Big Thumbs Up For EH 6CA7s

[vanhalen5150]

Lets hear it.

[Tone Slinger]

+1

[ValveStorm]

What is the PC number on the EH 6CA7s that you like? I find they are all pretty good... but I seem to like the 40-45 range more than the 30-39 range.

[vanhalen5150]

What is the PC number on the EH 6CA7s that you like? I find they are all pretty good... but I seem to like the 40-45 range more than the 30-39 range.

Whats a PC number? Mine are labled "50" from the Tubestore. Just a matching number?

[OnTheFritz]

Have to try these, didn't care for the JJ's at all. At least these *look* similar in construction to the originals.

[vh junkie]

Yeah, big thumbs down for the JJ 6CA7s...

Usually, there are two numbers written on stickers on the tube bases and/or boxes... I was talking about the larger number(26 -50 range, PC or Plate Current?).

From another site:
"That's a "plate current" rating at a standardized test voltage of 400 volts... Basically it's telling you that the tube will reach its full bandwidth response at xxmA(PC) at 400v (idle current or bias current). If your actual voltage is higher, then the mA requirement for full bandwidth response will be proportionally lower. "

The other number(3.0 - 4.6 range) is the transconductance(gm)... I am not an expert, but depending on the tube type, I think the smaller PC means earlier breakup, the larger, later breakup?

[Tone Slinger]

my quad came labeled 36.2 36.3 36.4 36.8 Lord Valve/NBS Electronics

Tubes that are used in amps that are either cranking and or attenuated (attenuator) will obviously render more differences in tone. Practice and/or 'reasonable' gig volumes arent gonna render as much difference. In those scenarios (average gig volume..... pretty low) an el-34 tube is gonna be a better choice, that is, for crunchy brown rock tones.

[rgorke]

So, I'm gonna go out on a limb but I don't necessarily buy this whole "matched" tube stuff. Back in the day, a tube blew, they grabbed one from the box or whatever and threw it in. This way, you have a bit of tension between some tubes working hard and others kinda cruising. This, IMO, adds an intangible to tone. Not sure it is something one can measure but I have tubes that are within 10 ma but not "matched" and haven't had any problems in three years and getting, again, IMO, pretty good tone.

[fivecoyote]

I always wondered about that matched thing too. Back in the day, the guys playing this stuff knew next to nothing about it all. Some still don't! They just know what they like, and tweak whatever they're playing to get there....