Build quality of well known amp manufacturers, anyone able to give some input??!

ICBM

jpfamps said:

We change more transformers on Marshall amps than ALL the other brands put together by a significant margin.

I think one of the reasons for this is not just the quality of the transformers themselves - although it is a factor - but that the amps and cabs have switching in the speaker current path using jack switches. This is utterly terrible design if you know anything about valve amp reliability - a duff switch contact in any one of the jacks (the cabs have four, and they get stressed when the cables are tugged in use) and the amp is left with no load.

Coupled with several other design errors that no-one with a lot of real-world repair experience would make, you really have to wonder about their R&D department...

This is nothing new though, the appalling quality of their voltage and impedance selectors in the 1970s was responsible for a lot of blown transformers as well.

Psygoat

One of the Mesa I saw had a section of the pcb that was potted, presumably so that it couldn't be copied.
Of course this was where the problem was and I seem to recall that they weren't vey helpful.
It might be a myth, but I've heard that Mesa's were designed for the US and don't work so well on European mains voltages.
I can't really see why this would be the case tbh, as I've never heard of this being a problem with anything else.

ICBM

Psygoat said:

One of the Mesa I saw had a section of the pcb that was potted, presumably so that it couldn't be copied.
Of course this was where the problem was and I seem to recall that they weren't vey helpful.
It might be a myth, but I've heard that Mesa's were designed for the US and don't work so well on European mains voltages.
I can't really see why this would be the case tbh, as I've never heard of this being a problem with anything else.

Myth - if you get a proper export model with the correct voltage transformer, anyway. A US 120V model with an external stepdown transformer might not work as well because the transformer is slightly less efficient at the European 50Hz than the US 60Hz.

Some Mesas are a real nightmare to work on as DJH and jpf said.

jpfamps

Psygoat said:

One of the Mesa I saw had a section of the pcb that was potted, presumably so that it couldn't be copied.
Of course this was where the problem was and I seem to recall that they weren't vey helpful.
It might be a myth, but I've heard that Mesa's were designed for the US and don't work so well on European mains voltages.
I can't really see why this would be the case tbh, as I've never heard of this being a problem with anything else.

I think this myth has come about because US MESA amps don't have taps for voltages other than US mains, which of course prevents someone importing a MESA from the US and rewiring the amp to UK voltage, thus avoiding the purchase of a step down transformer or a UK mains transformer.

The cynical view is that this is a barrier to people taking advantage of the huge retail price difference of MESA amps in the US vs the UK.

Psygoat

Yeah, I thought it was a myth, but might as well mention it anyway.

I like the cynical view. btw.
+1 for Marshall customer service though and their spares are very reasonable.
i haven't delat with Peavey for a while, didn't they shut down or move their UK operation?

ICBM

Psygoat said:

Yeah, I thought it was a myth, but might as well mention it anyway.

I like the cynical view. btw.

I also believe the cynical view is correct - it's a deliberate strategy to block grey imports and maintain the 'boutique' pricing of Mesa in the UK. (And elsewhere, eg Australia.)

Psygoat said:

i haven't delat with Peavey for a while, didn't they shut down or move their UK operation?

All the musical instrument distribution is done from Peavey Europe now. Peavey UK has become a commercial audio installation operation, I think.

fandango

It looks like it's eventually coming out in the responses, but I will spell it out - there’s quality of design and quality of workmanship.

It's clear a number of amp makes fail because of design, so regardless of how well they're made, there's still an issue to overcome e.g. by modding the circuit or the cabinet. But modding a poorly made amp means your chasing the law of diminishing returns as you make good all that poor workmanship as well as design flaws.

Grocer_Jack

Any thoughts on recent (last ten years or so) Voxes, @ICBM ;;?

HHwarner

jpfamps said:

I pretty much concur with the above.

Some random observations based on our repair work

We change more transformers on Marshall amps than ALL the other brands put together by a significant margin.

I wonder if this is something to do with the switching inputs on the 1960 cabs. I’ve seen so many of these fail!!! I hate the things and wouldn’t use them myself. 

ICBM

Grocer_Jack said:

Any thoughts on recent (last ten years or so) Voxes, @ICBM ;;?

Variable, but not too bad. One major flaw is the standby switches being in the wrong place in the circuit which tends to kill rectifier valves. I also recently had an AC15C1 which had cooked itself just by being accidentally left on overnight though... not impressed. The faults were actually caused by (in my opinion) unnecessary extra complexity intended to reduce noise - non-polar caps alongside the main filters which had shorted, and a DC filament supply. They do tend to run very hot in general, and valve access is poor on most models.

jpfamps

HHwarner said:

jpfamps said:

I pretty much concur with the above.

Some random observations based on our repair work

We change more transformers on Marshall amps than ALL the other brands put together by a significant margin.

I wonder if this is something to do with the switching inputs on the 1960 cabs. I’ve seen so many of these fail!!! I hate the things and wouldn’t use them myself. 

I think it's mainly due to the poor quality of the transformers; I see both mains and output transformer fail.

That's not to say that some of them aren't "mugged" by poor design choices elsewhere.

jpfamps

Grocer_Jack said:

Any thoughts on recent (last ten years or so) Voxes, @ICBM ;;?

The newer VOXs are OK build quality, and generally I've not seen too many failures due to design faults.

As @ICBM  says valve access is poor in some models, and extracting the chassis can be troublesome. I've seen several AC30s where the chassis bolt threads have been stripped, or the T-nut is not gripping.

DJH83004

webrthomson said:

riffpowers said:

I'm surprised at that, and also surprised at Mesa, I'd always assumed those were well built, good quality amps.

I've had a ton of mesa's over the years and for the most part they have been pretty bullet proof - the only exception and where I've had repeated issues has been with the channel switching on a DC10 and a reborn recto - both had issues.

My DC5 and Mark series have all been great - no issues at all.

Apologies for the confusion, wasn't saying Mesas are bad amps at all, just the opposite, but they are a pig to work on when they do go wrong. getting access to the track side of the board invariably means disconnecting a host of cables as generally the pots are wired to the boards as are the transformer connections.

Regarding modern Vox amps, I have had quite a few mains transformer failures but that said they are Chinese, and I do get a lot of Chinese transformer swaps choose what brand of amp they are in.   

Grocer_Jack

Good info on the Voxes - thanks! I had a couple of the Custom Classics AC15CC and AC30CC1 and they both blew rectifiers. I thought that had been fixed on the new AC15/30 classics though?

ICBM

Grocer_Jack said:

Good info on the Voxes - thanks! I had a couple of the Custom Classics AC15CC and AC30CC1 and they both blew rectifiers. I thought that had been fixed on the new AC15/30 classics though?

Yes, by the simple method of not using a valve rectifier .

Grocer_Jack

Ha yes I hadn't realised that - Ta! I played an AC15C1 with greenbacks for 30 mins or so today. What a great sounding amp - might have to get one. Just wondering if the Alnico Blue speaker is worth the extra dosh.