Vox AD60VT Valvetronics

[guitarwine_red]

I have had the amp for about 3 years and it has generally been pretty good. I sorted out some dry solder joints just after I got it and which were pretty much the only problems until now.

I am experiencing problems with sound cutting out entirely at any volume level. I have cleaned all of the input jacks with contact cleaner but the problems still exist.

I would be keen to get hold of a schematic for the amp as I have an electronics tech mate who is willing to have a look at it for me.

Thank you in anticipation.

[Rob Mercure]

GR,

I'm not familiar with this amp but if you've got any sort of effects send/recieve jacks these usually break the circuit chain so cleaning these may help a well as cleaning potentiometers (although these shouldn't be cutting out completely on a 3 year old amp). Since you've already experienced problems with cold/dry solder joints you might consider - depending on the how hard it is to get to them - remelting all the solder pads for the front and back panel jacks and controls. When I was doing Crate warranty their Blue Voodoo series was notorious for cold front panel solder joints and once I had the circuit board pulled - no matter what the reason - I routinely remelted each and all of the front panel connections to prevent the customer returning the amps after service.

Rob

[Mark Black]

On the AD60, look for a large resistor mounted up on its leads from the main amp PC board on the left side looking in from the open back (I have also seen these folded over so they stick sideways instead of up on their leads). Give it a little tug up from the board to see if one of the leads is broken, but still set in the hole. I discovered the first one of these almost by accident after looking elsewhere for a while - the experience came in handy on the next amp I saw where it was the exact same problem and made for a fast fix.

If not a broken lead it is still a likely place for cracked solder.

Good luck!

[guitarwine_red]

Thanks very much Rob and Mark. I will check the amp out tonight and see how I go.

Rob, there are send and return loop jacks on the back of the amp as well as a headphone jack with level control, and a line out jack. There is also a foot controller jack which uses a RJ45 type connector - I will have a good look at them all (although the foot controller jack does not have any "manual" switching, so not likely to be a problem)..

Apart from these minor problems that I am experiencing it is a great amp and excellent value for money.

Jeff

[guitarwine_red]

Hi Mark and Rob,

I pulled the amp apart last night - separated all of the PCBs and went over them with a fine tooth comb. One of the FX loop jacks was faulty and possibly causing a weak connection. I removed it from the board, disassembled it and got everything realligned and retensioned and fixed it back to the PCB. In addition I found that the external speaker out jack had two legs that were badly soldered and loose on the PCB - easy fix. I also found that the level control pot for the phone out and line out jacks had one cracked solder joint and one which appeared to have missed being soldered when the board was assembeled. Although the leg was in contact with the PCB it was an obvious weak contact - again an easy fix. The "large" resistor had one cracked solder joint. Tag2, Org2 on the main board also had a suspect connection. It was misalligned and had a very hit and miss solder joint.

I put the apmp back together and gave it a real good workout and not a problem. I don't think that I have heard it sound so good. Even though I thought the amp was good from the start, it is even better now. The sounds on the clean amps are a lot cleaner and the higain amps are less muddy and noisy.

Thanks very much again for you advice.

Jeff

[Wes]

I just had one of these come in. Similar problems with dirty FX S/R jacks and dirty "power" pot.
Most of the solder joints in this amp looked ok, luckily I only had to retouch a few.

Just wanted to add to troubleshooting this model amp.