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Need help finishing/debugging my builds (overdrive/boost and tremelo)

Started by CaptainLark, January 13, 2014, 02:36:59 AM

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CaptainLark

January 13, 2014, 02:36:59 AM
Hey guys,

I am currently building a couple of clones, one being that of a Super Duper and the other is a EHX Pulsar. I have used the layouts from Tagboard effects/Guitar FX Website.

http://tagboardeffects.blogspot.com.au/2012/01/zvex-super-duper-2-in-1.html#comment-form
http://tagboardeffects.blogspot.com.au/2013/07/ehx-pulsar.html#comment-form

My issue with the Super Duper is that side 1/input side works well. I am also able to get a bypass signal. When the second boost is engaged by itself it seems to work, but whenever switch 1 and 2 are both engaged together, then i have no signal. The Volume reacts with Stage 1, but not the second.

And my issue with the Pulsar is when the toggle switch is in the down position, whenever the Intensity pot is below 75%, i experience a low hum . The tremelo effect is still working, but it is not the guitar coming through, just a sort of watery low sound. Also, the speed knob works, however once it reaches 50%, it starts to slow back down from anything after.

Happy to post pics if required. Both builds are on stripboard aswell. I have followed everything that the layout describes (no major changes were made, if any).

I am relatively new to the art, however, I have been quite successful with previous builds, so it isnt my first builds. At the moment, I am a bit stuck and racking my brain. Any help or pointers would be greatly appreciated.

Thanks in advance. If any more information is needed, please just ask.

- Lark

duck_arse

#1
January 13, 2014, 09:38:23 AM
post the pics, and we'll go from there. just me typing that cures the problem about 20% of the time.
" I will say no more "

GibsonGM

#3
January 13, 2014, 06:39:16 PM
Why don't you go here, and read what it has to say?  http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

Getting the info you're asked to provide will help us figure out what's wrong!!   :icon_cool:
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duck_arse

#4
January 15, 2014, 09:16:32 AM
the first two links are the same.

this won't help, but I'm begining to think green wire is the problem. lots and lots of builds w/ problem seem to be wired with nothing but that shade of green wire. as you were.
" I will say no more "

CaptainLark

#5
January 16, 2014, 01:52:06 AM
Hey,

If you click on the link, it should take you to all of the photos. The first 2 are the super duper and the second 2 are the pulsar.
I am still experiencing the same problems from both of these pedals.

I am able to "fill out the form" for fault diagnosing, I just thought it would be easier to explain the issues I am experiencing, and I am also not confident in performing the measurements of the transistors etc. I do own a DMM, but really only understand how to check for continuity.

Can anyone help? Any help would be appreciated.

aron

#6
January 16, 2014, 03:49:43 AM
Really hard to tell.  I wish the 2 switches were oriented as on the layout. Switch 2 looks miswired. Look it over carefully.

duck_arse

#7
January 16, 2014, 08:58:26 AM
captain, I click, I go, but all I get is the one image displayed on a page, no arrows, no menus, no options whatsoever.

and even though tagboardeffects is in aust, as am I, I can never get a page to load fully in a resonable lifetime, and can never seem to get any circuit diagrams.

if you could post the circuit diagrams of both circuits, as well as the layouts, we can go from there. as for using your multimeter, have a go on googoo and look for a how-to, then practise on your circuits here, and we'll help. follow and post the debug page as best you can, and ask us questions if you're stumped. it sounds like you're describing a simple wiring error, which you may well find using just the continuity setting and the circuit diagram.
" I will say no more "

CaptainLark

#9
January 26, 2014, 05:36:25 AM
For The Pulsar:

Here is the checklist to fill out:
1.Speed knob climaxes at 12'o'clock, then decreases once it continues to rotate clockwise. When pedal is in one of the settings (either Trem or Chop) the intentsity knob creates a strange sound, where the effect is present, but very minimal. It sounds as if the sound is extremely muffled, and not responsive. It is very hard to explain. It doesn't sound correct until it is turned to 75%.

2.Name of the circuit = EHX Pulsar

3.Source of the circuit (URL of schematic or project) = http://tagboardeffects.blogspot.com.au/search/label/Tremolo

4.Any modifications to the circuit? Y or N

5.Any parts substitutions? If yes, list them. No. Nothing major. Maybe a different value resistor, but everything is pretty close to the original. I used a DPDT switch for the Trem/Chop instead of a SPST.

6.Positive ground to negative ground conversion? No

7.Turn your meter on, set it to the 10V or 20V scale. Remove the battery from the battery clip. Probe the battery terminals with the meter leads before putting it in the clip. What is the out of circuit battery voltage? => No battery clip

Now insert the battery into the clip. If your effect is wired so that a plug must be in the input or output jack to turn the battery power on, insert one end of a cord into that jack. Connect the negative/black meter lead to signal ground by clipping the negative/black lead to the outer sleeve of the input or output jack, whichever does not have a plug in it. With the negative lead on signal ground, measure the following:
Voltage at the circuit board end of the red battery lead =
Voltage at the circuit board end of the black battery lead =

Now, using the original schematic as a reference for which part is which (that is, which transistor is Q1, Q2, etc. and which IC is IC1, IC2, C1, and so on) measure and list the voltage on each pin of every transistor and IC. Just keep the black lead on ground, and touch the pointed end of the red probe to each one in turn. Report the voltages as follows:

Q1 (Left top)
C = 1.2
B = 162.00
E = 0

Q2 (Left bottom)
C= 1.2
B= 0.532
E= 0

Q3 (Right)
C = 0.242
B = -2.3 (?)
E = 0

IC1 (or U1) (Counterclockwise from top left)
P1 = 144.5
P2 =7.91
P3 = 7.83
P4 = 0
P5 = Goes from 0 to 200 repeatedly
P6.= 14.37
P7 = 7.89
P8 = 145.1


D1
A (anode, the non-band end) = 15.0
K (cathode, the banded end) = 14.36


I hope this helps.....

CaptainLark

#10
January 26, 2014, 05:43:34 AM
Heres the Super Duper

Here is the checklist to fill out:
1.Gain 1 works fine, Gain 2 I get no signal. No signal when both switches are engaged. Get bypass signal when both are disengaged.

2.Name of the circuit = Zvex Super Duper 2-in-1

3.Source of the circuit (URL of schematic or project) = http://tagboardeffects.blogspot.com.au/search/label/ZVex

4.Any modifications to the circuit? N

5.Any parts substitutions? If yes, list them. No. Nothing major. I used 2 x 4.7M together instead of 1 x 10M resistor.

6.Positive ground to negative ground conversion? No

7.Turn your meter on, set it to the 10V or 20V scale. Remove the battery from the battery clip. Probe the battery terminals with the meter leads before putting it in the clip. What is the out of circuit battery voltage? => No battery clip

Now insert the battery into the clip. If your effect is wired so that a plug must be in the input or output jack to turn the battery power on, insert one end of a cord into that jack. Connect the negative/black meter lead to signal ground by clipping the negative/black lead to the outer sleeve of the input or output jack, whichever does not have a plug in it. With the negative lead on signal ground, measure the following:
Voltage at the circuit board end of the red battery lead =
Voltage at the circuit board end of the black battery lead =

Now, using the original schematic as a reference for which part is which (that is, which transistor is Q1, Q2, etc. and which IC is IC1, IC2, C1, and so on) measure and list the voltage on each pin of every transistor and IC. Just keep the black lead on ground, and touch the pointed end of the red probe to each one in turn. Report the voltages as follows:

Q1 (left)
D = 10.48
G = 3.97
S = 3.12

Q2 (right)
D= 14.13
G= 4.55
S= 13.71



D1 (left)
A (anode, the non-band end) = 0
K (cathode, the banded end) = 4.00

D2 (right)
A (anode, the non-band end) = 0
K (cathode, the banded end) = 4.6


Please let me know if anyone has any ideas. I really want to finish these ones off.

duck_arse

#11
January 26, 2014, 09:17:20 AM
cap'n, the pulsar.

http://www.tonepad.com/getFile.asp?id=29

working with the above as our circuit diagram. I just wish they would fully annote these things, with part ref and value. anyway.

there is something very wrong with your pulsar voltages around IC1. I can't really make out anything in your photos, we need clear shots of the top and bottom, so as we can see resistor colours, etc. pin 4 and 5 of the IC are connnected together and should both be 0V! and not moving. pin 8 should be at your supply voltage, which you haven't posted. (step 7). and pin 3 should be a little more than half the supply voltage, and not varying.

now I look again, you are using 15V supply for a 9V circuit? check your electros are 25V at least, and check you are not applying AC volts instead of DC volts. power off, probe around the IC on ohms range, and see what is connected to what. I still can't get anything out of the tagboards site.

I'm unfamiliar with the oscillator section, so I'll have a bash on the breadboard tomorrow to see what is.
" I will say no more "

duck_arse

#12
January 26, 2014, 09:33:36 AM
for a circuit:

http://1.bp.blogspot.com/-ffxJwQk4zok/TyEiPb_eyLI/AAAAAAAAAuk/HL3-cV2rMyU/s1600/Super-Duper+2+n+1.gif

again you've not posted yr voltage, and it still looks to be 14V or more, on a circuit designed for 9V. it may not matter at all, but watch your cap voltage ratings! the voltages on Q1 and Q2 will both vary with the 5k level pots, so set them both either 0 or 10, and retest your voltages. you can then swap the two transistors and see what the voltages do. both sections are identical, so Q1 in Q2's hole shold read the same as when it is in Q1's hole. you can also bridge the "A" connection to the "D" connection to test the second section.

that should be enough to go on with, let us know what you find.
" I will say no more "

CaptainLark

#13
January 26, 2014, 07:55:17 PM
Thanks duck.

I'm just at work at the moment, so I will have a look at this when I get home. I'm fairly sure I was using DC on my meter, and that it was set to 10V. Sorry mate, I am still learning these things, especially on how I use my DMM, so I appreciate your help and patience. Look out for a reply later on.

Cheers

duck_arse

#15
January 27, 2014, 10:04:00 AM
well, I look at the super thing again, and something jumps out at me. both transistors/mosfets are supposed to be facing the same way. the flat face of both should be facing your thumb in that picture. that might help somewhat.

when you do voltages on these pedal circuits, mostly you will use DC, sometimes shown as a straight line over a dashed line. when taking the voltages, take them without anything making a signal at the input. always, except in some specific circumstances, put the tip of the black probe on earth/ground/0V of you circuit. you can alligator clip it to the input jack sleeve, for instance. then poke about with the red probe, and see what you get.

your 9V supply sounds dodgy. it may go as high as 15V when unloaded, so you should measure the dc voltage with no circuit connected, and then with a circuit, and give us the readings. also tell the nameplate ratings on the supply, please.

as for the pulsar, you'll need to redo those voltages around the IC, and the voltage at the junction of R8//R9 please (5V0?). pins 1, 2 and 3 should all be VERY close to this voltage. have a read of this thread about pin numbering on ic's.

http://www.diystompboxes.com/smfforum/index.php?topic=104701.0

and in and around Q2 and Q3, set your meter to AC Volts, with the ~. your meter may give lots of beeping if it autoranges, if it does, try moving the rate pot towards the middle. you should read more than 1V AC on both transistor collectors and bases, depending on the rate setting. if no ac readings, the your oscillator needs attention.

let us know how you go, if you need more or less help.
" I will say no more "

CaptainLark

#16
January 27, 2014, 05:40:55 PM
Hey duck,

My bad on the Super Duper Transistors. Had a brain snap, and put one back in the wrong way when I was experimenting. I wished that it was the problem, but it is still the same as before. I tried powering the pedals on my Effect Pedal Power Brick, and there are still no changes, however, I suspect the Power Supply I use is not specifically for effect pedal use. I have tested what you have asked on the circuits, both with and without power. Here are my results:

Pulsar with Power


Q1 (Left top)
C = between 1 and 2 (fluctuates)
B = 137.1
E = 0

Q2 (Left bottom)
C= 0
B= 55.2
E= jumps between 60 to 75

Q3 (Right)
C = 0.255
B = -1.5 (?)
E = 0

IC1 (or U1) (Counterclockwise from top left)
P1 = 144.6
P2 =8.06
P3 = 8.06
P4 = 0
P5 = Goes from 0 to 200 repeatedly
P6.= 14.67
P7 = 8.06
P8 = 145.2


D1
A (anode, the non-band end) = 7.0
K (cathode, the banded end) = 0

R8/R9 Junction - 7.93/7.91


Now the Pulsar without power


Q1 (Left top)
C = 0
B = 0
E = 0

Q2 (Left bottom)
C= 0
B= 0
E= 0

Q3 (Right)
C = 0
B = 0
E = 0

IC1 (or U1) (Counterclockwise from top left)
P1 = 144.5
P2 =7.91
P3 = 7.83
P4 = 0
P5 = Goes from 0 to 200 repeatedly
P6.= 14.37
P7 = 7.89
P8 = 145.1


D1
A (anode, the non-band end) = 7.0
K (cathode, the banded end) = 0

R8/R9 Junction - 0/0

CaptainLark

#17
January 27, 2014, 07:29:35 PM
Here it is for the Super Duper

With power

Q1 (left)
D = 11.67
G = 4.22
S = 3.61

Q2 (right)
D= 14.34
G= 4.66
S= Goes from 0 to 200 repeatedly



D1 (left)
A (anode, the non-band end) = 0
K (cathode, the banded end) = 4.2

D2 (right)
A (anode, the non-band end) = 0
K (cathode, the banded end) = 4.65


Without power

Q1 (left)
D = .385
G = 186
S = 0

Q2 (right)
D= .345
G= 156
S= Goes from 0 to 200 repeatedly



D1 (left)
A (anode, the non-band end) = 0
K (cathode, the banded end) = 144.4

D2 (right)
A (anode, the non-band end) = 0
K (cathode, the banded end) = 141.9

Do you think the movement from 0 to 200 on the 2nd transistor could be some sort of voltage leak?

What were your thoughts on the values of the electro caps?

thanks

duck_arse

#18
January 28, 2014, 10:41:01 AM
wwwweeeelllllllllll ............

there is still a problem with your measuring method. something is not right. if your supply is 9V, you won't have any voltages around these circuits any higher than 9V. and although you show betwen 11 and 14 on your drains in the souper, the gate voltages look about right. the D1 and D2 kathode voltages match your gates, but the anode volts don't match the source they should be connected to. and when you say "without power", what do you mean? there should be 0V at all points in the circuit without power applied.

so, if the first section still works, you get an output that varies with the "level" pot, and the second section doesn't work, swap the transistors and see if the first section still works. and if just the second section does work, and provides an output that varies with the second "level" pot, then it must be something off-board causing the problem, and that would be the switch wiring, jacks or volume pot wiring. that is where you switch off the supply, and use the lowest ohms range on the meter to follow the wires from point to point on your diagram, and make sure they are indeed connected and not shorting to others around them.

as for capacitors, you only need a voltage rating  at least as high as the voltage applied to it, but it is usual to use caps rated at least 130% of the supply voltage, for extra bulletproof-ness. your cap ratings are fine and dandy for 9V use.

and the pulsar. well, I breadborded it, and it works. again, you have some voltages that are higher than the supply voltage, which apperas to be 8V according to pin7 of the IC. BUT, the voltage at the R8//R9 junction on my board wa near 5V, with a 9V supply, so you have a problem there somewhere. you need the meter on ohms, and circuit power off, and probe around to see why there is not enough resistance between the junction of the 2 resistors, and the supply rail, V+. pin 6 will follow the voltage at pin 3, so we can tell there is something screwy with the voltages as shown.

so it looks like you've still got some work to do with the meter. let us know.
" I will say no more "

GibsonGM

#19
January 29, 2014, 06:34:32 PM
Hi Captain,

Don't get discouraged...everyone is here trying to help you.  Can you set your meter for how you would measure a DC voltage, and take a pic for us?  Something is not right.

Try setting it that way, and putting your black probe on the "-" of a known-good 9V battery, with your red probe on the "+".  You should show nearly 9V.  8.4, 7.9, or whatever is fine.  If you don't get SOME reasonable reading, something is VERY wrong!

To measure DC voltages in your stomp circuits, you would clip or otherwise attach your black lead to the circuit ground...the "-" of the power supply.    Then you probe around with the red probe, being careful not to short adjacent contacts together.    Learning about your meter is the BEST thing you can do to make yourself faster at debugging, and better all around in the art of electronics.  It is FUNDAMENTAL! 

We'll help get this up and running as you get better at those skills :o)   

https://learn.sparkfun.com/tutorials/how-to-use-a-multimeter
  • SUPPORTER
MXR Dist +, TS9/808, Easyvibe, Big Muff Pi, Blues Breaker, Guv'nor.  MOSFace, MOS Boost,  BJT boosts - LPB-2, buffers, Phuncgnosis, FF, Orange Sunshine & others, Bazz Fuss, Tonemender, Little Gem, Orange Squeezer, Ruby Tuby, filters, octaves, trems...
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