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Which current 6CA7s have beam forming?

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Doug Elick
Posted on Friday, September 03, 2004 - 12:28 am:   

Of the following current production 6CA7 tubes, which have the beam former?

Groove Tubes (pretty sure this one does, but is too expensive)
Electro-Harmonix
Sovtek
J.J./Tesla
Sovtek

My HD-130 has Jolida 6CA7s that are on the verge of being microphonic. Am looking for *affordable* tubes that sound good and'll hold up. Which has the most "sparkle" to it's sound?

I'm assuming that all of the above brands can handle the 700 volt plate voltage the M.M. uses.

Doug
Doug Elick
Posted on Friday, September 03, 2004 - 12:30 am:   

....Or are there EL34's I should consider as well?

Doug
michael kaus
Posted on Friday, September 03, 2004 - 07:42 am:   

Of the above tubes mentioned(actually, the true 6ca7's are not being made), the JJ E34L's are my choice. I use them in my MM and they hold up to by abuse pretty well. You have to be carefull not to bias them too hot as these amps had a habit of goi ng into meltdown even back in the 70's when GOOD tubes were made. I bias mine at around 21mA of idle current and they sound good and last. I started with 15mA and worked my way up to the minimum they they got balsy and still last a long time. This is a long way from the calculated holy grail of 70% disipation on the tube but they last and sound great. Sovtek= junk. Grove tubes are just graded and relabled junk. EH supposedly is making a good tube again but they have no track record yet. Give them a few years. MIke.
Steve Kennedy
Posted on Saturday, September 04, 2004 - 01:47 am:   

Actually, Groove Tubes now manufactures the GE 6CA7 in the U.S. on the old G.E. machinery using the G.E. formula for the cathode coating and vaccuum.

They are spendy, but not as much as NOS GE or Sylvania 6CA7s and they are a true 6CA7. The Electro-Harmonix 6CA7EH is also more 6CA7 then EL34. This tube looks like a knock-off of a Sylvania 6CA7 and the construction looks VERY similar so I would consider this tube a real 6CA7 also.

In addition, I bought a pair of Orion-branded 6CA7 tubes that also look like a Sylvania knock-off as far as plate, getter and spacer construction goes.

I just haven't had to change tubes in recent history so I can't say how well they work as compared to the original tubes or current EL34 types.

Steve

Steve Kennedy
Posted on Saturday, September 04, 2004 - 01:50 am:   

There is a post right here in this topic about the beam-forming GE 6CA7 with photos:

6CA7 Link

Steve

Doug Elick
Posted on Saturday, September 04, 2004 - 03:25 pm:   

GT 6CA7s would be my first choice except that I'm generally cash free right now. The EHs seem to be the most attractive tube for the buck in the 6CA7 form factor and I'm leaning towards them, but posts about good EL34's being more "chimey" or "glassy" (a plus to this humbucker fan) as well as breaking up a little nicer/easier are preventing me from ordering a matched quad (of 6CA7s) right now. God knows it would be nice enjoy tube distortion just below paint peeling, window shattering, neighbor killing levels instead of right at them.

What would go suggest as a good, affordable set of EH34s?

I just don't have the bucks to "roll tubes" so this purchase has to be a wise one.

Either way, any quality replacement for the microphonic Jolidas (People's Republic of China) that are in the amp right now is going to be a big improvement. In that respect, I can't go wrong.

Doug
Steve Kennedy
Posted on Saturday, September 04, 2004 - 04:24 pm:   

I agree with Mike, it is hard to go wrong with the JJ EL34L. They may not be the cheapest, but they are probably the best sounding of the current crop.

Steve
Rob
Posted on Sunday, March 06, 2005 - 02:21 pm:   

GT 6ca7's are starting to come down a little ...I've found them for 30 a peice which is better than 40
Mike Algozino (mike_a)
Username: mike_a

Registered: 10-2012
Posted on Monday, October 29, 2012 - 08:29 pm:   

What would be the best replacement power tube for the HD 130 head used exclusively for BASS.}
Lars Verholt (lmv)
Username: lmv

Registered: 11-2009
Posted on Monday, October 29, 2012 - 08:44 pm:   

Winged C, imho.

-Lars Verholt
Mike Kaus (mm210)
Username: mm210

Registered: 05-2006
Posted on Tuesday, October 30, 2012 - 01:53 pm:   

Winged C tubes are good-just high as hell right now. Kind of curious about the new crop of JJ actual 6CA7's that they are making. Wish somebody would try THOSE! Mike.