Discussion in 'Amps and Cabs' started by MrKite89, Oct 10, 2018 at 6:08 PM.
I've heard the RCA's are a little "cleaner" than other EL84s. Any insight on that?
I really like the JJ's, although the only EL84 amp I have is a modded Blues Junior with an adjustable bias, so my EL84's tend to live a fairly long life. I'm no expert, but I have to wonder whether the "problem" with short EL84 life is that the EL84 tube is spec'd by design for a max dissipation of 12 Watts and often amp manufacturers seem to insist on running them in situations WAY over that design spec, isn't that a recipe for significantly shorter life of any tube type really? In an adjustable fixed bias amp like my modded blues junior they sound much nicer biased back down to around 70% (cooking at way over 100% in the stock amp, I believe Fender finally addressed this in the newer IV model BJr and backed off the bias). Even for Cathode biased amps wouldn't it be better to target max dissipation just below 100% in the amp's design?
Get you some 6p14p’s for that bad boy.
Also, a couple anos tubes can be had on eBay from a couple good sellers that cost as much as new production stuff and would make that amp sing, in my humble opinon.
When were these Russian 6p14p military tubes made? I see them advertised as NOS...were they 80s?
I could use some for my Matchless Lightning...
Hey guys, thanks for all the inputs!
I just checked the voltages in my AC15H1TV, just to be sure, and the plate voltage is around 350v, is it too high? Could it be the reason why this amp eats tubes?
According to this 1960 schematic the plate voltage should be ~310v:
This is the schematic for the AC15H1TV: http://dealers.korgusa.com/svcfiles/AC15H1TV&L_SManual.pdf
I measured between ground and the triode pins on the pentode\triode switch, just next to the OT and above\below C21 in the schematic, which seem to be directly connected to pins 7 (plate) of the EL84s: the power tubes and their sockets are not easily accessible in this amp, but I think I measured in the right spot, do you agree?
If, and I say IF, 350v is over specs, a different rectifier could bring that voltage down a bit or should I replace some resistor?
The amp sounds good, maybe a little stiff\stiffer than usual...
Thanks for any tip!
In my H2X, which is about the same circuit, I actually prefer the JJs over the 6p14p.
In other amps, the 6p14p win.
I have spare quads of each, so I just see what sticks in a certain amp.
the preamp tubes, especially the PI, make a lot of difference here, too.
btw, important tip about buying EL84 :
use a dealer that gives you measurements per tube.
the actual value is not really relevant, but that way you can order a reasonably well matched replacement tube in case of failure.
Beats throwing away 3/4 of a quad by a mile ...
I've got a set of NOS RFTs in both my Marshal 2061 and my OR15.
I've had great luck with this tube.
They sounds significantly better than JJs, and they're long-lasting little bastards
better as in "more clean headroom", or better as in "more crunch at lower volume" ?
More clean headroom. Clearer all the way across the tone spectrum, particularly in the highs.
The 6P14P-EV was a Soviet, cold-war era tube made for military use. It was not made for commercial use. When the military demand dried up, the story is that Sovtek elected to produce a commercial version for the civilian markets. The EL84M is supposedly the current commercial production version of the 6P14P-EV. It is made in the Reflektor (Sovtek) factory.
However, there is some question as to whether the quality of the commercial tube (EL84M) was the same as the military version. Many musicians who used the early commercial version thought it sounded dull. Reviews by musicians (including comparisons here) were unflattering. That led folks to seek out the left over 6P14P military versions - of which there are a few variants: 6P14P (2000 hour service life); 6P14P-K (designed to withstand high vibration for 3000 hours of service life); 6P14P-ER (10,000 service life); 6P14P-EV (5000 hour service life).
I have a quad of 6P14P-EVs in a Crate Vintage Club 50 head. That head cooks EL84s running them at near 400 volts on the plates. It came stock loaded with regular Sovtek EL84s, which have survived fine and sound better in that amp than in any other amp in which I have ever heard them. To my ears, the problem with the Sovtek EL84 is that it is midrange heavy. The 6P14P-EV has a more even tone distribution and delivers a nicer, fuller, more pleasing tone.
I also have a pair of 6P14P-EVs in a Monoprice 15/Laney Cub12R. That amp is only running at about 292 volts on the plates, so the 6P14P-EVs will last forever in there. But I didn't put them in there for that reason. I tried all of my different EL84s in that amp: Shuguangs, JJs, Teslas, Eis, Sovteks, Gold Lions, etc. To my ears, the amp sounded best with the 6P14P-EVs. I also have a pair in an Epiphone Galaxie 25.
The Tube Store sells the 6P14P-EV as their "Preferred Series 7189," but there are other vendors on E-bay, the internet and elsewhere that still sell it (not the current production EL84M).
Good luck, all.
very cool, that sounds right up my alley.
do you happen to know if there was basically one single version, like with their preamp tubes, or if I should look for specific years / models ?
yup, agreed on all points.
especially about differentiating per amp.
not sure, but I have hazy memories about a certain 6p14 version that was not pin compatible to EL84, can anybody confirm ?
I liked to think of me as vintage, but there are days when I fear I'm just getting old ...
I have had the exact results with my BillM mods with my BJ too. I have also had a Maz38 and a AC15 for awhile. So I tried those russian tubes Dr. Z recommended. Although I believe they last longer, the JJ's sound better to my ears when I rolled them in all threes amp models mentioned.
yes, my MAZ likes the JJs as well.
don't forget, manufacturer tube recommendations have to be taken with a grain of salt.
I would never doubt Z's or most other builders' competence, but they have to take other criteria in account as well, supply, reliability, consistency between batches, even (irrational) public perception.
to us players, one great set is good enough ...
all that said, ime the sound difference between JJ and 6p14 is absolutely there, still - I could live with either, in any of my amps, no problem.
wish I could say the same about EL34s ...
I’d go with any other brand of EL84 for reliability.
Especially stay away from the EL844.
I generally use mullards in my hw voxes. Sounds fine to me. Got that advice from Brian at tophat back when I played that. I preferred them to the stock Rubys and the jjs that I use elsewhere, but honestly, I haven't noticed a huge life altering difference. Maybe I don't play loud enough. But the mullards are solid and they sound good, so whatever.
Now preamp tubes made a hell of a difference.
Always wanted to try some of these secret handshake, low pro tubes but never got around to it. And for every hot tip you get, theres plenty of dudes out there to tell you how much they suck. So whatever.
Man, get yourself a good NOS ef86 in there. No one makes a good one today. I recommend NOS Mullard, Telefunken, Dario Miniwatt,
Also known as 6n14n (with various suffixes....EB being the longest lasting) depending on whether you're using the Roman or Cyrilic alphabet.
at $40 a pop, NOS GE’s have been in my AC15 since 2010.... still testing strong. that’s 16 x 6 month cycles that they have lasted for. best deal going?
Do you use your amp alot? I mean like 2 hours minimum every day plus one or two full length 4 hour gigs every week? I seriously doubt even NOS el84s would last 9 years at that usage. I'm happy to get 6 months out of a pair of JJs. That's $40 a year for amp maintenance. Not bad. Plus check NOS tube prices now. There not $40 a pair. They're more like $50 each. And that's for the cheaper ones. NOS Mullards can be $100 EACH.