Ampeg svt classic problem buy?

JDLowEnd · #1 03-20-2013, 04:46 PM

I have the opportunity to purchase an svt classic at a reasonable price. It is priced low because the owner stated that he ran a sansamp bddi through the front of the amp and thinks there is an issue in the preamp. He stated that the standby red light comes on and stays on and there is no sound. I am hoping to purchase this an take it to get fixed up. Just curious what I might be getting into. I understand that this may be a "failure" in the amp. I am curious if that preamp pedal would cause a minor issue with the amp. Any advice? Stay away? Make the purchase?

Made the purchase see page 3 for results (not brought to tech)

creis2 · #2 03-20-2013, 04:49 PM

How much are they selling it for?

You'll have a bunch of people throwing suggestions at you. Anything between a bad preamp tube (easy and cheap fix) to who knows ($$$$$).

You can find a good working SVT for $800-1000, there's lots of them out there.

Just so you know, tube amps are very dangerous to work on. Even when unplugged, they can hold enough voltage to kill you, and then some.

If you buy it, bring it to a tech.

Any broken item is a risk. If it was me, I would buy a good working head.

RickenBoogie · #3 03-20-2013, 04:53 PM

+1 I'd never buy an amp that has issues, and even then, only a qualified amp tech should service it. My advice, find a working one, and have it looked over anyway.

B-string · #4 03-20-2013, 04:54 PM

Maybe as simple as a bad standby switch. I can't see sansamp doing any real damage. Go for it.

JDLowEnd · #5 03-20-2013, 04:55 PM

Selling for roughly half of the going prices you listed. I was hoping for an easy fix in the preamp and save some money to buy a cab. I can grasp the idea that it may be expensive, there are a few certified ampeg techs in the area, I would definitely not take the task into my own hands.

JDLowEnd · #6 03-20-2013, 04:56 PM

Quote:

Originally Posted by B-string

Maybe as simple as a bad standby switch. I can't see sansamp doing any real damage. Go for it.

That's what I am hoping for, owner stated it he used the pedal as an overdrive, my thinking leads me to a blown preamp issue (tube or cap)

creis2 · #7 03-20-2013, 04:57 PM

For $400-$500 I'd say go for it. It's defiantly a gamble.

Could end up being a cheap fix. If not, you can probably unload it to someone who knows what they're doing for what you paid for it.

How old is it? What kind of shape is it in?

Quote:

Originally Posted by JDLowEnd

Selling for roughly half of the going prices you listed. I was hoping for an easy fix in the preamp and save some money to buy a cab. I can grasp the idea that it may be expensive, there are a few certified ampeg techs in the area, I would definitely not take the task into my own hands.

JDLowEnd · #8 03-20-2013, 04:59 PM

It's in great shape, cosmetically it looks brand new!

JimmyM · #9 03-20-2013, 05:01 PM

It's not often that an SVT repair costs $500, so that would still put it around market value even if it costs $500 to fix it. But it is a possibility. And it's rare that all the tubes go out, but not completely unheard of. But if it's closer to $400 than $500, I could be talked into it. And your comment about the condition makes me think it's likely a decent deal.

JDLowEnd · #10 03-20-2013, 05:06 PM

Thanks Jimmy, I appreciate the information. I'm just curious what kind of damage overdriving the preamp would cause as far as an issue.

B-string · #11 03-20-2013, 05:10 PM

Over-driving the preamp could possibly damage the first preamp tube. The amp should still come out if standby (unrelated).

Downunderwonder · #12 03-20-2013, 05:19 PM

Can you find out what cab he was running? If it was an 8 ohm and pushing hard that can cook the output transformer.

Also if the amp was turned on with no cab plugged in that's bye bye transformer time, probably taking some tubes with it.

I'd only take the gamble if you can afford an extra $500 if it turned out to be a major meltdown.

creis2 · #13 03-20-2013, 05:19 PM

If you buy it, let us know how it turns out. I love hearing about good deals.

I was looking for a practice bass last year, I found an estate sale and they had "squire guitars and basses".

When I got there, there was a 71 P bass with a $250 price tag on it. I kind of felt guilty, they didn't know what they had. I heard the guy and his wife talking, long story short, they were not very respectful towards his father who died. They were just horrible people. Calling them gold diggers would be a compliment.

I gladly gave them the $200. All original. No guilt.

fdeck · #14 03-20-2013, 05:36 PM

I've been tempted by "needs minor repair" or "as is" gear in the past, but have generally steered away from it. There is always a chance that the seller knows what is actually wrong with the amp, and has decided to dump it because the repair cost is prohibitive. Worst case is that something went awry in the power amp, and took out the power supply on its way down. That's a general comment, not specifically related to this particular model.

Knowing what I do about amps, I would not proceed unless I could narrow down the problem somewhat. If I could turn it on and confirm that the power amp is OK by plugging into the effects return, it would change my thinking about it, because preamps rarely contain expensive parts.

I'd be willing to bet that the preamp tubes can't be damaged by being overdriven by any audio signal.

JDLowEnd · #15 03-20-2013, 05:39 PM

Knowing what I do about amps, I would not proceed unless I could narrow down the problem somewhat. If I could turn it on and confirm that the power amp is OK by plugging into the effects return, it would change my thinking about it, because preamps rarely contain expensive parts.

I'd be willing to bet that the preamp tubes can't be damaged by being overdriven by any audio signal.[/quote]

Would it be okay just to plug an active bass into the effects return?

B-string · #16 03-20-2013, 05:44 PM

Sure can. BTW If the power supply or output transformer shorted the main fuse would blow as soon as you tried to come out of standby MOST cases. If the OT blows open it would come out of standby but have no output.

fdeck · #17 03-20-2013, 06:02 PM

What's the standby circuit consist of? It could be what's broken.

JDLowEnd · #18 03-20-2013, 07:09 PM

Most of the schematics I was looking at are of the vintage models and vr model. No luck!

cvtmqvuj · #19 03-20-2013, 07:45 PM

I would definitely not take the task into my own hands.

rodl2005 · #20 03-20-2013, 07:46 PM

Forgive me if I'm on the wrong track here, but,

Couldn't you plug into the FX return / pre amp IN (I Think SVT-CL's have this) & see if the POWER amp's still functioning properly at least... ????