Tubes for Marshall JCM 2000 - TSL 100

[Pax25]

It appears I blew a couple tubes in the above amp head. My Sweetwater rep recommended replacing them with x4 Genalex Gold Lion N709/EL84s, but upon arrival these tubes appear much smaller than the tubes that came with the amp. Am I missing something here? I reached out to my rep as well. Thanks.

 

[Dogs of Doom]

hmmm... The amp requires EL34 tubes, not EL84.

tell them the rep was wrong in what he suggested & sent.

Be careful. These amp's are problem childs & there could be something more problematic w/ your amp.

Check to see if the fuse blew.

How comfortable are you looking inside & working on amp's?

Amp's carry lethal voltages inside, so, if you're not technically inclined in electronics, you might want to have it looked over by a tech & have him do the tubes installation, etc., just to make sure that everything is ok.

The reason I say this, is because you blew a pair of tubes. Typically what happens in these amp's, is that a resistor in the bias section blows & sends high current/voltage to the power tubes in a pair & the pair red plates & burns up &/or blows...

If 1 tube goes out, it's typical & it might take that same resistor out, &/or another one, or it might take out the fuse. A pair going out isn't normal, for a normal amp. It might be normal for the TSL, but, only because of it's bad reputation, for having problems that fries tubes...

 

[Dogs of Doom]

here's a tube size comparison:

 

[Pax25]

Thank you so much. Yeah they look more like the EL34s. I think my rep was simply wrong.

I bought the amp in 2006. Only used it a couple times, then started using it pretty much daily since beginning of 2019. I've never had any problems before so I'm pretty sure it's a bad tube and/or blown fuse (which I've read can be caused by a bad tube).

I have somebody ready to do the swap and bias, but I told the guy that I had already ordered the tubes. He was simply going to install, bias, and/or make sure there was nothing else wrong.

You are right, these amps can be incredibly dangerous, so I had no intention on trying to work on it myself.

 

[mcblink]

Thank you so much. Yeah they look more like the EL34s. I think my rep was simply wrong.

I bought the amp in 2006. Only used it a couple times, then started using it pretty much daily since beginning of 2019. I've never had any problems before so I'm pretty sure it's a bad tube and/or blown fuse (which I've read can be caused by a bad tube).

I have somebody ready to do the swap and bias, but I told the guy that I had already ordered the tubes. He was simply going to install, bias, and/or make sure there was nothing else wrong.

You are right, these amps can be incredibly dangerous, so I had no intention on trying to work on it myself.

Just curious: you bought the amp in 2006 new, or used?

 

[Pax25]

Just curious: you bought the amp in 2006 new, or used?

I bought it brand new at Guitar Center.

 

[Dogs of Doom]

If you look here, at R9, on the board:

underneath it is some black soot/carbon, that blew out. Because of that, the bias to the power tubes, on 1 side went from 90mV to 200+V. The tubes were turning red instantly. 2 tubes. If I would have ignored it & just played, the 2 tubes would have blown/melted.

Not too far from this position, is the opposite side R6. It controls the feed to the other 2 power tubes. Either of these can go out & it will do that to the pair of tubes it's controlling.

Have your guy look at those 2 resistors.

 

[Marshallmadness]

I have a DSL100 and a TSL100 and actually find both of them to be pretty reliable as long as they have fairly fresh power tubes and reasonable bias set. Marshall recommended 90mV on the pins and that’s way too much and will cause trouble sooner or later. They have to be set lower.

Power tubes can cause all kinds of problems even brand new. I’ve had a brand new 6550 red plate instantly in a 2203, a new Shuguang short in a DSL100 and arced between traces on the board, and a new JJ blow in a TSL100 at 90mV in minutes. Any modern amp with a lot of circuit board and traces like the DSL and TSL do not react well to power tube problems and often damage things elsewhere. The DSL arc burn was fun to fix but it hasn’t had a problem in like 6yrs afterwards with different tubes. This is why I really love the earlier amps like pre 84 2203/04 amps that are wired and have a small PCB with a few components. When tubes strike back they rarely damage anything else.

I have had great luck and sound with the JJ E34L’s in both the DSL and TSL. They make those amps sound huge and punchy like none other for metal. I also use the JJ gold pin ecc83’s in both amps and they have a little more open crunch in them and work really well for me in those amps.

 

[Pax25]

Have your guy look at those 2 resistors.

No I haven't. I'm actually terrified of messing around inside the amp (even if it's just removing the back cover). I plan to let me tech handle everything.

Do you guys have any recommendations for replacement tubes? I'm a working musician in a 90s rock cover band, not a metal player, and I loved the sound of the original amp and tubes. I play through a Marshall 4x12 1960A with very few pedals, so that's a big part of my sound as well.

Thank you so much for your help.

 

[Pax25]

So my Sweetwater rep is now recommending the following:

Groove Tubes GT-EL34M Mullard Power Tubes - Medium Quartet

https://www.sweetwater.com/store/de...s-gt-el34m-mullard-power-tubes-medium-quartet

1) Will these fit in my amp? (most important)

2) Would you recommend them?

Thank you.

 

[Dogs of Doom]

sure, sounds like they'll work ok...