Randall RT2/50 problems

[wengnutt]

I know this is the Egnater forum, but I heard Bruce designed these poweramps and thought maybe he, Jeff, or somebody could pop in and help me out.

So I ended up getting a GREAT deal on a used RT2/50, and it got shipped to me last week. I plugged it in, and noticed a electrical/smokey smell, then noticed that the 2nd channel, first LED for the tube failure was on. I quickly looked at the back of the amp, and the tube farthest to the right was glowing an insane blue. I've seen tubes glow blue before, but not this kinda blue.

So then I just tried checking the first channel to see if that would work, and the volume is not getting very high on it. I can turn it about half way, and it just doesnt get any louder.

I'm planning on changing all the tubes out with EL34's, and KT88's, and replacing all the fuses as well as give it a good cleaning (the tubes had quite a bit of dust collecting)

So all in all, could the power tube problems be attributing to the smell, and loss of power, or could it be something deeper? Would it be a good idea to try and replace the tubes now, and see if that fixes the problem?

Thanks everyone!

 

[muudrock]

I know this is the Egnater forum, but I heard Bruce designed these poweramps and thought maybe he, Jeff, or somebody could pop in and help me out.

So I ended up getting a GREAT deal on a used RT2/50, and it got shipped to me last week. I plugged it in, and noticed a electrical/smokey smell, then noticed that the 2nd channel, first LED for the tube failure was on. I quickly looked at the back of the amp, and the tube farthest to the right was glowing an insane blue. I've seen tubes glow blue before, but not this kinda blue.

So then I just tried checking the first channel to see if that would work, and the volume is not getting very high on it. I can turn it about half way, and it just doesnt get any louder.

I'm planning on changing all the tubes out with EL34's, and KT88's, and replacing all the fuses as well as give it a good cleaning (the tubes had quite a bit of dust collecting)

So all in all, could the power tube problems be attributing to the smell, and loss of power, or could it be something deeper? Would it be a good idea to try and replace the tubes now, and see if that fixes the problem?

Thanks everyone!

Definitely sounds like bad output tubes. Get ALL of them out there, retube and bias it. Might want to do the driver and PI tubes as well. Check/change your fuses.
Fire it up. If you blow tubes again, no sound or if the smell gets worse, you're gonna have to have it repaired.

 

[Buckeyedog]

[

Definitely sounds like bad output tubes. Get ALL of them out there, retube and bias it. Might want to do the driver and PI tubes as well. Check/change your fuses.
Fire it up. If you blow tubes again, no sound or if the smell gets worse, you're gonna have to have it repaired.

+1

 

[jkdsteve]

Pair of power tubes furthest to the right (looking from back) is for channel one..am guessing (at least) that tube is toast and a burning smell is probably a component failure....honestly wouldn't power it up until a tech has looked at it unless you feel like risking another tube pair.

Generally speaking, what I do at this point is take teh lid off and look (no touching!) for burned components...and even if I do or don't find any, it's tech time...so basically I may as well not bother eh?

Free bump for ya!

 

[wengnutt]

Thanks for the tips guys! I'm gonna pull out the ol' multimeter tonight and see what the bias is currently set on. I should have probably done that to begin with. I'll pop open the lid and see if I find any burn spots.

Man, I REALLY hope this isn't anything major

 

[jkdsteve]

Thanks for the tips guys! I'm gonna pull out the ol' multimeter tonight and see what the bias is currently set on. I should have probably done that to begin with. I'll pop open the lid and see if I find any burn spots.

Man, I REALLY hope this isn't anything major

You get real lucky if it's just a popped tube...has happened to me tho' .. had a tube burn out (even on correct bias)...scared witless and needless to say it was an EL34 that went..LOL...amp was fine after.

 

[wengnutt]

Thanks for the tips guys! I'm gonna pull out the ol' multimeter tonight and see what the bias is currently set on. I should have probably done that to begin with. I'll pop open the lid and see if I find any burn spots.

Man, I REALLY hope this isn't anything major

You get real lucky if it's just a popped tube...has happened to me tho' .. had a tube burn out (even on correct bias)...scared witless and needless to say it was an EL34 that went..LOL...amp was fine after.

Man, what is up with new EL34's these days? I've heard all sorts of people on the MTS forum that were having some problems previously. Hopefully my Tung Sols I got from Tube Depot are a good batch. I originally bought them for the Shiva, but the Shiva just got sold an hour ago. Oh how I'll miss her

That's why I've got get the module system up and running

 

[muudrock]

Thanks for the tips guys! I'm gonna pull out the ol' multimeter tonight and see what the bias is currently set on. I should have probably done that to begin with. I'll pop open the lid and see if I find any burn spots.

Man, I REALLY hope this isn't anything major

You get real lucky if it's just a popped tube...has happened to me tho' .. had a tube burn out (even on correct bias)...scared witless and needless to say it was an EL34 that went..LOL...amp was fine after.

Man, what is up with new EL34's these days? I've heard all sorts of people on the MTS forum that were having some problems previously. Hopefully my Tung Sols I got from Tube Depot are a good batch. I originally bought them for the Shiva, but the Shiva just got sold an hour ago. Oh how I'll miss her

That's why I've got get the module system up and running

EL34s are shitty quality right now. Alot of bad ones floating around. Be careful if you use them, they are known to arc and fry the PCB in the amp.