Puzzling issue w/ an A12 that used to work properly *solved*

[brad347]

I have one A12 and one N72, and they've both always been great. I'm a satisfied customer, so much so that this weekend I'll be ordering another N72 and a J99.

But lately my A12 has been exhibiting an issue that SEEMS to be a faulty rotary switch for the stepped gain attenuation. Hopefully Tim or someone can shed some light to diagnose what I should do here.

This issue kind of reared its head awhile back, but I've been living with it as I've rarely needed to use the highest gain settings. I feel certain the unit worked properly for several months at least after I assembled it.

Well, the other day I needed a lot of gain, and found that I couldn't get the top 3 or 4 positions on the switch to work properly no matter what I did.

Here's a full on description of the issue.

The first 8 positions on the selector seem to work as expected, fairly predictably.

When I get up to the 9th position, the gain increases momentarily (very briefly), and then drops off sharply after a few ms, down to the level of about the 4th position on the dial--very low, almost as though I went "past" the position somehow (more on that later). Positions 10,11,12 stay at that low "position 4-ish" level no matter what I do, with no momentary "spike" in output as I click past.

Going back to position 9, I find that if I "balance" the switch in between position 8 and position 9, I can get the "level 9" amount of gain, looking at the meters in my DAW (if that makes sense).

Nothing, however, will get me steps 10, 11, or 12.

Any insight? I tried cleaning the switch to no avail, and once when I first noticed the issue I tried re-doing all the solder joints on the stepped attenuator/resistors, to no avail.

Also, if Tim chimes in... if we do determine that it is indeed a faulty rotary switch, do you sell those separately, as in could I add one to my upcoming order? Thanks,

--b

[brad347]

Squirted some DeOxit in the switch, re-flowed a few connections, and it's working like a champ now.