Bad amp tech's !!!!

[soundguruman]

Guy says my 1968 Ampeg SVT still doesn't work after another shop had it. Will you take a look. Attached is a look at the power amp guts. No further explanation possible.

That amp has been hacked severely.
Same guy worked on the Hiwatt?

[soundguruman]

Nice "cap job". Hopefully the customer didn't have to pay much for the repairs, but that's not usually the case. Sadly, how it usually works is that the worst techs get more money because it takes them longer to figure things out and they charge hourly- something for the guys who know what they're doing to remember. The experienced guys are often guilty of under charging because it takes them far less time to do the same repairs (I include myself in this scenario). Every once in a while I have to step back from things and check myself on rates. I usually find that I'm not charging as much as I should be. All those years of experience should count for something.

What takes the time is un-doing a mess like that and cleaning it up to working condition.
Experienced tech is going to spend plenty of time, because it's an abortion.

[The Dude]

What takes the time is un-doing a mess like that and cleaning it up to working condition.
Experienced tech is going to spend plenty of time, because it's an abortion.

Agreed. I was referring to a "normal" repair. It generally takes longer to fix someone else's mess. Sadly, the customer ends up spending a lot more than he should to get things put right.

[Tone Meister]

...If you put 4700 ohm resistors in as screen grids in a Fender, I think anyone could hear there's something wrong with that.

Yeah well, once I put 470K ohm resistors in as screen grids on one of my own Fender amps and it took me awhile to figure out what happened

...I get plenty of second-hand jobs where a customer has paid for a repair somewhere else and then the equipment finds its way to me...

Yeah well, that is what happens here a great deal. While I am certainly not a tech by any stretch, I do have standards and know enough to find help and the folks in these parts know it. There are a couple of long-time "techs" in this area, but more than half of the stuff I see are the result of their handy work. In years past, I learned to work on my own gear by necessity, and now I have more and more folks asking me to look at their stuff rather than take it to one of the local "techs."

I've seen the same scenario with computer repairs and guitar techs. That's why I learned to do all my own guitar work...I'm sure I fixed at least 50 computers that were already worked on by another local shop, and the guy was making way more money than me, and the most common comment was that he sent it back to them worse off than when he got it...

Basically the same for guitar techs. I started learning more because ...

... I don't even claim to be anywhere near an amp tech, I do a top notch soldering job but that's about it. I know a little, probably just enough to be dangerous. Thing is, I know that and I tend to ask questions of people who do know, like here, before I touch anything. But with guitars and computers, nobody touches mine but me. I've fixed enough of other people's shoddy work...

Don't even get me started on carpenter work...after doing trim work for 8 years I wouldn't go anywhere near a new house. Fixed a lot of shoddy framing there too.

^^^ This post sounds exactly like I wrote it myself; it describes my experiences to the letter!

[km6xz]

That photo is interesting. It appears that the tubes were never intended to be replaced because the created the whole module as an easy to replace unit. That could have been a selling point, if one went bad, the dealer would sell a drop-in board with tubes included. That was, by being modular there dealers could service them even if they had no tech. That is the only rationale I can think of since it takes more work to bond those tubes to the PC board.

The main reason there are a lot of bad techs is that information is available on the internet which was not generally known by hobbyists and everyone, armed with a few buzz words think they are an expert in the field they dabble with.
There are few techs available and there never will be enough who can diagnose without causing more harm than good on a surprisingly high percentage of units. It is that way in most fields that are related to a hobby, there are a lot of people willing to do it for free or pretty close to it. The same skills needed for higher unit cost non-hobbyist fields pay much more than anything to do with hobby fields.
If they know what they are doing they probably have migrated to more lucrative fields and keep amp teching as a hobby. There are those who are into it and the lifestyle that they willingly work for poverty wages as a life choice.

I have yet to find a tech who is a skilled diagnostician under 45 years old. I have never met one. There are few fields where to be effective, one much known 4-5 generations of technology intimately like in pro audio, where vintage gear is expected to interface and inter-operate with any generation. I know in my studio we had a mix of 1950s, 60s 70s and 80s which meant gear intended for +8 or 12 dbm or more as 0vu needing bridging transformers with limited fan out capability, and keep it happy with dbv bridging paths, and into digital and back, including control systems, time code etc.. Later when I built up my last big repair shop, all that sort of gear was expected to play nice with -10dbv unbalanced, be controlled by cheap pc controllers or midi. So technology of tubes, discrete sold state, integrated circuits, and a couple generations of digital.
A tech or engineer working in just about any field is only working with recent or contemporary generations. So for a tech to be very effective in audio, he has to be old enough to have absorbed each of those generations technologies and be fully up on each to solve problems that would involve spanning several of those generations.
Not many still alive and there were never that many even when it paid a living wage.
It is NOT going to get better, with more good techs than bad.

[Ronsonic]

As a step sideways, I suspect that the profusion of bad repairs is one ugly consequence of the high quality of this and perhaps other internet forum

Around here we blame the Weber and Pittman books for making people think they can do this stuff. I work a lot with hobbyists and that doesn't bother me a bit. And, all techs have bad days and part shortages and budget and time limitations and we all see each others mistakes. That doesn't bother me either. The guys who get something wrong and then shrug and say "well pay me to fix it again" when the thing comes back, they bug me.

I've heard the guitar described as the easiest instrument in the world to play badly, but one of the hardest to play well. I suspect that amp repair may have some similar characteristics.

There is just so much that can go wrong. And the problem with guys who don't know is they don't even know what it is they don't know. Go google up "Dunning Krueger Syndrome" you'll see.

[drewl]

We should start a photo thread with the bad work we encounter.

I usually take pix of this stuff to show the owner.
Hell, I've had new stuff that looks bad too!

I have pix of an early Mesa with stuff just tie wrapped in place and stuff labelled with Dymo tape etc.

[Leo_Gnardo]

And the problem with guys who don't know is they don't even know what it is they don't know. Go google up "Dunning Krueger Syndrome" you'll see.

I'll have to look that one up - thanks for the suggestion. I'd call it "Rumsfeld" syndrome.

- - - - - -

edit: Just read the wiki on Dunning Kruger effect. Fascinating, and how true. Hey these guys won an IgNobel prize! Don't let that cause anybody to underestimate their research. Recommended reading! And a collection of further reading at the bottom of the article. Good stuff Ronsonic, thank you!

[Leo_Gnardo]

I have pix of an early Mesa with stuff just tie wrapped in place and stuff labelled with Dymo tape etc.

Early days, that's how it was done. Even Fender, Marshall, others, when they started out had no idea they would be long-running major MI companies. I've heard of early 100W Marshalls that used two 50W output transformers in parallel. At the time, Radio Spares didn't have a 100W OT, so Marshall's engineer - Ken Bran - had to punt. I've also run across a big-buck boutique amp that had two 50W power transformers to support a 100W output section. Wassamatta? For all the loot he charged, the guy couldn't spring for a 100W PT? Hmmm, go figure...

[soundguruman]

I donno if it's Weber / Pittman, but something makes people think that it's easy and anyone who owned a soldering pencil and a voltmeter is now an amp tech.

Of course, it's not easy. And I'm sure 90% + of attempts by novices wind up FUBAR. Yeah, it's the soldering that fails them (see pics)!

[soundguruman]

Early days, that's how it was done. Even Fender, Marshall, others, when they started out had no idea they would be long-running major MI companies. I've heard of early 100W Marshalls that used two 50W output transformers in parallel. At the time, Radio Spares didn't have a 100W OT, so Marshall's engineer - Ken Bran - had to punt. I've also run across a big-buck boutique amp that had two 50W power transformers to support a 100W output section. Wassamatta? For all the loot he charged, the guy couldn't spring for a 100W PT? Hmmm, go figure...

Yes, the Marshall Kitchen prototype has 2X 50 Watt trannies, I know of one sitting on a mantle shelf.
The chassis is aluminum, and the transformers sink right down into the craters.
The trannies have sunk so low, it's no longer playable. But, still very cool to look at.

[Leo_Gnardo]

I donno if it's Weber / Pittman, but something makes people think that it's easy and anyone who owned a soldering pencil and a voltmeter is now an amp tech.

At least Aspen Pittman disqualified himself as a tech right in the beginning of his book. Good salesman though. The type that could sell snowballs to Inuit. (Formerly known as Eskimos.)

OTOH, GW :"Ive bolloxed up lots of amps, and you can too! Just follow these simple directions."

Anybody looking for a good guide, Ken Fisher's "Trainwreck Pages", reprinted inside Pittman's "GT Book of Tube Amps" and other places.

[Aloha_Mark]

If you fellows see that an amp has been hacked up by a previous repair tech, why not pass it up? Having to check each and every component for the correct part value is too daunting. Even if a hack puts the right value resistor into the circuit, it probably has the wrong power rating. In point-to-point wiring there is even the possibility that a wire is connected to the wrong pin.

[Rhodesplyr]

You should see the horrors I see as a Hammond Organ tech. I think some of the worst ones arise from the church musician circuit when they get the idea that they can milk the cow both as a musician and as a "organ repairman." I rip out and replace hack-job Leslie hookups on a weekly basis, many of which are dangerous: high voltage connections hanging in midair outside the chassis, lightswitches from Lowes electrical-taped to the organ console as power switches, etc... A lot of these guys have no grounding at all in electronics and just use a paint-by-numbers approach. If they can't fix it, they tell the church it can't be repaired. There was one occasion where I suspect one of these guys paid me to do a repair he couldn't do and then charged a markup for it back at the church. They have boxes of random, mismatched output tubes they'll stick in an amp--and charge for--if it gets it out the door. Grid emission? Thermal runaway? They've never heard of such things. They stick any 15" woofer they have on hand in Leslies. 8 Ohm? 16 Ohm? Who cares?

In any event, it keeps me busy with work, but I often wish that I'd been the first to get the repair before Hack-Job Harry got his paws on it.

[Enzo]

Aloha, we always have the right to pass on a repair. But a hacked up amp is not an all or nothing thing. Chances are the hack did not replace all of the parts, just some. And as an experienced tech, I already have a darn good idea what something ought to look like. I charge by the hour, so if someone else's work has to be undone, I get paid to do it.

Rhodes, I know a organ repair guy, who will remain nameless, who gets out his tube tester for very repair. He'll look at some old Lowrey or whatever, the kind with 100 tubes in there, an oscillator for each note plus dividers for all the octaves, and test them all. They are oscillators, and if they oscillate, they are working. But he'd show them that a lot of their 30 year old tubes were "weak" - says so right on the tube tester meter - and he'd sell them a whole "set" of tubes. Talk about padding your bill.