will ya!!!

S

[Ridgeback65]

OK, so it's no trouble accessing the sockets from within the chassis? (no worries on the high-voltages, I built my own tweed 5E3 once so I understand about the filter caps).

Anyway, you sometimes hear about how difficult working on new amps can be due to all of the circuit boards "in the way", etc. That they aren't as service friendly.

[Ridgeback65]

Just a follow-up. I took the amp to a tech and low and behold, it WAS the socket pins that needed to be retentioned. Sweet! Way less $ than a solder joint.