stupid question? JMK Hamlet + 18v?

[heathfball20]

Im building the JMK Hamlet+ Delay.... it is an 18v pcb. i dont have an 18 volt power supply. Will it still work on 9 volts? Do i need to make any changes?

[heathfball20]

Schematic link here

http://jmkpcbs.com/wp-content/uploads/2014/03/Hamlet+.pdf

[slacker]

You don't need an 18 volt supply, it's powered by 9 volts, it then uses an LT1054 charge pump chip to generate the 18volts.

[heathfball20]

Awesome! Thanks bud!

[heathfball20]

Also, what does the biasing trim pot do? Do i need to adjust this to get sound?

[slacker]

It sets the bias for the FET stage which provides the output for the delayed signal. Just adjust it until it sounds good.

[heathfball20]

Here are my pin voltages......

Pt2399
1=4.94
2=0
3=0.53
4=0.66
5=2.46
6=0
7=2.48
8=2.47
9=2.46
10=2.46
11=2.46
12=2.46
13=2.46
14=2.47
15=2.46
16=2.46

Taptation
1=4.95
2=3.50
3=fluctuates
4=4.35
5=fluctuates
6=fluctuates
7=4.76
8=4.95
9=0
10=0
11=4.76
12=1.15
13=3.12
14=0

LT1054
1=1.18
2=6.08
3=0
4=0
5=0.14
6=2.54
7=1.39
8=11.04

MCP41100
1=4.95
2=0
3=0
4=0
5=2.47
6=2.47
7=0.05
8=4.95

D1 1N5817
k=21.4
a=16.82

D2 1N5817
k=16.85
a=11.05

D3 12v zener
k=11.08
a=0

D4 1N5817
k=11.08
a=11.43

D5 LED
+=0.53
_ =0

REG 78L05
I=11.11
G=0
O=4.95

Q1 2n5088
1=2.14
2=1.85
3=11.44

Q2 2N2457
D=0
S=0.71
G=3.71

Q3 BS170
D=0
G=Fluctuates
S=0.05

[heathfball20]

No sound at all. With the effect off, not guitar sound. With it on, no guitar sound. No ground buzz or anything. Its quite frustrating. Its like there is no continuity at all between tips.

[heathfball20]

Just used my meter, and there is no continuity between tips

[duck_arse]

recheck those voltages on the PT2399 for me. pin 1 should be fed from a 5V regulator, and pin 2 should always be 1/2 pin 1 voltage. yours is 0V. also, pins 3&4 should be 0V, ground, hard, with no difference between. yours aren't.

also find if your in-tip reaches the board input, and your out tip reaches your board out. and can we see photos?

[heathfball20]

Ok, so i was looking at the pinout numbers on the schematic. I take it they're actually in order rather than how the schematic reads?

With them in order,
Pt2399
1=4.94
2=2.45
3=0
4=0
5=2.68
6=2.47
7=0.59
8=0.70
9-16 same as above

[heathfball20]

Also, i do have continuity between the in tip and the board, as well as the out tip and the board. Which leads me to believe its something within the board.

Fyi, i dontknow why i didnt think to include this earlier... I had to do a jumper from the 3rd leg of the mix pot, to R13, to the 2nd leg of the repeats pot. I found that the copper wire was torn from the 3rd leg of the mix pot, so i looked at the schematic to verify where it was running and created a jumper. How much will this affect things?

[heathfball20]

http://www.aronnelson.com/gallery/main.php/v/Schematics-etc/image_001.jpeg.html

[duck_arse]

if your "9-16 same as above" means "2.46" as in your first post (we are very pedantic here, it cuts down on misunderstandings), then those readings are ok. if you have tip to board, in and out, that is good. you won't get continuity from tip-in to tip-out because this circuit is not true bypass, and there are caps and transistors in the way.

your link - my circuit shows the mix pot connects to C9//R14, not to the repeats pot (see pedants note, above). please check and update us.

the pip or ding or hole on a DIP IC means from this end/corner, pin 1 then around anti-clockwise to pin 16, in this inst. IF IN DOUBT (ever), check the datasheet. check the datasheet anyway, keep a copy handy. hell, find datasheets for all the IC's and transistors used in your build, you might spot something.

[midwayfair]

Bypass is tails (active). The dry path is in the signal path regardless of the status of the effect.

First, your multimeter is either reading voltages too high or you aren't using a 9V adapter. Replace the battery in it if it's 9V. If it's 12V ... well, you probably won't damage anything, but it just makes it hard to comment on whether some voltages are correct.

Second, you can troubleshoot only the dry path by removing the 2n5457 and the PT2399. Get that working. It's only 5 parts. (You do need to have the bias trimpot turned up to its maximum resistance while doing so.)

Look up the datesheet for Q1. The pins are collector, base, emitter, not 1,2,3. Regardless, your base voltage, assuming it's the pin you've labelled 2, should be higher. The collector voltage in my builds usually settles closer to 9V, so you're probably fine there.

After you get that working:

Your FET voltages are completely incorrect. You need to look up the datasheet for the transistors you're measuring and remeasure those pins.

If you want to test the FET without the PT2399 in the circuit, you should still get signal with the mix and repeats pots up all the way.

Your drain voltage should vary with the trim pot between your total supply voltage after D1 and about ... maybe 1/3 of that (i.e., ~6V or lower depending on the exact FET). Your gate should also have 0V. Looking at your voltages, it looks like you mixed up the pin names, and have the trimpot all the way up. One of those pins should change when you change the trimpot.

Pins 7 and 8 on your PT2399, as listed, are incorrect. Pin7 at least is clamped to 1.7V by the green LED (the LED that prevents the PT2399 from overdriving). In a properly working effect, it literally CAN'T exceed 1.7V. Pins 7 and 8 are also "dynamic" voltages; they have a resting voltage that changes based on the current run through the chip. (They're current control pins for the chip.) So you've either measured those two pins incorrectly, have a short, or simply listed them wrong.

Someone else can comment if anything's wrong on the TAPTATION stuff; I don't do much with the digital chips.

Finally, audio probe results will help narrow down the location of the problem. Identify where you lose signal.

Also, some tough love: You sound like you're quite new at this. And this is an expert-level project. While I can do my best to help, a project of this complexity assumes a general level of troubleshooting ability. If you can't fix the dry path at least based on the information you've been given, then you may want to put the project aside and work on a few other things in the meantime. You can breadboard the analog parts of the circuit (the two transistor circuits involved) and the PT2399 path easily, so you can have a reference copy of the project to help troubleshoot the PCB.

[heathfball20]

Thanks Spephen and Jon P. I think im reading the schematic incorrectly.  I am new... this is only my 6th build. Is there a thread that could help me understand the schematics more? That i think will help me understand what im testing and why. I appreciate your input on the matter.

[heathfball20]

Stephen, pt2399 pins 9-16 are 2.46.

Jon, when you say the base leg of Q1 2N5088 needs to be higher.... how much higher? What is my target? So that i know i have fixed that...

[heathfball20]

Stephen, i dont see how the 3rd leg of the mix pot connects to c9 and r14 at all. Per the schematic. R14 is off the 2nd leg of the delay pot, and C9 is off the bypass.

[heathfball20]

Jon, ive found that i do not have continuity between the 3rd leg of the output pot and C3/C2. Should i solder a jumper between the 2? When i do a clamp jumper, there, i get clean tone from my guitar. Per the schematic, if im correct, that should fix the input dry signal issue...

[J0K3RX]

If you have found 2 open traces on this board that makes me wonder how many other open traces there may be that you haven't found yet? It doesn't look like the board has been damaged with the iron but, I can see the very fine trace going from pin 3 of the mix pot on the outer edge of the board all the way over to the center lug on the repeats pot and I also see it going to R13.. Running traces that close to the board edge is not good practice for obvious reasons. To go "down the rabbit hole" is to enter a period of chaos or confusion.