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I was hoping someone could give me a hand troubleshooting my VRM install. Prior to install the amp had no noise, hiss, numbers were all in range. After I installed the VRM and fired it up with the switched pot at full volume everything is normal. numbers all in same ranges as before. when I turned the switched pot even a quarter of a turn lower, I got a horrible noise coming out of my speaker cab. it did not matter if there was a guitar plugged in or not. I was scared to leave the pot at that setting to take readings. I followed the recommendations of rectifier>standby>VRM>Filter cap as far as order. I grounded the VRM board by itself. Since this problem shows itself when the imputs are not even in use, I would not think it would be associated with the input layout? I am attaching a few pictures, I would appreciate any advice, or troubleshooting steps for this. I love the amp, sounds great, I wanted to control the volume levels as to not disturb the family all the time so I would love to resolve this otherwise I fear I could damage the amp. [img][img][/img][/img]

Layout sounds OK. Board looks OK too. I would have suspected the control wiring but I see its twisted & bundled. Try routing the wires away from the PT. Also turn the volume down and see if the voltage changes.

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Stephen I got it sorted out. I changed the location of the board to get it away from the PT it was cause causing interference. I also changed the pot wires to shielded wire. this got rid of the noise issue, however I found that some wire strands had poked through the sila pad under the VRM and were shorting the circuit. I just posted on the previous post regarding wire strands. How ironic. But is sounds great. Thanks for the help.

We normally put them within less than 2" of the transformers, but it's important to braid the control wires if you didnt attach the control direct to the board.

Glad it's working fine for you now.

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Yeah if you look at the picture of the board and wires you can see the wires were basically "on" the transformer, I had them bundled and braided, but they were just too close with out being shielded, I think just moving the board and wires 90 degrees put it within a proper distance. I will post some pics of the completed build this weekend. cannot wait to get some NOS tubes and a head cab so it can travel safely.

cheers