Tube problems!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

diatribe

diatribe

New member
Hey all,
I just retubed my 2 channel dual rec.=>quad of kt88's, high gain ecc83, and gz34 rectifier tubes.

Since I recieved my tubes, one kt88 has blown, one high gain ecc83 has blown, and now one of the gz's sparked and only half of it is working and this happened when i was in solid state mode.

The company that i bought the tubes from(for the low price of 221.50) has replaced the kt88 for free, and i am waiting on the ecc83(was gonna pay shipping but he said i didn't have to) and it has been over a week since it was shipped.

My gz just blew about an hour ago, and I was in Solid State Mode! I have also noticed some discoloring around the inside base of the kt88's, and i believe this is do to the strain the bad one but on the power section.

I don't know what to do, I want to get my money's worth and not give this guy a hard time, but i am disappointed and somewhat skeptical about these tubes.

I was just wondering what you think would be the best coarse of action from my end of it?

My amp worked great before any of the new tubes were installed. I was also very careful installing them, wearing brand new jersey gloves and making sure not to touch any with my bare flesh.

Anyway i will tell what kind of tubes these are after the problems have been resolved, and i am thankful for the input-
DJM
 
Re: Tube problems!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I thought Rectifiers used 6L6's and those big rectifiers.....5U4's, or something like that?
Who advised you to put KT88's and GZ34's. I would think the KT88's MIGHT work, but if those rectifier tubes are the wrong ones, there's your problem. Don't run the amp till you find out!!!!!!!!!
 
Re: Tube problems!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Have you checked the bias with a probe?
 
Re: Tube problems!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

You just plugged in the KT88's without any biasing mods? KT88's need more power supply than 6l6's or el34's... GJ is right those are the wrong tubes
 
Re: Tube problems!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I'm thinking it's the rectifier tubes. GZ-34's are 5AR4's, I think. Those giant bottles in a Rectifier are 5U4G's, I think. The pins might not do the same thing in those tubes, therefore, electricity is shooting the wrong direction through the tube.
Try the KT-88's with your old rectifier tubes, and see if the problem goes away.
 
Re: Tube problems!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I just did some research, that IS your problem. GZ-34's can't go in that amp, you need 5U4's.
 
Re: Tube problems!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I'll go with Joneser on this one.
I don't think the rectifiers have different pin assignments, but they have different voltage handling characteristics, and the amp is probably designed within particular guidelines.
 
Re: Tube problems!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Bob at Eurotubes talked me into the same thing with the GZ34s, and I had problems with my Dual Rec at the 1st gig I did after that (one of my pre-amp tubes blew also). He's a nice guy, and clearly knows more about how amps work than I do, but sometimes he goes overboard with the mad sceintist thing, to the detriment of some perfectly innocent tubes (if not someones amp?). If you check out the .pdf's on this page:

http://www.guitaramplifierblueprinting.com/Primers.html

you will see that Bob's recommendation goes directly against going "down" vs. going "up" when substituting rectifier tubes, which increases the voltage.
 
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Re: Tube problems!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Thanks for all of the input, it helps alot.

Spark- Did you get the tubes replaced from bob? What did you end up doing about the gz34's?

Thanks,
DJM
 
Re: Tube problems!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I don't personally know Bob, but I'm getting the impression he's just a glorified Tesla JJ salesman. If you want the best selection for the cheapest $$$'s, buy your tubes from www.revolutionguitar.com Yep, another shameless plug! LOL
 
Re: Tube problems!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Gearjoneser,

Sorry to go off-topic, but whats the deal with these:
"Groove Tube Marshall High Gain Kit - SAG"
 
Re: Tube problems!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

DirrtyCraig said:
Gearjoneser,

Sorry to go off-topic, but whats the deal with these:
"Groove Tube Marshall High Gain Kit - SAG"
Click to expand...
it's just a set of preamp tubes, selected for gain
 
Re: Tube problems!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Gearjoneser said:
I don't personally know Bob, but I'm getting the impression he's just a glorified Tesla JJ salesman.
Click to expand...


Very possibly, but he DOES know a ridiculous amount about tubes and amps, but I would agree that he does get a bit *too* experimental for my tastes sometimes.
 
Re: Tube problems!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Curly said:
it's just a set of preamp tubes, selected for gain
Click to expand...

uh, yeah I got that much out of the description,, LOL. I thought maybe he worked there or owned the place so was looking for some more details.
 
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