Triple Recto: Switch on, blue flash. Dark tubes.

[dogboy131]

I posted this in the tubes section but it is kinda urgent and needed a faster response.

I had a triple recto delivered yesterday and when I switched it on, there was a blue flash from within the chasis, and an electrical burning smell. Not the smell of burned plastic but "that" smell.

I looked at the back and one of the tubes, was dead (not hot) and there was not much volume.

There were 4 new Sovtek 5811 that were glowing fine, the rest (JJ) were not looking so good.

There were HUGE drops in volume when flicking the switching from vintage to raw, but the modern switch seemed fine.

There was a mix of Mesa, Sovtel and JJ power tubes in there. I was playing it at half power.

My first move tells me to buy a quartet of sovteks to match the ones that are glowing normaly in the back.

Good move or should I go amp tech? (Very long drive)

And what tube dealers know how to match tubes for Mesa Rectos fixed bias? Sad

 

[Platypus]

Definetly replace the tubes first.. which tube was dead?

Sounds preamp related..

 

[dogboy131]

The preamp tubes were all brand new tung sols I had. One of the dead ones was a 6l6. I'll get new power tubes.

 

[Platypus]

The preamp tubes were all brand new tung sols I had. One of the dead ones was a 6l6. I'll get new power tubes.

Using different tubes are fine.. but make sure they're matched. Are your pairs at least matched properly?

What are your 6 power tubes? Are the 3 pairs matched?

 

[dogboy131]

I am not sure if they were matched. It was shipped to me yesterday. I think they all may be pretty random tubes because there are 4 sovteks, a mesa, and 1 JJ (dead/cold) in the 6l6 section.

I have heard of the term "pulling tubes" before.

If I have a bad tube, can the amp stull be used? Is it safe?

Do people remove power tubes etc?

 

[Platypus]

I am not sure if they were matched. It was shipped to me yesterday. I think they all may be pretty random tubes because there are 4 sovteks, a mesa, and 1 JJ (dead/cold) in the 6l6 section.

I have heard of the term "pulling tubes" before.

If I have a bad tube, can the amp stull be used? Is it safe?

Do people remove power tubes etc?

How you ran it technically would be alright but there's no sense in chancing it.. I would at the very least make sure your tubes are matched in their pairs.. (2, 2, 2) If you're ordering new tubes, get a sextet of matched tubes.. if it were my amp I wouldn't be running 3 different tube types in the power section but that's me... especially not paired properly.

Yes it is possible to pull tubes, there are tons of posts about it already so check out the search at the risk of being redundant.

 

[Elpelotero]

I believe that a triple recto can not run at half power. There's an issue with how many ohms to run that is not present with the Dual Rect.

I would just buy a new set of tubes. If it was delivered to you yesterday, I assume used, the previous owner probably gave you his oldest set of tubes. Replace the tubes before you start blowing fuses and electronics.

 

[dogboy131]

I did order tubes. Better safe than on fire eh?