Express 5:25 HOW does it make 30W with only a pair of 84s?

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blaren
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Express 5:25 HOW does it make 30W with only a pair of 84s?

Post by blaren » Sun Jun 28, 2015 10:14 am

Yes 30W. If you look at the power selection switch on the rear it goes from 5watts to 30 watts.
Typically an EL84 makes (I know it doesn't MAKE watts but...) around 9 watts.
A normal 18w amp uses a pair of EL84s. A 30 (AC30) or 36W (my Ceriatone) runs 4 EL84s to make ~30W

I realize that there have been a couple of amps that have made even FIFTY WATTS using only a pair of EL84s (one was a Peavey the other... a mesa?? I cant remember) but ...yeah.
I know that the Mesa has the "DynaWatt" tekmology but still.
And it DOES seem like an honest to goodness 30watts. It is LOUD.

The other shocker is...
My Contour circuit was not working so I pulled the chassis. It was just the ribbon cable plug had come a bit loose from the LED/switch/pot board.
When I pulled the chassis out of the cab though I almost pooped in my trousers.

I've had MAZ18s, 100W Marshalls, 50W all kinds including MESAs, I've had 1970 SF Twins loaded with JBLs (Wylie E. Coyote would have used one instead of an anvil) and I've had HRDevilles and Deluxes.....
I'm old now so I don't usually reach for the heavy 100W heads and 4-12cabs when heading to a gig. Been all about combos for a long time now. Combos and low-watt heads w 1-12 cab...you know.

I mentioned my Ceriatone...it was the 36W prototype. It had JTM45 iron. It is as heavy as a 50 or 100w.

When I pulled the chassis..and pooped...I could not BELIEVE how lightweight this thing is. The power transformer looks the size of an old Marshall's choke.

I mentioned that I'm old? To me, in order for a tube amp to be "real" it has to weigh a bit. The 5:25 is my favorite amp right now. It kills at tiny gigs or jams and KICKS at the biggest outdoor festival stage.
Since I realized how LIGHT it is though, I don't trust it anymore. Plus I think it's a big fat LIAR. I mean I know its making all that power, I can hear and feel it but it's damned near impossible to do that (reliably especially...I know I know..there is a very little amount of V on the screens).

HOW can this amp be so light and HOW can it make 30W on a pair of 84s??

I (when I played it all the time) used to get all KINDS of compliments on my Ceriatone 36RP. It's in a smallbox Marshall head so looks Marshallesque. The top of the h is busted-off so it's a Marsnall.
EVERY gig, at least a couple of guitar geeks would approach me on breaks to ask .." :-O is that a REAL PLEXI?? :-O "
Yes, yes it IS a real plexi! KIDDING. It's just a home made amp pretty much.

I haven't been playing that amp as my main rig for the past couple years. Been having a lot of amps come through for me to sample. Tried the HRFenders, had a MAZ18, a Stiletto, some OLD 18watters, a DSL100....
When I bring the Express to jams, guitar players compliment me on it. They always say the same thing. WOAH!! That PRS you're playing sounds amazing and it's SO beautiful!!
Well thanks...BUT...its the same PRS I always play. It's the AMP you're hearing. And I'm using NO PEDALS!! Well I have the Zoom MS-50G that I take as a tuner and delay or whatever else might be required....awesome wee pedal. GET ONE!
You are hearing the MESA clean and the MESA dirty. It's ALL amp you're hearing.

:-O

I'll tell you what. The MESA 5:25 Express is the best amp I've ever owned I think.
I prefer a DSL with a 4-12 cab on the big festival stages...kinda..the express can handle it easily though too.
The 5:25 is absolutely my desert island amp. It is the amp I bring when I can only bring one (I somehow trust it). It's the only amp I have ever owned where both channels are useable. Well the Stiletto too. Ok that might be a MESA thing lol. I haven't ever even tried my favorite (G12-65) speaker in it yet and probably wont. This amp will not benefit from a less efficient speaker.
And I'm NOT even a Mesa guy. I don't do high gain.

I think the contour plug is off again but I don't even care. I don't use that part of it and I wouldn't use the 5-band on the 5:25PLUS. I actually used to run an EQ pedal as a clean boost with my rigs but not anymore.

OK...I'll end this rant now. Sorry fellas.
Points are though...HOW does the 5:25 Express DO it??? How does it make SO much power? How does it do it while weighing as much as a laptop ...and...if you're like me, gig a lot, need versatility in an amp but don't want to carry big heavy gear...you NEED to try the 5:25. Seriously. Try to find a deal on a used one...the pre PLUS models should be affordable now.

morgan138
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Re: Express 5:25 HOW does it make 30W with only a pair of 84

Post by morgan138 » Tue Jul 14, 2015 5:01 pm

blaren wrote:Yes 30W. If you look at the power selection switch on the rear it goes from 5watts to 30 watts.
Typically an EL84 makes (I know it doesn't MAKE watts but...) around 9 watts.
A normal 18w amp uses a pair of EL84s.
I had a Peavey Classic 50 that rated at 50 watts with 4 EL84s, and a Classic 100 that rated at 100 watts with 8 EL84s. The Mesa 50 Calibers are also 50 watts with 4 EL84s if I'm remembering right.

Based on that, I'm not surprised Mesa could squeeze 30 watts out of a pair of them. Is that 9 watts per tube number for triode operation or something? It seems on the low side.

Anyhow. Did you post this before? I'm having deja vu.

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phyrexia
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Re: Express 5:25 HOW does it make 30W with only a pair of 84

Post by phyrexia » Fri Aug 21, 2015 12:38 pm

Do you want the truth, or do you want to ignore everything except the beautiful sounds coming out of your amplifier?
“A journey of a thousand miles must begin with a single step." Lao Tzu

Monsta-Tone
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Re: Express 5:25 HOW does it make 30W with only a pair of 84

Post by Monsta-Tone » Mon Aug 31, 2015 11:02 am

:lol: That great tone is the sound of your tiny transformers screaming for mercy! :lol:

Put a small dab of silicone on the ribbon cable connector (make sure it goes on the male and female side). Once it dries, the plug should never come off again on it's own.
Elvis said.......
Amp techs do get shocked. :shock:

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screamingdaisy
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Re: Express 5:25 HOW does it make 30W with only a pair of 84

Post by screamingdaisy » Mon Aug 31, 2015 11:51 am

My understanding of Dyna-Watt is that it's a stiffening capacitor used to reinforce heavy transients on the low end and it's why Mesa's small amps don't typically sound like small amps. Most manufacturers seem to get around the problem of mushy low end on low powered amps by cutting it off. Mesa's found a better way.

As for the 30w thing.... No idea.
Ignore the hype and trust your ears. Play more, buy less = better tone.

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