Archibald with mods

[benh]

Hi Folks !

So here's the Archibald I made a little while back (and forgot to post about). A few mods in there that might be of interest to folks, and a few "issues" (screwups by me ? :-) in no specific order:

* Took C18 out (between LT1054 pin 1 and ground). I don't know why it's there and Mr Bean either... but in my case it causes the charge pump to fail to start on a cold start 80% of the time, resulting in a rather shitty sounding pedal :-) Pin 1 is "shutdown" when driven to ground. It looks like this cap is big enough to cause my "variant" of LT1054 to see pin 1 asserted before the cap has time to charge and shuts itself down. The cap eventually charges, so a quick power off/on of the circuit kicks it into life. No C18 works best :-)

* I replaced R5 with something much smaller (1k5 off the top of my head). This is closer to some variants of the Tube Driver schematic where that resistor is absent and gives a bit more "clean" range at the beginning of the drive pot. There's some sweet spot there for a mild tube sound which I quite like when I'm not cracking it up fully.

* R18 to V- instead of GND. Otherwise the JFET buffer operates between GND and V+ instead of V- and V+, you lose half your headroom and I've observed it clipping early with the scope, which is not what you want your buffer to do.

* I used a 1590BB2 because Tayda doesn't do BBS and ... it's TIGHT :-) It would be nice if that circuit ever get respun, to have the tube sit one or two mm closer to the face instead of so far down near the lid. I had to "incline" the PCB downards (by taking out the inner nut of the switches and screwing them down further) to avoid having the tube hit the lid. It's unfortunate because it should fit with that one mm extra. If that makes the tube socket too close to the angled connector, then maybe put the connector on the side of the tube rather than below it, a bit like the "wings" that SushiBox/CCE uses ?

* I was dumb and put the jacks & power on my usual spot for a 1590BB2 rather than one the side like the Archibald template suggests. As a result the tip of the output jack almost touches the tip of the tube ... it's very very close. I dodge a bullet here, pfiew !

Otherwise it works and sounds great ! (The little drawing is courtesy of some random online AI :-)


 

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[jessenator]

Nice! 

Yeah, I was working with a friend on some designs for it, and the tolerances are just enough between the S and the 2 to be mildly irritating. 




Looks good!