EH Scott Radio Enthusiasts

The Fine Things are Always Hand Made

Hi all,

I am trying to get my AC10 in its best possible operating condition and have a few questions:

1.  The left hand knob is a trimmer capacitor which works great when tuning, but it is spring loaded and wants to return back to the "home" position, which defeats its purpose.  I assume it should remain at the position that provides the most gain and not spring back to "home".  Is my control defective or am I doing something wrong?

2.  Has anyone performed the balancing procedure to align it?  If so, did it help much?

3.  How many of these were produced?

4.  Who has one?

Thanks,

Joe

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Joe -

In answer to some of your questions: 

1. My trimmers do not return, they stay where set. I have two AC-10 sets at present and have owned others.

2. I have not tried to balance and AC-10, the ones I've owned played pretty nicely without that effort.

3. We don't know. Based on the number that seem to be around, I can guess Scott built maybe 500 or so. Some of the later ones do have a serial number on the tuner, but I have not tracked these. Also, the early ones don't have a serial number. 

4. As mentioned: I currently have 2, I've had others. There are several variations on the sets as well.

Kent

Kent,

Does your left hand knob (trimmer) have any spring-loaded feel to it at all?  Mine has a "torsional" spring on it.  I am thinking that maybe yours does to, but the shaft has enough friction to prevent it from returning home.

I don't understand why mine would be spring loaded like it is.  Any ideas?

Joe

I suspect that what appears to be a spring is actually a positive electrical contact to the rotor and the homing of the trimmer is due to some extent by gravity. The trimmer should rely on friction to stay put. Some trimmers have end play adjustments that can be set for increased friction.
Another possibility is that it is a spring to overcome gravity and the trimmer has been installed such that the forces from the spring and gravity are complementary.
Norman

Norman,

Thanks for the great information.  I will check it out.

Joe

Joe - I agree with Norman a gravity issue.

As per Norman, that "spring" is likely a flexible metal strip serving as the contact for the rotor (moving portion of that small tuning cap). My restored and working AC-10 left control had a broken metal contact strip which  I  replaced using length of de-soldering braid with great success.

As for production volume: I have no basis to confirm nor dispute Kent. In addition to an early AC-10 with large the large metal escutcheon lacking serial number (as does Kent), I also have two later examples (small dial escutcheon)  and both have serial numbers above #1000. However, when Scott began assigning serial numbers during production, he may have started with a high serial numbers such as 1000.

I have tried peaking the several IF transformers, with modest benefit. (Frequency generator and VTVM). I had to shift the IF freq a tad to meet the adjustment range of the IF adjusting screws.

The AC-10 is a really sensitive set, BUT you have to keep your left hand on the left control adjusting it a bit as you tune up/down the dial. That little 9 inch Scott D-90 pedestal speaker is nice and in a cabinet sounds very good. It has a more precise dial arrangement than the subsequent 2-DIAL model in my experience.

AS with other models, there were some evolutionary changes with both the receiver and the amp/power supply. 

 

Thanks, David

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