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DIY Effects


JackLondon

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Has anyone come across one of these foot switches before? It's on my ashdown hyperdrive, it's playing up.... I have a spare 3pdt switch but not much clue to wire it? Does it need a bridge wire as the original has what looks like a connecting line? IMG_20200429_201251.thumb.jpg.566671769d155559e9c720c080897a36.jpg

Cheers

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Yeah it's a DPDT, the middle lugs may look connected but they aren't. You can just transpose the wiring to the 3PDT and just use 2 of the poles.

Ideally you need to check what kind of switch it is first, I assume its controlling a buffered bypass, so it might be momentary rather than latching. Unlikely for a DPDT but not impossible. Best way to check is with a multimeter if you have one. 

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Completed Bug Crusher. Using mostly scavenged parts I managed to build the whole thing for about £10. In my excitement to finish it I completely forgot to paint any control labelling and also neglected to leave space for a battery inside but hey ho. Sounds fantastic anyway!

Discovered in the course of researching the pedal that it was actually designed in my home town of Bristol 😍

img_1831.jpg

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I've been very busy doing DIY board layouts lately. More like onboard preamps and a bass amp board retrofit than effects per se, but this thread seems the closest in spirit, I think. So:

 

New three band preamp that went into my Marco Bass MV fretless a week or so ago:

 

PW25B_MV4FL.jpg

 

And the new main preamp board for my 500 watt DIY bass amp build from 2015:

PW8B_V3_MainBoard.thumb.jpg.f31a94adc5a19dc2364023a8aa68c443.jpg

Which is waiting on an opamp shootout tomorrow before completion and installation, which I hope to have done by week's end. There's a new daughtercard  containing a one band full parametric EQ and a variable high pass filter as well.

 

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Just finished my latest kit, an Echo Blue Delay from Fuzzdog.

This is the first one I've done with the daughter board for the switch. It does make everything a bit easier to assemble, and with a bit of ribbon cable between the main board and the switch makes for a very neat job.

Some things I did differently this time: identified all the components and taped them to the bill of materials for easy identification once the build got underway; bolted the pots into the encloser and put the board on top to solder in place; and left a few components until after the pots were installed, to give a bit more room to solder the pots in.

Not sure if any of that made a huge difference, but the build seemed to go very smoothly. You have got to hand it to Fuzzdog, he does a great job.

Not sure how many of these I'm going to do though. My eyesight seems to be getting worse, even with helping hands and the magnifying glass.

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Looks like I spoke too soon. The pedal circuit works perfectly, but I have a huge 'pop' through the amp when switching it on and off with the footswitch.

The input and output capacitors appear to be connected to ground so I'm not sure what to check next. I might try re-soldering the output cap just in case, but the pot will have to come off to get at it.

If anyone has any suggestions for what to look at next, I'd be very grateful.

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1 hour ago, pete.young said:

The input and output capacitors appear to be connected to ground

That sounds odd.

Can you post the circuit?

 

Could be a short across output capacitor.

Is it switched on all the time or is it switched on by the footswitch?

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1 hour ago, Stub Mandrel said:

Could be a short across output capacitor.

I would say almost certainly that is the one thing it couldn't be, there would be no pop in that case.

its something to do with the part of the circuit that isn't connected gets to build up a charge, and when you switch that part in it discharges through the amplifier input. Something not grounding the output, so the opposite of a short

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Recently built up this JMK Bass Overdrive pedal as a lockdown project. Unfortunately there’s a fault and while the bypass is fine, engaging the pedal results in no effect, a very quiet clean signal and a constant high pitched tone. Volume control has a small effect, but gain and tone controls have no discernible effect.

I was a bit of a numpty and didn’t test the board before I wired it up....so I don’t know what’s at fault. Have replaced IC and transistors (as they’re socketed) to no avail. Only one LED is lighting, but it’s my understanding that’s bot really an issue with this clipping.

I’ll try reflowing the switch next, if no improvement, I’m not sure I have the inclination to unbox the whole thing to test the board lol....we’ll see.

Anyone want to troubleshoot it for me? 😂

FC441026-3036-4FA5-99AD-FE73A7B15DEC.thumb.jpeg.b291a6d2aaa873cdf6fd708f3917fc74.jpeg

 

Si
 

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13 minutes ago, Sibob said:

Recently built up this JMK Bass Overdrive pedal as a lockdown project. Unfortunately there’s a fault and while the bypass is fine, engaging the pedal results in no effect, a very quiet clean signal and a constant high pitched tone. Volume control has a small effect, but gain and tone controls have no discernible effect.

I was a bit of a numpty and didn’t test the board before I wired it up....so I don’t know what’s at fault. Have replaced IC and transistors (as they’re socketed) to no avail. Only one LED is lighting, but it’s my understanding that’s bot really an issue with this clipping.

I’ll try reflowing the switch next, if no improvement, I’m not sure I have the inclination to unbox the whole thing to test the board lol....we’ll see.

Anyone want to troubleshoot it for me? 😂

FC441026-3036-4FA5-99AD-FE73A7B15DEC.thumb.jpeg.b291a6d2aaa873cdf6fd708f3917fc74.jpeg

 

Si
 

Is the output jack wired to the wrong lug of the footswitch? Should be soldered to the middle lug of the right hand side, looks like its connected to the bottom one?

Edited by Higgie
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5 hours ago, Higgie said:

Is the output jack wired to the wrong lug of the footswitch? Should be soldered to the middle lug of the right hand side, looks like its connected to the bottom one?

No, it’s wired to the middle lug on the right ☺️
CB45612E-B0BA-4F17-A75B-3FE3B4847E5F.jpeg.a0cacc1a0021eaca0673dcf15b0bff3d.jpeg
Cheers

Si

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13 hours ago, Woodinblack said:

I would say almost certainly that is the one thing it couldn't be, there would be no pop in that case.

There would be, because when switched in it would put a dc offset on the output, it would then work normally because the capacitor on the amplifier input would convert it to a transient.

 

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14 minutes ago, Stub Mandrel said:

There would be, because when switched in it would put a dc offset on the output, it would then work normally because the capacitor on the amplifier input would convert it to a transient.

Oh you mean an inline output capacitor? yes, I was thinking of a parallel one. Yes, that could do it. 

Either way the thump is caused by a large DC offset on the output when not connected, so there is nothing bringing the output down such as a bleed resistor or something.

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21 minutes ago, bobbass4k said:

It might be hiding but looks like you're one connection short, is the circuit output connected at the top right? 

Is it the JKM big bass drive? If so that switch looks nothing like this. Well, the left and middle does, but not the output!

switch.thumb.png.7ff4a5e2a679bb493fdf64aa1d36fc1e.png

Edited by Woodinblack
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27 minutes ago, Woodinblack said:

Is it the JKM big bass drive? If so that switch looks nothing like this. Well, the left and middle does, but not the output!

switch.thumb.png.7ff4a5e2a679bb493fdf64aa1d36fc1e.png

Yes it’s that pedal and switch arrangement, I can assure you it’s correct, it’s just funny angles 😊

B014AF0D-3739-479E-9AB8-7BAE8890D778.thumb.jpeg.7403acd08cd983ce6b40208f132356ae.jpeg
 

Si

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18 minutes ago, Sibob said:

Yes it’s that pedal and switch arrangement, I can assure you it’s correct, it’s just funny angles 😊

Well, thats a shame, that would have been an easy fix!

OK, its hard to see on a picture and the layout I can see on the net is a bit different from the circuit I can see on line, and obviously I am looking straight down, and I don't want to offend by being wrong or 'teaching to suck eggs' but those orange capacitors, I assume they are the normal ones where the cathode (the minus) is marked on the side, some of them the mark seems to line up with what is marked with a + on the layout I can see. I mean one of the ones near the power is, but the other two are in a different place. Although if that is the case I would think you would find out quite quickly!

Could that be it? 

Edited by Woodinblack
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12 hours ago, Sibob said:

Recently built up this JMK Bass Overdrive pedal as a lockdown project. Unfortunately there’s a fault and while the bypass is fine, engaging the pedal results in no effect, a very quiet clean signal and a constant high pitched tone. Volume control has a small effect, but gain and tone controls have no discernible effect.

I was a bit of a numpty and didn’t test the board before I wired it up....so I don’t know what’s at fault. Have replaced IC and transistors (as they’re socketed) to no avail. Only one LED is lighting, but it’s my understanding that’s bot really an issue with this clipping.

I’ll try reflowing the switch next, if no improvement, I’m not sure I have the inclination to unbox the whole thing to test the board lol....we’ll see.

Anyone want to troubleshoot it for me? 😂

FC441026-3036-4FA5-99AD-FE73A7B15DEC.thumb.jpeg.b291a6d2aaa873cdf6fd708f3917fc74.jpeg

 

Si
 

Ahh, got it, the board is laid out for a CA3130/TL071, you';ve used a 386 which is NOT a drop in replacement, different pinouts and different functions. You'll need to get a single op-amp. TL071, CA3130 etc.

- Slightly more awake now and realized it's a BBOD clone - you might struggle to get a CA3130 (long obsolete and a lot of fakes about due to the demand), a TL071 will do the job.

Edited by bobbass4k
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26 minutes ago, bobbass4k said:

Ahh, got it, the board is laid out for a CA3130/TL071, you';ve used a 386 which is NOT a drop in replacement, different pinouts and different functions. You'll need to get a single op-amp. TL071, CA3130 etc.

- Slightly more awake now and realized it's a BBOD clone - you might struggle to get a CA3130 (long obsolete and a lot of fakes about due to the demand), a TL071 will do the job.

Hmmm, that’s odd as the build instructions show an LM386 as a legit replacement?!

AB24BF60-31D0-45D5-BD22-A150BC21B47B.thumb.jpeg.8e54fafcbd72d2964cfdfc23227688c4.jpeg

Unless they just mean that tonally it works, but fail to mention the 386 pinout is different?!

Hmmmm

Si

 

 

Edited by Sibob
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6 minutes ago, Sibob said:

Hmmmm, that’s odd as the 

Hmmm, that’s odd as the build instructions show an LM386 as a legit replacement?!

AB24BF60-31D0-45D5-BD22-A150BC21B47B.thumb.jpeg.8e54fafcbd72d2964cfdfc23227688c4.jpeg

Unless they just mean that totally it works, but fail to mention the 386 pinout is different?!

Hmmmm

Si

 

 

Hmm, I didn't get that far in the build doc, but it's a mistake. The 386 is a very low wattage power amplifier, even if you did patch the pinout it's never going to replace an op-amp, it might pass sound but it would not sound great. Yank it out, put a tl071 in there and email JMK to get that changed. 

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6 minutes ago, bobbass4k said:

Hmm, I didn't get that far in the build doc, but it's a mistake. The 386 is a very low wattage power amplifier, even if you did patch the pinout it's never going to replace an op-amp, it might pass sound but it would not sound great. Yank it out, put a tl071 in there and email JMK to get that changed. 

True. The NE5534 is a dual opamp, so isn't a pin-for-pin replacement either. 

 

The most common single opamp ICs that will drop straight into that socket and perform as it should are the TL071 (or TL061 or TL081 are pin-for-pin replacement too) or the good old LM741, which I love in overdrive/distortion pedals. The 741 gets a lot of stick on electronics forums from Hi-fi buffs, as it's old and noisy in comparison to newer ICs, but that's precisely why it sounds so darn good in O/D units!

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