someone upped this on "another" forum...worth a look!!!!!

[R.G.]

Actually, I got the fall plate board in 3"x4", the console board is 4"x1.8". 'Course this all assumes the schemos are correct... 

[Keppy]

Actually, I got the fall plate board in 3"x4", the console board is 4"x1.8". 'Course this all assumes the schemos are correct... 

Looks good R.G., I like how you got rid of the extra long parallel traces to squeeze the components closer together! AND if it's really only 3" x 4" it will fit on the photosensitized boards I use!

[Keppy]

Did you use .1" inline spacing on the transistor leads, or go for the triangle thing? I'm wondering if I can use standard inline sockets for those. The spacing looks tight enough that my transistor sockets might not fit.

[pinkjimiphoton]

definitely trimpot r29 is the issue...i shorted it, pink 2 &3 together, and i have formants. first thing i'm gonna do is take the board out and re-solder everything...if that don't cut it, i'm off to the store for more trimmers, hopefully can find a suitable replacement...

[R.G.]

They're 0.1", three in line. The trimmers are Bourns 3319 on the fall plate, and 3306 on the console board. Non-electro caps are all 0.2" spacing box style. Transistors are all TO-92, EBC pinout.

There were some modest failures in there.
- I could not get the fall plate to route without jumper wires.
- I could not get at least one side free of off-board wires.
- I could not get all transistors or trimmer pots into the same orientation, although I did get the electros all facing the same way.
- all the diodes *were* the same direction, but I traded that away to get the console board down to 4" wide.
- I generally try to use 25mil traces on 50mil centers, but there were some tight places that needed to be closer than that; that's what takes it out of toner transfer territory.
- R74, the 3.9R power resistor really ought to be bigger, but I wasn't willing to sacrifice board space. I'd recommend making that a vertical ladder of four 1/2W 18R resistors just for luck if the implementation uses lamps. I really suspect that anyone cloning this will use LEDs anyway.
- Given the pressure I put on it for size, this layout is fairly rigid, in that big circuit changes are going to need a lot of rip-up and retry. It's a fixed-purpose board.

It's single sided, but I had to use six wires/jumpers on the fall plate to avoid going double sided. Probably a fair trade off. The console board is single sided, no jumpers. For commercial protos, I'd probably toss a grounded plane on top of them both, but they have complete ground paths without the plane, so the plane would just be icing on the cake.

The fall plate board is actually 3.00" x 4.00" as designed. The console board is another 4.00" by 1.80".

I quit using transistor sockets years ago. A transistor costs $0.05, and so few fail or get inserted wrong that I just clip them off and put another one in. In fact, I don't use IC sockets any more, either, except in unusual cases.

[Keppy]

I quit using transistor sockets years ago. A transistor costs $0.05, and so few fail or get inserted wrong that I just clip them off and put another one in. In fact, I don't use IC sockets any more, either, except in unusual cases.

I was thinking of socketing them just for prototyping, to find modern transistors that work. Seems easier to socket those than to desolder a few dozen components if the first ones tried are not suitable.

Thanks for the rundown!

When might we see the transfer images posted?

'Course this all assumes the schemos are correct...  

When the gutshots went up, I checked the traces in the photos against the layouts I did from the schematics. The traces all went to the same place. There's still room for mistakes as far as component values or off-board wiring (like the preamp/treble booster thing), but the connections on the board appear to be as advertised.

[R.G.]

I was thinking of socketing them just for prototyping, to find modern transistors that work. Seems easier to socket those than to desolder a few dozen components if the first ones tried are not suitable.

Oh, sure, be reasonable and prudent ...

Thanks for the rundown!

When might we see the transfer images posted?

Good question. How much are you feeling like a guinea pig?

[pinkjimiphoton]

hi guys....good news, heck, GREAT news. i ran to the parts store and got jimpacks (remember those?) of all the trimmer values this thing took. i'm a sucker for overkill.

replaced r29 trimmer (150 ohm) with a 100 ohm trimmer, and she came back to life instantly. so i re-set the others, which all seemed to be fine (even tho i bought backups in case)
and she's working GREAT. 

also replaced c1 with a 10mfd 250v cap. no more hum, no more microphonics. no idea why it needs that large a value voltage wise, but hey, i'm NOT complaining.

she now sounds just like i remember, that trimmer must have been really bad...i was having intermittent problems that made no sense, but now she's stable and seems to be healed. thank (the) god(dess)!!!

so i buttoned her up, and won't mess with her guts anymore...tho i am more than willing to open her up if anyone needs voltage or resistance readings etc.

thanks for the encouragement when i started to lose it...this is a precious thing to me, and the thought of losing it after a 33 year search was really disheartening.
but your suggestions helped me to clear my head, and figure it out. thank you all, from the bottom of my heart.

when my girlfriend goes out this week somewhere where i have a little time, i'll shoot a video demo of this thing.

i do have a couple suggestions for mods, tho....

the 100 ohm trimmer, r-29 may be worth moving off the board to a pot...this is the crucial trimmer to set the range of the formants.
r31 is also cool to replace...it not only sets the range of the pot, but also controls how much feedback the unit has. you can literally turn it into a free running oscillator under wah control....really cool!! i wouldn't do it to the original, but it may be worth exploring for the clone/improvement.

anyways...thanks again, every one!!

namaste
jimi

[Keppy]

When might we see the transfer images posted?

Good question. How much are you feeling like a guinea pig?

Well, I do have a wah shell/pot I haven't built anything with yet...

I guess if you're looking for a guinea pig, I could build it. I was actually about to order the parts anyway.  

I don't have a huge stock of transistors, and this takes about thirty, so I'll need some suggestions on what to order. I have many types, just not a ton of any one of them.

BTW, did you include that weird off-board circuit on either board when you laid them out?

[Keppy]

Great news, Jimi!

[pinkjimiphoton]

thanks keppy...i am crazy relieved!!!

i am psyched you're gonna play guinea pig...i will still buy the boards from ya when the time comes, cuz i wanna build a bunch of these for all my friends!

[Keppy]

Sounds good Jimi! It's R.G.'s layout now though, so I'll need his permission to sell you boards 

[pinkjimiphoton]

ok. maybe we can all work something out.

[R.G.]

I guess if you're looking for a guinea pig, I could build it. I was actually about to order the parts anyway.  

One has to be tough to try a first build!

I don't have a huge stock of transistors, and this takes about thirty, so I'll need some suggestions on what to order. I have many types, just not a ton of any one of them.

If it were me, I'd buy 25 to 100 of whatever I needed most of. That gets the price per transistor down under $0.10 each. Some, like the 2N3904, are as little as $2.00 per hundred.

I still need to do some introspection on the design. Clearly, the transistor at the voltage-regulator end has to be a high voltage type, and a 30V device there will probably be failing quickly. I know Jimi has sworn off messing with his unit, but perhaps we can get pin voltages on the transistors before he seals it up for good. 

BTW, did you include that weird off-board circuit on either board when you laid them out?

I didn't. I reasoned that it was a late inclusion, and may need tweaking anyway. In any case, it's simple - I think. I haven't done the head work to get the schemo for that out yet.

If you want to do a photo version of the layout, I'll help you get one done just to check the accuracy.

i will still buy the boards from ya when the time comes, cuz i wanna build a bunch of these for all my friends!

It's R.G.'s layout now though, so I'll need his permission to sell you boards

As for more boards, I quit coordinating group buys years ago, because it takes so much time.  However, If someone wants to do the legwork, organize the herd of cats, collect up money, handle the shipping, etc, etc.,  commercial boards could be had at a reasonable price for a limited quantity. I *do not* want to go into the board sales business again. And I *am not* interested in making money on boards. So someone who wants to go to the trouble can run this deal. I will not. I also do not have time to debug copies of a clone which may or may not work. So if one of you guys wants to mess with this, you need to PM me.

I'm just being straightforward about this. There may be hidden problems. Someone who was conservative and cautious would wait until at least one guinea pig had verified that the layout could produce a working unit. There is a fair chance of issues lurking inside. And also the wiring between the two boards and the controls (not all of which have been scoped out and become well known yet)

I feel grateful to the folks who gave me a pot load of information. The least I can do is provide some information in return.

[pinkjimiphoton]

hi guys, i'm a little afraid to open the top up again, as with my luck, i'll break something else, lol...

but i'd be more than willing to open the fall plate up and read voltages on all the transistors if it'll be helpful!

one question...can i blow anything up doing that? it's just black lead to ground and red lead to the different legs of the transistors, right?

should i get a blow up of the layout done and write the voltages near each part (maybe more trouble than it's worth) or is it cool to say, do it like this:

t1
e=
b=
c=

and so on down the line? will that be enough info, or is it too confusing to do it that way?

i humbly await your instructions, sirs!

[Keppy]

ok, i figured since there's only like 5 caps in total that i thought were 25mf, i blew the schematics up about 7x the original size...

i still can barely tell, but it appears that on the bottom board, c14, 22,23 and 32 are ALL 2.5mfd, and on the top board, c1 is also 2.5mfd.

thanks r.g., without you i would have probably messed up heinously!!

so here's an updated and hopefully right BOM for the electrolytic caps:

bottom board

c 1 10mf@25v
c 13 10mf@25v
c 14 2.5mf@25v
c 15 10mf@25v
c  21 10mf@25v
c 22 2.5mf@25v
c 23 2.5mf@25v
c24 10mf@25v
c 31 10mf@25v
c 32 2.5mf@25v

top board

c1 2.5mf@25v
c6 1mf@25v
c8 100mf@25v
c9 10mf@25v
c10 10mf@25v
c11 100mf@25v
c11 100mf@25v
c12 50mf@25v

There are a couple of electros missing from your list: C6 on the bottom board (10uF) and C2 on the top board (1uF). Probably no biggie since the electros appear to be 25v across the board, but it'd be nice to complete the list.

[R.G.]

hi guys, i'm a little afraid to open the top up again, as with my luck, i'll break something else, lol...
but i'd be more than willing to open the fall plate up and read voltages on all the transistors if it'll be helpful!

I don't blame you a bit.

one question...can i blow anything up doing that? it's just black lead to ground and red lead to the different legs of the transistors, right?

You're correct - black lead to ground, red lead to each point you measure, then write it down, go the next. There is little danger in this. The only danger is if your probe slips off the lead you're measuring and shorts it to another lead. That's probably not a big deal in a low power circuit like this. However, just to improve the chances of not having even a non-fatal booboo, you can wrap the probe tip in tape or paint it with nail polish except for the very pointed tip so a slip is likely not to be even an issue. Not a big danger at all.

should i get a blow up of the layout done and write the voltages near each part (maybe more trouble than it's worth) or is it cool to say, do it like this:
t1 e= b= c=
and so on down the line? will that be enough info, or is it too confusing to do it that way?

That would be fine for my purposes. No need to annotate the drawing for me. I probably want to include a couple of voltages on filter caps, as well. It will really fill in the operation for me.

It's fine to just do the fall plate board. I'm curious about the console board, but not enough to ask you to open it back up.  

[pinkjimiphoton]

guys, just as an afterthought...

make all the cap voltages MINiMUM 63 volts, and the bigger ones 100 volts.

25 may be asking for problems.

that said, ya know, the "mystery circuit" can be easily defeated simply by pulling off one lead from the fall board...

so tomorrow, i'm gonna do that, and report back as to what the heck it seems to do. it's either a preamp, or a treble boost...or a simple buffer, it's a .1mf ceramic disk, one resistor, and a single transistor. it connects on the right side of the fall board (with the notch cut out at the bottom) fifth notch up from the bottom, (parrallelled with the red lead)
and on the left side 2nd from the bottom. so it should be easy to disable just by pulling that one lead. if the thing stops working, ghosts start flying around, or anything truly weird happens it should be obvious...but i have a feeling it's there to limit bass on the input to limit motorboating, as this circuit will run away into oscillation all over the place if you let it.

if it doesn't seem to have any effect, i'm with R.G....screw it, get it out of there. but if it IS  crucial part of it, hey, we'll know, so hold off on etching a board or anything til i can report back. no sense starting to build up a clone, and then do what ludwig did, right? if it's important, i can't imagine adding a couple more components to the board at this stage would be that big a deal. if rg's right, cool...but if he's not, better to catch it now in my opinion.

also that said, i will definitely pull that wire tomorrow to see what happens...may take me a day or two to get the voltages, as my woman is ready to slaughter me in my sleep for spending so much time online and in the phase II's guts!!

onwards and upwards...i too will try to be a guinea pig, once we know what transistors to use, etc..

more tomorrow, g'nite guys...peace!

[R.G.]

if it doesn't seem to have any effect, i'm with R.G....screw it, get it out of there. but if it IS  crucial part of it, hey, we'll know, so hold off on etching a board or anything til i can report back. no sense starting to build up a clone, and then do what ludwig did, right? if it's important, i can't imagine adding a couple more components to the board at this stage would be that big a deal. if rg's right, cool...but if he's not, better to catch it now in my opinion.

Oh, sure, do the smart, right thing. 

Don't worry, I'm not etching yet.

[Keppy]

Sorry about my earlier post, Jimi. Upon further review, I found you answered my cap question already. This thread's getting long...