RCA BA6 and AM864 frontend/

[b2]

Hi ,

For some days ,I've take a look at the front end of this 2 limiters.Both used 6SK7 pentode.

I've experiment this front end in a AM864 type limiter,it works fine and  I like the sound of th is limiter  12SK7+6SN7+ edcor in/out.

BUT If we want to get a nice front end with this topology both tubes must be closed,matched.

I've noticed 2 things in the RCABA6 which might be interesting to fix in the AM864.

The pots bal a and bal b.

With" bal a" we can adjust the voltage on both cathode and "bal b" adjust the voltage  on one tube G2 grid to get the same as the other grid G2.

So I was wondering if anyone knows the value of this 2 pots  "bal a","bal b" :, AND I've noticed the value of 56K for cathode resistor in RCA BA6....just want to know if it's a correct value seem a bit high?? :

I want to put a 1OOR pot as "bal a" directly on both cathode  with no resistor.

If I remember well the voltage on G2 on both tube in my AM864 was around 11,5V,12V.So,I was wondering just if I can  put a 10K pot to act as a voltage divider on the G2 grid of one tube and so I can balance nicely the voltage grid G2..... ;D

Needs more info about this "bal a "and "bal b"... ;D

Here's the RCA BA6 schematic.

Best regards,bruno.

 

[schlamn]

Hi,
Value of Bal A is 100R and Bal B is 10K..

I have R3 and R4 as 16R not 56K ! This I think has been discussed before as a mistake in that schem.

Here is another schem for you with no mistakes (that I am aware of)

http://i641.photobucket.com/albums/uu138/Schlamn/BA6Abig.jpg

Hope that helps...

 

[b2]

Hi,
Value of Bal A is 100R and Bal B is 10K..

I have R3 and R4 as 16R not 56K ! This I think has been discussed before as a mistake in that schem.

Here is another schem for you with no mistakes (that I am aware of)

http://i641.photobucket.com/albums/uu138/Schlamn/BA6Abig.jpg

Hope that helps...

Hi,

Thank's for the infos and schematic ,the value are what I was thinking :

Regards,Bruno.

 

[diyfanatic]

it mean you're not selling it anymore?
it could have been nice to let me know since I've made an offer to you...not serious...
anyway, the good thing is I decided to make my own!

Cheers.
Jr.

 

[b2]

it mean you're not selling it anymore?
it could have been nice to let me know since I've made an offer to you...not serious...
anyway, the good thing is I decided to make my own!

Cheers.
Jr.

Hi,

Sorry for the delay BUT I forgived to mail to you  : : :that's I've sell it to the first  who has mail to me  at time .I've wrote this topics cause  There's some upgrade mods to do in the AM864 ,as release time ,and  front end, as I explained...



Best regards,Bruno.