The most unreliable amplifier ever….

Voxsupertwin

The Vox T60 transistor head for bass in 1964 is a clear winner for this title. 

Excellent concept let down by its circuit design which led to thermal runaway of the output stage.
 ie Too hot results in more current which results in more heat which ends up with smoke, possibly flames and no sound.

The Burns Orbit range, another early 60s tranny design.

Sounded ok in the shop, on stage once the drummer started they were inaudible.

Turning them up, usually to full, didn’t improve the situation much, they just sounded worse rather than louder.

Inevitability they blew up …

Let’s hear your stories guys…….& gals of course !!!

pt22

Vintage English electronic unreliability? I refuse to believe it. 

Voxsupertwin

pt22 said:

Vintage English electronic unreliability? I refuse to believe it. 

This was when they were new…..they weren’t vintage at the time but ‘cutting edge’.

Danny1969

I think the Vox AC30 deserves a mention. There's been a lot of different models since the original but all are flawed in one way or another. 

Voxsupertwin

Danny1969 said:

I think the Vox AC30 deserves a mention. There's been a lot of different models since the original but all are flawed in one way or another. 

In terms of reliability the AC30 IMO was the stalwart of the 60’s, they were used by virtually any band that was gigging the dance halls and clubs.
Flawed maybe but unreliable not so, but of course being a valve amp they required some respect in transportation etc.

We used a non top boost AC30, a Supertwin AC30 and an AC30 head with a T60 cab from 1962 to 1966 with no issues….all bought new from Barratts of Manchester.

impmann

Marshall DSL. 
End of. 

BillDL

I bought a Peavey Triumph 1x12 100W valve combo around 1991 that had a design fault which Peavey refused to acknowledge.  They mysteriously released a "new improved version" and tacked "PAG" onto the model name.  I think this stood for Parallel Axis Geometry or something like that, and I think the only change between the versions was an alternative placement of the valves.

The amp was a real beast that sounded rich and thick, but the guitar volume would fizzle out to a whisper and the amp would just start singing by itself in a high-pitched feedback whine at the most inopportune and unexpected moments.  This was before people had access to the Internet to exchange stories and thoughts, so it wasn't widely known about until amp techs began realising the problem was inherent and telling customers.  It turned out that it was caused by the placement and/or orientation of the valves or their close proximity to other components and wiring, but by that time I had spent quite a bit of money replacing what I thought were microphonic valves, and also having it inspected by an amp tech who at first thought it was to do with the reverb tank, then possibly the send-return effects loop, and I think he even tried putting in some kind of screening plate.  Nothing worked, and he conceded that it was a poor design and said he had been hearing from others about the exact same issue.

Peavey refuted this when I wrote to them complaining.

ICBM

Voxsupertwin said:

The Vox T60 transistor head for bass in 1964 is a clear winner for this title. 

Excellent concept let down by its circuit design which led to thermal runaway of the output stage.
 ie Too hot results in more current which results in more heat which ends up with smoke, possibly flames and no sound.

To be fair, these were among the very first practical solid-state amps, so it's not surprising they hadn't identified and ironed out all the pitfalls yet. I actually know where there's one with its original power transistors, never been blown... it must be rare to the point of unique.

The mid-70s Marshall 'flat' lead and bass 100W heads are less forgivable, they're almost as prone to power transistor failure but were more than ten years later.

impmann said:

Marshall DSL

And TSL100 (same main PCB) and TSL60 (worse!). I'd be interested to know the proportionate failure rate, but they certainly do have several serious design flaws that can't be fixed completely.

The Mode Four is *much* worse though - whoever had the idea of building an amp using not one but *four* of the already notoriously unreliable AVT100 power modules, wired up in a way that almost guarantees cascade failures...

The Mode Four takes it, for me. When I was doing repairs I had a point-blank refusal to ever accept one for work after I saw the first one - they simply could not be guaranteed, and I didn't want the comeback.

There was something deeply wrong at Marshall in the 90s and early 2000s - a whole succession of flawed designs with serious reliability problems that should have been obvious to anyone with real-world repair experience before they were even put on the market. Thankfully, they seemed to have improved after that.

Several Trace Elliot valve guitar amp models from the 90s aren't good either.

impmann

ICBM said:

The Mode Four is *much* worse though - whoever had the idea of building an amp using not one but *four* of the already notoriously unreliable AVT100 power modules, wired up in a way that almost guarantees cascade failures...

The Mode Four takes it, for me. When I was doing repairs I had a point-blank refusal to ever accept one for work after I saw the first one - they simply could not be guaranteed, and I didn't want the comeback.

Oh hell yes, the Mode Four... or the TSL60. The Anniversary combo was pretty shonky too.

But yes, you are right the Mode Four was awful.

spirit7

Marshall TSL60.  The worst amp ever made. 

Moe_Zambeek

The most unreliable ones I’ve had have been older Oranges - original OR and GRO models. Mainly blowing fuses and dying (probably valves) but also mysterious cutting out and sudden compression and general weirdness. Had a few dodgy Matamps as well, though later ones were better.

Most recently I’ve had 2 brand new Oranges with exactly the same rattle, a buzzing Hook Little Lenny, and both a Suhr Hombre and a 68 custom pro with rattling output tubes.

I’ve also this year tried in shops a 68 custom twin where the reverb was faulty and the amp had an unexplained loud hum and a Marshall Astoria that was basically dead and crackling on power up. 

I think it might be me…or maybe just that tube supply issues are causing issues in modern production valve amps.

HoraceB

The new Bad Cats are not filling me with much confidence. In the last month I've had to return two Black Cats that kept blowing mains fuses and and now returning a Hot Cat that the volume keeps cutting out on. 

Ddigger

HoraceB said:

The new Bad Cats are not filling me with much confidence. In the last month I've had to return two Black Cats that kept blowing mains fuses and and now returning a Hot Cat that the volume keeps cutting out on. 

Holy moly!  If I want unreliability, I can pay a lot less to get it.

Also...

pt22 said:

Vintage English electronic unreliability? I refuse to believe it. 

I thought everything was better in the olden days?

ICBM

Ddigger said:

pt22 said:

Vintage English electronic unreliability? I refuse to believe it. 

I thought everything was better in the olden days?

That reminds me of the old joke about British car electrics...

Lucas - Prince Of Darkness

pt22

ICBM said:

Ddigger said:

pt22 said:

Vintage English electronic unreliability? I refuse to believe it. 

I thought everything was better in the olden days?

That reminds me of the old joke about British car electrics...

Lucas - Prince Of Darkness

Best reason not to buy a British car! 

impmann

ICBM said:

Ddigger said:

pt22 said:

Vintage English electronic unreliability? I refuse to believe it. 

I thought everything was better in the olden days?

That reminds me of the old joke about British car electrics...

Lucas - Prince Of Darkness

Yup... and then you try working on Italian car electrics, and start wishing for the simplicity and reliability of Lucas...

DartmoorHedgehog

The most unreliable amp I've personally experienced is the Ashdown combo the bassist in my band uses.  It's completely died at least three times in the time we've been playing together (which is admittedly about a decade, but still seems like too often) and seems to be constantly suffering from various weird dropouts and volume issues.

When it's working it does sound really good though.

EDIT: Googling for pictures, I think it's probably an EB 12 150

Danny1969

DartmoorHedgehog said:

The most unreliable amp I've personally experienced is the Ashdown combo the bassist in my band uses.  It's completely died at least three times in the time we've been playing together (which is admittedly about a decade, but still seems like too often) and seems to be constantly suffering from various weird dropouts and volume issues.

When it's working it does sound really good though.

EDIT: Googling for pictures, I think it's probably an EB 12 150

Ashdown amps, particularly their bass amps are notoriously unreliable. I've been in 2 different bands with bass players using Ashdowns and had to repair both. 

@Voxsupertwin ;
I think maybe Vox AC30 amps in the sixties were more reliable in the sixties due to  the higher quality of the valves available back then. I don't know any owner of a Vox AC30 now who hasn't had some issues. I've just done 3 AC30's belonging to one owner. 
Shame because it's a great sounding amp when it's on form and nothing else really sounds like it. 

AntonHunter

I had three Fender Hot Rod Deluxes in as many months once. Probably around 2004, and Sounds Great in Heald Green (RIP) were great at replacing them, something about having changed factories recently and one particular component kept failing.

Finally went back to get one about ten years later and it's still going fine now with just a bit of servicing.

ScreamingDave

Funny, I’ve had three Marshall DSLs and a TSL over the last 18 years or so and never had any problems. Just the usual valve replacements when it’s gigged and rehearsed hard. Just goes to show, you never can tell ….

Sassafras

Bird Golden Eagle.
I threw a fortune at that bastard, 
Never could get it to work properly.