Wiring the OPT to Tubelab SPP

[Duke58]

There is a wiring diagram to wire a Tubelab SPP in UL configuration, but I can't find one for wiring in triode mode.

I'm wiring Edcor CXPP25-8K OPTs with 4, 8, and 16 ohm taps on the secondary side of the transformer.

Use with jumpers in FB positions, all other wires like UL configuration?

 

[OldHector]

Since the goal is just to link the screen to the anode, and the principle is the same as for the SSE, and both boards share the same connectivity, then the wiring diagrams for the SSE should be a good starting point ...

SSE Wiring diagrams

 

[Kay Pirinha]

The most usual way is to simply tie the screen resistors' right ends to the related plate. I.e. connect the right end of the upper 100R 2W to L-PRI_1-2 and the lower one to L-PRI_2-1, resp.
Good luck and best regards!

 

[Duke58]

Thank you for your replies!

Another question- do jumpers need to be installed if feedback is not being used- in other words, no capacitors installed in the C101 and C201 positions on the PCB?

 

[Duke58]

To clarify- there are no caps installed in the C101 and C201 holes on the PCB. So, I shouldn't need jumpers L_FB and R_FB?

 

[Duke58]

I went ahead and wired the SPP board per Kay Pirinha's advice, with and without the feedback jumpers.

With the jumpers I got oscillation. I then used 50k Ohm resistors as jumpers and no oscillation.

 

[Kay Pirinha]

Swap L-PRI_1-2 and L-PRI-2-1 terminals.
Best regards!