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Input Transformer Question (Bellari MP110)
Old 2nd March 2012
Gear interested

Thread Starter
Input Transformer Question (Bellari MP110)

Hey all,

I've been working on modding a Bellari MP110 to try to start learning more about how gear works, how to tweak it, etc. I have replaced the opamps as well as the pots but I wanted to change the input transformer until I noticed something. The two input wires for the transformer were removed, and soldered over and only the four output wires were actually soldered to the PCB. I bought a Jensen 115K-E to replace it, but I'm not sure how to go about wiring it as the reduction from 6 wires to 4 is confusing. The PCB is labeled colors Black Red Yellow White, which are all coming from what appears to be the output of the xformer. On the Jensen, however, the four output colors are Black, ORANGE, Yellow, White, with the Red wire coming out of the input side along with a brown wire (soldered shut on the stock xformer). If the input stage is wired shut then how is the transformer actually doing anything? Is the red wire from the input side meant to be soldered to the PCB and not the orange wire? If I do cut and seal the input wires, would I join them together, or separate their conductivity?

Hopefully someone can answer this. I've done a lot of electrical studies from a theoretical standpoint but I haven't done much hands on practical work if at all. I'm not stupid I just need a bit of guidance if someone can help. Thanks!
Old 2nd March 2012
Gear interested

Thread Starter
Shameless bump, really stumped
Old 2nd March 2012
Lives for gear
Vintageidiot's Avatar
Find out what make the original input transformer is and contact the company that makes it to find out which wires were removed. Either that or get ahold of the schematic for the Bellari and have a tech ascertain where the 115e will wire into the topology correctly. Jensen should be able to guide you if you supply the schematic.
Old 2nd March 2012
Gear interested

Thread Starter
I can't find a schematic online for it anywhere. What if I took a picture of the PCB? There isn't even a manufacturer name on the xformer or anything it's just blank.
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