Opinions on EH6CA7's

How do they sound? They would be going in a VHT EL34 combo.
Also, anyone using Ruby EL34BSTR. Whatchya think of those?

Those tubes f'n rock!! They give a more "beefy" sound than regular EL-34's. With these tubes, you will not have to set the bass control on your amp so high. They are very reliable, and sound great when you achieve power tube saturation. Get yourself some!!

not used the EH6CA7,but i do run the Ruby EL34BSTR in my 2 channel dual and i love them.
there shuguang tubes rebranded rubys by the way.imo crunchy,in a good way.

I do wonder if it won't be any problems since the EH6CA7 is tetrode? Was thinking about ordering it for a Road king. I hope it will work just as a EL34, regarding the ability to switch between triode and pentode operation?
Anybody chime in before I order them? I heard some clips, and I dig the tone of those EH 6CA7's!

I have used EH6CA7s in my Carvin Vai Legacy for years and absolutely love the tone they give that amp. I've tried bouncing between different EL34s (Svetlana, JJ, TUng Sol) and nothing sounds as good as the EHs to me. I've seen others with the same amp who have also switched to the EHs, so I would have to guess it's not just my ears for that particular amp. To me, they sound like an EL34 on steroids with a fuller, rounder bottom end. I have yet to try the JJ 6CA7s, and I doubt I will in that particular amp. I tried them briefly in my Dyne, but preferred the tone from Tung Sol EL34s. Depending on what you are looking for in tone, and the nature of the amp you are using them in, you can't go wrong with EH 6CA7s in my book.

I came across this a bit late.
I have been looking into the 6CA7's as alternates to the 6L6GC...

The EH6CA7 is a triode tube, however, the JJ6CA7 is a pentode.

When I got my Mark III it came with the Mesa 6L6GC and large bottle EL34 tubes . Since the mark III was biased to run an integrated quad I stayed with the EL34 combination. The large bottle EL34 which were probably 6CA7's were no longer available when I wanted to replace them back in 1990. The skinny EL34's just did not sound the same so I decided to run with all 6L6GC. Seeing that the large bottle EL34 substitute is back I may give them a try.

The EH 6CA7 is actualy a tetrode.
Since there's no mention of g3 on the MkV schematic the JJ 6CA7 will probably be used as a tetrode in the MkV (pin 1 and 8 hardwired in the amp).

crane said:

The EH 6CA7 is actualy a tetrode.
Since there's no mention of g3 on the MkV schematic the JJ 6CA7 will probably be used as a tetrode in the MkV (pin 1 and 8 hardwired in the amp).

Click to expand...

Hmm, no connection to pin 1 in the Mark V? Had the amp open many times and never looked. Could always connect it with a jumper wire since it is not used with 6L6, perhaps it would either perform well or not. What does the Pentode switch do in Channel 3 ?

In triode mode it connect g2 to the anode (via a 470/1k ohm R)

:?:
So all in all, I can use a 6CA7 in my Road King with the Pentode/Triode switch ?

If your RoadKing can handle EL34, no problem at all.

Not to hijack this thread.. What harm will it do to an Amp that runs only on one type power tubes (6L6/EL34?) and does not have a bias pot or switch, if I put different tube? let's say 6v6, KT66,KT77 etc..

I bought a used line 6 spider valve (6L6) :mrgreen: & I've been tempted to put EH6CA7 on it.

It will probably work but don't expect them to last long. The voltage and current will be off. 6L6 and EL34 are almost compatible but not quite. Say your amp only runs EL34, suitable replacement tubes would be 6CA7 or KT77 (if they have available space to fit). Check out Eurotubes, they have some good resources for some makes of amps and suitable power tube options.
Direct replacement for 6L6: 5881, 7581, not sure about others...
Some amps have a low voltage option (may be called tweed or variac) and you may be able to burn up a set of 6V6 in place of 6L6. However, what happens when the tube fails will let you know if it was a good idea or a bad one. There is something called a yellow jacket that allows you to install tubes not designed for your particular socket. Not sure if there is any bias resistors or voltage reduction circuits built in.

Worse thing that will happen, say goodbye to your output transformer, bias components and filter caps. All depends on what it is you are going to swap in. You may wind up pulling more current than the power supply is designed to handle.

Fixed bias amp, I would stay within recommendations made in the documentation of the amp.