Going Pro...M.I. Amp repair

[octal]

I've been a consumer electronics tech for the past 20 yrs, and have owned my own shop for the past couple of years- specializing in factory authorized service for a [redacted] brand of high end A/V components. I'm ready to do something a bit different, like opening a 2nd biz specializing in guitar amp repair. I feel pretty good about my ability to diagnose and make the actual repairs, having scratch built numerous amps and fixed a fair number of tube guitar amps as side projects. I have all the test equipment I might need (scope, sig gen, multimeters, dummy loads, etc.) What I don't know much about is running a shop that specializes in M.I. Amp repair....

- What parts should I expect to stock?
- What are some reasonable warranty policies on repair to vintage amps?
- I'm guessing that gigging musicians are going to need super-fast turnaround times. How do you deal with the need to get it done vs. doing a high quality repair? I.e. do I throw in a generic 6600ohm to 8ohm output transformer or wait/special order for an exact match? Supply a loaner amp?

-How do you deal with clients who want piecemeal repairs on vintage gear that really needs a a full restoration?
-How do you deal with designs which are inherently unreliable? (i.e. certain models of vintage amps with high B+ & no screen resistors.)
-How do you deal with clients who are inherently unreliable? :-) The "you changed three capacitors, now my vintage tone is RUINED!" types?
Is it possible to specialize in such a thing nowadays and be successful? Or is the market oversaturated with every 3rd music shop having an amp tech hanging out in the back room?

I guess I'm hoping to glean some wisdom from those who have been there and done that. There's a big difference between doing something as a one-off "Hey, you're good with electronics, can you fix my Fender DRRI?" "Sure!" and doing something on a professional basis.

[Enzo]

I think we have this conversation more often in the Music Electronics section. Not saying move this, just saying go up there and look through the thread titles for the last year or so. Some were about running the shop, some are about customer this or that. I am sure you could recognise a thread title as potentially useful. But we do talk about this regularly.

First, why does your shop have to be either/or, or some sort of spin-off. Unless you are afraid some long haired musician at your counter would scare away the BMW driver with his broken Bose radio? Just fix both. If your consumer shop is anything like all the ones I have seen, the average repair is simple. More guitar amps come in for broken jacks and controls than for all the weird electronic crap you might think of. I call that free money. Your stereo stuff, is there a lot of noisy balance control, or tactile switch goes bad under a panel button? Got a lot of CD/DVD pickup lenses need cleaning? I suspect that is free money to you. Why give up that easy stuff just to say you fix guitar amps? Just put up a Fender banner next to your Sansui banner - or whatever - and start greeting new customers along with the old. You can always decline repairs, "We no longer service that model, sorry". I have a customer here who does snow plowing. he brings me the little control box for his plow when it breaks. it is a home made joystick thing with four microswitches inside. I put a $4 microswitch into it, charge him half an hour. I got free money, he is tickled pink he didn't have to shell out $300 for a new "control assembly".

We deal with everything from 70 year old Fender combo amps to current production DSP with a power amp stuff. We see guitar amps and feedback processors, lighting dimmers to reel to reel decks. So if you intend to fix everything, well there is no list. if you want to limit what you take in, then there may be some common stocks, but I suspect they are similar to what you already have.

Shop, I am sure you have that. You need a tool box, a good meter. That is 95% of it. A scope if you intend to be at all serious. And a signal genny, sure. Even that need not be fancy. For a test signal I use a line from my cheap Technics stereo receiver on the shelf, and use music from an FM station as my signal. I only grab a sine wave for specific tests. Music has a full tonal range, so it is handy for checking EQ, plus distortion is easy to hear.


OK specifics:
what parts to stock? What are you going to work on? Gonna do ONLY tube amps? Gonna NEVER do tube amps? Gonna do PA stuff, mixers, 3000watt amps, processors? Tube stuff? get the schematic for a Fender 5E3 Deluxe. The parts in that are about as common as it gets. certain resistors come up a lot, like 1.5k, 100k, 220k, others. E-caps in 450-500v, 10,20uf common 22uf/25v common. Axial leads. 1N4007 rectifiers, and sone 1N4148 diodes. I know you have those.

No matter how much stuff you collect, you will ALWAYS be ordering parts anyway. Don;t pretend you will ever catch up. Pots, just I am sure like consumer goods, pots are all custom for the OEM, so 1meg pots might be on your shelf in 10 different shapes. And that is when it will be a Marshall B2k pot you need instead.


A gigging musician has backup amps and understands repair takes time. If i can take care of a guy while he stands there, if he wants to, I will, especially a guy who drove in from someplace an hour or two distant. But most understand they have to leave it. it is the amateur who has one amp and if I don't fix it it will screw his "record deal". So loaners? Not here. Music stores have loaner policies, because , gee, it promotes sales. How many amps do I need to have around to cover the choices a loaner must fill?

Warranty? I warrant my work. if it ain;t right, bring it back. You want a number? 90 days. They want a parts warranty? Sure is a year enough? the stuff I do isnlt going to fail. I am not worried about the 100k resistor in the plate lead of a Fender 12AX7. if I install a "doghouse" full of filter ecaps, I have no reason to expect them back anytime soon. SO if they express concern, I'll give them a warranty. Hell, if they come back a year from now and I see I made a crappy solder joint, I'll warrant that even though it is past its time. I should have done it right the first time. That is the attitude that wins customers, not a GUitar Center blanket warranty policy on paper.


When the customer comes in with the repair, that is the time to determine two things. What does he WANT and what does he NEED? If he is all concerned about vintageness, then establish that. Educate the customer. "I can leave the parts original, but these caps - these blue things are called caps, see - but that will leave the amp humming for all time." I always return the dead parts with a repair anyway. they can keep them if they want original parts.


If you had a Classic 57 Chevy with bald tires, would you drive on them? or would you put new tires on it. Do you think the collectors would fault the car for good new tires? Solution, I have the original bald tires in the garage, I'll throw them in if you like.

Temporary transformers? Not me. There are darn few parts that are more than a couple days away if they are available at all. And they can be there within 24 hours if it matters to you.


How do you deal with a high end audio customer who brings back an amp yelling his midrange is now all grainy but it sounded good before... and you know all you did to it was replace the speaker relay? Every repair industry has its problem customers. MY dear mother was convinced that ANYTHING that went wrong with a TV set was because the picture tube had broken. And if the repair guy tried to tell her differently, he must be lying. We all get them.


If you get the customer who just will not stay out of it, then remember, you have the right to decline the work. If i see caps spooging their innards all over, I want to change them. If the guy adamantly refuses to have new caps, I tell him I cannot complete such a repair in good faith. I cannot put my name on a repair I don;t think will work reliably

-How do you deal with designs which are inherently unreliable? (i.e. certain models of vintage amps with high B+ & no screen resistors.)

But that is the thing, those are NOT inherently unreliable. Leo Fender ran 6V6 tubes 100v over the "maximum" voltages in the RCA guide for DECADES. Those amps are not piling up in corners of shops across the land. I had a tech once who every time he saw those white Mallory e-caps he wanted to change them all out. Are they bad? No, but I know they are unreliable. OK, this amp has been working for 35 years so far, how unreliable do you think they are? Point is that those Mallorys may have had a higher than average failure rate, but that was not the same as they are all bad caps. And if they made it to 35 years, chances are any failures now are not due to any inherent unreliablility


I don't get into reengineering amps for people unless that is what they hire me to do. Chances are you don;t get a home theater unit in for service and instantly open it up to swap out the op amps for some Burr Brown darling of the month IC.


If McDonalds wanted to start selling crab cakes, they wouldn't open up a new chain of McCrabby's, they'd just put up a sign on the existing restaurants "NOW!!! Crab Cakes" Oh lord is that a scary thought. And McSushi.

And I have no idea where you are, but you can certainly explore the local market. How many shops are there? "Hey, did you hear? Joe's TV repair is fixing amps now". The word will get out.

[DrGonz78]

OMG!! UGH!!
McSushi



McLobster

[mac dillard]

Enzo, that has just got to be a classic. It ought to be posted where we can always find it and then we could just copy and past the next time this comes up..

[Enzo]

Well, thanks, but take my advice, look through the back threads where we have already posted the same ideas.

[octal]

Thanks Enzo, there were some pearls in there, although I kind of get the vibe that you think I asked some jackass questions. Perhaps I did. :-) My apologies for posting in the wrong forum. I'll poke around and see if I can find some other threads in the Music Electronics section. As for why I can't just add MI amp repair to the existing shop, the existing shop is a 1hr commute from my home, the single brand we service comes with a lot of unpleasant, unprofitable, high volume warranty work obligations...and yes, I don't think the clients would mix well with musicians. In short, I'm hoping to phase out the existing shop and start fresh doing something else, but I want to have some overlap between the two shops so I don't wind up living in a van down by the river. Not that there's anything wrong with that.

[Jazz P Bass]

Enzo, that has just got to be a classic. It ought to be posted where we can always find it and then we could just copy and past the next time this comes up..

Like this?

[Enzo]

Nothing wrong with that at all. That is why I asked.


No, I didn't think it was jackass questions, but I did see certain assumptions built into the questions, so I wanted to be sure you had not decided what to do too early. I see not now that you explain, but I had to ask.


I have been running a shop for quite a long time, and I don't see it as very lucrative.