Recent content by 365nut

Wiggled wires between level control and balance control, that is.

Found the problem: bad solder joint on the balance control. I diagnosed the problem by "wiggling" wires between the balance control and balance control with a wooden ice cream stick with the amp on and playing (one hand in pocket). When my stick hit the right wire, the loud volume stopped...

Appreciate everybody's replies. Will further diagnose & see what happens. This does appear to be a volume control--even though designated a loudness control. This is a pretty difficult amplifier (actually an integrated amplifier) signal trace in. Pretty complicated but do have the schematic.

Scott 299 preamp. Turn Loudness control down to lowest setting but volume stays at high level. How do I diagnose? What do I look for?

After a lot of tinkering around, the "cure" seems to be a missing connection between the Channel B terminal on the Selector Switch and a terminal on the Loudness-Volume Switch. My final output signals on both Channels A & B are strong and equal on the scope. The sound is great. I'm going to...

Thanks for all the comments. Very much appreciated. I have a Sams schematic & a Scott schematic. They do differ which, as I understand it, is not unusual. The Sams' has a parts list. The Scott does not.

Working on a Scott 130 preamplifier. Main issue is very low signal on Channel B. Have traced good signal to the 2nd amplifier stage (Pin 7 of 12AU7 grid) but after that lies the problem. Have questions on attached schematic –notes 1 & 2 with yellow circles. Note 1 – C27 is shown on Channel...

I appreciate your post. I What you say makes a lot of sense. I have suspected the switch but these rotating switches are very difficult to access to clean adequately. I will follow up with your suggestions as best I can. Thanks.

When switched to mono mode, the balance is perfect which I assume means the balance switch & circuit are working properly.

Also would note, using signal tracer have traced equal signals to both Channel AF amp 12AU7s. So problem obviously is beyond that stage.

Thanks, will give that a shot.

Out of commission at the moment. Thanks.

Feel kind of stupid on this one. After completely re-capping, re-tubing bad tubes, cleaning tube sockets and controls on this Scott 130, find I have uneven balance with balance control in center position--one channel substantially louder than the other. When I reverse the output channels with...

Gadget, Again, very much appreciate your willingness to provide expertise. Under stand the "dangers" of high voltages associated with OPTs. I'll be going on vacation until July 9 and will get back on this project after return. Will keep you informed. Thanks again.