EL84 Variant

[scott fitlin]

Thats why I use a line level component, with a tube, instead of tube amps. Tubes in line level gear offer the taste of tube flavor, but last a long time.

Amps in my application, long hours, hard use, tubes do not last. And vintage tubes are a finite source, and as many are now learning the joy of vintage tube sound, I see the source drying up even faster.

When it comes to 12AX7A,s Im partial to Amperex and RCA, both are absolutely amazing sounding. The tubes made now, well, I found them to be too much tube coloration, I used Sovtek, JJ, Ruby, and Electro Harmonix.

The old tubes sound natural, clean, and smooth, yet extremely dynamic, in that real sort of way only tubes do. Vocals through my vintage tubes have an acoustic sound, something I have grown very fond of, and Im getting this sound out of CD,s no less. Vinyl can sound absolutely incredible.

They always used to say that McIntosh stopped making tube amps when they did, because they couldnt get good tubes anymore. In my listening comparisons, the new tubes, well, they are tubes, but they dont really sound the way tubes sounded when tubes were really it! I like tubes from the 1960,s!

The right tubes are some powerful magic, at least I think so.

[alexkerhead]

Like I said earlier, most newer tubes are made for guitar amps and not musical amps.
Even if they do not say so, they are relabeled guitar amp tubes 80% of the time.
I have a pair of Sovteks in on of my tube amps and they are definetely colored with crayons. Best thing todo is find NOS tubes that were designed for old tube amps, tube receivers, and console tube amps.

[moldyoldy]

Current unlimited ebay search results for el84 nos and 6bq5 nos. Note there's not a single one in Musical Instruments. Not definitive, but a pretty good indicator of who's depleting the NOS supply of this particular tube;

[Ducatista47]

I was speaking generally about tubes suitable for both home audio and instrument amp use. Your point is well taken about EL84's. I was thinking about Vox AC30's and 15's, but I suppose they are relatively scarce in North America. Perhaps less so in Europe. I sure used to see my share in 1966 on local stages.

Clark

PS In the me be dumbass category, my Mesa amp is a 100 slash 60 watt, not 50. Broke rule one, know thy amp.

[moldyoldy]

Understood. 6L6s, EL34s, and 6550s would be a different story.

[Ducatista47]

I think I'm about to have an occasion to test this theory... got a Lafayette LR800 tube receiver here, that used 7189s. We're about to order Ruby Tubes EL84MRs (basically 6P14s) for it, for a budget rebuild. Should get to test those tubes against normal EL84 and such, as for heater draw (just disconnect the B+ voltage, and test the heater current, with each of the three tubes, 7189, EL84 and 6P14)...

If I can get the tech to do this for me while he's fixing the LR800, I'll do it...

Regards,
Gordon.

It will be interesting to me too. All the sheets I have found, going back all the way to Mullard, show the EL84, 6P14P-EV and the 6P14P to have the same 6.3v, 760mA specs. The Russian sheets are also listing tolerances for heater current, plus or minus 60mA.

It will be nice to know the reality. Thank you for the information and research! You have forgotten more than I will ever know. As in "He spills more than I drink."

Clark in Peoria

[Ducatista47]

I should have mentioned for the triode only folks here that pentodes can make truly excellent triodes.

Two of the grids are taken out by wiring them to other tube elements. Usually, one already is. If a circuit is designed for this option, it can be a marriage made in heaven. My Grommes amp has rotary knobs built in for each channel, on the chassis top right next to the tubes, to accomplish the task.

Here is a link to a nice article on the simplicities and complications of the approach, with something to say about EL 84's and EL34's in particular. It is written by a local high end (but sensible) company.
http://www.decware.com/paper16.htm
I think most readers here will find his opinions and observations interesting. It was nice to see efficient speakers equated with "sensible" speakers. Horn guys are going to say "I told you so" about that and an observation about what the ultimate system would be (Steve Schell take note). I think I'm already sorry I posted this...

Clark in Peoria

[Hoerninger]

... that pentodes can make truly excellent triodes.

I would like to agree. I tried it with a Philips mono amp (2 x EL84). It sounded sweet. Max output is reduced, that was not an drawback for me.
____________
Peter

[moldyoldy]

......Let me generally recommend, highly, this tool: http://www.duncanamps.com/tdslpe/
It is free, very easy to use, and the data sheet links are fantastic.....

As of 08/09/2006, version 1.1 became available if current users want to update. Handier than a used hankie!

[Ducatista47]

Did you notice the search feature where you can insert parameters and get tube types that will build your design? So cool...
http://http://www.duncanamps.com/tdslpe/

Clark

[moldyoldy]

Yeah, but haven't needed it yet. Of course, you've entered your EL84 parameters already, any luck? Maybe some obscure but plentiful substitute?

I really don't know why we worry, 2 or 3 sets of good tubes will likely outlast most of us anyway. Seems like I remember talk of 5-10K hours if biased right, but that was over 10K days ago.