Pilot AA903 info needed

[Ziradog]

Does anyone have a SAMS for this unit, the EL-84 version? I'm trying to find out if the output transformer is the same as my Pilot 240. Thanks.

 

[radioactive]

Heres the schematic.
https://elektrotanya.com/pilot_aa-903b_power_amplifier_sch.pdf/download.html

 

[radioactive]

Looking at the schematic the output transformer number is 56-51.

 

[Ziradog]

Thanks

 

[Ziradog]

I wonder what the difference between 55-60 and 55-61 is?

 

[gadget73]

Its one better?

If you look at the feedback stuff that might be a clue. If the resistors and phase cap are the same, and if its got an HF limiting cap somewhere in there that is the same value, chances are pretty good that the transformers will perform close enough to be a sub.

 

[Ziradog]

I'm not smart/educated enough to figure that out.

 

[gadget73]

Hm, looking at it they may perform similarly enough to work, but the 240 is cathode bias and the 903 is fixed. Possible the primary impedance is not the same. Feedback stuff is the same value and I don't see any HF networks in there. It might work well enough.

 

[Ziradog]

"...It might work well enough".

Sounds like my epitaph.

For now I think I will keep looking,