Ludwig Phase II Clone Tech Notes

[Keppy]

Test complete. Result: Loud tone ~700Hz. It would appear the UJT works.

I was poking around the console board earlier. It turns out that just poking the meters with the collector sometimes triggers the flip-flop, which is why they both appeared to read .06v earlier, but with a 15v difference between them. Each time I touched one, it flopped low. So, the flip-flop appears to work fine, flipping between .06v and about 15.5v when triggered. It's just that oscillator...

[Keppy]

Careful comparison of the Ludwig to the test circuit R.G. posted revealed an error. The Ludwig schem has the UJT's bases reversed. I pulled it out and reversed them and, well...


We did it.

[geertjacobs]

Congratulations! 

BTW this thread is more addictive than a soap opera 

[R.G.]

Careful comparison of the Ludwig to the test circuit R.G. posted revealed an error. The Ludwig schem has the UJT's bases reversed. I pulled it out and reversed them and, well...

We did it.

Good work! I missed that completely, even grinding ever-finer on the UJT circuit.

Consider yourself toasted!

[pinkjimiphoton]

WOOT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[pinkjimiphoton]

i just tried to txt dino and failed.

i AM rolling up a phat one in your honor tho, since i don't drink.

once things settle down a bit, any way we can get a complete layout and BOM etc so we can ask aaron to host it all here?

keppy, i'm still down for a couple circuit boards when the time comes.

i can't believe this journey we've taken together. it's taken decades, but the 4 of us finally did it, we cracked the nut, planted the seed and grew us one of the coolest things that ever got stomped on.

i am speechless.



keppy, go play with it for a week, and tell us when ya get back what ya think. we need pics!! video!! audio!!

well done mates...well done!!

[Ry]

     Sweeeeet!

[toneman]

LOL!!!

(sorry about the size)

Never appologize if it's "too big"   

Especially if it's a wiring diagram.... 

Go Keppy Go.....

see, I said UJT's were easy....just use them "right side up"   

back to working on cars, not stompboxes .. . :-(

[pinkjimiphoton]

so...keppy? you alive in there, bud? 

[Keppy]

Yup, still alive. I've been at a battle of the bands all day, watching my students perform 

Everything's working, though! I just have to dial the trimmers to taste. Then, load up everything I own and drive 700 miles. 

[pinkjimiphoton]

owwwwwwwwwie!!

dude,, you gotta PLAY WITH IT!

best of luck with the move brother. ya done good!

[Brymus]

Nice work guys !!!
Good luck with the move,it always rain when I move,even here in the desert and thats unusual.

Watched your vid Jimi,
Your dog seems to like the camera 
But really,IMO alot of the sounds didnt seem that useful,while others were really incredible.

[digi2t]

I KNEW IT HAD TO BE SOMETHING STUPID WITH THE UJT!!!  YEAH BABY!!!

Congrats Kep, fantastic finish 

I writing from the hotel computer right now, I just wanted to check in, and see whazzup. I`m in Quebec City right now, my son`s team has a tourney all weekend. So far, they`re unbeaten, and my son pitched 6 innings of hitless ball, in a 3 nothing shutout. Player of the game honors. That and the Ludwig news... weekend in paradise! Thanks guys!

I`ll be in for 2 boards as well. Gonna have another brewsky in all your`s honors at tonight`s game. Jimi, since I don`t smoke, have an extra long haul fo me man.

Bravo zulu brothers!!

Dino

[pinkjimiphoton]

WHOO HOO~~~ STILL CELEBRATING HERE!!

[R.G.]

I'll have some time when I get home to update/correct the PCB. It's getting:
- another resistor for the amplifier circuit
- footprints that accept three different kinds of trimmer pots
- more space around the UJT on the console board for socketing
- an added resistor on t he console board that lets a 2N6027 go in there
- corrected pinout on the UJT
- part value updates (really a BOM issue)
- some more graphics work to show the final part positions

[Keppy]

Awesome! I think the only other thing it needs is some notes on how to set the trimmers. Jimi & Dino, do you think a step-by-step procedure is in order, or is it enough just to know what each one does? Given the oscillations this thing can produce if set incorrectly, it seems like there should at least be cautions about how to set them before tweaking, i.e. keeping R65 all the way counter-clockwise to start with. Oh, and which one to turn to begin hearing the formants at all.

Yeah, I think step-by-step instructions would be best. You guys have already made a few lists of what each trimmer does. Can you edit and repost those to indicate what order they should be adjusted in, and where each one should be set before plugging the effect in the first time?

[digi2t]

Yeah, I think step-by-step instructions would be best. You guys have already made a few lists of what each trimmer does. Can you edit and repost those to indicate what order they should be adjusted in, and where each one should be set before plugging the effect in the first time?

No problem. I`ll put that together this week. I believe that between Jimi and myself, we should have enough readings to be able to give a certain range for resistance, or voltage on the test points, for initial setup. I think the other unit will be in this week as well, so if I`m able to get it fully operational quickly, I`ll be able to factor in the readings from 3 units total. I think that should be more than plenty to set up a unit, and then some additional pointers from our experience so a person can just tweak it to taste.

Still celebrating here as well. It`s 1 a.m., and the game just finished. Total trainwreak, we won 20 to 4, off to the semis tomorrow morning.... today I mean

Good night y`all!!

[Keppy]

Am I right that the fuzz is created at Q5, Q6 & Q21 on the fall plate board? If so, should I expect to see any difference in sound substituting transistors there? I can't quite wrap my head around that part of the circuit.

[pinkjimiphoton]

lol...i just got home from a gig and had to check in. this is the coolest thing ever, i think...hats off to you gents, we made it happen...now we perfect it a little.


g'nite!

[R.G.]

Am I right that the fuzz is created at Q5, Q6 & Q21 on the fall plate board? If so, should I expect to see any difference in sound substituting transistors there? I can't quite wrap my head around that part of the circuit.

Yes. Fuzz is at Q5, 6, 21.

Q5 and 6 are a high gain complementary amplifier, set up to bang against whatever power supply voltage they get. One of those is ground, and the other is the emitter of Q21. Q21 gets a base voltage from the fuzz repeats/fuzz mix section. It acts like an emitter follower, and the voltage Q5 and 6 have to work with follow the Q21 base voltage. Changing the Q21 base voltage runs the size of the output at collectors of Q5/6 from nearly zero up to about 6V peak. The fuzz repeats signal feeds Q21 base with an envelope, and the output then follows it in size. The fuzz mix control feeds Q21 base with fixed voltage determined by the pot setting, and hence a fixed-size output.

I would expect no change in sound subbing transistors there, given only that the gains are high enough. Once you get to very low gains, there will be some change, so you can tinker. Most devices with a gain over about 50-100 will sound much the same, I think.