Great job repairing. Glad to see others using this head. For the XLR MSDI out, did you see an isolation transformer or two coupling caps? Just discovered a flaw in the grounding plane circuitry with the help of my engineer friend at Peavey. I'll be making a video on it soon.
Thank you. I do not see any isolation transformer in the XLR circuit. Signal is via C52 a 2.2U 100v cap and series dropped though resistors and a couple inductors. C201 a 2.2U 50v cap couples to pin 1 of the jack and C202 a 2.2U 50v cap on pin 3 to ground. C201 is essentially the output coupling at the jack. Not sure what you are looking for? This is a somewhat complex amplifier and the schematic is a challenge to follow....even with many, many years of schematic reading. Finding a part on the schematic and locating the physical parts can be an adventure. Power transformer and output transformers are only represented by pin connections no parts in the drawings. If you experience a hum issue, check out this XLR patch video ruclips.net/video/DRn-g-eYyN8/видео.htmlsi=J8EQADdoINxuubwN
@@SpencersMountain haha thats my video! I'm about to release an addendum to that video as I have learned new information. C201 couples to pin 2, and C202 couples to pin 3. Pin 1 ties to Chassis/Earth. The isolation transformer that was in my amp was the wrong type, that was the first problem. The 2nd problem was in the Grounding plane design between the main PCB and the patch board. Yes this amp is complex. The XLR circuit has all the inductors/resistors to match the response curve of an SM57 microphone placed 1 inch next to the cone of a speaker. I have a friend named John who works down at Peavey. He's one of the top engineers there. Helped me solve the issue. He didn't design the MK II head but he found a flaw in the ground plane bonding the other engineer/designer missed plus the wrong isolation transformer. Guess they threw in whatever they had on hand. Be on the lookout. Here I thought I was the only one making repair videos on this amp!
@@tomasvrkoslav5364 Best advice is to email Peavey and ask for the schematic with your serial number. Looking at the Peavey forum might help. Or someone there may sort out your particular issue. The MKII is a very interesting amplifier with power and class adjustments and very different from the first version.
Great job repairing. Glad to see others using this head. For the XLR MSDI out, did you see an isolation transformer or two coupling caps?
Just discovered a flaw in the grounding plane circuitry with the help of my engineer friend at Peavey. I'll be making a video on it soon.
Thank you. I do not see any isolation transformer in the XLR circuit. Signal is via C52 a 2.2U 100v cap and series dropped though resistors and a couple inductors. C201 a 2.2U 50v cap couples to pin 1 of the jack and C202 a 2.2U 50v cap on pin 3 to ground. C201 is essentially the output coupling at the jack. Not sure what you are looking for? This is a somewhat complex amplifier and the schematic is a challenge to follow....even with many, many years of schematic reading. Finding a part on the schematic and locating the physical parts can be an adventure. Power transformer and output transformers are only represented by pin connections no parts in the drawings.
If you experience a hum issue, check out this XLR patch video ruclips.net/video/DRn-g-eYyN8/видео.htmlsi=J8EQADdoINxuubwN
@@SpencersMountain haha thats my video! I'm about to release an addendum to that video as I have learned new information. C201 couples to pin 2, and C202 couples to pin 3. Pin 1 ties to Chassis/Earth. The isolation transformer that was in my amp was the wrong type, that was the first problem. The 2nd problem was in the Grounding plane design between the main PCB and the patch board.
Yes this amp is complex. The XLR circuit has all the inductors/resistors to match the response curve of an SM57 microphone placed 1 inch next to the cone of a speaker.
I have a friend named John who works down at Peavey. He's one of the top engineers there. Helped me solve the issue. He didn't design the MK II head but he found a flaw in the ground plane bonding the other engineer/designer missed plus the wrong isolation transformer. Guess they threw in whatever they had on hand.
Be on the lookout. Here I thought I was the only one making repair videos on this amp!
Hi, I'm looking for a Peavey ValveKing II 100w wiring diagram. He plays poorly. Tubes are tested. Thank you.
@@tomasvrkoslav5364 Best advice is to email Peavey and ask for the schematic with your serial number. Looking at the Peavey forum might help. Or someone there may sort out your particular issue. The MKII is a very interesting amplifier with power and class adjustments and very different from the first version.