Tubes out of order?

[Micha]

Hi people.
I have a problem
I played guitar with my preamp and my power amp Marshall EL34 100/100.
Suddenly there was a
Hush and the sound was less loud. I looked through the front window of the amp. A power tube was very bright red, but really more than the others.
I quickly turned off everything.


I noticed recently that a fuse broke often, faulting only one side of my dual monoblock amp.

So let's go and speculate .... What do you think it is? Just the tubes?

 

[JMP/HBE]

Re: Tubes out of order?

https://drtube.com/schematics/marshall/91009200.pdf

Looks like the 9100 & 9200 run on 5881's.

FWIW most 5881's made today are just a glorified 6L6.

 

[Micha]

Re: Tubes out of order?

I think the tubes burned because of a tension problem or something like that.


I therefore start from the fact that a repair is necessary before the change of the tubes.


It remains to know which tubes I will mount on this amp.
El 34 (electro harmonics, dd?), Kt66?

 

[JMP/HBE]

Re: Tubes out of order?

edited

 

[Red_Label]

Re: Tubes out of order?

I think the tubes burned because of a tension problem or something like that.


I therefore start from the fact that a repair is necessary before the change of the tubes.


It remains to know which tubes I will mount on this amp.
El 34 (electro harmonics, dd?), Kt66?

Wait... are we talking about tubes or strings here?

 

[Chris Pile]

Re: Tubes out of order?

Since the OP obviously knows NOTHING about tube amps, a visit to a competent and experienced tech is in order.

 

[eclecticsynergy]

Re: Tubes out of order?

Yep, get it checked out.

 

[devastone]

Re: Tubes out of order?

FWIW, the B+ voltage line (plate voltage) is sometimes called the high tension line in tube amps but is unlikely the culprit here, nor is the order of the tubes(?).

But, while it is possible there is something wrong with the bias circuit, it sounds like there is just a bad tube that red plated and it should be fine to replace the tubes with a rebiasing, which I agree, should be done by a pro.

 

[LLL]

Re: Tubes out of order?

Wait... are we talking about tubes or strings here?

He's probably saying "tension problem" because a common issue with tube amps is the powertube sockets' metal connectors get loose over time
and need tensioning.

 

[JMP/HBE]

Re: Tubes out of order?

"High Tension" IE; HT fuse ect.

This here be HIGH TENSION. 115kv [115,000 VOLTS]

 

[Demanic]

Re: Tubes out of order?

"High Tension" IE; HT fuse ect.

This here be HIGH TENSION. 115kv [115,000 VOLTS]

I'd like to hear an amp that could run the B+ at that voltage.
From maybe 100 miles away.

 

[PFDarkside]

Re: Tubes out of order?

I'd like to hear an amp that could run the B+ at that voltage.
From maybe 100 miles away.

A coworker is a HAM, he calls my 6L6 and EL34 tubes little baby tubes.

 

[Ascension]

Re: Tubes out of order?

Sounds like a bad power tube. FYI guys I owned a EL 34 Marshall power amp that was bought with my JMP 1 there were indeed a few of those that came with EL 34's.
This in fact was recorded in the studio with my JMP 1 El 34 powered 9200 set up in 1994.
https://app.box.com/s/dj8ykf22zdvko5qdm8vshy6goov0q9vo