2203 clone making blown speaker sound

[Rp3703]

Well after rewiring my 2203 clone using Doug’s method instead of star grounding, I got it running and the amp is nice and quite. Unfortunately when you play guitar through it, I get a blown speaker sound when I muffle the strings and mess with the tone controls. I checked the cab with another head and it sounds fine. When I shut the amp off, it makes a vibrato sound that speeds up as it goes down in volume. Other than that the amp sounds a slight bit lacking in gain from what I remember a 2203 sounding like but no blown speaker sound when you play full chords. It only makes the crap sound when muffling the strings or playing with the tone controls. I swapped all the tubes and no change. I’m sure this is some simple wiring issue, just wondering if it sounds familiar to anyone to help me narrow it down more quickly.

[FranciscoPerez]

Something similar happened to me in one amp that had a preamp ground wire attached to the ground buss, but forgot soldering the wire to the buss and the connection was not strong. I think it was the input jack's ground wire.


Once it was soldered, the noises disappeared.
Probably not your problem, but since you rewired the amp, I would check ground connections first.

[Ed_Chambley]

The sound you hear at shutdown is your caps draining.


If you are getting static crackle change guitars and patch cord, Dose it still do it.


If so, you probably do have a weak ground somewhere.  If you want more gain post your schematic and I will tell you how.  The question is how much gain do you want?

[Colas LeGrippa]

Hola amigo !

Before bolting a ground terminal to a chassis, always scrape off the oxide using a flat screwdriver, file or sand paper, for a good contact. Use a nut with a star locknut or a nylon nut. TIGHT IT SOLID. Solder the ground wire to the terminal before tightening it, as the chassis will act as a heatsink and the heat you'll apply to the terminal won't be sufficient to melt the solder.

Colas

[Colas LeGrippa]

TIP:  I always use the first input jack as the ground reference for all the preamp section, including  preamp power rail caps.  A/C cord is grounded alone. The filtering section, including HT and heater center taps are grounded together.  I never had problems doing that. When you have multi sections caps feeding the preamp as well, you have no choice with the ground: with the center taps.

Colas

[Rp3703]

Problem solved. Turns out one of the stand-offs holding up the board was too close to the presence feed to the phase inverter. It was maybe a couple a millimeter away but somehow was causing the sound. I removed it and no more static sound. I know, poor design on my part. Thanks for the help.

[Colas LeGrippa]

cool , you won't repeat the same mistake again