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I don't know if any of you guys have tried these yet, but I just got a quad.
I tried them in a 1971 DR103 immediately after playing the amp with a set of JJ E34L's.

Initially the amp is louder with more bass. I only had a few minutes to try them, but I will post more impressions later.

They appear to be a rugged tube. pictured next to a Mullard XF2.

Dr.HIWATT wrote: Initially the amp is louder with more bass. I only had a few minutes to try them, but I will post more impressions later.

Looking forward to your observations. Beat the heck outta those, if you can, please. Need to know how reliable they are as well as how they sound.

Dave

I'll need to have the house to myself for that!

Little Deuce may get blown out of his swing.

I have a set of NOS Sylvania 6CA7s that sound KILLER in a DR103. It'd be cool if the JJs were built similar to the originals.

The 6CA7 was a large and rugged US EL34 clone, using beam plates to get around Mullard's screen grid patent. Other notable beam power tubes include the 6L6 and KT77. The beam tetrode is more efficient than a true pentode, because you don't have to supply the screen current of a pentode like the EL34 (about 10% of the plate current).

--mark

mhuss wrote:I have a set of NOS Sylvania 6CA7s that sound KILLER in a DR103.

One of the "secrets" to one of EVH's sought after sounds (in "M" amps, of course).

mhuss wrote: It'd be cool if the JJs were built similar to the originals.

It certainly would be!

Dave

I'd like some 'feedback' about these too

Hmmm,I wonder if the DR half-power switch would work with beam tubes, since it works by limiting screen current.

--mark

Mark, I think you are wrong. Beam tetrodes have the same screen grid (second grid) as pentodes, the difference is between third grid, pentodes have true grid, while beam tetrodes have beam forming plate instead of true grid.

From radiotron handbook:

The beam power feature replaces the suppressor grid, so while the tube functions similar to a pentode, it remains a tetrode. The suppressor grid functions at ground potential, so it shouldn't affect the operation of a half-power switch.

As such, a 6CA7 is functionally comparable to an EL34, but isn't a clone either in construction or sound.

Popular beam power tubes for guitar amps include 6L6, 6CA7, 6550, and the entire kinkless tetrode (KT) series (KT66, KT77, and KT88).

riba2233 wrote:Mark, I think you are wrong.

Darn. There is a first time for everything.

You are both correct, of course. The suppressor grid is the replaced, patented feature. However, the beam tetrodes are still slightly more efficient than pentodes, all other things being equal.

That will teach me to post after beers.

--mark

mhuss wrote:
That will teach me to post after beers.

--mark

Mark !......Your fired !!! Hi ! Hi !

I have beat on them a bit more this week.
no redplating or break downs.

They certainly have a strong bass to them. I would describe them as "BOLD".

I would think them excellent for bass use.

I will update again after more beatings!

Dr.HIWATT wrote: I will update again after more beatings!

Maybe I can help you with that on Sunday?

Dave

OldSchoolDave wrote:

Dr.HIWATT wrote: I will update again after more beatings!

Maybe I can help you with that on Sunday?

Dave

Of Course!

My humble observations after a brief test drive of the JJ 6CA7's:

Dr.Hiwatt used the term "bold". I'd say "forward", "up-front", perhaps even "in your face" to describe the mid-range punch of these tubes. Not harsh, but very aggressive.

I'm sure these tubes will gain some fans. My particular tastes yesterday preferred EL34's "warmth" instead.

Dave