JLM Transformer mods for GAP 73, CL 7602 Mk1 and Mk2

[Joe Malone]

GAP 73 and CL7602 Mk1 COMING SOON

These 3 products use the same Chinese input and output transformers.

Step by step mod info ond photo's showing how to change input transformer to OEP/VTX type and output transformer to JLM111DC to give these pres some real fat Neve like Mojo.

If you order the OEP/VTX input transformer and JLM111DC output transformer from us mention in the comments box at checkout “CL7602 mod” and we will add in the 10 x 22uF 16v tant caps for free to the order.
Order transformers here

Overview of changes for CL7602 Mk2.
(Mk1 is the same except mic input transformer mounted on centre metal support panel with direct wiring no pcb and output transformer mounted on left hand side)


Find Mic Input transformer PCB


Remove Mic Input transformer PCB and remove transformer from it.
Replace with OEP/VTX with primary on same side a original transformer.


Cut 3 tracks as shown in red and fit 4 jumper wires shown in yellow.
Refit Mic input transformer PCB and retest CL7602 is working.


Remove card and change 22uF 35v caps to 22uF 25v tant caps.
(The very latest Mk2 versions should have tants already on this PCB)
Refit Preamp & eq amps PCB and retest CL7602 is working.


Remove card and change 10uF 63v and 22uF 35v caps to 22uF 25v tants.
(The very latest Mk2 versions should have tants already on this PCB)
Drill hole in bottom of case under trim pot to allow adjustment when card is refitted.
Refit Output amp & Preamp PCB and retest CL7602 is working.


Find output transformer


Mark wires going to output transformer as shown and remove original transformer.
Fit JLM111DC transformer and reconnect wires to number shown.
(cap and resistor on original transformer not needed for JLM111DC)
Power up and retest CL7602 is working.
Connect meter across JLM111DC +/-1 terminals and adjust trim pot for 1.5v. Enjoy

[ciscoheat]

sorry, I did not understand how to connect the wires to the output transformer, thank you!

[Joe Malone]

sorry, I did not understand how to connect the wires to the output transformer, thank you!

The numbers shown on the above photo are the numbers on the JLM111DC transformer that the wire needs to be moved too so the old transformer can be removed. So best to add paper tape on the wires to write the numbers on all wires and remove the old transformer. Then wire the wires to the new JLM111DC transformer.

[chrisp]

give these pres some real fat Neve like Mojo

... or you might instead just build yourself some BA's for fat AND silky

[Joe Malone]

give these pres some real fat Neve like Mojo

... or you might instead just build yourself some BA's for fat AND silky

So true . Just trying to save this gear from being used as door stops or dust collecting rack filler.