Dual Rectifier Tremoverb repair – Mesa amp repair

Dual Rectifier Tremoverb Repair

This Tremoverb repair was  for a customer who was attempting a combo to head conversion. It’s a lovely lovely sounding amp, but the 2×12 speaker box in which it was housed was too heavy for the owner. The owner performed the conversion himself but in doing so, the hand wired input jack became disconnected so the he brought it in for repair and basic service.

The Tremoverb input was easily and quickly fixed. My minimum fee is the 1 hour diagnosis period, so I proceeded to give the amp a full valve test in order to give best value for money.Mesa weird PCB layout

The Valve test revealed that one of the power 6L6 valves was faulty and the others were out of spec. Most Mesa amps require a specific set of valves and this Tremoverb Repair is no different so I fitted a matched quad of Mesa STR-440s.

Whilst giving the amp a look over I noticed a very wierd bit of PCB layout. The Opto isolators that Mesa always used on amps (pre-late nineties) were stacked one on top of the other. I hope I never have to replace the bottom opto on one of these. As I’ve said before, Mesa really don’t think about repair when they’re designing. Pity, when they sound so awesome!


If you have a Mesa Tremoverb repair please get in touch.

Mesa Boogie Bass amp Repair

Mesa Boogie Bass 400+ Repair

This mesa boogie bass amp repair had the highest power valve count I’ve seen. The amp uses no less than twelve 5881 6L6 valves!

Like the recent fender amp repair this valve amp was blowing fuses. Also like the fender repair, the failure was down to a damaged power tube. Two in fact.

Much is made of Mesa Boogie’s insistence upon the use of mesa branded valves on guitar forums and these guys come in for quite a lot of stick. You can read Randall Smith’s defence of the idea here. My opinion is that the principle is reasonable for the majority of non technical users.

In this case, the amp had been fitted with Sovtek valves. Aside from the two failures many of the valves no longer matched well.

By testing mesa boogie valves in my valve tester I know what non mesa valves are within mesa parameters for use in their amps. I could tell that 4 of the sovteks were out of spec, meaning that 6 of the 12 needed replacing. After completing this simple task the amp was fixed.

If you have a mesa boogie bass amp repair please contact me via the contact page.

Mesa Boogie Repair – Maverick (Dual Rectifier)

Mesa Boogie Repair - Dual Rectifier Maverick

This Mesa Boogie repair was one of the nicest amps to play, but one of the longest repairs of the year I’m afraid!

In this case, the Maverick had a problem with the channel switching. After a few minutes the rhythm channel would increase in volume, and the lead channel would bleed through an unpleasant fuzzy distortion. The fault was fixed by the opto-isolator replacement in the switching circuit.

It’s never a good thing to discover that your amp is faulty, but a broken amp is particularly bad news for owners of Mesa Boogie amplifiers. This is because Mesa Boogie construct their amplifiers in a way that lengthens the repair time.

The reason is that the amplifier is soldered into position on all four sides. Any changes to the board must be done after completely dismantling the amp (taking 30minutes each time). If several things are replaced in a more complex job, then the costs quickly mount up. Before I add to any myths, it’s NOT because the amplifier is PCB, it’s perfectly possible to make a PCB amp that’s easy to repair! It’s also possible to make a Point to Point amp that’s a nightmare to repair as well – I’ve seen them!

Anyway, what an absolutely great tone this Mesa Boogie has when it’s cranked. It’s completely unlike the rest of the Dual Rectifier series. The Black Widow speakers in this particular combo are brilliant speakers.

If you have a mesa boogie repair, please do get in touch and we’ll talk it through.

Dual Rectifier Repair – Mesa Boogie – Ampworks, Newark

This Mesa Boogie Dual Rectifier Repair is one of the more unusual problems I’ve come across. The Mesa was brought in with very low (and unpleasantly distorted) volume and blowing fuses. I tracked the issue to the output circuitry and checked for all the usual failures with no result. The output transformer looked to be the faulty component but the issue turned out to be a faulty component that was loading down the 4 ohm input with a low impedance. Component changed and the amp springs back to brutal METAL life!!

UPDATE 2016:
Mesa Boogie repairs are among the most difficult jobs to do, partly because of the complexity of the amp (which makes for a fantastic product) but also because they design their PCBs in a way that aren’t very friendly to repair. I’ve done many mesa boogie amps though (you can read about others here) and they are always worth fixing!

Mesa Boogie Repair

If you have a Mesa Boogie Dual Rectifier repair job that needs doing, please get in touch via the contact page.