Revox G36 Mod for preamp

[Jefra]

Hello,
I just tried to modify my old Revox G36 so as I could use it as a simple preamplier. But the result is not very good, so I would need some help.

I add a 4PDT switch to rout the signal from the second ecc81 to the last stage of the preamp. I took the signal at the VU meter point, and bypassed the recording cirsuit. It works, but there is a lot of distorsion.

So, what is the mistake ? Should I only use the 2 stages of the first tube ?
Here is the mod I did, thanks for your help :

[revintage]

Hi Jeffra,

There is no possibility to make the G36 work as a simple preamp.

Secondly, why on earth? G36 are highly priced, sell it and you can buy an advanced preamp.

[Steerpike]

You are probably upsetting the grid bias of V11 & V9.
Try capacitor coupling to that grid.

[Jefra]

Thanks, I will try.
Here is the link to the schem with the mod (the last one doesn't work on my computer...) :
Imageshack - g36mod.jpg