Ludwig Phase II tuning.

[Keppy]

Dino, go ahead and use whatever you want, and change it as you like. My post wasn't meant to be definitive, just reductive. Procedures like this get wordy fast, and we were due for an (over)simplified version. 

Now to film the demo, then back to the ring modulator... 

[Ry]

I simply cannot get CP8 below 5.5 v.  I can get the heel postion to 6.3, as well as the range from 2.7 to 6.3 v on CP9. 

I also find that I cannot get the voltage at TP 2 below about 15v at the toe.

Additionally, the animation is not working, but it may be due to the whacky voltages noted above.

I'm starting to walk through the board and see if I can see anything obviously wrong.  I'll start buzzing transistors to see if any look faulty.  Any other suggestions?

As for what is working...the fuzz sounds great and I can get the other tuning settings working easily.

[pinkjimiphoton]

well...if the fuzz sounds GOOD, that;s why your animation isn't working!

when mine screwed up, it was one of the trimmers on the fall board...suddenly th efuzz sounded great, but the animation etc wasn't working...so check them trimmers bro!

with mine, as soon as i replaced the 150r trimmer, the fuzz sounded weasily as sh*t, but everything else started working right, so try there...trimmers fail, and in this case, that one trimmer (on the original anyways) will cause exactly what you report...sublime fuzz, and that's about it. it also would probably account for the wack voltages you're finding...same thing happened with me, so don't give up. just for sh*ts and giggles, try jumpering that trimmer, and see if it comes to life, even if it's just a sudden formant/vowel/stuck wah sound. if it is, replace that trimmer...100r is in mine, but anything up to about 500r will work...Even a 1k pot will probably do. it wants to see about 100 ohms to work...so a 1 k barely on may do the trick, just for trouble shooting purposes.

i hate trimmers...i've had more fail on me than i've ever gotten to work.

keep your chin up ry!!


you'll get it!!

[R.G.]

I simply cannot get CP8 below 5.5 v.  I can get the heel postion to 6.3, as well as the range from 2.7 to 6.3 v on CP9. 

I also find that I cannot get the voltage at TP 2 below about 15v at the toe.

Additionally, the animation is not working, but it may be due to the whacky voltages noted above.

I'm starting to walk through the board and see if I can see anything obviously wrong.  I'll start buzzing transistors to see if any look faulty.  Any other suggestions?

I think it's time for the great DC voltages checkout. If you could, measure the DC voltage with no signal in on the transistors. Do this with animation on and off.

[pinkjimiphoton]

hopefully keppy can post some voltages...i have a feeling the clone is gonna be way different from the originals...probably in the ballpark, but different from what we expect.

i know for SURE from messing with mine that the fuzz only sounded great when the other stuff didn't!

[Keppy]

There was some confusion on this point in the past: the ANIMATION is distinct from the FILTERS. I had the filters working with the treadle long before the animation came alive, but because I wasn't specific on that point the group here spent a day trying to troubleshoot the part of my build that was already working. So, Ry, are your filters working at all? The animation won't do anything unless the treadle works first.

Also, when my first attempt did not have working filters, it was because some resistors on the filter board were the wrong value. I forget which ones were the culprit (36 & 57 maybe?), but check these:

- R32 4.7k
- R36 68k
- R38 4.7k
- R57 68k
- R60 4.7k

A pair of them were off by an order of magnitude (or two) due to misreading of a slightly blurry schematic. These are the correct values. Give a shout if the current BOM is incorrect.

[Keppy]

A few thoughts on this circuit:

- Why bother with a trimpot at 65 if we're just going to set it to 22k with the meter anyway? What is it about the function of that pot that we're missing?

- I've noticed that part of the unique sound of this unit seems to be that, even when it's not oscillating, it ALMOST is. The filters ring quite a bit, and there are little chirps and squawks that happen at the extremes of the treadle, especially with the animation on. Having not dealt much with filters before this, I'm kind of intrigued by the phenomenon. Any thoughts on the subject?

[Ry]

Keppy,

Thanks for the replies!  I am getting some filtering.  Not nearly as vocal sounding as in Dino's video at the start of this thread, but the filters are certainly present and they love to squeal when I change switch positions.  I will check over the resistor values you mention.  I started working through the schematic in a couple areas and doing just that, making sure the resistors were correct.

I have actually been puzzling over the 22k setting of R65 for the last few days myself.  I have tweaked this pot when nothing else works, just to see if it had a positive affect.  It didn't do anything that I could tell to the voltages or the sound of the pedal through an amp.

As for the ringing filters, that certainly describes mine.  There are times where it seems like they are oscillating, but not in a way that I can control with any of the pots.

From what you're saying, it doesn't seem like mine is too far from the mark.

R.G.,
I will set about measuring all of the voltages on the transistors with and without the animation on and report back.

Jimi,
I will look over the trimmers and try jumpering the one you mention.  It would be a shame to lose the cool fuzz sound, but it's a fair price to pay!

Thanks again, guys!

[Ry]

I've checked the resistors mentioned by Keppy and Jimi, they all look good.  So without further ado - here are the voltages on each transistor.  I double and triple checked most of these, but it's still possible that I made a mistake (there area lot of transistors and I kept getting backwards on Emitter and collector between the Fall and console Boards).  I took the readings with the FFM pot full on, treadle in the toe position, once with animation on, once with it off.  If the readings are the same with both animation on and off, I have noted so by indicating 'same'.  If the reading was in the mV range, I have indicated 0.  For Q2, I have likely called the pins the wrong things, I kept to the notation of EBC as with the other transistors.

It does look like some of these aren't active, especially on the console board.  However, this is with a number of the switches off, so they may be ok.

           With animation off           with animation on
          E           B           C         E         B         C
QF1     0         0.69       3.92                same
QF2     6.27     6.71      21.06               same
QF3     0         0.68       9.42                same
QF4     27.96   21.74     21.08              same
QF5     8.28     7.63       7.96               same
QF6     0         0.67       7.98                same
QF7     2.92     3.60       9.00                same
QF8     2.90     3.51       2.93                same
QF9     22.5   22.34       2.94                same
QF10    2.34     2.95      25.16              same
QF11    21.45   25.16     21.57              same
QF12    2.86     3.20      17.66              same
QF13    2.94     3.62       7.97               same
QF14    3.66     4.36       3.77               same
QF15    3.67     3.52       3.06        2.83    4.1   6.89
QF16    21.88   21.26      6.91               same
QF17     2.46    3.06        25.06             same
QF18     22.08  21.42       17.82             same
QF19     3.65     3.52       17.85              same
QF20     3.65     4.33       3.72                same
QF21     8.35     8.71       21.05              same
QF22     0.603   1.25       29.34     33.9      1.24   25.2
QF+1    0           .668      11.45              same

Q1        32.4      31          35                  same
Q2        0         11.46       0.5         6-11v     11.2    0.5
Q3        0            0          13.4                 same
Q4        0            0          13.64               same
Q5        0            0          25.7                 same
Q6        35        42.6        36.2                 same
Q7        15.4        0          0                     same
Q8        0            0          25.82               same

whew

[R.G.]

I'll go check through the schemo to see if that's reasonable.

Which switches were on/off? Rocker positions?

[Ry]

Rocker was in the toe postion,
All of the pots were actually in about the middle of their travel,
The fuzz repeat switch was in the FFM position (up)
I believe that counter was on...it is now, but I can't recall if I switched that at some point or not.  Let's assume that it was on.  If questions arise around this, I can double check some things.
All other switches were off.

[R.G.]

QF4     27.96   21.74     21.08              same

ODD for base to be higher than collector. Pinout?

Q1        32.4      31          35                  same

Pinout? Base should not be higher than emitter. Also, depends on the animation
footswitch.

Q2        0         11.46       0.5         6-11v     11.2    0.5

Different when animation is on is good. Other things to sort first.

Q3        0            0          13.4                 same
Q4        0            0          13.64               same

I think there's a problem with wiring or the switch.Both bases should not be at zero.
The collectors should be one high, one low, and flip-flopping in time with the changes
on Q2 when animation is on.

Q5        0            0          25.7                 same

Something wrong here. Q5 base should not be at zero. Check for shorts.

Q6        35        42.6        36.2                 same

OK. I think you missed the pinout; The center pin is the collector, but the emitter and base voltages are right.

Q7        15.4        0          0                     same
Q8        0            0          25.82               same

Check pinout. One or the other base should be at about 0.6V. One collector should be high at a time.

[Ry]

For QF4: I double checked the voltages.  They are as I reported.

For Q1:  also double checked with attention to the pinout. The results are the same as I reported before. The animation switch has no effect on the results.  EDIT: the animation switch does have an effect when the fast start switch is in the FAST position.  When it is and animation is Not engaged, the voltages are:
E.                                                                                                       B.        C.  
Ramps down to 0 slowly from about 34 v when animation switched off.    0v.      35v

With animation and fast start on:
E.                        B.                                             C.
Ramps to 34v.    Seems to settle around 31v.    Solid at 35v

For Q3 and Q4: I would like to revise my answer slightly, however there is still a problem-

           Animation off.           Animation on
           E.     B.      C.            E.       B.       C.
Q3:     0.      0.7.    0.            Same
Q4:     0.      0.      13.7         Same

I double checked the base of Q5 and found the base to be at 0.7 v

I Agee with your statement about Q6, I had the pinout wrong.

For Q7 and Q8, I had the emitter and collector pinouts reversed on Q7, and the base of Q8 is, in fact, at 0.7v.  The Collector voltages don't switch. Q7 remains at about 16v and Q8 is at 0 no matter what the animation switch is set to.

EDIT:  the above readings for q7 and q8 are only valid with s4 (fuzz rpt) in the middle (both) position.  Here's a run through of the voltages in the other 2 positions:

For q7 in the down position (fuzz rpt):
Emitter is always 0 with animation on and off
Base is about 0 with animation off and on
Collector is about 26 with animation on and off

For q8 in the down position (fuzz rpt):
Emitter is always 0 with animation on and off
Base is about 0 with animation off and on
Collector is about 26 with animation on and off

For q7 in the up position (ffm):
Emitter is always 0 with animation on and off
Base is about 0 with animation off and on
Collector is about 15.5 with animation on and off

For q8 in the up position (ffm):
Emitter is always 0 with animation on and off
Base is about 0.7 with animation off and on
Collector is 0 with animation on and off

I obviously have a few areas to check.  Thanks for the quick analysis!

[Ry]

I'm debugging Qf4. I've traced through the connections on the schematic within the build file. Everything is connected per correctly and has the proper values. However, I checked it against the Ludwig factory schematic and noticed that where the build file shows rf14 connected to cf5, the factory schematic does not show a connection, rf14 is only connected the the collector of Qf3.   This may be an error that was caught in the original work that was done reverse engineering this pedal.

[R.G.]

I'm debugging Qf4. I've traced through the connections on the schematic within the build file. Everything is connected per correctly and has the proper values. However, I checked it against the Ludwig factory schematic and noticed that where the build file shows rf14 connected to cf5, the factory schematic does not show a connection, rf14 is only connected the the collector of Qf3.   This may be an error that was caught in the original work that was done reverse engineering this pedal.

I believe it was an error caught in the early work. R14 and C5 were connected in the original layout that Keppy got running.

[Keppy]

The factory schem is ambiguous, as there's neither a junction dot or a crossover arc, just a plain, straight-line intersection. They are indeed connected in my build.

[Ry]

Ok, I'll continue to dig into why the base is higher than the collector on that transistor.

[R.G.]

Once you know that one stage is a problem, sometimes if you measure the voltage on each end of the resistors, it tells you a lot.

For instance, there is only one way a resistor can have the same voltage on each end - that's if there is zero current flowing in it. If that's true, then either there are two voltage sources, one on each end, of exactly the same voltage (unlikely!) or one end of the resistor is open.

[Ry]

Once you know that one stage is a problem, sometimes if you measure the voltage on each end of the resistors, it tells you a lot.

For instance, there is only one way a resistor can have the same voltage on each end - that's if there is zero current flowing in it. If that's true, then either there are two voltage sources, one on each end, of exactly the same voltage (unlikely!) or one end of the resistor is open.

That's a great tip!  It's something that I once knew, but never used in practice, and was forgotten.  I was working through the voltages on each resistor in that stage, working it back to the 36v supply.  I'll keep on the path.

Do my long winded results above my resistor question shed any light on any of the other issues with my build?  I'm sorry about the format, I was typing things in on my iPad real time and having trouble making it as readable as I'd like.  The iPad is great for it's portability, but not so fantastic as a text editor on forums.

[R.G.]

For Q1:  also double checked with attention to the pinout. The results are the same as I reported before. The animation switch has no effect on the results.  EDIT: the animation switch does have an effect when the fast start switch is in the FAST position.  When it is and animation is Not engaged, the voltages are:
E.                                                                                                       B.        C.  
Ramps down to 0 slowly from about 34 v when animation switched off.    0v.      35v

With animation and fast start on:
E.                        B.                                             C.
Ramps to 34v.    Seems to settle around 31v.    Solid at 35v

Actually, that now looks OK, given what that transistor does.

For Q3 and Q4: I would like to revise my answer slightly, however there is still a problem-
           Animation off.           Animation on
           E.     B.      C.            E.       B.       C.
Q3:     0.      0.7.    0.            Same
Q4:     0.      0.      13.7         Same

I double checked the base of Q5 and found the base to be at 0.7 v

This *may* be OK. To check it out further:
Temporarily pull out Q2. (By the way, did you use the 2N2646 UJT or the 2N6027 PUT?) and set the switch to the "both" position.
With Q2 out, temporarily solder a wire into the hole for Q2 that connects to R6 and C3.
Now touch the free end of the wire to either end of R7 while watching the collector of Q3 or Q4. You should see the collector going alternately to ground and then to about 13.5-14V, flipping once with each wire touch. Check both collectors to see that they both do it.

If that happens correctly, check the collectors of Q7 and Q8. If they are flipping up and down as well, the section involving Q3, 4, 7, and 8 is working correctly, and problems with animation are in Q2. We had problems with Q2 in Keppy's build as well.