Ampeg svt classic HELP NEEEDED

Kieran Imray · #1 09-14-2011, 07:49 AM

Hi guys,

I sold my svt cl on monday, yesterday the new owner got in touch to tell me this:

He put a new set of matched power valves in, biased ok, ran well for 2 hours. Then the amp went pop and went into the safe mode (flashing led on front). Powered it off and turned it back on again, and it was ok. It then did the same thing again when a bass was plugged in but not being played. He also said he was getting a light electric shock and buzz off of his basses. In addition the di output is only giving him radio signals and noise, no bass.
I think it's a bad earth somewhere bit wanted some more opinions. I should also note that none of these things happened in the 3.5 years I owned it. Just a bit worried I've sold the guy a broken amp! Any help appreciated!

staindbass · #2 09-14-2011, 07:57 AM

he changed the tubes, and biased it. that was not how you sent it to him. how are you to know if something he did may have caused that ? he modified the amp, its not your fault since you were not there to oversee what he did. if i bought a new car, then took it to an auto place to add a racecar air filter, added a part to the carberator, then something went wrong, if i took it back to the dealer they would look at me like i had 3 heads if i wanted them to fix it.

Low Sound Love · #3 09-14-2011, 08:00 AM

did he test it before swapping the tubes?

since he's the last one to open it up and twich it before it broke down, it's probably his fault.

Kieran Imray · #4 09-14-2011, 08:13 AM

It kinda needed the replacements if I'm honest, he wasn't trying to allocate blame to me, I just want to help get it fixed. It runs and sounds fine so I doubt he has made an error in replacing the valves. Any ideas what might be up anyway?

staindbass · #5 09-14-2011, 08:25 AM

i dont have any other ideas, sorry. but do you really think he got an amp and didnt try it out before replacing the tubes? i bet he did and it worked fine. tell him to bring it to a repair shop and email you an actual copy of the receipt. there is no way for you to know if he damaged the amp, and there is no way for him to know if the amp actually worked when you sent it. ( i still bet he tried it before changing the tubes). ask him why he changed the condition of the amp before testing it, that was not how you mailed it. maybe a shorted tube damaged the inside of the amp. tough call.

Kieran Imray · #6 09-14-2011, 08:41 AM

It originally needed 3 valves. I borrowed 3 from a friend to demo the amp to him (it worked fine during the demo session and on friday when I ran it for 3 hours to make sure it was ok as it had been sitting for 2 months). Offered those valves to him but he elected to replace them, so I gave it to him with the 3 power valves that were mine installed in it. I'm going to check it out tonight on the thinking that it's an earthing issue, taking a multimeter, power leads and speaker cables along with my other amp to try and see what's going on.

beans-on-toast · #7 09-14-2011, 09:40 AM

On the back of the amp near the fuse polarity switch. Try different settings for most quiet operation.

They may have a problem with the mains wiring. There could be a bad ground connection. Try the amp in a different room where the wall outlet is on a different circuit. Have them go to a hardware store and buy an outlet tester. Similar devices are available in Europe. This will test the wiring and reveal any faults.

BassmanPaul · #8 09-14-2011, 10:37 AM

IMO buying used gear is always a risk for the buyer. The OP sold the amp and it was working. Once the new owner had removed the amp from the OP's property the OPs involvement ends. The new owner replaced all the output tubes and "re-biased" the amp. Over the years I, like most folk who repair musical equipment, have had to repair equipment that owners have "fixed". If the new owner broke it it's up to him to get it repaired.

Kieran Imray · #9 09-14-2011, 11:19 AM

Thanks guys, by the time I got round to the buyers home to look at it he was fairly sure it's an issue with his electrical supply. Having tested sockets with a multimeter it looks like there is something on the circuit in the building (we turned off everything in his house) that is causing the noise/tripped the amps protection circuit.