New guy & question on Trace Elliot Supertramp

[Luddite]

Hi,
  I bought a used Trace Elliot Supertramp Stereo Twin Chorus a year ago (green tolex) and I'm having an intermittant issue with it. Background, whoever owned it before me cannibalized the Celestion speakers and replaced them with one crap Dean Markley vintage rock and one totally unmarked noname speaker. I plan on replacing these with some Webers. My problem is that a few times per week when I power the amp on it makes loud cracking sounds. Doesn't matter what's plugged in or where the volume is, or which channel I'm on. Usually if I turn the amp off for a few minutes, then pwer back on it fixes the problem, however today it didn't. Today the problem went away after the amp warmed up for a couple minutes. My question is if this nis indicative of a major underlying problem. I don't want to invest in replacement speakers if the amp itself is a bone. When it is working everything sounds just great and I love the amp. Thanks!

[joecool85]

Sounds to me like a bad solder joint somewhere, probably on one of the jacks.  If you go through and touch them up it should go away.

[Luddite]

Sounds to me like a bad solder joint somewhere, probably on one of the jacks.  If you go through and touch them up it should go away.

Thanks,
  I went in and didn't see anything obviously loose, but I tightened up a few items and at least for now it worked. One strange thing I saw was a bunch of what appears to be hot melt glue on some components. In some cases it was quite messy and I cleaned this up too. Is this common, or did someone try to do a fix without a soldering gun? At any rate thanks for the reply, now I can go get some new speakers!

[teemuk]

Hot glue is common. It holds the heavy components on place so they won't break their solder joints when the amplifier rattles (either when it's being transported or when it's sitting atop a vibrating cabinet). Solder joints are not very durable mechanically. That's why one of the most common problems in an amp is a "cold" solder: A component subjected to mechanical stress breaks its solder joints and causes intermittancy. Sometimes these problems may cure themselves when the amp heats up - just to reappear soon again.

Did you go through the solder joints or did you just tighten the jacks. Most broken solder joints are difficutlt to detect without a magnifying glass and a good light. Go trough: Jacks and switches, potentiometers, big power resistors and big capacitors. Likely you found goobs of the hot glue from the latter two.

If you removed the hot glue you need to replace it so that the components are securely mounted again. People who put these amps together generally tend to use big goobs of both glue and thermal paste. This is not needed so you can likely do a neatier job. (Just make sure the glue does what its supposed to).


Edit: Forgot to mention, those big crackling sounds may be signs of aging capacitors. However, since the amp is likely not extremely old yet I'm more keen on suspecting that its just a problem related to solder joints. I don't have a schematic for this amp but I do have a schematic for Stereo Quad Twin, which could be very similar. Anyway, if you need it you should find it from the Internet very quickly as well. (One of the first hits if you google: trace elliot twin schematic).

[gtrsean]

Hi Luddite,
I just spent a bunch of time writing you a "proper" reply in an effort to help you figure this out, and the forum timed out on me and the whole thing was lost!
Hopefully, I don't sound snotty, but I am going to be brief with this.
Try replacing the tube in your pre-amp.  Even better if you use Caig Labs DeoxIT Gold Pen to clean your tube socket and treat the new tube before replacing.  Also, let your amp warm up for a few minutes after you turn it on before you play through the amp (ALWAYS).  Not warming the tube up will put you right back where you started in short order.
OK, hope this helps.
Quest Forth.
Sean
 
PS  As a side note, the DeoxIT Gold can be used for your preventive maintenance on all of your gear and is one of the best investments you can make in your gear and sound.

[Luddite]

Thanks All!
    I have a lot to look at now  Funny thing is even after the little I did the amp sounds perfect again, but I'll continue looking. Thanks again,
jc