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Lavache (no box yet) with lots of sockets

Started by midwayfair, March 27, 2012, 03:05:06 AM

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midwayfair

I haven't boxed this up yet, but it's destined for a 1590a. (Still settling on a name. There's a really good restaurant here in Baltimore, Petit Louis, and that's the most likely choice.)

This was a fun build for me. I basically socketed everything that matters and turned it into half a breadboard. I learned a lot more than I usual do.

I'm really not sure anything can be done to improve Brian's version of the circuit. It definitely sounds like an amp at more settings than a Les Luis. Just dead on classic tweed. I tried a couple values in the 330 ohm slot and decided on Brian's stock value. Lower values just made the pedal too distorted, and higher values ... well, let's just say that I set my dirt pedals at unity. I ended up removing that socket and going with the stock value.

I ended up going with two germanium diodes in place of two of the BAT4x (I had to use BAT41s since that's what Smallbear had). I could swap diodes in and out all day, though. The differences are subtle. In the end I settled on this configuration because it offered the most volume in all positions with very little difference in gain levels between the position with Z1 & Z2 and the position with Z3. I'm also addicted to germanium, and the Z1&Z2 side happens to sound a little sweeter and more like a Champ than, say, a Deluxe. Less high end.

I also plugged an extra PNP rangemaster Ge transistor I had lying around. The gain is only ~51, though, so it doesn't really drive the circuit hard enough. It lent kind of an interesting character to the pedal, a lot softer but also a little hefty. It makes me wonder if maybe there's a couple other values I could change on the board to get the most out of a lower gain transistor.

The last thing I did that wasn't stock was use a 250k for the drive pot. It didn't seem to make too much of a difference in the gain range but it sounded a little brighter at higher gain settings (this might just be because I'm getting less of the diodes, though, and I wasn't testing at full volume).


nzCdog

Nice name!  Get it in that box and rock it man! ;D

gtr2

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alanp

Them things is fun!

You're not bothering with a boost switch?
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midwayfair

Quote from: alanp on March 29, 2012, 03:44:58 AM
Them things is fun!

You're not bothering with a boost switch?

I'm using 12mm pots (they're just easier to work with). Space is going to be really tight with just one switch - I don't want to push my luck.

I'll make a demo when it's all boxed up and decorated. I also have to film a demo of my L'il Teapot (Madbean Rangemaster in a 1590a, adapted to NPN and with a tone knob).