Rocket slowly dies out sometimes

[davidskywalker]

I have a new Rocket I've built a few weeks ago and has sounded great with no problems except that in the three weeks I've been playing it, twice I will be playing it for a few minutes after first turning it on will slowly die out. But if I turn the standby off and back on it will slowly come back in and I can play for hours and never happen again. But it may happen two weeks later.

Only thing I can think of is the Rectifier tube or the filter caps.

I wanted to get some ideas first before spending any more money on parts.

[RJ Guitars]

David,

It sounds like you've got the right parts in the right places. There is generally a couple thoughts on this kind of problem. One popular thought is that you could have some high frequency oscillations going on that essentially shut down the amp. I think the more likely scenario is that you have something that's not bonded securely and you're loosing contact intermittently. This is what I'd look for.

Check all your cables - guitar cables and speaker cables.

It can be really hard to find these intermittent problems but there are several clues helping you out.... it seems like the whole amp goes dead. Confirm for us that the light stays on when the sound goes dead.

Here on the forum you'll get some help looking for it if you'll post some pictures. Hopefully you'll be wiser if you also learn a few tricks to help you sort out where the problem is along with the extra eyes on the problem.

As a first approach take the cover off and turn it upside down make sure its secure without setting on the tubes. Look at every solder joint on it and reflow anything that doesn't look perfect... then reflow all the ones that do look perfect. See if it misbehaves after that.

You'll need the amp to be in the failure mode in order to really trouble shoot it... Using all caution and safe trouble shooting practices turn the amp on and see if you can force it into the failure mode. If so, you can use a set of chopsticks to move wires and components around and see if anything happens.

If it's stuck in failure mode then you can start measuring voltages... give all this a try and check in with us and we'll dig a little deeper if we need to.

[Richie]

Loss of heater connection or voltage,among many others, the amp may go quiet.

[RJ Guitars]

Yep, i agree. If the pilot indicator stays on but the sound is gone, see if your heaters are still lit. It would only take one preamp tube to quiet the whole amp.

[hitchcaster]

swap the el84s maybe? see what that does

[M Fowler]

If it is slowly dying out doesn't that mean the filter caps are draining so there has to be a misconnection or poor solder joint?

[johnnyreece]

If it is slowly dying out doesn't that mean the filter caps are draining so there has to be a misconnection or poor solder joint?

I would think either that, or a preamp tube losing filament voltage (the tube stops conducting as the cathode cools off). Some gut shots might help figure out what's going on. Sounds like folks here have you on the right track. Good luck!

[passfan]

First thing came to my mind is a heater slowly cooling down.

[pdf64]

Yes, a slow clean fade out and back in is characteristic of an intermittent heater problem.
Could just be a dry joint on a tube socket terminal, and be in either the 5 or 6.3V circuits.