[Billy]

It should be a low to mid gain pedal R15 is the resistor to change you can do the ultra drive mod you’d wire in a dpdt switch with the stock 47K on one side and a 4K7 on the other which gives you masses of gain

 

So check R15 for cold joints etc initially

[Billy]

Thommo,

All gpcb boards are double sided so you can solder the switch LED’s, wires etc to either side without components to worry about the choice is yours a wee bit longer wire or solder the switch etc to the other side

As long as you wire it correctly it’ll function exactly the same

[Billy]

Nice a very unique look I like it

You know everybody’s gonna ask for a gutshot don’t you? Don’t disappoint now Michael!

I’ve stolen quite a few ideas from people’s gutshots

 

[Billy]

Wiring looks OK not 100% on the Kill switch whether the signal would follow the path of least resistance so I’d jumper it across from one side to the other lug 2 to 8 and leave the middle pole empty less chance of a dry joint

If you look at the schematic A and B would connect bypassing the LFO and sending signal back up to Q2 and OUT so I’m not totally sure if the jumpers you have would affect it in some way by connecting lug 5 to 4 as well I didn’t put the Kill switch option on my build so can’t really say

What Voltage readings did you get on the top and bottom of R7

[Billy]

I’m at work at the moment it’s still fairly difficult to see but definitely better maybe draw your 3PDT on some paper with each wire colour where it connects to on the 3PDT lugs and where it goes to eg IN T pad, ground etc

Just to double check you know your 3PDT lugs should be horizontal

 

 

 

[Billy]

Even though it works on the switch I’d reflow your solder joints there you may have a dry joint causing the low audio in that position obviously don’t apply too much heat 3 to 4 seconds till it flows nicely

[Billy]

Aha now I see it and understand how you’ve confused it being a beginner

Sometimes the beginners eye is better than the more experienced I read and re read the build document and still missed it!

So well done for finding that error now and again with the number of build documents an error slips through albeit rarely thanks for bringing it to our attention

Again it does demonstrate that reading the guides is very important because I’m more experienced I would have compared it to the schematic and quickly realised R1 was at the input and the on board CLR (current limiting resistor) was R23

I’ve started updating the components guide so I’ll now include a section on schematics so thank you for the idea Lilian

[Billy]

Don’t switch any wires until you’ve confirmed it’s incorrect

Definitely don’t scrap the project it get’s frustrating but you will get there! many 1000’s of people have built this circuit successfully

Anyway zooming into your pictures I can see that your solder joints on the jack sockets and what I can see of the 3PDT and Kill switch look dry it doesn’t look to me as if the solder has melted enough you need to be careful with switch lugs but hold your iron tip on them until the solder pools and flows it should only take around 3 seconds, what wattage is your soldering iron? is that lead free solder

We really need pictures of both the 3PDT and Kill switch looking directly down onto the top of them so we can try and trace your connections

From what I can see your IN jack is connected correctly and goes to the correct 3PDT lugs as do your IN ‘T’ from the pcb I can’t see your OUT ‘T’ and can just about follow your OUT connections on the 3PDT which also look correct the middle row doesn’t really matter at this point it being for the bi colour indicator LED which works

When you get faint signal it is almost always a dry solder joint / poor connection causing a high resistance to the flow of the signal but as you say your voltages are not that far off my main concern would be the collector of Q2 at 9.7v check what voltage you get both ends of R7

 

 

 

 

[Billy]

Your green jumper should go from middle right to bottom left yours looks like it goes from top right to bottom left on the DPDT switch

 

[Billy]

Dpeyton

If you have tremolo audio OUT at volume lug 2 and not beyond that would suggest a problem with the wiring from the pcb to the 3PDT incorrect wiring or dry solder joint or the kill switch is engaged

We would need a picture looking down on your 3PDT so that we can trace which lugs the pcb IN and OUT ‘T’ pads go to I can’t actually trace it in the photos we have

Volume Lug 2 is the circuit out which goes to the OUT jack tip via the 3PDT it is also very easy when the 3PDT is the wrong way up to wire your IN to your OUT the wrong way round ie wire your IN to the right and OUT to the left the quickest way to check is simply put your IN cable from your guitar into your OUT socket on the pedal and your OUT cable to amp into your IN socket if you get audio you’ve wired it the wrong way round on the 3PDT lugs, note in that scenario you would still get bypass

[Billy]

Yes that’s where I’d start adjusting the bias resistors distortion is more likely to come from Q2 which amplifies the signal from the buffer Q1 that’s not to say a FET wouldn’t cause it best way to suss where it distorts is to audio probe it

And yes the speed pot on mine was the same there are different versions of the pcb  simply swap lugs 1 and 3 around at the pot lugs not pcb pads no chance of accidentally lifting solder pads with too much heat desoldering then plus it’s a lot easier to desolder pot lugs just heat and lift away no need for solder braid or sucker or new solder

D1 is part of the circuit if it’s not there then you d have an open circuit

[Billy]

For this circuit yes 2N5089 is an NPN BJT (bipolar junction transistor)   which you could replace the 2N5088 with but the  2N5457 is a JFET  (Junction gate field effect transistor) so they work differently

 

You can use other JFETs I’ve got a 2N5459 in mine but it has to be a JFET type being voltage controlled rather than current controlled as with a BJT transistor

 

The closest N channel JFETS would be the 2N5458 and 5459

http://www.dnatechindia.com/Transistors-and-FETs.html

 

[Billy]

Insert a jack into your jack socket and follow it round to the solder lugs to make sure your wires go to the correct 3PDT lugs

 

If you insert a jack like below you can physically see what the tip of the jack connects to on the socket and then follow it round to it’s solder lug as Barry says it is difficult to see in both your builds if you have the IN jack tip wire from the 3PDT connected to the ground solder lug on the socket

 

[Billy]

That’s correct place your black probe to ground and touch each transistor pin with your red probe with your meter set to 20V DC

So you’re not getting signal into the Gate of Q1 is that correct the pin with the arrowhead on it in the schematic?

I’m assuming you’re using an unregulated power supply with over 10v that would affect the voltage going into the JFET 2N5457 Q1 and Q3 these are voltage controlled devices

 

If you don’t have audio going into Q1 then your problem lies prior to it C1, R2, R3

R2 and 3 form a voltage divider giving you half the power supply 4.5v

Here’s the transistor pinouts you can find this information in the datasheets or by searching 2NXXX pinout which I find easier to do there is some information on page 15 of the beginners guide to components

Q1 and 3 2N5457

 

Q2 and 4 2N5088

[Billy]

Just heat the joint for around 3 to 4 seconds until the solder melts and reflows heat the solder pad and component leg at the same time to get a good electrical connection, just for info the audio path is highlighted here in blue

 

Where is it you actually lose audio? The only part of the circuit you should get audio is in the aptly named ‘audio’ section in purple below

 

Here are the voltages you should be looking for.

Power Supply  9V

Q1
D  9V
S 5.2V
G 4.5V

Q2
C 5.4V
B 1.7V
E 1.1V

Q3
D 0V
S 0V
G +0.5V to -4V

Q4
C 0V – 7V
B 0.7V
E 0V

 

[Billy]

Where your audio stops is usually your problem area

 

What is the last component where you have audio going in but not coming out?

 

The first thing I would do is reflow your solder joints where you lose audio this would normally indicate a dry solder joint causing a poor connection

 

 

 

 

[Billy]

Excellent glad you got it fixed enjoy your new creation and don’t forget to let us all see it in the show off your build forum

[Author]

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