Aion Straylight (Uni-Vibe) biasing

[tootsMcgee]

New 9203 LDRs raised up to face the bulb fillament didn't do too much. I think the phaser depth issue comes down to adjustment of the gain/offset, which I still haven't gotten down yet.

I've also been doing it into a clean amp at low volume or even straight into my audio interface, which isn't helping. I found a thread somewhere that implied that Hendrix's Uni-Vibe was very dark sounding and only sounded bright at stage volume. It might be that I'm adjusting it too bright to compensate for not playing at volume.

I'll take a look at the transistors next but I'm not sure how much effect they'll have on the incandescent bulb. I've seen clones use 5088, 3094, and KSP13s here and I imagine they all work roughly the same.

[micmac1]

Hi Toots, everybody,

I boxed up mine a few days ago (some pics here). Everything like in the BOM, LDRs NSL-5542, and one of these lamps.

I didn't want to go too crazy with the "calibration", after all I'm just a hobbyist. So I just put my DMM between ground and emitter of Q12 and turned the gain trim till I got 200 Ohms of resistance, because RG wrote in his Neovibe docs that "the circuit seems to like about 200 ohms of emitter resistance" (Link). That was lazy move #1

Next I put Intensity to 9 o'clock, put the speed up a bit, say 12 o'clock and turned the offset trim from where the lamp was off to a point where I started to hear the effect (faintly, but definitely). And that's where I left it. Lazy move #2.

The Phase trim is a bit difficult. It's hard to hear the difference. If you can't hear a difference put it to 12 o'clock. I connected a scope and a sig gen and then I could see that the notches squashed the signal the most somewhere close to the middle of the trim (~12 o'clock). I think that's what RG referred to as cancellation here in post #14. But where exactly in the middle was hard to tell even with scope (maybe there's a better way to use it and I just haven't found it). I ended up with the phase trim almost in the middle, a small tick to the left. So if unsure I'd definitely put it at 12 o'clock.

All in all sounds great to me. Happy customer (me). Nice feature having the cancel switch. Saves the lamp if you're not using it. And if you put the internal switch to Modern you can use it as a bit of a boost if you're so inclined. And the two small red speed indicator LEDs are neat, too. Loving it! I'll shut up now, I'm feeling like a lil' fanboy.