Trace Elliot GP12 Repair – Keld Ampworks, Newark

Trace Elliot GP12 Repair

The symptoms exhibited by this Trace Elliot GP12 repair were a loud hum and distortion evident during note decay. Unfortunately I wasn’t able to replicate the customer’s problem which makes repair difficult, so I took a number of steps.

I left the amp on soak test for 2 hours, which involves heavily driving the output stage – this normally shows up faults that are temperature or power supply related.

What I did find was that one of the internal IDCs was causing audible noises when manipulated. I’ve seen this before with another Trace Elliot GP12 repair Mostly crackles, although there was a slight increase in hum sometimes which matched the symptoms described. Cleaning the IDC fixed this and that connection is now stable. I also cleaned the FX loop sockets because unused FX loops are a prime candidate for noises such as those described.

As part of a general service I also cleaned the Graphic sliders as there were a few little crackles – nothing to do with the described fault.

The next step in hum busting would have been to replace the reservoir caps. I avoided this because it adds significant cost and I had no concrete reason to suspect them. The description of the distortion on the note tail does sound a bit like caps, but the soak test didn’t reveal any problems with them.

The amp was returned to the customer. When I contacted him again the next month, the amp was still working well, another successful repair!

Note that the image is an old image, not the amp in question, it’s actually

If you are in need of a Trace Elliot GP12 repair, please get in touch via the contact page

Trace Elliot GP7SM Repair


A recent Trace Elliot GP7SM Repair, a amp service actually.

The owner brought the amp in for a check over before sale. This is a really beautiful Trace Elliot!

This particular AH350 (from the early 90s) uses the Trace MOSFET output stage, with Lateral type audio FETs. These are expensive, but worth it – the other Trace Elliot Bipolar output stage has some reliability issues that I’ve seen in the past.

This GP7SM was fine though. No problems.

It’s got a really cool optional UV light at the front. I haven’t seen one like this before. Makes the green front panel glow nicely. Great, if you like it!

Available to buy (as of Nov ’14). If you’re interested I’m obviously not going to publish customer’s details, but I can put you in touch.

Trace Elliot Repair – GP7SM 200W

Trace Elliot Repair

Trace Elliot Repair – GP7SM 200W

This Trace Elliot repair is actually a service. My solid state service procedure involves the following steps:

  • Cleaning of all pots and connectors
  • Re-soldering dry or suspect joints
  • Any preventative maintenance required
  • Replacement of out of tolerance or defective components
  • Output power test.


I’ve seen a couple of Trace Elliot repairs in a pretty sorry state. The main cause of trouble is normally the ‘bipolar bear’ (bad electronics joke by the designer) output stage. This unit uses a lateral MOSFET output stage that is more reliable, so the customer has little to worry about. I’d recommend that owners of a Trace Elliot amp with the original stage have the output stage replaced at some point if the amp gets really heavy use.

Here’s the owner’s feedback, taken from the now extinct review site ‘’ before it merged into ‘’ and deleted all old reviews!
“ Rowan at Ampworks very kindly serviced my Trace Elliot GSM200 solid state head at extremely short notice. He did a thorough job of making sure everything was as it should be inside, re-soldered any suspect connections, checked the electronics and pots. I can’t recommend Rowan and Ampworks enough. John (Leicester) “(pigbobman, 28-03-2013)
Thanks for the kind words John. I’m glad you were happy with your service.

If you have a Trace Elliot Repair job that needs doing please, get in touch.