Output stage CFP to EF on LJM amp?

[ljm_ljm]

Thank you for all the replies!

I have taken one first step on this slippery road, and will probably end up in the ditch

I modified the schematic to better mimic the L12-2 with double outputs better, and some resistor values for current sources etc.
I changed the existing compensation cap values to 0, and then tried a cap over the feedback resistor (which I also changed for lower gain). Suitable cap value seems to be around 5p. This gives better OLBW , and as far as I can understand it stays within the recommended margins? -So in theory it seems to do the trick.

How about in practice?
I have seen some advice against this, so what do you say about it, if RC and LC is used on the output?

The transistor models in the simulation are not correct, so I need to find replacements to simulate this correctly, or just try it on the boards..

Sorry about the bad screenshots..

CFP structure of l12-2. Change to ef. There is no problem.
It's just that you need a d669 transistor. Installed with output power tube.
No problem. It's simple.

 

[Rallyfinnen]

Yes, like this: Output stage CFP to EF on LJM amp?

I also had to modify the VBE multiplier to get stable bias with temperature (I did it by adding and tuning a resistor on the emitter), or Iq would be really high at start up, and then go down a lot with temperature. However, the PCB's are now too bad to use because of all the cutting and jumper etc.. This is why I emailed you about an EF amp to modify instead. I have ordered a L20V10 to make some experiments with.