Difference in sound between a AC701k and 6072A in a ELA M251?

[rock soderstrom]

Ach so!

A Valvo EF86 to replace an EF12 ?
Ok ok, Rock.

Is the apparatus in that pic yours?
(sorry, it's a bit off Topic - AC701k vs 6072A - oops)

M

Yes, this is one of my DIY adapters for in-lab use. I have built a few, EF86 for EF12k or 6SJ7, EF804s for EF12k or even EF86 and so on. It works perfectly and makes sense in many places. Really good EF12k/EF14s, for example, are becoming rare and expensive, not only for microphone applications but also as V1 gain stages in mic preamps.

It's no secret that EF86, EF800, E80F, EF804, some similar US versions and also Soviet tubes can be very good replacements for older and rarer tubes.

Not to forget the 7pin and also the subminiature tubes, there are many interesting models that are also very well suited for adapters (especially in microphones) due to their size.

To cut a long story short, adapters can make sense and will become increasingly necessary in the future.

 

[supermatt]

Then is probably this one 5906 tube, 26.5V cousin of 5840 tube...

Here is one such adapted 5906, well guessed ! Sounds somewhat ok but gets rather hot.
Matthias

 

[rock soderstrom]

Here is one such adapted 5906, well guessed ! Sounds somewhat ok but gets rather hot.
Matthias

Thanks for posting No resistor?

 

[supermatt]

Thanks for posting No resistor?

Nope !