METRO LOOP PROBLEM WITH JTM45, NEED HELP!

[bwgintegra]

JTM45 style build with Marstran transformers. I am getting about 450 vdc B+ node and about 380 vdc on the other end of the 8.2k CC 2 watt resister or at the phase inverter supply. I tried using both to supply about 300 vdc to the loop with the 2 watt metal oxide resistor and was able to achieve this. My problem is when I switch the loop on the volume is much lower than the loop bypass volume. I have tried to adjust the trim pot on the loop and it makes no differance. I have jumped the loop with just a cable and also tried using a delay pedal and get the same results. With the delay pedal in the loop I can hear the delay pedal functioning properly but my volume is way lower than bypass just like with the loop jumped with cable. Any thoughts or opinions would be great because I have ran out of ideas. Also, I bought the loop used and have contacted the seller and he said it worked perfect when he removed the loop.

Thanks, Brett

[neikeel]

If the trim pot is ineffective and a jumper does not work you have to suspect a wiring problem first and defect with the second hand loop next.

I suggest a couple of clear photographs of the loop and its connections on this thread and then shoot SDM an email or a pm for his opinion.

Good luck!

[bwgintegra]

below is a picture of the loop. This is a master volume type of JTM45. I removed the jumper from the middle of the treble and at the outside lug of the master. That's where the two shielded cables come from. Like I said in my original post the amp worked fine before installed and when the switch is in bypass is works fine. When I turn loop on with switch I just get a little bit of sound, not even close to bypass volume. The internal trim on the loop board does nothing for the volume issue in trying to match bypass and loop on.

[neikeel]

Definitely sounds like a pm to SDM in order, he is pretty busy but I know he monitors the loop section in this section.

[bwgintegra]

Definitely sounds like a pm to SDM in order, he is pretty busy but I know he monitors the loop section in this section.

Today Steve and I have shared a few emails and is helping me out.

Thanks