Did the world's worst tube amp tech just repair my Peavey VB-2?

Moogeddy · #1 05-31-2010, 12:36 PM

I think so. Heres the story.

So I'm at a gig/audition for an outdoor music festival at the end of April, went to power up my amp and one of the tubes gets red hot and then dies, thus no sound. Luckily I had a giggable combo for a backup amp.

So I take it to my "Authorized Peavey Dealer" the next day (the same place where I purchased the amp). The store is Mother's Music in Sasaktoon. I let them know what happened and leave the amp with them, just replace the pair with the one blown tube, and make sure its good to go, those were my instructions I gave the guys at the front desk. I didn't talk with the tech on this visit.

Went to pick up the amp a few days later and took it home. Turns out I also blew a resistor so he had to take the chassy out and replace it aswell. Now I just bought an Orange AD200 and have been playing it and looking to sell this VB-2 so I didn't play it until the day before yesterday (May 29th). So I hook up the amp correctly, turn it on, it powers up fine, tubes look good, go to turn it off standby.... and for the life of me I couldn't get the amp to put out sound. For the record I have 4 mesa tubes in the amp and 2 electroharmonix tubes (2 new mesa tubes that got put in) but after the amp wouldnt put out noise I noticed that the tubes are in this order in the amp:

EH - MESA - MESA - MESA - MESA - EH

Is this right? I have always been under the impression that paired tubes are meant to be connected side by side like so:

PAIR 1 - PAIR 2 - PAIR 3

Is this right or am I wrong?

Regardless, this morning I took the amp into the same shop. This time the tech was at the front of the store and I took the VB into the amp room to show him the problem. Heres where things get crazy... First thing he does is go up to a GUITAR stack, starts to take the head off and throws my amp up on the GUITAR cabinet, plugs it in and trys to find the ohm rating of the cab! I told him its most likely a 16 ohm cab and its a GUITAR cab and it wont work. I go and plug it into a Mesa BASS cab and the tech powers the amp up, then he pretty much INSTANTLY switches the amp off standby and plugs a cable and bass into the head. no sound. then he proceeds to switch the power off while the amp IS NOT IN STANDBY and then puts it in standby after the amp is already powered down. ***...

Now that I knew it wasn't a problem on my end with my equipment, I talked to the manager of the store and told him about the problem and that I'm not paying for to fix the amp this time because obviously it wasn't fixed right in the first place. Then he told me that I have to take it up with the tech because he isn't a direct part of the store he just rents out the back room for his business and he does the shops repairs as well as his own. Thus the reason I always have to pay him cash. I talk to the tech, let him know that I'm not paying a cent for him to fix the amp and that I don't approve of his handling of my amp, I let him know that I ALWAYS let it "warm" up and "cool" down before switching it off standby initially or shutting the amp off. He says I don't have to pay but the thing about handling my amp is "bull@#$%" and starts to get kinda angry with me telling him how to operate a tube amp correctly and saying you dont have to let it cool down which you probably dont REALLY have to do but it just gives your tubes a longer life. He also said that it doesn't matter where the tubes are positioned and I told him that I believe they should be paired side by side like it says in the manual I received with the amp.

This guy responds by saying that hes been dealing with amps since the 70's. Wouldn't he know stuff like that by now?

I left my amp there, probably a bad idea but whatever... hes going to give me a call when he gets it going.

Now I'm an 18 year old guy and he might have been a bit pissed because someone thats 30 years younger than him telling him how to operate amps but this is just what I was taught to ALWAYS DO NO MATTER WHAT. Wait before switiching off standby, pair tubes, and let the amp cool in standby before powering down.

Comments anyone? I just don't know what to do in this situation or if I am right or wrong!

Mr. Foxen · #2 05-31-2010, 12:49 PM

Plugging a bass amp into a guitar cab is fine as long as you aren't planning on cranking bass through it. Standby isn't really necessary at all, plenty of amps don't have it. If it is a case of flip it on to see if sound comes out, then off again, probably not an issue, although poor work doing it with someone else's gear.

Depending on the amp, some have individual bias on the valves so you don't need matching.

Rick Auricchio · #3 05-31-2010, 12:54 PM

As for the order of tubes, it's the actual tube type number that must be in the proper socket. Not brand.

As for standby before powering off, that's nice to do, but can't always be done. What happens when a power cord gets pulled or there's a power failure?

BassmanPaul · #4 05-31-2010, 01:08 PM

By turning the AC off while not in standby helps to drain the high voltage charge from the filter caps. The tech did nothing wrong.

with amps that have more than two output tubes pairs are immaterial. The tubes are paralleled to get up to the required power level. Because of the output transformer primary to plate wiring it is easier to wire the tubes in rows. So V1 > V2 > V3 to one side of the OPT primary and V4 > V5 > V6 to the other side.

Unless each tube has its own bias pot then each tube on that side should be matched to the others. If the amp has two bias pots then triples can be installed and balanced to the other side with the pots. If the amp has just one bias pot then a sextet would be best.

Paul

suraj · #5 05-31-2010, 01:24 PM

Your tech didn't do anythign wrong. For Just a check if sounds comings out f the amp, if he took it off standby without waiting long is fine and wont do any damage. tubes last for years, so something like this will probably shorten tube life by maybe a minute

He also switched it off the right way. What Paul said is completely true.. and if you were worried about it cooling down be4 powering it down, it probably din even heat up cuz ur amp was switched on and off in a very short duration i suppose. Anyways you dont need to cool it down be4 turning it off..

Rick Auricchio · #6 05-31-2010, 01:48 PM

Quote:

Originally Posted by Moogeddy

Now I'm an 18 year old guy and he might have been a bit pissed because someone thats 30 years younger than him telling him how to operate amps ...

And perhaps the fact that tubes haven't been manufactured in the US since twice your age. (I know that's snarky, but you should trust the tech.)

You're doing good things to treat your amp carefully. Let the tech figure out the problem and he'll fix it. And, yes, there are good and bad techs.

**B-string** · #7 05-31-2010, 04:05 PM

Quote:

Originally Posted by Mr. Foxen

Plugging a bass amp into a guitar cab is fine as long as you aren't planning on cranking bass through it. Standby isn't really necessary at all, plenty of amps don't have it. If it is a case of flip it on to see if sound comes out, then off again, probably not an issue, although poor work doing it with someone else's gear.

Depending on the amp, some have individual bias on the valves so you don't need matching.

I have to take issue with this, newer amps with a tube rectifier don't have standby switches. Newer tube amps with SS rectifiers still have standby switches and it IS best to use it.

deekay911 · #8 05-31-2010, 04:14 PM

Quote:

Originally Posted by B-string

I have to take issue with this, newer amps with a tube rectifier don't have standby switches. Newer tube amps with SS rectifiers still have standby switches and it IS best to use it.

Hang on - it's called 'standby' - not 'warmup'.....

**B-string** · #9 05-31-2010, 05:59 PM

Quote:

Originally Posted by deekay911

Hang on - it's called 'standby' - not 'warmup'.....

That tells me you know very little about tube amp functions and the effects of high voltage on cold tubes. Almost 40 years in repair and my degree came when SS was still in its infancy. Have you read amp manuals?

KramerBassFan · #10 05-31-2010, 06:21 PM

Quote:

Originally Posted by deekay911

Hang on - it's called 'standby' - not 'warmup'.....

http://www.google.com/search?hl=en&c...andbys&spell=1

Its also known as cathode stripping, i believe.

lbwdog · #11 05-31-2010, 06:21 PM

Quote:

Originally Posted by Moogeddy

Turns out I also blew a resistor so he had to take the chassy out and replace it aswell.

Comments anyone?

Well, first off, there's no such word as "chassy"....although that is the way it's pronounced.

A chassis (plural: "chassis") (pronounced /ˈʃæsi, ˈtʃæsi/) consists of an internal framework that supports a man-made object.

Second, the tech didn't do any bad thing. He was just checking to see if any sound would be produced, and it didn't matter what he used as a test cab.

Now this guy could be an awful tech, or a great one. None of us would know just by this story. Sounds like your'e overreacting a bit though. Good luck anyhow!!

Moogeddy · #12 05-31-2010, 06:56 PM

Thanks for the replies everyone. Some really good, much needed clarification from you guys was exactly what I needed to get me some piece of mind. Now I don't have to have nightmares about some mad scientist amp tech having his way with my gear!

It seems I was over reacting to his actions in the store and on the first repair. Sorry if I came across as an ignorant prick, I did create the thread as soon as I got home so I could explain the situation as well as I could to you fellows.

I plan on apologizing to him when I go and pick up the amp, I'm sure he will appreciate that and if it turns out hes a good tech I really don't want to get on his bad side.

lbwdog · #13 05-31-2010, 07:13 PM

You know, I'm wondering, did you ask him if he tested it out before releasing it to you the first time? I can't imagine a tech who wouldn't, but I've seen stranger things.

If he did, and it worked at the shop, there may be something wrong elsewhere, like a short in your cab or something......just sayin'.

Moogeddy · #14 05-31-2010, 07:43 PM

Quote:

Originally Posted by lbwdog

You know, I'm wondering, did you ask him if he tested it out before releasing it to you the first time? I can't imagine a tech who wouldn't, but I've seen stranger things.

If he did, and it worked at the shop, there may be something wrong elsewhere, like a short in your cab or something......just sayin'.

I tried it at the store with a different cab, power cord, speaker cable, instument cable, and bass.

I said that in my first post... just sayin'

Rick Auricchio · #15 05-31-2010, 08:54 PM

Quote:

Originally Posted by Moogeddy

Now I don't have to have nightmares about some mad scientist amp tech having his way with my gear!

Sometimes they're the best ones.

Quote:

Sorry if I came across as an ignorant prick...

Sometimes the smart ones are the worst ones...

Seriously, though, I can understand why you'd be anxious about the situation.

Floyd Eye · #16 05-31-2010, 09:19 PM

Quote:

Originally Posted by Rick Auricchio

And perhaps the fact that tubes haven't been manufactured in the US since twice your age.

Not quite accurate. There are 2 or 3 US companies still producing vacuum tubes here, although for our purposes ( Tube amplifiers) it's pretty much just KT88s.

**B-string** · #17 05-31-2010, 09:25 PM

Quote:

Originally Posted by Floyd Eye

Not quite accurate. There are 2 or 3 US companies still producing vacuum tubes here, although for our purposes ( Tube amplifiers) it's pretty much just KT88s.

Who?? I have not seen US production for a long time. I really want to know who and where.

Jim Campbell · #18 05-31-2010, 09:30 PM

Quote:

Originally Posted by Moogeddy

I plan on apologizing to him when I go and pick up the amp,

good plan....shows character.....

somedumbguy · #19 05-31-2010, 09:31 PM

Plugging the amp into a guitar cab will NOT hurt your amp. It may hurt the cab if he was to play a lot of bass, because guitar speakers can't play those low notes, but I digress.

Also, just turning the power off without letting it "cool down" is 100% ok. It will NOT hurt the tubes life expectancy. The "tubes" need to warm up because the capacitors need to be fully charged before sound can be made. However, once the power is cut, the capacitors will discharge on their own, at a pretty slow rate, regardless if it was in "standby mode" or not.

The guy most likely knows what he's doing with the tubes. You probably don't have the only bass amp he's seen. I'd just trust him, and let him work his magic.

Floyd Eye · #20 05-31-2010, 09:43 PM

Quote:

Originally Posted by B-string

Who?? I have not seen US production for a long time. I really want to know who and where.

"Westrex Corporation, Kansas City, MO

Makes the reissued Western Electric 300B for high-end audio. Claims to be developing a KT88, WE308, WE274A and other old WE types for future manufacture. Corporate and sales offices are located in Atlanta and Chattanooga. Also has sales office in UK. Tube manufacturing facility was relocated from Kansas City to Huntsville, AL. This firm is independent of AT&T Corporation and has licensed the brandnames from AT&T."

I also heard about some company in NY that is producing tubes. I forget now where I heard it, but I believe they were also supposedly making KT88s