Tuesday, December 16, 2014

After a long while (10+ years) of periodically checking for 2.75"/70mm throw sliders to fill the gaps on the Langevin AM301, I finally stumbled across an auction for unused Duncan Slidelines and decided to procure one for every channel.

Granted, these are 100K lin as opposed to 50K log, but this gives me an excuse to fumble around with changing the law via external resistor AND to finally dive into this unit.

Off with its face!

This explains some of the non-functional channels, some others have fader assemblies that are breaking apart (not pictured, yet).

Better oust these old electrolytics while I'm at it.

Here's a shot of the stock wiring.

Here's someone's mod, I guess. Dual gang to unify two channels across one fader? It does explain why there has been an empty slot staring back at me as long as I have owned this thing. Mind you, I don't think this "fix" is still functional. Was it ever?

The stems on these faders are slightly smaller than the stock Slidelines, meaning I will be going with another sort of cap (I know I mentioned seeking some red Rollo looking caps last time). Onward & upward.

Monday, November 17, 2014

Here I am, working around the inherent constraints of SMT componentry for use in your garden variety free form "rat's nest" point to point build.

Saturday, November 15, 2014

Found out what was rattling around in my old Pioneer SR-101, something sheared the top of a 6BM8.

More inspiration to stop gigging the antiques.

Saturday, November 08, 2014

Whew! So I have to remind myself how HTML works every time I post. Clearly I'm not being active enough, but rest assured, the wheels have been turning in the background. I've got a couple "filler" angles I can exploit, and while I detest the notion of coughing up fluff, if I have to stop and think about how to break a new paragraph something has to give.

Anyway, been tearing down some organs lately and have wound up (literally) wading through piles of interesting parts.

Low tech switch design. Left depicts an open condition, right depicts an operational failure. Easy fix, of course; sort of like brushing the bugs out of an early computer.

Lots of gritty potential.

More 1970s analog drum machine guts!

Daughterboard sounds as follows: #5 = BASS, #3 = SNARE, #4 = CLAVE, #6 = CONGA. Presumably the BRUSH, CYMBAL & SANDBLOCK (?) are handled on the inductor laden side of the main board. I'm a bit apprehensive about snare being built around the same circuit topology as bass & conga (the daughterboards are identical PCBs stuffed with different values), but whatever the sounds I have to thank the good people at Gulbransen for clearly labelling voltage supply points, etc.

I guess I should mention that the lowest daughterboard in that picture is a signal amplifier, not a one shot oscillator. I'm too fond of individual outputs to leave that section alone, but I'm certain it will see use in some capacity.

Once I scrape the dust off this it'll be a snap to try out.

Sunday, August 03, 2014

Playing at an outdoor fest next weekend and have wound up supplying the low frequency component of the PA system, which will be run by someone else. The last time the bins were cut loose outdoors this happened. Fortunately a while back I wound up with a PCB for a stereo 3 way crossover that appears to be based on the Linkwitz Riley circuit, so I decided to build it with crossover points of 40 and 120 Hz.

Of course, it would appear as if the capacitor type I had on hand with sufficient quantity (for matching) and value (1uf, to maintain a reasonable range for resistance) is a touch larger than original design...

...which led to something of a congested stuff.

I figure I can use the low range of <40 Hz to throw away subsonics (and audible stuff below the horn loading of my bass bins, sorry) in a live setting, and route that to CV stuff in a studio. Not saying I'll opt to shave deep lows in a recording atmosphere, don't be silly, it's just nice to have the ability to prune a branch in that manner.

Of course, if I REALLY like it, I may go crazy and build one with DOAs.