Pigtronix Philosopher's Tone Germanium Gold LTD  [traced]

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jwpartain1
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Post by jwpartain1 »

OK, here's mysticwhiskey's unfinished layout with runs that I found in RED. Still unfinished, as you can see the runs not connected to anything circled in GREEN. Maybe some more experienced members can fill in the gaps?

Obviously, red lines that intersect AREN'T really intersecting, they will be on opposite sides of the board if they do in this depiction.

One thing, under U2 those two unconnected runs, probably are connected, I just couldn't see the actual connection.

And another thing! The strip of four diodes to the right of our vactrol, the unconnected run there goes underneath the vactrol, just hard to see under there.

Sorry I didn't redo the layout myself, I don't have the skills yet required to do so. Thanks!
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Philosopher's layout.png
Philosopher's layout.png (153.22 KiB) Viewed 1424 times

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mysticwhiskey
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Post by mysticwhiskey »

Here's an updated version of the layout including jwpartain1's corrections.
PCB Trace - Second Draft.png
jwpartain1, do you have a multimeter to check continuity? If so, I have a couple of questions that hopefully could be answered:

Where is the via near C10 connected?
Does C5+ connect to U2-1?
Does C13- connect to ground?
Does U2-7 connect to the red traces you've put in?
Do U1-5 and U1-6 connect to the red trace you've put in?

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Post by jwpartain1 »

Hopefully this answers your questions! :) I heated the leads on C10 a little and pulled it out just a smidge - enough to see the connection to the lead there. Probably not good practice, but whatev' the pedal still works! :D

As for the lead under U3, I looked from every angle down there, can't find anything from it yet.

Another thing to note, the run I've highlighted in purple ( :lol: I know, what's with these colors, right?) isn't the actual trace on the board, the red one is (coming off C6).

Some more updates as well, I think this layout is pretty close to finished.. I'll have to go over it a few more times though. Thanks for the help mysticwhiskey! If anyone wants to try for a schematic, go ahead, I won't be trying, being the n00b I am :shock:
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Philosopher's layout 2.png
Philosopher's layout 2.png (168.66 KiB) Viewed 1351 times

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mysticwhiskey
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Post by mysticwhiskey »

Excellent! I'll update the layout with the changes. I've started a schematic, so hopefully with these new connections it will start to make a bit more sense than it does now.

Don't suppose you could check one other thing for me - I'm not sure about the right-pin connection to the uppermost diode on the far right (in the column of 6 diodes immediately under U3). From the looks of the picture of the PCB, I think the blue trace might actually connect to the next diode down, like so:
PPTDiodeConnection.png
PPTDiodeConnection.png (29.62 KiB) Viewed 1348 times
Any chance you could confirm this?

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Post by mysticwhiskey »

OK here's an updated layout including the latest corrections (and including the proper date this time, obviously I haven't yet adjusted to writing the year '2011' :D)
PCB Trace - Third Draft.png
We're missing 5 connections:
* Upper pin of C4 (I suspect this goes to ground)
* Pin 2 of U5
* Via under U3
* Pins 2 and 5 of U1

I'm working on a schematic too - it's incomplete due to the missing connections, and it highlights some likely mistakes on the layout. But I think we can make an educated guess at some of the connections based on the schematic. Will update once I've double-checked it and converted it from my hand-drawn one to an electronic version.

We're going to have to start naming the resistors and identifying their values. Since the actual names are hidden under the resistors themselves, we're not going to end up with the same names as the original. Any suggestions for the order in which we should name them? I guess it's kind of arbitrary.

Also need to name the diodes - I see there's some labels visible for some of them, but I can't determine which ones apply to which diodes.

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Post by mysticwhiskey »

Here's the first draft of the schematic. Quite a few places where there are missing connections. Also of doubt is the connection to 9V at the resistor after the 'Sustain' pot. I'm kind of guessing this would go to an opamp input (most likely choice would perhaps be pin 1 of U1?).
PigtronixPhilosophersToneSchematicDraft1_201101232005.png

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Post by mysticwhiskey »

Not shown in the schematic are the supply connections to the 3 dual-opamps. All have VCC+ = 15V, and VCC- = GND.

Still fumbling my way through using Eagle... :D

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Post by Hides-His-Eyes »

I actually helped in the design of this, so hopefully my insight is useful.

PGS asked us for an exclusive variation of the Philosopher's Tone. We tried a large number of variations of the grit control with Germs. (Only four of those diodes are for clipping, the others are for compression). Turned out that asymmetrical clipping sounded better for germanium. Gave us the softer germanium sound with a bit of bite that lacked when we used all Germanium. So to make it more pronounced we used 1 Germ and an LED. We wanted it to sound good, not just throw germanium diodes in it for the sake of them.

TLDR; we tried more and it didn't sound good. Less, is apparently, more.
Testing, testing, won too fwee

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Post by jwpartain1 »

Man! That's some quick work mysticwhiskey! I'll try to find some answers for the things you were wondering about later tonight, I've got a busy schedule today.. Thanks for all your help.

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Post by jwpartain1 »

OK, I've got some more stuffz.

C4 does GND on that top terminal.

I have continuity between U5-2 and U5-6.

I have continuity between a terminal of one of the diodes in our unconnected run under U3 and U3-6.

I tested the resistor in question VS. TP1 (the 9V test point) and it is continuous. (as well as pin 3 of our sustain pot, just double-checking)

I have continuity between U1-1 and U1-2.

U1-5 is continuous with TP1 (9V).

Hope this helps! :thumbsup

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Post by jwpartain1 »

mysticwhiskey wrote:Excellent! I'll update the layout with the changes. I've started a schematic, so hopefully with these new connections it will start to make a bit more sense than it does now.

Don't suppose you could check one other thing for me - I'm not sure about the right-pin connection to the uppermost diode on the far right (in the column of 6 diodes immediately under U3). From the looks of the picture of the PCB, I think the blue trace might actually connect to the next diode down, like so:
PPTDiodeConnection.png
Any chance you could confirm this?

Hey, sorry about the trip-post :( You are right here, it's as you have drawn it in this post.

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Post by mysticwhiskey »

Here's the latest layout and schematic. The section around U1B somehow doesn't quite look right to me. Same with the row of diodes underneath U3B in the schematic. :scratch:

We have one missing connection, pin 2 of U1. It's probably connected to pin 1, which would make U1 a unity-gain buffer.
PCB Trace - Fourth Draft.png
PigtronixPhilosophersToneSchematicDraft1_201101242005.png

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Post by Hides-His-Eyes »

I would expect to see the Ge diode used in asymetrical clipping, not in series with anything, from what the guy said to me that I posted above.
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Post by mysticwhiskey »

Hides-His-Eyes wrote:I would expect to see the Ge diode used in asymetrical clipping, not in series with anything, from what the guy said to me that I posted above.
Yep, you're probably right. jwpartain1, could you check to see if we've missed any ground connections in any of the diodes on the far right of the board?

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Post by mysticwhiskey »

I've been playing around with the 'Grit' sub-circuit in Spice and could not get the signal to clip as the schematic currently stands.

However I think I have missed a connection. jwpartain1, do you think you could check something for me - in the column of 6 diodes on the far right of the board, does the third one up connect to the trace running down the middle of the diodes, like this:
PCB Trace - Proposed Diode Feedback Correction.png
PCB Trace - Proposed Diode Feedback Correction.png (18.66 KiB) Viewed 1171 times
On your photo of the trace-side of the board, it looks like this connection could be there. When I make this change in my Spice simulator, I get assymmetric clipping of the signal. Just want to confirm if that connection is there on the board.

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Post by euronymous0001 »

as i see it when zooming on pic of the pcb, there is a connection there.
but my eyes could be failing on me :mrgreen:

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Post by mysticwhiskey »

Just waiting on jwpartain1 to confirm a couple of things:

1. The feedback diode connection question a few posts up
2. All resistor values

I have made the schematic changes in anticipation of (1) and it looks good on paper at least. Will post this once/if this is confirmed.

I have also put together a breadboard layout (in DIYLC) so I can test the circuit, but I can't do much more until we get resistor values.

jwpartain1, any chance of a hi-res photo of the board's component side, to help start the resistor identification?

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Post by dellamorte »

i have breadboarded the compressor section of this circuit and it sounds great so far .
here are the values i used
R1 - 10M
R2 - 10K
R3 - 10M
R4 - 10K
R13 - 2.2M
R16 - 10M
also i reversed C14 to get it to work
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Post by mysticwhiskey »

Great stuff dellamorte!

Since we haven't heard from the OP in a while, I thought I'd go ahead and post my revised schematic, assuming the feedback diode connection is as I think it should be:
PigtronixPhilosophersToneSchematicDraft_20110207.png

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Post by mysticwhiskey »

Let's try that again:
PigtronixPhilosophersToneSchematicDraft_20110207b.png

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