Tube Change Question

[braintheory]

So I just got today a set of SED Winged C EL-34's for my mark v. I was wondering if when I change from the stock 6L6's to these EL-34's if all I have to do is remove the 6L6's, put the bias switch to EL-34, and then just put the EL-34's. Also it says that these SED Winged C EL-34's are pentode. Does that have anything to do with how it would affect using triode or pentode mode on channel three or anything really? Also when I switch to these new tubes will the wattage change at all? I am a noob when it comes to tubes, so I know these questions may sound silly.

 

[eudaimonia02912]

Yes, just put the EL34s in and flip the switch to EL34. (I presume you told your dealer these were for a Mesa amp, so they sent you tubes that will bias in Mesa's range.) The reason the tubes say they are pentode is that some tubes (not EL34s) are triode only. The pentode and triode switches will still work normally. I did find that with SED EL34s, but not other brands of EL34s, the amp got slightly noiser in triode mode.

 

[braintheory]

(I presume you told your dealer these were for a Mesa amp, so they sent you tubes that will bias in Mesa's range.)

Actually I did not. I just simply ordered them off of amazon because I found them for a good price. I hope these tubes will still work okay. Also, I don't know if this matters, but on three of the four boxes for the tubes there is a circular sticker that says 25 on top and underneath 4.5 and the other one says 25 on top and 4.4 on the bottom. Does the 25 have to do with wattage and the 4.5 have to do with this range you were talking about?

 

[LPJunky]

I think you should discuss it with the supplier to get their opinion or the true meaning of their rating system.

 

[J.J]

+1 on talking to supplier.

With the Mesa amps being fixed bias you have to use tubes that are selected to be within the correct range. If your ones are to cold the amp will sound bad and if they are too hot, there will be reliability issues.

Hopefully with some luck what you have will fall into the acceptable range.

 

[braintheory]

What is the acceptable range for a mark v?

 

[braintheory]

I noticed that on the EL-34's I ordered one one of them said 10 at the bottom with a small space and then 50 next to it and another one of them said 1143 at the bottom also with a small space. Does this have anything to do with the range or is it just a serial number.

 

[J.J]

Those numbers against no parrameters mean nothing.

As to what the acceptable range is, I don't think it is published. even if it is different test setups will give different results.

The tube suppliers that know the detail presumably have tested a range of Mesa tubes on their testers and can match other tubes based on their data with their test equipment.