Leroy's 700B

[laatsch55]

And yes, I did check my test equipment, put it in the system and yes........it comes out the speakers in a very objectionable volume..

 

[Skratch]

You got a Gremlin

 

[laatsch55]

Yes indeed Mr. Mark...

 

[Skratch]

Are you near fluorescent lights or dimmers?

 

[laatsch55]

No, don't have any, checked another amp in the same place, no noise..

 

[Gepetto]

No, don't have any, checked another amp in the same place, no noise..

Bridge?

 

[laatsch55]

Scope shot of the output, right channel. AC coupling..
WTF is going on here..wiggling a few wires at the buss bar we're at 18 mv..

 

[laatsch55]

Well, the more I mess with the wires around the caps, the worse it gets...

 

[Gepetto]

Well, the more I mess with the wires around the caps, the worse it gets...

Maybe your noise source is there Lee. Have you used your scope probe as an antenna?

Connect Ground clip alligator clip to probe tip. Move the probe around and look for noisy sources.

 

[laatsch55]

Scope shot of both channels..

 

[Gepetto]

Scope shot of both channels..

Right at 8.3333333msec.

 

[laatsch55]

Like so...

 

[laatsch55]

Can't seem to pick up anything that way Joe...

 

[laatsch55]

Why are they inverted to each other Joe?

 

[Gepetto]

Like so...

Yeah the ground wire is the antenna.

 

[laatsch55]

Doesn't pick up anything I can see Joe..

 

[laatsch55]

By pushing the black secondary winding wire, it will go from 10 mv to 80 to 100 mv

 

[Gepetto]

By pushing the black secondary winding wire, it will go from 10 mv to 80 to 100 mv

Is there a buss bar somewhere in there? I don't know what you are pointing to. The pic is not the best.

Are those crimps good? They do not look crushed.

 

[George S.]

Break out the big gun and a little paste flux.

 

[laatsch55]

Yes, there is a buss bar, and I don't know about the crimp. I just tightened the positive and negative cap screws and dropped the noise level to 4mv from 13 mv.