Help! 1959SLP HW PTP Clone - Making Noises/Microphonic

[jc298607]

Hello all!

This is my first post on the forum, though my amp is a hand wired clone, it is not a genuine Metro product so I do hope I'm not breaking any rules here. Also, I am not an electronics expert by any means so I am hoping some of you could shed some light on the issue I'm having ..

I just received my 1959SLP clone, it is a hand wired PTP 1969 circuit copy with a PPIMV mod and a Resonance mod, 6550 output tubes, Classic Tones trannies, SoZo components, etc. The amp was built by Jim of Top Gear Guitars in La Mesa, CA, but I did not buy it directly from him, I won it from the original owner in an eBay auction. It shipped to me via UPS from CA to OH (probably the culprit right there) and it's not quite right. Unboxed it, did a visual inspection to make sure nothing was obviously wrong, checked that all the tubes were sat properly and didn't look visually damaged, etc. Plug it in, turn on power to warm it up, all seems normal. Flick standby and it comes right to life no problem, played on it for about ~20 mins and it sounds great. Mostly just played with all the knobs to make sure everything worked and slowly increased the volume to about halfway or so, it's really loud but sounds awesome. Then, out of nowhere, it starts feeding back strangely, kinda squealing like, and there is a horrible noise. The noise sounds like when you have a loose input jack on your guitar and it makes that scratchy "hand rubbing a microphone" sound. This noise is seemingly unaffected by what volume the amp is on and whether or not the guitar is plugged in, and on all channels. It comes intermittently, it's not a constant. Since that first incident, it seems to be more and more frequent that it happens. I have only had the amp a couple days at this point, but I have noticed the noise get progressively worse and comes and goes more frequently. The pre-amp tubes have also gone micro-phonic, I can gently tap on the outside of the amp head case and it is picked up and mic'd through the speakers at all volumes. Lastly, it seems to me like it's down a bit on power/volume. I have never owned a 100 watt all tube amp before, but have owned 40-50 watters, comparatively it doesn't seem to be impressively loud? Maybe that's just me and my early-onset deafness lol.

I have tried some trouble shooting, i.e.: tried a different speaker cabinet, multiple guitars, several different cables and line outs, check all input jacks and what not, everything keeps leading me to an issue with the head. Being as I am not an electronics expert and I know a whole lot of power goes through this thing, I am not about to go poking around the innards. I would really just like some input from people who have more "know" than myself on what the culprit likely may be, so that I have an idea when I take it to a shop this weekend and I (hopefully) don't get hosed on a repair bill. Thanks for any and all help! Sorry for the verbose prose...

-JC

[Haze13]

Have you tried other tubes? It's hard to tell without looking inside the amp. Volume wise I compared my JCM800 50w clone vs JCM800 100w ri and 50 watt can be loud as 100watt to a some point. Just like a 3 watt can be, to a some point

[danman]

Do as Haze suggested and try some different tubes. Get yourself one 12ax7/ecc83, that you know is good, and try it in each preamp spot for several minutes and see if the issue continues or stops. One of them may have been damaged from the shipping process. I would suggest the same process for the power tubes but that will involve you checking and rebiasing the amp.