El84 substitute a 6973?

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radioeng2
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El84 substitute a 6973?

Post by radioeng2 » Thu Mar 12, 2015 7:23 pm

Supposedly, RCA did the 6973 kind of late in the game. (Rather than pay royalties, often RCA made a ripoff version of stuff, just enough different to avoid royalties, though not always legal issues.) A maybe slightly higher power version of the 6BQ5/EL84 capable of a tad higher plate voltage. Did that get your attention?

Here's a comment from an old Bob eBay ad....

"Q: hi bob this amp is incredible WOW! awesome keep upping the ante. I was wondering if you could make me an amp using 6973 tubes ..these tubes are very sweet .mostly find in old juke boxes .But im interested in more power as these only produce 12watts a piece .Looking to get monon blocks with these tubes but 50 - 100 watts a side .Your design seems to work can we do this with the 6973 tubes ..they are very impressive tubes and deserve to be used thank you bill.Ps its been noted that these tubes out perform the el 84 May-11-11

A: Hi '839, I guess I have been "upping the ante" so to speak. Oh well, I'll say it again - Bob's my name, and amps are my game. I can't help it! But honestly, I cannot think of ANY way to up the ante again after this almost unimaginable effort! 6973 tubes represent the last and the zenith of tube development in sensitivity and power response. They are remarkable tubes, and if you have some, they deserve to be used in a lovingly built amp. I don't have the time to build one for you, as fun a project it would be, but you are welcome to use my circuit and build one yourself. It would really work and sound wonderful. A ctually it would sound awesome! Happy building! Bob Carver
"


Soooooo...anybody here ever run across this tube or try it? Might be interesting in the CF amp/Baby Black Beauty.

Here's links to data sheets...Look them over before substituting! I haven't compared them closely!


http://www.tubebooks.org/tubedata/HB-3/ ... 2/6973.PDF

http://tdsl.duncanamps.com/dcigna/tubes ... l-458h.gif

Mark
I was there "At the Fest!" Hope you were too!

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MRHP
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Re: El84 substitute a 6973?

Post by MRHP » Sat Mar 14, 2015 10:58 pm

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radioeng2
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Re: El84 substitute a 6973?

Post by radioeng2 » Sun Mar 15, 2015 10:23 am

Looking deeper into the 6973. It is certainly similar but NOT a direct sub for the EL84/6BQ5!

RCA put it out late 50's or so. It went into a lot of jukeboxes. Has been used in a few well liked guitar amps. Ampex made an amp with it that some thought was REALLY good sounding. It was some of that I'd ran across that caught my attention. Along with the comment from Bob. The little more robust output power I knew would be a cool thought for some.

But it has a different pin out and you'd have to bias it a little different...and maybe other changes like desire for more drive voltage. If you were building a CF amp again, it might be a thought. It certainly would sound different by all reports I can find.

The tube was made again by EH more lately but demand outruns availability it seems and keeps the price a bit high. Even Parts Express had it listed for about $23 each, though now out of stock. The old stock around is from RCA which pushed the tube to the market pretty hard trying to have an exclusive and break away from the EL84/6BQ5.


Image

Oh...it gained some attention some time ago among guitarist in part because Jimmy Page used an amp with it for some of the early Zep albums.

Mark
I was there "At the Fest!" Hope you were too!

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