12bh7 in place of ecc82

[ginetto61]

Hey Gino, I found a nice kit for you: check out the Aikido Cathode Follower.
You can choose the tube you want, too...

Thank you very much indeed !
It is in line with what I am looking for.
In the meantime I have found another brand that uses the 12bh7, VTL

ST-150 Data Specification

And yes ... I thought about the ecc88 as well.
Anyway very interesting kit. Very.

Kind regards,
gino

 

[popilin]

My take on 'tube rolling' is that if a circuit designed for ECC82/12AU7 gives genuinely better performance with a 12BH7 then either the circuit was poorly designed or the ECC82 happened to be a poor choice for that particular application. 'Everybody knows' that the ECC82 is a poor choice for any audio application, yet I found that in a quick lashup test circuit an RCA 12AU7 gave the lowest distortion; 6CG7 etc. were worse.

Strongly Agree !

Not only that, in certain topologies like SRPP, you can use VERY high voltages due to the ECC82 Vkf, and get ridiculously low THD figures.

And the advantages of the ECC82 does not end there, interelectrode capacitances are the lowest in its category.

http://frank.pocnet.net/sheets/010/e/ECC82.pdf

http://frank.pocnet.net/sheets/093/1/12BH7A.pdf

http://frank.pocnet.net/sheets/093/6/6SN7GTB.pdf

Not to mention its low noise...

The ECC82 has always been the Cinderella between valves, and that's unfair, not only that their sound is excellent, there are also fewer differences between brands.
I myself have used brands like RSD (former East Germany) with amazing results.

 

[nigel pearson]

I know you guys don't like this . Did you ever try MJE 340 and 350 as current sinks or sources ? They are superb . I had some in my useful box . As CCS I use an LED reference , not because everyone says they are best for CMRR . No , because they resemble better how a LM317 looks on the analyses as a sink . If it is Early effect or not I can not say . To me to use an LM 317 is too much . I used a pentode screen supply as a totem pole . That is input pentode g2 supply upper arm as CCS bias and lower arm to next stage CCSink . 1 mA bias current . The sink to an EL 34 . Keeps everything clean and simple . Not to use a transistor as a current amp seems odd . 6 MHz is fine as this isn't a class AB transistor amp , even then it is fine .

A triode with CCS works great . I would suggest cathode verses collector fed seems on paper better a collector ( CCS verses SRPP ) .