Ampeg svt 4 pro clipping too early

[km6xz]

Juan, many shops have flat rate lists by equipment type, and some qualifier such as "Guitar (solid state) Amplifier 50 watts or less $75 plus parts". It is popular in that it allows approval of estimates before actually taking it apart for diagnosis then reassembling for storage waiting for a detailed estimate to be approved.
Hourly rate works best with projects that are primarily labor with diagnosis such as building a snake.
We used an hourly rate of $65 for years and most estimates were 1-2 hours, but really minor repairs like correcting a broken solder joint or wiring an XLR cable/connector was usually free.
The reason for "free" involved being good PR but mostly because it was not a repair, so did not fall into the broad interpretation of warranty of work as customers believed a warranty to be. If a tube fails the next week and I had charged $15 to fix a solder joint, my losses covering the warranty of the entire amplifier is not worth the risk.
You can specify in a signed disclaimer that warranty only covers work performed but that clause only works when the customer can be expected to be knowledgeable that there are separate sections of a circuit that are somewhat unrelated.
They would accept that a transmission repair does not include warranty for headlights in a car but that does not work when, to a layman, everything in the amp chassis is one continuous circuit that you worked on.
In most places in the world the biggest concern with repairs or any other customer service issue is NOT whether you are possibly risking a $50,000 legal bill and court nightmare. When someone is disappointed or just thinks they can pull it off, in the US, the normal reaction is to seek a gigantic lawsuit settlement in the US.
Any work done has to be detailed and any parts used need to be detailed and charged for and proper tax charged. Doing so protects the shop, besides being a law in most states, also since there is a record, in writing that described what was done. That helps discouraging most people from suing if you can prove that your repairing the line cord was not repairing the speaker jack that the customer complains suddenly just broke a week after you worked on the amplifier.

So be happy that you are not doing repair work in the US. A disclaimer or detailed limited warranty policy does not end the shop's responsibility at the end of the shop warranty period, which really can give greif long after the normal shop warranty has expired if the customer's complaint includes a claim of a latent defect being installed in the unit during the repair.

[J M Fahey]

So be happy that you are not doing repair work in the US.

You bet.
Or *any* kind of work.
Hate running at the wheel, faster and faster, under climbing pressure, just to stay in the same place or worse, slowly go backwards.

For me, USA is a beautiful place to visit, enjoy as a tourist or visiting Family or friends, but won't get myself inside the meat grinding machine and push the "start" button if I can avoid it.

[diydidi]

Dont want to jump the gun here, but I think I might have solved the problem. The "early clipping" I described was in fact the amp going into intermittent "mute" mode. This was due to a dry joint on the rear panel Mute/ EQ jack socket. A foot pedal can be plugged in here and used to switch the EQ in and out and/or put the amp in mute mode.
I have asked the bass player (owner) to come-in later this week so that we can verify this, as I have not been successful in recreating the original scenario the client complained about in my shop.
Lets hold thumbs....

[Leo_Gnardo]

I get baffled by the common USA shop practice of charging "by the hour".
So If I'm a moron and take 3 hours to find a problem will get 6X the revenue of a bright guy who solved it in 10 minutes and charged "1/2 hour minimum"?Don't think so.

An example of what can go wrong:

One of my regular customers made the mistake @ late 80's of taking one of his Strats to a local music store for a pickup change and 5-way switch change too. Novice tech fiddle faddled with it hours on end while the store manager ran the stopwatch. One day I stopped in and the tech asked me "what am I doing wrong? It buzzes all the time. I've tried wiring it seven ways from Sunday and no joy." I spotted the output jack. Had black wire to hot, white to ground. Traced the black wire back, it was the ground. "Swap these two." Guitar worked perfectly, just one small wiring error. Sometimes it does take another eye on the project then all comes clear. "You're a genius!" No, just not looking where the problem isn't. The shop charged my friend over $250 for a job I would have charged at that time, maybe $40. Needless to say I've been wrenching his axes ever since.

Also, what's the point of long detailed lists like:
1 .047uF ceramic cap .... 45 cents
1 2N3391 transistor ..... 50 cents
.........................................
1 fuse ..... 20 cents
.....................
And so on.

Somebody said something about "A nation of shopkeepers?"

I like your method Juan BUT in the USA we have to keep a lookout over our shoulders for the IRS and state tax authorities. "So Mister Gnardo, you bought 416 vacuum tubes last year, 1756 resistors, 439 capacitors, 27 transformers ... etc. SHOW US where they all went." It's called a tax audit and many live in fear of that. So - we can whistle thru the graveyard or keep books. Keep in mind not much work will actually get done, mostly scraping together records and shaking in our boots, while the audit is going on. Even if not much is found, and they ALWAYS find something, nobody finds the experience a happy one. Frazzles the nerves.

Also, if I see the same piece of gear again I can look thru my invoices on computer and get reminded of what I did in the past.

As a side note, I do not get into a useless argument on:
"Hey!!, you billed me $30 for a 6L6 !!! I can get them on EBay/GC/Tubedepot for $20 !!!!! "

As I often say customers (if they are silly enough to argue that way): "parts are FREE, I'm charging my Job"

I tell 'em "go ahead, buy that and I'll install it. Don't forget to count shipping into your cost. And if it goes bad YOU return it to the seller for a refund with YOUR time back to the store and/or communicating, packing, going to post office or UPS or FEDEX." And some do anyway. But not many.

So whatever works Juan - as long as the customers are happy and keep passing along recommendations, and the tax man is off our backs, it's all good. 'Viva la difference.' My customers do all my advertising for me. Also never spent a dime on ads besides home printing business cards. There's another subject for another day.

[Enzo]

All my parts have to be taxed. I can't give them away and avoid that. There are states in the USA with no sales tax, but most have it. When I sell part, I have to charge tax on them. If I give them away, I still have to pay "Use tax" on them. That is a little better, in that tax is 6% regardless, but use tax is on my cost, whereas sales tax is on what I sold them for.

[tired eyes]

Fender recent vintage amps like the Hot Rod series, like to crack their 6L6 socket pins solder, and lot of their solid state amps with that chassis that slopes from a tall rear panel to a small control panel like to crack solder under the large filter caps. But for the most part, resolder is not what I find.

Every one of those I've had with 'cutting out' issues, if it isn't the input jack, has been bad solder joints. The 15V is dropped with a zener through a 5W resistor which gets very hot, and I guess that contributes to solder breaking down over time. I redo all the solder on the high wattage resistors.