Ludwig Phase II settings and sounds demo.

[Ry]

Thanks for the advice on the external pot!  It will come in handy down the road here.

So I'm slowly stuffing resistors and noticed two unmarked ones on the parts placement diagram.  I haven't found what these are yet, but I'm not half done either.  Any ideas what they are? 
They are located in the following places:
1) on the Fall Plate just to the left of RF74
2) on the console board under RF31

Thanks!

[R.G.]

Those resistors are some of the leftovers and departures from the original PCBs.

The two resistor spaces, one marked RF74 and the other unlabeled one next to it are to be left open. RF74 is the 3.9 ohm resistor the original used in series with all the incandescent lamps. It's not needed with the LEDs I used in this version. The unmarked position is a resistor on the filter board of the original, but I moved that resistor to the console board. I left an empty space for it in case there are some "originality" nut... er, enthusiasts  who wanted them. Best advice: leave them empty.

The resistor under RF31 (which I moved from the filter board, it belongs with the console circuitry) is actually the tapering resistor that was mounted out on the footpedal pot in the original. It was not on either PCB in the original. I don't like mounting parts out on pots, switches, jacks, etc. so I put a position for it on the console board. You can ignore that position, and put it on the pot if you like.

UK had already found those, and the next iteration of documentation has clearer descriptions on those resistors.

[Ry]

Thanks, R.G.!  I will put the tapering resistor on the board, I hate to complicate control wiring with resistors when I don't have to.

I found one more unmarked resistor on the Fall Plate right under CF14, between RF33 and RF34.  What is this one?

[R.G.]

I found one more unmarked resistor on the Fall Plate right under CF14, between RF33 and RF34.  What is this one?

It's a board position for a 1M resistor that was soldered on top of R33. One of the "victim" units had it, the other didn't. I think it was a last minute addition in manufacturing like the post-amplifier that was constructed on terminal strip. Leave it open until you test your unit and we find it's needed or not.

[Keppy]

Actually, I think two of the three units had it. Jimi's and one of Dino's. Dino reported that it sounded ever so slightly better with the resistor in place.

[digi2t]

Actually, I think two of the three units had it. Jimi's and one of Dino's. Dino reported that it sounded ever so slightly better with the resistor in place.

Yup. I added a 1M resistor to the other, earlier, unit. I find that it cuts back a tiny bit of very high end hiss. Maybe they had complaints from people using high gain equipment? 

[R.G.]

Hmm. I thought it was only the one unit. In that case, put a 1M in that position.

[Ry]

Will do!

[Ry]

Ok, back at it. I have found that the bom calls out rf+3 both as a 47k and 68k resistor.  I have it currently populated as 47k. Which is correct?  The schematic says 68k. I'm guessing this is probably the correct value.

I've also found that rf32 is both a 4.7k and 470k resistor. I currently have it populated with 4.7k, which is what's shown on the schematic.

Edit: r32 is 470k, it is not present on the bom, it is listed as rf32.

Ry

[digi2t]

I've also found that rf32 is both a 4.7k and 470k resistor. I currently have it populated with 4.7k, which is what's shown on the schematic.

I'm looking at the original schematic (copy from the inside of the unit), and it shows RF32 as "47" on that filter. The mirror resistor on the other filter (RF56) is a 4.7K. I don't have access to my units right now, but I can crack one open tomorrow to check if RF32 is ohm, kohm, or what.

Ok, back at it. I have found that the bom calls out rf+3 both as a 47k and 68k resistor.  I have it currently populated as 47k. Which is correct?  The schematic says 68k. I'm guessing this is probably the correct value.

I believe that this the extra terminal strip circuit in the original. In the original, there are only two resistors, a 10K, and a 47K. I don't recall seeing a 68K across B and C of the transistor. Again, I'll take a look tomorrow.

Edit: r32 is 470k, it is not present on the bom, it is listed as rf32.

R32 (console) = 470K.
RF32 (fallboard) = as mentioned above, to be confirmed.

Dino

[Ry]

Ok, I have another question (more of a request if anyone has this info handy).  The BOM says that all NPN transistors can be 2n5551 and all PNP can be 2N5401...but there isn't a list correlating which transistor numbers are npn and which are pnp.  I can ultimately work through the schematic and pick out which is which, I know the difference, I just wondered if anyone had a tabulation of the transistor numbers on the layout with an indication of which type corresponded to which transistor.

The build is going quite well, done with film caps, diodes, jumpers and resistors with the exception of the outstanding questions above.  I will likely get to electros and some transistors tomorrow!

Ry

[Keppy]

R.G. put that information in a PDF that he sent me when I was making the first one. I'd PM him for a copy. I've got one too, if he doesn't mind me sharing it.

[digi2t]

Ry,

First off, sorry for the delay, it slipped my mind.

Resistor RF32 is 4.7K.

I believe that this the extra terminal strip circuit in the original. In the original, there are only two resistors, a 10K, and a 47K. I don't recall seeing a 68K across B and C of the transistor. Again, I'll take a look tomorrow.

Sorry again, I gaffed here. There are 3 resistors on here, as per R.G.'s schematic in the "Build a Clone of..." article. there's a typo on the list.
RF+1 = 10K
RF+2 = 47K
RF+3 = 68K

That should put you in the right.

Cheers,
Dino

[Ry]

Thanks for checking it out Dino!!  No worries, I didn't get back to it until yesterday.  I'll check over which values I have populated and adjust accordingly.  I'm starting to get excited about this build as I see the boards being more and more populated.

Ry

[Ry]

Hey guys, what is the value of the tapering resistor across the lugs of the pot in the wah enclosure?  I can't seem to find it.  In the picture that dino posted of his, it looks to be 31k?  I don't trust my eyes and thy seems high for a 5k pot...

Thanks!

Ry

[Keppy]

33k.

[Ry]

Thanks!

[Ry]

It's all soldered up.  I plugged it in and...nothing.  No LEDs, no sound, not even bypassed guitar signal.

I suspect there is something wrong in the power supply.  I'll start debugging it on Monday, working through the voltages.  I need to get a wah enclosure together and get the 5k pot in there as well.