Plush 1000s

[Irish77060]

Hi all,
Newbie here. I have recently been reviving a Plush 1000s amp for my own use. I've done extensive work with the help of another person who isn't available anymore. I'm down to two problems that I think are simple, but I'm believing that they are connected and I've caused them. I recently replaced the power cord with a grounded cord. The usual go to Fender Dual Showman Reverb schematic is not useable here, as the Fender has a separate ground polarity switch, the Plush has a single 3position toggle that reverses polarity. Just after doing that and a few other things, the previously rebuilt reverb system/circuit stopped working and I began receiving a horrible FM station and a loud buzz through the reverb system. Unplug the Fender footswitch it goes away. Footswitch plugged in, and switched off, little or no noise. All tubes New JJs.

Did I possibly wire the power cord wrong? If so, how do you wire it to the 6 prong switch? In these old electronics do the white neutral and black hot wire do something silly like wire in reverse? Crazy. Before this, the reverb was a deep resonance and clear as a bell.
Thanks
Richard

[The Dude]

Welcome to the place!

The hot and neutral wires should go to the same place they did originally and the ground wire to chassis. There is a "death cap" on the polarity switch that should be clipped out. The polarity switch is no longer used or necessary when you add a grounded power cable.

[Leo_Gnardo]

No DPDT switch needed, without it the wiring becomes clear & easy to do. With a grounded power cable, there's no point in deciding which side of the power line goes to your death capacitor, because you don't need one. Cut it out. Throw it away, or save it for some other project. Get a simple SPST switch, use it to switch the hot side of your AC line (black). Neutral (white) common to one of your power transformer's primary leads. Ground (green or green/yellow) to a nice firm chassis attachment, preferably its own bolt & nut, with paint or anodizing finish scraped off the chassis so you're assured of a proper connection. It may pay to check your cable, make sure the color codes are correct because in rare cases they aren't and that will make for the sort of surprises you don't want to encounter.

Can't be sure this will cure your radio pickup. Sometimes that's due to poor ground connections at the guitar input jacks. Make sure they are tight, it also pays to scrape the chassis metal clean on the inside where the jacks mount, and use a toothed washer between the jacks and chassis.

[Irish77060]

I have essentially done what you've both described. I clipped out the convenience socket as it wasn't needed and would not affect resell value if I ever do sell it. I also clipped out the death cap when I installed the line. Where the white and black wires came through the strain relief, I connected to the original white and black wire circuits inside the amp same to same. The ground wire I soldered a ring onto a ring and bolted it onto a transformer lug. Tight and clean.

I was trying to keep the original switch for originality and because the face shows both positions as on with the middle as off.

The black wire comes in to the top left of the 6 pins. From that pin there is a jumper that goes to the bottom right. On the left side, the black transformer lead connects. The bottom left is unused.

The white wires goes to the fuse, then on to the top right of the switch. At the same connection is the other black transformer wire.

The right middle is empty. The right bottom only has the jumper from the top left.

I will switch to a single toggle if I really have to.

[TimmyP1955]

The live (black) lead should go to the fuse post, then from the fuse post to the switch, and from the switch to one side of the transformer's primary (the neutral/white being connector to the other side).

If you happen to have a UK sourced AC cord, live will be brown and neutral will be blue.

[Leo_Gnardo]

I essentially done what you've both described. - - - -

All sounds good then. Now we have to wonder, is there something wrong with that Fender footswitch, or its cable plugs? There should be an RCA plug with shield attached for the reverb, no shield for the vibrato. The shell of the footswitch should be grounded with a wire jumper from the cable braid to the switch enclosure metal, soldered right on to it.

[Irish77060]

That confirms my suspicions. The old wire was non polarized. And circuits weren't grounded. So, how could I know if those didn't switch out? The hot wire going to the fuse confirms it.

[Irish77060]

I switched it, no results. Same issues. But, at least that is the right wiring now.

[Irish77060]

Leo, do you mean inside the footswitch itself? This one is not grounded to the shell. The two wires split off, red to reverb and white to tremolo. Then a red jumps the two switches together. On the reverb side, there is another smaller wire that goes to a different post on the same switch. I am assuming that is a ground as the Vibrato side does not have it.

[Leo_Gnardo]

Leo, do you mean inside the footswitch itself? This one is not grounded to the shell. The two wires split off, red to reverb and white to tremolo. Then a red jumps the two switches together. On the reverb side, there is another smaller wire that goes to a different post on the same switch. I am assuming that is a ground as the Vibrato side does not have it.

Interesting, that may be an aftermarket replacement switch. In any case both reverb and trem/vibrato are controlled by switching the appropriate wire to ground. I'd expect the wire that connects the two switches to be connected to the ground/shield of the reverb control cable. In the standard cable the trem/vibrato wire is outside the shield - because it causes a click if it's inside. In any case try clipping the ground to the pedal shell, see if that might quell your radio pickup. Also worth a try, break out your ohm meter & make sure the reverb plug shield really does carry through to the pedal & wind up where it belongs.

[J M Fahey]

Remember that the Fender reverb footswitch *requires* a shielded wire because it carries live audio.
If you use an unshielded cable there or shield is not properly grounded (or not at all) it becomes a very effective antenna, to feed all kinds of electrical noise back into your amp.

[Irish77060]

Remember that the Fender reverb footswitch *requires* a shielded wire because it carries live audio.
If you use an unshielded cable there or shield is not properly grounded (or not at all) it becomes a very effective antenna, to feed all kinds of electrical noise back into your amp.

I ordered a new Fender switch today. This one is too dicey. Couple of things I noticed if anyone has the inclination. Although the tube is new, the reverb is very weak if working at all. I got the old cord from inside the amp that had the old Fender short RCA plug that is grounded on the outside, and fashioned a plug to "fool" the reverb to off and on. When the cord wires are touched, the reverb is noisy as hell with FM blaring. Noise level reacts to reverb knob. Disconnected from one another, silent. The third tube from the right in the preamp tubes is a 12AT7, which is the correct position for the reverb. And it's new. And they all glow.