Elrog 300B vs Takatsuki 300B tubes

Hi Al,
It's hard for me to response (quick), because my contributions must be verifyed by an admin ;-)

ok...try this link for the datasheet:
http://www.mif.pg.gda.pl/homepages/frank/sheets/084/3/300B.pdf

And yes, the ER300B can handle more than 800V of anode voltage (not specified, but tested yet ;-))
It can handle more than 200mA too, but not at the same time ;-)
Our datasheet specified the power dissipiaton at 40W.

I have build some reference designs for using the ER300B in a perfect environment. All they working with very high anode voltage but with lower anode current.

It is very important the anode dissipiaton is not higher than 40W in any case.
As I measured, the autobias will work well using a 1kOhm cathode resistor if the tubes are very close to the design center values and close to the plate curves in the datasheet.
But tubes have deviations any time. I own a lot of WE300B. And they have differences between 53mA and 82mA at the operating point 300V/-58V...where they should have an anode current of 60mA. This is absolutely normal...and all the tubes of all other manufacturers have deviations...

The problem is not the deviation itself, the problem is the handling by the amp. Autobiasing is a nice feature...but not at the top end of the operating conditions! If this should be done, a potentiometer (for changintg the resistance of the cathode resistor or for changing the fixed bias voltage) and a ampere meter should be the minimum equipment...

The next question is how the heater voltage looks like in this amp.
If an EML 300B XLS is the right choice we have 1.5A heater current at 5V. There is no voltage regulation. A transformer a rectifier bridge and a CLC only. May be the XLS is underheated (so I hope) ore all other (right) 300B are overheated, because they draw 1.2A (some russians and chinese 1.25A)only. This would result a heater voltage above 5V...not so good for any 300B and very bad for an Elrog 300B, because the use of thoriated tungsten for filaments. Higher heater voltage will result a (much) higher anode current and a much lower lifetime...

Regards, Matthias

Hi Charles,
Why not work together with Israel? I am an open mind ;-) And I am lerning every day. Think You will have Elrog tubes working well with Franks without any changes in the amp. In the moment I'm collecting facts, numbers and values...then we will modify the tubes and all we are happy.
For me this is not a question of guilty...this is a challenge.

Regards, Matthias

Al,
Yes, that type of selection/testing for suitable tubes for the VAC is what Elrog will do for certain amplifiers to match the operation points. This to ensure a successful 300b and amp match. This is a smart move. Al your system must sound really special with your recent changes. I only hear/read good comments about Herron components.Thanks for providing that thread, I miss Raquel's postings.
Charles,

Matthia,
I do appreciate your good attitude and knowledge. I can't wait to get these new modified Elrogs, what a sound you all have developed. Thanks.
Charles,

Thanks, Charles. I'm still fairly early in the process of "dialing in" the DEQX, which is a somewhat complex and lengthy one especially given that I've chosen to do it all myself without utilizing the optional service they offer of assisting remotely via Skype. But it's proving to be educational and fun, and even without its speaker and room correction features it's already providing significant sonic benefits just as a preamp and DAC upgrade.

Matthias, thanks for providing the link to the WE datasheet, which as you had indicated does state 400V, 36W, and 100 ma as maximum ratings, with the words "design center values" added.

So it seems that between issuance in 1939 of the datasheet I have, and issuance of the one you linked to in 1950, WE made their specs more conservative, for whatever reason.

And thanks also for the rest of your post, all of which sounds right to me.

Best regards,
-- Al