identifying valve 6N1 Pi-EB (an old useless rapirman cited them as 6DJ8 replacements?)

[Depanatoru]

For SRPP that gain is normal , miu is the max theoretical gain for a single triode using a current source for plate resistor and no significant load in the next stage .

 

[patrickblue]

Further researching the datasheet it looks like I failed. The ECC85 is a normal RF double triode, not a variable mu tube.

the ECC89 is a variable MU version of the ECC88. Maybe you're thinking of that,

 

[mashaffer]

it was a Broskie CCDA line amp, no, i did not hear any difference in sound , i did not measure the gain but i am pretty sure there was a drop in gain...

Hmmm... This talk of subing in 6CG7 for 6DJ8 got me to thinking (shudder) I have a Kegger style SEUL KT-88 with plate to plate FB that I built several years ago in which I used a 6CG7. I love the sound but the input sensitivity (gain) is a little on the low side. Obviously I couldn't substitute a 6DJ8 because of the low Va spec but I wonder about a 6N1P. Obviously Rp is lower and gm higher. In a normal gain stage that might not be a killer but with P-P feedback my guess is both of those numbers are important and moving in the wrong direction. I will have to see if I used a stopper. Thoughts?

 

[6A3sUMMER]

Be careful with vacuum tube data sheets . . .

The Svetlana 6N1P datasheet lists:
Gm 7,500 MicroMhos
rp 4,400 Ohms
That is incorrect.

It should read: 6N1P:
Gm 4,400 MicroMhos
rp 7,500 Ohms
Correct numbers.

if you look at the Svetlana data sheet Curves, you will see the Corrected values to be true.
And, If you have ever used the 6N1P (I have), you will know it from experience.

Therefore, the 6N1P is Not a substitute for a 6DJ8.