JP amp - parasitic oscillation

[shakti]

I don’t have a switch for my amp yet, still need to find a nice looking footswitch box. I think the ones Marshall uses for their HW 18 amps looks close to what Page had for his amp. I need something that matches that nice Cannon XLR inlet I found (which is an exact match with what Page’s amp had).

I noticed that noise issue with the Royal clone I used to have - if the footswitch wire was close to a mains power line, it would induce hum and squeel. To be honest, I rarely use the footswitch anyway, it’s always in cascaded mode and then I use the guitar volume control.

[gtomax]

I have mine wired per stock:

• No switch inserted or inserted with contacts connected: quiet mode

• Switch inserted and engaged/contacts broken: loud mode

I considered reversing it so the default state of the amp is cascaded but I think I'll leave well enough alone, source some nice coax and see if I can make a reasonable footswitch setup that doesn't cause the problem. Otherwise I'll use the blank 'shorting' (though really 'opening') plug. Let's face it i'm not playing RAH anytime soon.

I love the Marshall 18w footswitches, they're very difficult to find. I got one for a series 1 18w clone I made with NOS RS transformers and it took a few months to find one available as spares. Gorgeous look and feel on it. Part number is Marshall PEDL-10034, looks like there are a couple stores with them in stock in Europe. Cheapest looks to be about $80 US shipped all the way up to $130 pre-shipping

[shakti]

Do you have a link to some of those? I am looking for a few, both for these two JP Hiwatt conversions I did and for a Bluesbreaker restoration.

[gtomax]

@shakti emailed ya!