marshall jcm 900 4102 - 4 tubes blown at once!

[olddawg]

When I was a bench tech we would cover a call back output device failure once. We even had little printed cards that said, "Your problem may have been caused by a speaker load fault. Failure to correct this may void your warranty." Assuming that your speaker cable and speakers have no issues, have you simply called, asked to speak to the manager/owner and stated your concerns. It seems to me that a reputable shop would cover the tubes. This kind of thing gets a shop a bad reputation.

[Chuck H]

I positively agree with this, the other strategy for a business plan. And great companies are built on this principal also. But there are others that operate very much as described in my post and do just fine. For them it's about what you can get away with. Sometimes that means what you can get away with without the need for too much damage control.

I wasn't proposing this as an argument about business practices. I was only pointing out that we do come across this sort of thing on a semi regular basis in life. It's a common obsticle.

[Prairie Dawg]

OOOooo... That depends entirely on what your definition is. When someone makes money and doesn't pay out much they are considered successful. Someone who loses money is considered unsuccessful. It's common business to give as little as you have to for your returns. Those who succeed at his practice drive nice cars and live in big houses that they own. People look at them and think "They are successful. I'll patronize them instead of that guy in the '74 woodside station wagon with one hubcap and an orange door." Even though the guy in the station wagon has spent his life doing the "right thing" and being emminently fair to his fellow man. Thus he has no money and looks unprofessional. It absolutely ceases to matter if success was gained by preserving profits at any opportunity even when it's as base as not paying out when you don't have to. Even when you should. The goal is to get money. Not to help people. Helping people is a product. A successful business plan is to get money and offer a product, in that order, with priority.

There is a line to be drawn though. If you offer a grossley bad product and people know about it you won't sell anything. This has proven to be a very gray area in things like construction, appliance repair, etc. Amp service and repair has many parallels. If no one here patronizes Voodoo that's not much of a loss for Voodoo. We fix our own amps. And who is stoma going to complain to? Probably not a potential client of Voodoo. So the priority becomes preserving money. Which is a very professional business practice.

EDIT: Please understand that I am playing devils advocate and do not subscribe to this morality (or rather, lack of).

I understand what you're saying about the 'professional appearance' and how people perceive something that looks good as inherently good-but that doesn't fit these facts. In all probability it was a failure that could have been located by a good burn in, and the net result was an expensive meltdown.

So fine. I pay for my screwups, in all likelihood you also do. It's part of the price of doing business, and if a shop can't do that, it bespeaks some serious problems internally in their organization if they won't eat it.

[Chuck H]

I understand what you're saying about the 'professional appearance' and how people perceive something that looks good as inherently good-but that doesn't fit these facts. In all probability it was a failure that could have been located by a good burn in, and the net result was an expensive meltdown.

So fine. I pay for my screwups, in all likelihood you also do. It's part of the price of doing business, and if a shop can't do that, it bespeaks some serious problems internally in their organization if they won't eat it.

Preaching to the choir comrade. But the problem as "I" see it is, under the current circumstances with the way things have transpired, will Voodoo step up? I don't see a way to force the issue should it come down to that. How can you even make Voodoo present a detailed work order? Will the police march up and demand it? Do you pursue the cost of four power tubes in some small claims court or arbitration? This just has $h!t all over it.

[Prairie Dawg]

My sister's first husband operated a successful auto body shop for many years and I worked for him a couple times. He once remarked to me that one well done job, on the average, yielded two more jobs, even if it took a while. I've found this to be a reliable truth. One Gibson amp I overhauled for a local music shop yielded me, by my counting, four repair jobs so far. It stands to reason that this principle can work in the negative as well. For smallish tradesmen, word of mouth is the only reliable way I know of generating more business. Happy customers are more likely to pass your name along, and musicians are notoriously social and chatty folks. I guess if you get big enough that doesn't matter too much any more, and unless you are a stickler for principle and are willing to fund it, legal action over smallish amounts of money is a waste of effort.

But that's why the things we do are viable, at least on a smallish, manageable scale. Which keeps me happy.

[jrfrond]

I am not a big fan of burning-in amps in absentia. I sit with an amp until I am thoroughly satisfied that it passes muster, and only THEN do I button it up and release it. Now, this DOES take longer, and if it was a production line, would be horribly inefficient, but if it's going to blow up, I want to watch it happen, because that could tell me a lot. I could also cut the power before everything went up in smoke catastrophically.

I don't know what happened, but I do know it was NOT the tubes. Most likely the bias supply, but I wouldn't rule anything else out either.

[dumbassbob]

Just like the tech who never called me,never fixed the problem that I said was wrong with amp ,pulled out the other modwork that I paid a guru to do for me, and never asked me Then keeps my money I paid $235.00 to have nothing

[soundguruman]

Well the truth is that there HAVE been issues like this before, and we have seen it happen many times.
1. your speaker cable or speakers are defective. This has been the primary cause, in many cases.
The last (similar) failure I saw was caused by a new speaker cable purchased on ebay. The speaker cable was NEW and also, DEFECTIVE.
2. The PC mount switch, on the output board is failing. The contacts in these plastic switches burn up and fail. The power select switch fails.
3. Arcing / burning on the output jack board. I have seen them burn all the way through. Basically, the design is defective. There have been a load of problems with that board.
4. Bias failure...well, voodoo should have tested the amp better and it may be their fault. Don't know for sure yet. The bias filter capacitors certainly are capable of failure.

[soundguruman]

Once again Bob, look for a tech with Ethics.

[clyde1]

I once had a new build that kept blowing fuses, owner would replace them, finally he brought the amp back to me asking for a refund. I refused saying I would fix the problem. I put the amp on a dummy load for 3 hours almost wide open with the PT so hot you could barely touch it, nada! I gave it back and next time it blew the fuse, it took out a pair of KT88's. The CTS bias pot was intermittent. I ate the tubes and now have a happy owner.

[Chuck H]

I appreciate all the ethical business people here. But is this really an argument as to whether or not there are unethical business people? Or even people who run what they believe as fair, which implies no givaways. Listen, I do it all the time in my business. I'm a self employed painting contractor. Cutomer says "OOooh... I really thought that soffet would be better in the cieling color. But now that I see it..." And I say "No problem. I'll just change it." That sort of thing. In mant cases it comes down the customer making some minor mistake due to lack of familiarity of the issue. Not unlike when a customer brings an amp back for the third time with the same failure because they've been using it incorrectly. As professionals it's not that hard for us to correct the issue and we have happy customers. There, see? I'm just as cool as everyone else. But just because many, if not most, businesses apply this practice doesn't mean there aren't many that operate from a different perspective. Any implication that a business which doesn't cottle the customer can't survive is just plain wrong. It happens all the time. And my concern is simply that the OP might be dealing with this sort of thing. Which leaves the OP in a tough spot.

EDIT: I think this is really wierd actually. I mention unethical business ideals and everyone needs to step up with how they aren't like that. Even implying that businesses can't run like that. Which is hogwash. Really? No one here has ever seen this sort of thing? Because that would be truely amazing. And to be sure, just because I recognize the phenomenon doesn't make me responsible for it. I'm reminded of something Al Capone said: "Just because you think they're all out to get you doesn't mean they aren't." Don't kill the messenger. I'm so proud to be among such upstanding people. And to be sure, I'm of like mind. Let's hope the OP is dealing with someone as courteous and helpful.

[soundguruman]

I once had a new build that kept blowing fuses, owner would replace them, finally he brought the amp back to me asking for a refund. I refused saying I would fix the problem. I put the amp on a dummy load for 3 hours almost wide open with the PT so hot you could barely touch it, nada! I gave it back and next time it blew the fuse, it took out a pair of KT88's. The CTS bias pot was intermittent. I ate the tubes and now have a happy owner.

Ethical.
Now that's the tech you want to take your amp to.

[tedmich]

on the bright side he'd have to get 2-3 more Voodoo sessions before they don't make any money

I'd think these "ship your amp businesses" would really need a CYA QC policy like a simple burn in certificate, but if the people keep buying...

[soundguruman]

Well lookie,
The guy with the bad speaker cable, Marshall tubes turning red, swore up and down his speaker cable was 100% new and good.
And he was completely wrong. He was ripped by an unethical e bay vendor. He really thought that the problem was my fault.
But should I pay for that? I mean really.

And people tell me their speakers are great, and wired correctly, all the time, and have no clue that a speaker might be blown and eating the output tubes. Should I pay for that?

So if you are so sure that your speakers are good, and the cable is good, and the impedance is right, should YOU pay for that? (4 tubes) I mean really.

[dumbassbob]

Where

Once again Bob, look for a tech with Ethics.

I thought I checked this guy out....TOO