Nearly new Klone day - help requested.

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KalimnaKalimna Frets: 1534
edited May 2021 in Making & Modding
Whilst im not quite finished, and ive put together more complex layouts, this is the most tricky wiring ive done so far. Especially as im trying to reduce the length and number of off-board wires as the layout has a few duplicates - mostly in the grounding.

And its on Veroboard, not a PCB kit.

Here we are so far : 

https://imgur.com/gallery/ufiOJrH

Comments welcome, as always

Adam
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Comments

  • KalimnaKalimna Frets: 1534
    Ok, so I finished wiring it up, plugged in and it *sortof* works. In bypass, great sound, switched on the volume and treble work as expected, but the gain is odd. To add, when the controls set appropriately the tone is superb. I used 4558's instead if 072's as that;s what I had.
    There is a variable volume output as the the gain is rotated (loud -> quiet -> bit louder with OD), and there is a blip at the end of travel, I think the offboard wiring is correct, so I suspect there is a solder bridge somewhere or a misplaced component around the gain circuit.
    Time to troubleshoot.......

    Adam
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  • pogulpogul Frets: 25
    edited May 2021
    Looks good! I want to try something like this soon. Do you have a link to the project details or is it your own klon recipe?
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  • KalimnaKalimna Frets: 1534
    Well, it might look good, but it aint working properly :( 
    However, im certain that its a fault with my build rather than the layout. Id love to be skilled enough to draw up my own layout but Im not there yet.
    Here's a link for you

    http://tagboardeffects.blogspot.com/2014/05/klon-centaur-with-optional-bass-control.html?m=1

    First job tonight - power on and measure some IC voltages. Hopefully that will give me a clue where the error is. I'll go over it again to check there are no misplaced components or solder bridges before re-doing the whole veroboard.

    Adam
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  • KalimnaKalimna Frets: 1534
    I have now been over the circuitboard with a blade between the tracks, checked each component again, and also checked IC pin voltages.
    The only thing I can find not quite right is an almost-but-not-quite voltage on ground connections of two of the IC's (2.1mV, not 0V, for 1st opamp and voltage multiplier.

    So if anyone can help me out, I would very much appreciate it.

    Here's a couple of build pix.

    https://i.imgur.com/e4XtuMd.jpg

    https://i.imgur.com/VhvbUao.jpg

    https://i.imgur.com/MQd5Gf4.jpg

    https://i.imgur.com/tSQCFdI.jpg

    https://i.imgur.com/4rBNODR.jpg

    The offboard wiring is far from perfect, but im quite pleased with the flip-flop paint enclosure.

    Cheers,
    Adam
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  • pogulpogul Frets: 25
    Thanks for the link! Good luck with troubleshooting!
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  • KalimnaKalimna Frets: 1534
    Unfortunately, I think the troubleshooting will involve starting the veroboard from scratch again.......
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  • springheadspringhead Frets: 1583
    Not quite 0V when it should be is perhaps down to a not quite perfect solder joint. Have you reflowed, or solder sucked and resoldered?

    Have you checked that all the tracks are cut where required?

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  • KalimnaKalimna Frets: 1534
    Thanks for the suggestion. As far as i can tell, all the cuts are where they should be. And all the tracks have been knifed a couple of times. Each component (except the IC's, though ive tried different op amps) was checked with a DMM prior to installation, as was a solder-bridge check after *each* solder joint. However, its quite possible i missed something. 
    The behaviour of the gain pot is most baffling to me, and i might just try 2xB100k pots instead of the dual.


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  • Danny1969Danny1969 Frets: 10356
    Although opamps are pin to pin compatible there are reasons some types are used over others, the behaviour when the gain pushes the input voltage close to the rail etc and the offset voltages vary between opamps. 

    So is your rails are good on each chip and circuit works almost as intended then get some 72's before going any further. Then see where you are. 
    www.2020studios.co.uk 
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  • springheadspringhead Frets: 1583
    I'd check your grounds thoroughly.  From the -ve of the battery snap or DC jack to the op-amp sockets, top side.  Proper 0R? 

    You're using bipolar instead of fet op-amps, don't know if that can cause an issue in a Klon.  I build mine from a fuzz dog pcb based kit with all the relevant parts.



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  • KalimnaKalimna Frets: 1534
    Danny1969 said:
    Although opamps are pin to pin compatible there are reasons some types are used over others, the behaviour when the gain pushes the input voltage close to the rail etc and the offset voltages vary between opamps. 

    So is your rails are good on each chip and circuit works almost as intended then get some 72's before going any further. Then see where you are. 
    Thank you - i do have some 72's on order, but as far as Im aware, the standard OD opamps (4558, opa275, 5532 etc) should all work even if some are 'better' than others. I hope it's something that simple though.
    By rails, do you mean +ve and gnd connections? If so, would the slightly not 0V likely be part of the problem?
    I'd check your grounds thoroughly.  From the -ve of the battery snap or DC jack to the op-amp sockets, top side.  Proper 0R? 

    You're using bipolar instead of fet op-amps, don't know if that can cause an issue in a Klon.  I build mine from a fuzz dog pcb based kit with all the relevant parts.



    Is that to check for poor solder joins?
    Also, i assume then that the 72 is a fet input?

    I am at the frustrating stage of knowing a little, but far from enough, to allow good troubleshooting technique. Im getting there, slowly.

    Thank you for your help.

    Adam
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  • idiotwindidiotwind Frets: 387
    edited May 2021
    In my recent builds I found an audio probe very useful for debugging. Just made it out of an old guitar cable and a .1uf ceramic cap, then used a loop pedal to send an input in so I had both hands free. It let me follow the circuit round to find where the output didn't make sense and helped me focus on the appropriate section.



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  • springheadspringhead Frets: 1583
    Kalimna said:
    Danny1969 said:
    Although opamps are pin to pin compatible there are reasons some types are used over others, the behaviour when the gain pushes the input voltage close to the rail etc and the offset voltages vary between opamps. 

    So is your rails are good on each chip and circuit works almost as intended then get some 72's before going any further. Then see where you are. 
    Thank you - i do have some 72's on order, but as far as Im aware, the standard OD opamps (4558, opa275, 5532 etc) should all work even if some are 'better' than others. I hope it's something that simple though.
    By rails, do you mean +ve and gnd connections? If so, would the slightly not 0V likely be part of the problem?
    I'd check your grounds thoroughly.  From the -ve of the battery snap or DC jack to the op-amp sockets, top side.  Proper 0R? 

    You're using bipolar instead of fet op-amps, don't know if that can cause an issue in a Klon.  I build mine from a fuzz dog pcb based kit with all the relevant parts.



    Is that to check for poor solder joins?
    Also, i assume then that the 72 is a fet input?

    I am at the frustrating stage of knowing a little, but far from enough, to allow good troubleshooting technique. Im getting there, slowly.

    Thank you for your help.

    Adam
    Yes to checking solder joins. And yes to 072s being fet so potentially behaving differently to the 4558 in this circuit. 
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  • PeteCPeteC Frets: 409
    I'd be tempted to try the 72's; re-flow all your solder joints , and even if you think there are no solder bridges examine it under a strong light and a good magnifying glass.  Many , many times its a solder issue.   solder bridges can be specs or thinner than hairs and can be a pain to find.  

    Another thing I do is to take a small section of the board at a time and examine it coordinate by coordinate, as it were.  Theres often a "doh" mistake in there somewhere ( at least in most of my builds ! )   Resistor values are a frequent culprit. 

    Finally check each off board connection several times to make sure there nothing wrongly connected off the board. 

    Have you also read through all of the posts on the project website ?  - I have found that sometimes "verified" circuits don't perform as the originals, and eventually someone will pick up the original circuit tracing error and post it. 

    Good luck - always fancied a Klon but never made one yet. 
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  • KalimnaKalimna Frets: 1534
    Sorry for delay in replying, but Ive taken the first step - tried the 72's. No change in gain pot behaviour.

    I will go over the board again, and your suggestions are all very sensible. If nothing comes up with another check and reflow of solder, i may just build another board and repopulate. And again I *think* the offboard wiring is correct, and unless theres a solder bridge on a pot somewhere (esp on the dual gang gain pot) there must be a dodgy connection on the board itself.

    Ive had a look through all 200-odd messages on the tagboard forum, and nothing too useful for my problem. Several people seem to have it working too, so i dont think there's an issue with the layout.

    Anyway, back to the solder board (in between other pedals, the current guitar build and amp kit no.2 that is!)

    Adam
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  • andy_kandy_k Frets: 818
    Sounds like you do actually know what you are doing ( as opposed to me ) but have you tried comparing the circuit to a Fuzzdog ? I think most Klones are pretty similar, and it might give a eureka moment if compared?
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  • KalimnaKalimna Frets: 1534
    Thank you for that assumption, but i talk a good game ;)
    I know a bit, but not enough to compare circuits (especially as i dont have a 'circuit' of the Klon as such, more a layout of where components are on the veroboard. Its possible to derive one from the other, but beyond my time management skills!)
    I shall certainly look at the Fuzzdog version, as you say it might spark a Eureka moment.

    Cheers,
    Adam
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