Valve amp convert

JayGee

timmysoft said:

Danny1969 said:

Mesa quality is great but there's nothing wrong with the BS quality ... PCB is superb, so is the soldering. Pots and chassis are great. I've gigg'ed the fuck out of mine, 100 + gigs a year just chucked in the back of the van, no cover or case. Badge fell off but amp is rock solid. 

Not my experience at all. 3 out of 4 went down in one tour, bent chassis, dry joints and loose pots! Finished the tour on hiwatts, now that's saying something about reliability! 

Mmmm....

My S1 *feels* pretty solid and well made but It failed twice in the first nine months or so I owned it.

Regular readers may recall a saga when I was without the amp for about 8 weeks with what turned out to a dodgy power valve (hence not under BS's control, and they did revalve the whole thing, all the power valves, pre-amp valves and all and only charge me for one EL34) because the one tech who was qualified/experienced to work on them was out sick (again not entirely BS's fault, and certainly not the fault of the tech concerned who turned out to be absolutely lovely and bent over backwards to get the amp back to me to meet a deadline once he was back in the shop)

The second failure was in the return side of the FX loop (which left the amp otherwise fully functional) but was turned round promptly, efficiently, and fuss free between gigs with a replacement FX loop board.

I'm willing to write off the first failure as outside BS's control (there's a reason why amp warraties don't usually cover valve failures for the full warranty term) and the amps been trouble free since over a year or so of weekly rehearsals and gigs but I'm still slightly concerned that the service department had a single point of failure and that some failure modes (like my FX loop failure) are apparently only fixable by board level replacement...

Danny1969

My comments only relate to the HT5 .....  because that was the amp the threads about. That is a very well designed and built little amp. I have done about 300 gigs with mine over a 3 year period and the only failure was a valve .... or technically half a heater in the valve ..... which still isn't fixed but works once the valve gets hot enough
The amps left in the van with no cover in all seasons so it's not got an easy life

ICBM

JayGee said:

I'm still slightly concerned that the service department had a single point of failure and that some failure modes (like my FX loop failure) are apparently only fixable by board level replacement…

Given the way many modern amps are built, replacing the whole board can be the quickest, cheapest and actually best method of fixing the problem, if you have easy access to the replacement boards. Usually you will have to remove the board to work on it anyway, and replacing components on a through-plated board with thin traces, or surface-mount ones, can sometimes be difficult to do well at least without being extremely time-consuming.

So given that the FX loop board probably doesn't contain any very big parts and hence isn't an expensive assembly - and they had to have it out anyway - I can perfectly understand why short-cutting the process and simply fitting a new one at that point is the best solution. You might also find that if there is a history of that fault, that the new boards have been upgraded, so it's even better than repairing the old one.

Danny1969

Board replacement is common in all walks of electronic service, I only exist as a repair guy BECAUSE manufactures won't repair at board level. If the buck convertor supplying the CPU core voltage on your Dell laptop goes bang the Getronic's engineer is just gonna change the motherboard, he doesn't need to know (and probably doesn't) how a buck convertor works cos he's got another board in the van. A boiler engineer will change the PCB is a 78p 5 watt resistor has gone open circuit. A mechanic will change a relay panel on a SEAT car because one relay out of the 12 has gone bad. A Shoprider mobilty scooter engineer will change the motor control PCB of a Shoprider if one Triac blows. 
All the above are examples of recent board repairs I've done for out of warranty repairs ..... where the official answer was change the whole PCB. 
Working on a lead free modern board is time consuming and difficult to rework unless you have a lot of experience. A sends return board with sockets and (maybe ) buffer opamps would cost less than an hours minimum wage labour 

JayGee

ICBM said:

JayGee said:

I'm still slightly concerned that the service department had a single point of failure and that some failure modes (like my FX loop failure) are apparently only fixable by board level replacement…

Given the way many modern amps are built, replacing the whole board can be the quickest, cheapest and actually best method of fixing the problem, if you have easy access to the replacement boards. Usually you will have to remove the board to work on it anyway, and replacing components on a through-plated board with thin traces, or surface-mount ones, can sometimes be difficult to do well at least without being extremely time-consuming.

So given that the FX loop board probably doesn't contain any very big parts and hence isn't an expensive assembly - and they had to have it out anyway - I can perfectly understand why short-cutting the process and simply fitting a new one at that point is the best solution. You might also find that if there is a history of that fault, that the new boards have been upgraded, so it's even better than repairing the old one.

I don't have a problem with any of that, the only thing I find slightly concerning is that it's all dependent on availability of the replacement board. Fast forward 5 years or so to a point in time where the Series One has been replaced by a hypothetical Series Two, Series One's are all out of warranty, Series One FX loop boards (which I'm assume are largely SMD) aren't in stock, and the contract manufacturer who actually makes them doesn't want to know unless there's an order for 500 pieces and what happens? 

Arguably that shouldn't matter, because (even at pub gig levels of payment) the S1 has already paid for itself and economically I should just walk away from any repair beyond consumables and buy a new one but I grew up in a world where 100 Watt valve amps weren't things you treated like consumer "white goods" and old habits die hard...

Incidentally, in the interests of fairness I feel I ought to point out that while they aren't everybody's cup of tea I really, really, really like my S1-104. Between 4 channels and 6 distinct voices it covers a lot more ground than the unashamedly R-A--W-K cosmetics, marketing, and artist endorsee roster would lead you to expect, the MIDI channel change means it integrates into a system with my Joyo PXL looper really neatly, and, while it's controllable enough to use around the house every time I get to stand in front of it with the volumes up off idle in a decent sized room it makes me giggle like a small child with the sheer fun of the amount of glorious noise I can make with it... :-)

ICBM

JayGee said:

I don't have a problem with any of that, the only thing I find slightly concerning is that it's all dependent on availability of the replacement board. Fast forward 5 years or so to a point in time where the Series One has been replaced by a hypothetical Series Two, Series One's are all out of warranty, Series One FX loop boards (which I'm assume are largely SMD) aren't in stock, and the contract manufacturer who actually makes them doesn't want to know unless there's an order for 500 pieces and what happens?

I know, and as a repair person that doesn't fill me with great enthusiasm either. What I said doesn't mean that the boards aren't repairable either, just that at the moment replacing them may well be the best solution.

At least with most of this analogue stuff you can still get the components if you have to. The problem with digital gear which often uses custom chips is that you're totally out of luck even if you can work on SM components.

impmann

ICBM said:

The problem with digital gear which often uses custom chips is that you're totally out of luck even if you can work on SM components.

Wisdom right there.

Even when you have "standard" chips, often the code is blown onto them at the Contract Manufacturers using jigs etc that are not available even to the manufacturers of the product.

A perfect example of this is the flash chip on board the Line6 Spider Valve Mk1. No pre-blown chips exist, no code exists to blow the code etc as this was all handled by the CM in China, who has since disposed of all of this. The chip is standard, the code and the method of putting it onto the chip is bespoke and no longer exists.

ICBM

impmann said:

A perfect example of this is the flash chip on board the Line6 Spider Valve Mk1. No pre-blown chips exist, no code exists to blow the code etc as this was all handled by the CM in China, who has since disposed of all of this. The chip is standard, the code and the method of putting it onto the chip is bespoke and no longer exists.

So presumably if it dies then the amp becomes a glorified "valve powered monitor" with a pretty light-up display… since you can at least plug a Pod or something into the power amp input .