EL84 vs EL84M?

[jmaul]

My understanding is that the EL84M is more hi-fi oriented but allows for a hotter bias. I have also heard matchless used the EL84M's, and while there is obviously more to the matchless tone, I am wondering if swapping and rebiasing to EL84M's might not be a good idea.

Has anyone here tried this, and if so what were the results?

They would be going into a blackheart handsome devil head.

 

[Billm]

They cost more and they don't sound as good in guitar amps.

I don't get it.

 

[telebluesrocker]

hmmm. my epiphone galaxie has el84m's and it hardly breaks up at all even at near full volume. not good for a bluesman like me. need to change them sometime. any ideas what to?

 

[Tim Swartz]

They are more akin to a 7189 which is essentially an EL84/6BQ5 that can take 400V.

 

[jefrs]

Hmm, when is an EL84 not an EL84 (?)
A little delving revealed "EL84M Sov/Russia Heavy duty mil. grade EL84, used by: Gibson®, Hughes & Kettner®, Matchless®, Trace Elliott®,EL84M / E84L"
Also found refs to 6BQ5WA
A further search for 7189 returned Harma (Sovtek?) EL84/E84L military grade etc etc and TAD EL84-C/STR (which I have in Laney L5T)
Found TAD RT372 Röhre EL84M - see TAD website (I didn't check their stock)
I did find a bloody stupid price of £93 !!!
A review of some EL84 including EL84M here http://www.watfordvalves.com/cgi-bin/documents/testreport_33.pdf (Watford don't seem to have any)
The Sovtek EL84M gets a bit of a panning whereas that EL84-C is the best EL84 I have for that amp, strangely my EVJh prefers the stock Sovtek EL84.
It seems the ruggedized / military / selected types will handle a bit more juice and abuse than the standard spec. A fair few guitar amps pump more volts in than they are supposed to...

Re Epi Galaxie, schematic for Galaxie-25 ? here (link removed)
uses a pair of EL84 running 375V so nominal 15W amp.
EL84 are generally quite cheap. Watford were offering their own brand Mullard rebuild EL84-retro, the TAD EL84-C/STR is solid, the stock Sovtek EL84 works. Imo avoid 'cryo', added bs.

 

[jefrs]

Another thought, generally more HT = cleaner amp (more headroom)
EVJ 350V, WEM Dominator and Laney LC15 300V, Laney LC30 290V
At 375V the Galaxie-25 will run quite hot and clean, whatever flavour valve is used.

 

[Rick330man]

The Galaxie 25 tends to have a lot of high end shrill. The stock Celestion 70/80 adds to the problem because it also tends to have a lot of high end shrill. A speaker change helps. Some folks really like the Eminence Red Fang, which tends to be dark sounding. I think the Eminence Legend 122 alnico fits the bill better.

Another solution is to swap the power tubes for these Sovtek EL84M/6P14P-EV offerings. These tubes do a great job of taming the shrill highs and turning the Galaxie's clean into something of beauty. And since these power tubes are essentially 7189 equivalents, they are better suited to the high plate voltages the Galaxie 25 likes to run at. Mine runs at around 368 - well beyond the 300 that should be the max for standard EL84s.

 

[jefrs]

Lawks! - a zombie!

imo suffix letters after the valve type are generally added bs.

The Seventy80 is not shrill, I have a pair in a closed 2x12 cab. Often the sound of a speaker will depend on the volume used and whether open or closed. That cab is used from parlour to stage level. Imo the Seventy80 is less shrill and harsh than the OEM Eminence Pot Luck found in my Epi BC30 or the thing in the BJ. Another harsh one is the Vintage30, again it sounds better when being thrashed in a closed ext cab.

Why on earth is the Galaxie, a "15W" amp, running a 70W speaker?
- try a 25W G12M-25 Greenback, a pair of them suited my Epi BC30 very well.
- perhaps the Epi Galaxie would benefit from some of the anti-shrill mods we did to the Epi BC30 (search here and over on Gibbon/Epi)

 

[ATubes]

I've done a lot of testing of the EL84 EL84M. My personal observation is the EL84 tends to break up much quicker and has a little lift of the high end frequency. The EL84M has a good bit more headroom before breakup and a much flatter frequency response.

While I liked the review at http://www.watfordvalves.com/cgi-bin/documents/testreport_33.pdf I don't think the Vox is the best amp to use for a listening test (I have an AC30HW2) The Vox has too many of it's own idiosyncrasies to be a balanced test.

 

[jefrs]

I've done a lot of testing of the EL84 EL84M. My personal observation is the EL84 tends to break up much quicker and has a little lift of the high end frequency. The EL84M has a good bit more headroom before breakup and a much flatter frequency response.

While I liked the review at http://www.watfordvalves.com/cgi-bin/documents/testreport_33.pdf I don't think the Vox is the best amp to use for a listening test (I have an AC30HW2) The Vox has too many of it's own idiosyncrasies to be a balanced test.

You'd prolly notice similar between a JJ, Sovtek, Mullard, Trigon, Brimar, Mazda, RFT, Telefunken, etc.

The 60s AC30 was 46 watts, and it cooked the valves. But is is the classic 4xEL84 amp, we all know what it sounds like. Can't think of many other big pro stage amps that use EL84 (and are not based on the AC30). The EL84 is desired for breaking up, if you want clean headroom, don't use an EL84.

Funny thing is, the EL84 is not a "good" valve, it was designed as a cheap jobbie for domestic radios. It has enough gain to delete an ECC83 in the pre. Essentially the bottle is too small. The EL34 is considered better. But the EL84 works nicely in guitar amps. And yes, they all sound different. What is good in one amp is not necessarily so in another (my EVJh hates good NOS EL84, it prefers Sovtek).

 

[Rick330man]

I've got two of the Crate Vintage Club 50 heads. They have spectacular cleans. I ran them with a quad of JJ EL84s. Sounded great. After about 25 hours, one power tube died. I then ran a quad of Ei EL84s. Again, sounded great. Again, killed a power tube after about 25 hours. Checked the B+. It was around 390 with the JJs and 385 with the Eis - absolutely fatal territory for standard EL84s. In went the 6P14P-EVs. No problems since. Clean headroom galore and more spectacular cleans, but the drive is not so good.

As for the Galaxie 25, out went the Celestion 70/80. I tried lots of speakers, but the Eminence Legend 122 alnico and the Red Fang were tops. Also good was the Reverend Alltone 1250. Throw in the 6P14P-EVs to better tame the shrill highs and you have a pretty nice sounding clean amp to build your sound on.

 

[norumba]

i just put in a EL84M in Black heart LG. I'm getting tighter lows, more natural, sweeter highs; mids are better defined and more forward but not thick or over emphasized. Interestingly enough, they seemed to bring out a little more Voxy chime as well than what was in there, so thats a plus as well for me.