Swapping ECC 83 s for 12 AX7

[tannoy man]

Hi, I want to know is it ok to swap the pair of ECC 83s in my Croft Micro Basic for NOS Mullard or Telefunken 12AX7. The other tube is I think a Jan, GE ? 5965
my Croft is the lower output version and I dont want a rise in gain.

[Ali Tait]

Yes it's fine. It's an equivalent.

[tannoy man]

thanks

[worrasf]

Hi, I want to know is it ok to swap the pair of ECC 83s in my Croft Micro Basic for NOS Mullard or Telefunken 12AX7. The other tube is I think a Jan, GE ? 5965
my Croft is the lower output version and I dont want a rise in gain.

Hi Paul - yes absolutely no problem. 12AX7 and ECC83 are synonymous and can be interchanged with no issues. the 5965 is a low gain version of the ECC81/12AT7 and again can be interchanged. The JAN GE 5965 is a military spec tube (Joint Army Navy). It is the presence of this tube that is reducing the gain you desire. They are very quiet and good tubes.

Regarding the ECC83/12AX7 you will be aware that the Mullards and Telefunkens have very different sounds and it's all down to taste. Lots of good info here: http://www.jacmusic.com/nos/ECC83.htm

For what it's worth I have spent much time and dollar tube swapping in my Croft 25R having tried TESLA (NOS not re-issue),Mullards, Telefunkens, Brimar, Phillips Miniwatt, JAN GE etc etc and I have settled on a pair of NOS (1960's) RCA 12AX7A's (the A is important here) and where you have the 5965 I have a Brimar 6060 Yellow T (1950's). Now the Brimar is higher gain so you probably dont want to go down that road but it is sublime :cool:

Steve

[camtwister]

I understand (but I'm prepared to be corrected) that the ECC83s sit in the phono stage of your Micro 25.
Because of this, try to source replacements for the JJ Tesla in situ that exhibit low microphonics.
I have a pair of Mullard yellow print valves for sale that are from the Blackburn factory with 1964 date codes. They are used, however, not NOS. I've rolled my Micro 25 with these and several other brands.
They finished in second place in my list of favoured tubes.
You're welcome to send a PM if you'd like to discuss them.

[tannoy man]

Thanks guys, great answers, I'm having a think.
Steve I've got NOS Siemens EL34's and the smaller Tubes are Mullards in my Radford and it sounds fantastic.
Johnny I'm a Cardiff boy and would love to hear your system, hint, and you could give an opinion on mine.

[Mike]

You could also try 5751 too, slightly lower gain than ECC83/12AX7 though.... About 70%ish

[worrasf]

I understand (but I'm prepared to be corrected) that the ECC83s sit in the phono stage of your Micro 25.


Correct - in the attached photie the phono stage valves (RCA 12AX7A) are the 2 on the left.

Steve

[tannoy man]

Their certainly cheaper. too many options, my head is going to explode, I NEED A BEER:scratch::scratch:

[worrasf]

my head is going to explode, I NEED A BEER:scratch::scratch:

If you think it's bad now just wait "till you actually start tube rolling - I hope you don't have OCD :lolsign:

Steve

[tannoy man]

I'm on a financial Tightrope, when I make a choice it has to be the right one and as long as the system is singing, HAPPY DAYS