Tremoverb, DR & Mark Series Design Flaws??????

[TremoJem]

Just had a discussion with a reputable engineer and searched the forum here to confirm.

My problem is that there is not enough information here to help me out.

Here is the deal.

I have two Tremoverbs. One is vintage 2000 and the other is vintage 2001.

Do I have a problem with "Screen Grid" failures or risks?

Do I have a problem with "Low Voltage Supply Resistor" failures or risks?

Do I have a problem using EL34s, because the design is not supportive of the EL34 voltage?

Please help and let me know how to proceed.

Thanks!?

 

[domct203]

Do I have a problem with "Screen Grid" failures or risks?

No more than any other comparable tube amp.

Do I have a problem with "Low Voltage Suppy Resistor" failures or risks?

I don't fully understand this question.

Do I have a problem using EL34s, because the design is not supportive of the EL34 voltage?

The Trem-O-Verb is designed to correctly use either 6L6GC or EL34 output tubes. What is this "EL34 voltage" you mentioned? The only voltage that needs to change for EL34's is the bias voltage, which is covered with the "bias select switch" on the rear of the amp. The rest of the amp has been designed to cover both 6L6GC & EL34's.

Hope this helps,
Dom

 

[TremoJem]

Sorry if the questions are incomplete or confusing.

I am just trying to quote what the engineer said.

I am just trying to make an educated decision as to whether or not I should have this "repair" done.

Thanks

 

[94Tremoverb]

Tube failures can occasionally blow screen resistors. Mesa is less than ideal on this because they use carbon screen resistors which do have more of a tendency to burn out than wirewounds, as some other manufacturers use. They also do not use HT fusing which some other companies do, so the amp will sustain a larger overload and for longer before the main fuse blows. These two things together mean that a Mesa is slightly more prone to blowing screen resistors than some other amps. But not much. If you're really bothered, have a HT fuse fitted (T1A), and possibly have the screen resistors replaced with 5W wirewound. (I did the fuse but not the resistors on mine, if it matters.) I think many of the more modern models do use wirewound resistors anyway, I've seen them on a few of the recent Mesas I've worked on*

I've never seen one with a failed Low Voltage Supply resistor, although this can happen and I've seen many in other amps.

It's absolutely fine to use EL34s. The amp is designed to take them and all you have to do is flip the bias switch on the back. If you don't, no harm will occur and the tubes will just run much too cold. But *don't* forget to do it if you swap back from EL34s to 6L6s, or the 6L6s will run much too hot. (Usually mostly in the Bold/Diode mode, but also a bit in Bold/Vacuum Tube.)

Some techs do not like Mesa amps and will tell you all sorts of strange things about them. I'm also a tech and they seem much better built and more reliable than most other amps, in my experience. Not perfect, but very few - if any - are.

(*Which is not very many. They just don't come in for repair very often.)

 

[jpdennis]

I do not know when the Tremoverb went out of production nor is there any great consensus on the quality of the EL34 tubes which are being produced today.

Tommy_G and I have and/or are reviewing our individual Heartbreakers with that in consideration. Tommy is using 1/2 power and EL34 power tubes. I am using various settings and the 6L6 power tubes.

For the most part it is the best idea to talk with a qualified amp tech, as there are several on this board and elseware. I use both a guy in Sacramento and will drive to Petaluma as needed. I have been told, as 94Tremoverb has stated, the carbon resistors should be replaced as well as using a better fuse type.

I have opted for the carbon resistors being replaced when I need tech service done. I have been using fuses rated at about 1/2 to 2/3 of the standard value recommended by boogie since I haven't had any changes in that area yet. I have been doing that for all my amps for some time just figuring that if the lower rated fuse blows it should do it before any major damage.

I tried that trick because many many many years ago I used tin foil as an emergency trick - not good - didn't work - DON'T every do that!!!! [Typed to the tune of "Cryin' Time Again" since I fried many components with that bone-head idea]

Anyway, good luck on your search and your end-decision and results.

Dennis

 

[Stratocaster]

TremoJem,

No offense meant my this, and I wish you the best in not taking it with offense...
You sound like a woman. Stop with the questions, and just play the damn thing.

If you break it, cross that bridge when you get to it.

Strat

 

[TremoJem]

I get it.

It's just that this is all new to me and I don't want to experience the nightmare that this tech described.

Catastrophic, actually.

And to boot...it is cooking right now and may burn up the entire amp at any time.

So instead of jumping in a car with my amps and racing to take these to the tech...I posted it to see what was really going on.

Thanks

Oh, and with total respect and no offense to Stratocaster...subjects/posts on forums are much like tracks on a CD...skip over the ones that don't interest you.

 

[Stratocaster]

Point taken, with no offense.



Enjoy your gear!

 

[94Tremoverb]

It's just that this is all new to me and I don't want to experience the nightmare that this tech described.

Catastrophic, actually.

What exactly did he describe? I've never seen a Mesa amp with a catastrophic failure, and I would think it was unlikely it would happen unless the amp was deliberately fitted with the wrong fuse. (Or tinfoil .)

And to boot...it is cooking right now and may burn up the entire amp at any time.

What do you mean by 'cooking'? These amps do run quite hot, the combos especially. Or do you mean some component is actually burning out?

The design is absolutely fine, unmodified. If it's running much too hot or a component is failing there is something wrong and it needs to be fixed, but the fix is likely not big or difficult.

 

[YellowJacket]

Sounds to me like this tech is trying to drum up business!

 

[TremoJem]

This is what I thought too.

I am glad I asked and thank you for all of your input on this subject.

It was alarming though.

To answer 94Tremoverb:

He described a resistor that is undersized and cooking every time I use the amps and if it blows it could take out the tubes, board, etc.

Then something about a supply voltage resistor that is not right and it too is a huge risk, oh, and something about using EL34's and how it is a huge risk. Believe me I have my bias switch set to EL34 in the amp that has them installed.

I just tried to understand and write it down as fast as I could.

My bad, I am not up on this stuff.

 

[jpdennis]

Hmm, maybe get a second opinion. :?

The other side is, do you know this tech personally or have you had a friend who know this tech :?:

I "interviewed" three techs after calling four within 80 miles of my home. The one I chose had great references from players I contacted as well. He was very helpful, offered to do the intial work on three of my amps for a single bench fee, and then explained what "had" to be done and what "would be a good thing to do" and then "what might be good to plan for in the future" on each individual amp. He used terms I understood and clarified those I did not.

I have not been disappointed since.

Dennis

 

[TremoJem]

Thanks Dennis, I have three techs in the area and am in the process of doing just that.

 

[benjamin801]

Sounds to me like this tech is trying to drum up business!

And you know what they say about drummers.

 

[siggy14]

The early tremoverbs had an LDR issue, but you should be fine, but do a search for LDR.

 

[TremoJem]

Thanks Siggy14