These forums are read only, please use our new forums here.

Main :: Spider Valve



SV head made a weird sound, power amp tube glowed bright red?
by Cyanide008 on 2011-04-20 12:10:34

Yesterday I turned my amp on and I"m not entirely sure but I'm pretty sure it was in standby.

It made a loud noise. Not like a hiss, More like a short roar.

I examined the tubes to find that the right most power amp tube was glowing bright red.

I turned the amp on for one minute, a few hours later. The tube seemed to be glowing normally again.

I haven't changed the tubes since i bought this amp about 2 and a half years ago.

Am I good to go?


Or should I just retube?

How hard / dangerous is it to retube and bias a new set of tubes yourself?

Do I need to replace the tube fuse thing?

If so, what exactly is it called, what's the best one, where can I get one, how much does it cost?

Thankkkkyewww!



Re: SV head made a weird sound, power amp tube glowed bright red?
by spaceatl on 2011-04-21 09:59:33

That tube is likely close to going...Better to change before a tube blows...If the tubes have not blown and the amp is still working now, if you leave it powered down until you change the tubes then you probably will not need to change any fuses...If you let the tubes blow, then you usually end up changing out some fuses because they blow to protect the amp on a tube failure and there are several...one on the back the some inside too...

If you have never biased an amplifier then I would suggest you get someone that has...the voltages on the power amp can kill you dead...But only the large power tubes would need an adjustment...The smaller preamp type tubes are plug and play...just pop in new ones and go...



Re: SV head made a weird sound, power amp tube glowed bright red?
by Cyanide008 on 2011-04-21 11:27:59

Someone suggested the tube might be "red plating" and that basically when that happens, the amp is done for?

Anyone care to verify?



Re: SV head made a weird sound, power amp tube glowed bright red?
by spaceatl on 2011-04-21 12:36:23

hmmm...I don't know...more like the tube is done for I think...at least in my experience...2 years is a little while for power tubes if you use the amp a lot...

However, when a tube fails it can damage the amp. My MK2 blew a tube when it was a couple of weeks old...I was not surprise as the amp shipped accross the country via ground...Not surprised a tube failed...When it blew, it took the plate fuse with it...That one is inside...Same value as the back but half the size...Replaced the tubes and the fuse, adjusted bias and all has been fine...I think your power tubes are on the way out...One thing, it is a good idea to change the 12AX7 inverter (V2 I think) at the same time as the power tubes...Even though this is a preamp type tube, an inverter circuit is high current and that tube wears nearly as fast as the power tubes do...The other 12AX7 (V1) is more like a typical cascaded preamp circuit and will last much longer...



Re: SV head made a weird sound, power amp tube glowed bright red?
by Cyanide008 on 2011-04-22 11:44:32

Alright. I'm hoping for the best. I'm gonna get my amp checked out and probably just give it a complete retube. JJ Teslas all around!
What's a fair price for a consulation in USD?

and what about for a bias? 



RE: SV head made a weird sound, power amp tube glowed bright red?
by Line6Hugo on 2011-04-22 12:58:06

Strongly suggestion contacting a service center for repair.

Bench rates vary from place to place, but you should contact the different service centers to shop around:

http://line6.com/service_centers/

Regards,

Line6Hugo



Re: RE: SV head made a weird sound, power amp tube glowed bright red?
by Cyanide008 on 2011-04-22 14:27:44

I called the first three centers and they said they've never worked on a line six amp before.

They weren't sure if they even need biasing.

Do they?



RE: SV head made a weird sound, power amp tube glowed bright red?
by Line6Hugo on 2011-04-22 15:03:00

The power tubes need biasing when replaced. If they have any questions on the repair or procedure they have access to the service manual, or should contact us directly if they have questions.

Regards,

Line6Hugo



Re: RE: SV head made a weird sound, power amp tube glowed bright red?
by Cyanide008 on 2011-04-22 16:54:35

Ok thanks. I'm just concerned cause these guys are telling me 85 dollar per hour flat charge. More if they have to order parts from you guys. and i have to buy my own tubes.

Suppose it is redplating and they need to change the fuse or something else too.
Would that generally take more than an hour?

I really would rather not get ripped off.

Or perhaps i'd even prefer to do it myself.

Is there any way i can check the fuse / plates for damage?

I'm well versed with soldering and taking the amp apart and putting it back together so that's no problem.



RE: SV head made a weird sound, power amp tube glowed bright red?
by Line6Hugo on 2011-04-25 16:02:13

Cyanide,

You are free to go ahead and look around in the head yourself, however, we cannot provide you any assistance with that as we only recommend you have an authorized tech go through our hardware. As mentioned earlier, there are lethal voltages in the amp and so we really don't want you getting injured.

The truth of the matter is we do not know how much time it would take to get your amp repaired without having someone take a look as we are still speculating what the problem even could be. Some repair centers charge ~$100 an hour, so $85 is a better price than some. It is ultimately up to you if you decide to get it serviced.

Regards,

Line6Hugo




The information above may not be current, and you should direct questions to the current forum or review the manual.