Replacement Tubes EL84!!

gezza · May 23, 2009

Hello Guys,

I see that this topic has been sort of covered.

Can you replace the Mesa EL84 with any brand or does it have to be a specific EL84 to match MB Specs.

In other words can I use any EL84 to replace the MB-EL84 or do I have to ask the supplier to make sure it matches the MB Specs.

Does any body know what they are??

I have a Bias Probe, But got the 8 pin for EL34, 6L6 8 pin tubes.

But from what I can gather the plate voltage is approx 400V, so that would mean the EL84 should be between - 15ma for cold, 18ma for ave, 21 for hot, mind you 21ma is 70% of plate dissipation, this is normally where a tube sounds best.

So if a buy another brand and put it my amp, how do I know if It will be a good match, as the MB have all fixed bias, so you can't adjust anything.

Have any of you guys replaced your Power tubes yet??

Thanks,

Gezza.

bobby wasabi · May 23, 2009

I've used JJ's before and they sounded good. I'm back to the Mesa's now...no apparent reason other than they are readily available at most of the music stores in town. I always ordered the JJ's in from The Tube Store. I just told them in my order what amp I was using and they sent out a set with a number on them. I always ordered the same number.

gezza · May 24, 2009

Hey Guys,

Yep more questions.

My EL84 Tubes have written on them,

AC Red - 10.

From what I have read, C stands for China- Red stands for late break up - 10 also highest for breakup.

What did you guys get, the same or different??
So will changing my tubes affect the clean tone!!!!

Are they cheap Chinese tubes??

Thanks guys,

Gezza.

Newysurfer · May 25, 2009

Gezza

You can put any suitable tubes in a Mesa.
Mesa use Chinese tubes as stock and while they're ok they are not the best.
Myself and many others have significanlty improved the tone quality, increased the gain range and reduced amp hum by swapping the tubes.

If you want great tubes while saving a ton of money got to http://www.dougstubes.com and email him asking what tubes he'd recommend for your 5:25. I specifically asked for a tube set that would keep the same cleans, increase gain and reduce amp hum. I got the tubes Doug recommended, cost $100 for a full tube swap, they did exactly what he said they would and made a big difference to my 5:50. They ship to Aust. Took a week to arrive. Once you receive the tubes you can insert them straight in yourself, no amp re-bias required. Takes about 15 mins.

johnbowen · May 28, 2009

I am a big gear tweaker. Always changing tubes, etc, etc. Here's my findings, for both preamp and power amp tweaking;

Preamp: I had read the reviews about reduced hum, noise, etc, by switching out the stock Mesa tubes. First i replaced all preamp tubes with JJ red 12AX7, with a balanced gold JJ 12AX7 for V4, which is the phase splitter/driver. I heard very little difference. Next I ordered tubes from Dougs Tubes; again i did not notice a difference. I listened for a difference. I measured the noise level; with all JJ tubes, with Doug's recommended tube arrangement, and with the standard Mesa tubes. Absolutely zero difference in noise or hum levels; with an increase in harmonics at V2 tube location when using the JJ tubes (Doug's set up includes a JJ tube for V2).

Bottom line; I heard no difference in the quality of sound, or the subjective "tone" quality. Objectively, no change in the DB level of hiss, hum, or noise, any tube configuration, but a much increased tendency to squeal (no cables plugged in) on the burn settings with the gain and master turned past 2-3.

Power tubes: I replaced the standard Mesa power tubes with JJ EL84. No difference in hum, hiss, etc. Subjectively, I'd have to say I like the sound best with the standard mesa tubes.

Currently I'm running all mesa tubes in the preamp, except for V4, which has the JJ Gold 12AX7. I'm using the mesa power tubes. I may switch back to the JJ, but really cannot hear much of a difference.

if anyone wants to see my sound levels spreadsheet let me know.

jo

soundchaser59 · May 28, 2009

I've said before that (imo) of all the gear and parts we can change, tubes will make the least amount of difference in the sound. I'm like you, the difference is extremely subtle, if it is there at all. I can hear a slight different (I think I can, anyway) between using all chinese and all russian made tubes, with the chinese tubes seeming to give the amp a harsher and brighter edge that I definitely don't like. But switching between various brands of russian made tubes, etc........ good luck hearing any change.

I think by far the one piece of gear (other than the amp itself, obviously) that has made the biggest difference in my tone is the pickups. A more subtle but still noticeable difference comes with changing the speaker. After that, it's all in the amp, pedals, and fingers.