pimping cheap pedals

[zaqzaq]

hey guys, i was wondering if changing the resistors and caps in cheap pedals (eg, behringer Flanger Machine FL600) would really improve the tone, has anyone tried it? or does the 'tone suckage' lie on the circuit schematic? i thought of building an ibanez PM7 (schematics: http://www.effectsdatabase.com/model/ibanez/tonelok/pm7 , took from http://www.diystompboxes.com/smfforum/index.php?topic=47686.0 ) with more expensive caps and resistors (like exchanging mylar and ceramic caps for film), do you think it would stop the mid-range filtering the box has (kind of like a radio box / radio music sounds)? my bought pm7 has a rather weak-squashy sound, with lots of mid-range, that i think might be the caps.

im a new in town, so sorry if i made any mistakes! i did use the 'search' function, and i thought this discussion could be good cause many users say these pedals really got something to offer, but the bypass/tone sucking/"wrong tone" (too much trebble, etc) problems many times arent adressed. so... should i try it, or am i wasting my precious time? thanks for your insights!



#tag improving cheap pedals / upgrading cheap pedals

[Canucker]

Wouldn't know the answer to that question cus I'm pretty new to all of this myself but if you don't find something in the search that your looking for no worries people around here are really cool and seem to know everything (that I've ever asked). Even if you do find it in the search sometimes the topic is so old its worth restarting!

[Muthauzem]

Maybe there would be some improvement, but minimal.

If it's just the tonal response of the pedal, you can try changing capacitor values, not just their type.

For an overall improvement, I would aim to active devices, like transistors and OpAmps. See what they are and what would be better/quieter.
Another improvement can be change it to true bypass, if they are not.

[Mike Burgundy]

a lot of these are knockoffs from existing, more expensive pedals. The only major immediate improvement is the case its in - usually plastic, which is vulnerable and doesn't shield against EMF, possibly increasing noise.
The "tone-suck" you mention isn't caused by inferiour parts  (unless there's a fault in the pedal), but by the circuitry. Some pedals may be true bypass, but that would involve a more expensive switch so probably not. Most pedals will be a variation on the buffered flipfliop bypass as seen in for example a TubeScreamer and BOSS pedals. This may or may not be a good/bad thing, it all depends on how it's done and how you treat it. True bypass is not the holy grail, especially not when using a LOT of pedals together.
I doubt there's much improvement to be had replacing parts, although I can imagine reliability being an issue along the line. Maybe pots wear out more quickly, electro's dry up, solderjoints might develop problems. As far as actives go, have a look, check the specs on a datasheet and see if you can improve with a different type - but that goes for BOSS stuff just as much. I doubt replacing a factory TL072 with one of your own will make a difference at all.

[Mark Hammer]

If I am not mistaken, the FL600 is a copy of the Tone Core Liqui-Flange, which is a digitally-based pedal.  It is also wave-soldered surface mount.  You'll pardon me if I am assuming too much, but if you ask the question you did, you're not likely prepared for such microsurgery.

The PM7 is a more likely candidate since I gather it uses through-hole parts.

[zaqzaq]

first of all, thanks a lot for all the answers! adressing each one of them:

@Canucker, i was relying on the forum's kind responsiveness, and rightfully so! i'm amazed at the support given here, for the quality as much as for the attention given to all. like wikipedia, i think its amazing what you get when you allow people to cooperate, simply providing the tools, its a much different scenario than the one prophesized in ecnomics. but i digress; about the search, i did search and the only answers i found were very restricted to one given pedal, not really a general outlook (or at least something appliable to behringer or ibanez).

@Muthauzen, i confess that my knowledge on electronics basically amounts only to soldering, i could never build a circuit myself. i think i'll give it a go to changing the caps values, probably a higher value would make the tonal range wider? i couldnt find the exact description for the input cap in the PM7, but im guessing its a mylar 0.0223 50v (sometimes its written '50VJ' instead of '50V', anyone knows why?), so maybe if i changed it to a 1uf eletrolytic/film itd have a fuller tonal range? these pedals arent truebypass, but im more interested in making the tone better when they are engaged (maybe taking the buffers out would help, but i dont understand any of this, also nothing about opamps and transistors.. :/)

@Mike, i think i didnt express myself well, the main problem about tonesuckage from these pedals that im worried is for when they are active, and not on bypass (i think a truebypass box would suffice my bypass problems), and if its the circuit, then i have a big problem cause i cant rebuild it, to the present date all i know is ohm's law.

@Mark, bullseye:) i havent got a clue of how hard it would be to mount those, but i thought i could use sockets if the soldering gets too complicated. checking the PM7 parts, i do think it would be a lot of work but feasible work, doesnt look much more complicated then soldering a chorus like the boss CE2. i a hope im not being too presumptuous, nor annoying, but im really looking foward to these upgrades, if possible. youre right also about the copycat http://acapella.harmony-central.com/archive/index.php/t-1951861.html its a line 6 originally.

guys, many many thanks for your replies!! i really appreciate the help, id be awesomely happy if i could have these cheap pedals in an upgraded version (i dont think they are taken from an expensive pedals, cause i dont know a pedal like the pm7 or the fl600, maybe some better ones, but with the same features i dont, but thats just me), i'll research some more and post here the results, but if anyone would like to give more suggestions im all ears! thanks again!



#tag , one tag i forgot! #making cheap stompboxes better

EDIT: "i dont know any pedal like the fl600.." except for the aforementioned liqua-flange (line 6, i never used it, just saw some videos on youtube), which is another cheapish pedal - my point is that i dont know an expensive pedal quite like it, maybe some really expensive that do a world of other things too and are huuuge

[EATyourGuitar]

the only thing I can add to this discussion is that behringer understands fully the problems associated with plastic boxes not having shielding. these circuit are straight up clones on %99 of behringer pedals as far as I know. but behringer does add something to the circuit in strategic places to minimize the effects of EMI, RFI, and power rail noise. I would rather have something in a metal box than have more active stages and/or filters added to make it ready for sh*t industrial design. if you feel like tracing it, you can remove everything that should not be there and rehouse it. as for the true bypass debate, this is a problem for people who like the unbuffered sound of the guitar but have more than 10 pedals with a long cable run after it. not everyone falls into this category anyway.

PIMP ON

[senko]

You can always get something from a functional yet cheap guitar pedal.  At the very least, you'll have a case that doesn't need a lot of drilling to get another project done. 

As for filtering, you can experiment with resistor value swaps and not alter the circuit permanently.  I throw resistors in parallel with the ones that are already present.  You can drop the value and get a feel for the tone difference.  Then, you can remove that resistor and put a potentiometer in its place & adjust that resistor until you find a sweet spot.  Keep doing this for all of the components and you'll probably come up with something better than what it was. 

See if you can find a schematic, figure out how it works (most guitar pedals are simple circuits), and then mess around with the component swaps. 

[zaqzaq]

:Di'll pimp on alright! indeed, mr. Hammer (too formal?) already pointed that the FL600 is a copy of the line6 liqua flange, but from my few google searches i dont think the liqua flange is a direct copy of something else, its more sort of a do-it-all digital flange. but maybe the liquaflange was a bad choice afterall, if im not mistaken, the PM7 is fully analog, so for a first project i think ill stick to it.

my fear of changing resistors is maybe frying things up.. of course i could do little changes, but then again, i dont have the knowledge to do good changes. would you kindly suggest me some values? the only problem with checking each resistor for a sweetspot is that i dont have the apparatus (like a veroboard with prototype-things) and the PM7, for example, has 75 resistors. but if the resistors are to blame, i can solder in some sockets and try my luck, its just that i thought the caps did the magic

this reminds me of a good (very noobish) question: if i put a pot in the end of the circuit (like 1 M ohm), just before the output jack, to control the overall volume, would it affect the tone in any way (if i let the pot with 0 resistance)? do i need a cap if im not worried with trebble bleed when increasing the pots resistance? oh, and one more: if i put a 2k pot between the dc jack and the circuit, would it work alright like a dying battery simulator? or can i burn something in process? i saw this on beavisaudio and started to wonder

EDIT: reading further on beavisaudio, i thought about introducing a tone control http://www.beavisaudio.com/techpages/BigMuffToneControl/ to attenuate the midrange and increase the high/low end, could this actuallty solve the mid-range problem or will i only have a sharper/quieter mid range sound?

[Canucker]

I'm thinking the between the lines advice I'm reading here is build something from the ground up. Easier to modify a design and then build it rather then tear something apart... I think its more satisfying to build something that looks like you built it too rather then have a cheapy looking thing that sounds better then it originally did. Still I can understand why you'd try to do something with a complex effect like a delay...but a fuzz unit I would never think of doing anything but building from the ground up.

[EATyourGuitar]

this reminds me of a good (very noobish) question: if i put a pot in the end of the circuit (like 1 M ohm), just before the output jack, to control the overall volume, would it affect the tone in any way (if i let the pot with 0 resistance)? do i need a cap if im not worried with trebble bleed when increasing the pots resistance?

I dont think I have ever used a 1M volume pot in my life. even at 500k it usually sounds muddy as you start to turn it down. there are some tricks with treble bleed caps but that is not really as important as selecting the right value for the pot.

oh, and one more: if i put a 2k pot between the dc jack and the circuit, would it work alright like a dying battery simulator? or can i burn something in process? i saw this on beavisaudio and started to wonder

you probably wont break anything by trying. dying batteries are sometimes more interactive and mysterious than you might first expect. people have tried limiting current. people have tried voltage dividers. for some pedals, you get the sound of a dying battery but for others, you do not get the same sound you get with a dying battery.

EDIT: reading further on beavisaudio, i thought about introducing a tone control http://www.beavisaudio.com/techpages/BigMuffToneControl/ to attenuate the midrange and increase the high/low end, could this actuallty solve the mid-range problem or will i only have a sharper/quieter mid range sound?

could this solve the problem? depends on the problem. whats the problem? will you have a sharper sound? if by sharper you mean more attack on the front of the note, no it will not perform transient reconstruction. will it have quieter mid range, yes, the BMP tone control is like a wide band notch filter. it will reduce your mids. try the tonestack calculator so you can see exactly what it looks like.

[zaqzaq]

first of all, a merry ending xmas and an excellent new year to you and your families!! and thanks a lot for all the replies so far!! i'm actually quite impressed with how fast i got the response

@Canucker , yes but that's exactly what i have in mind (although my mind is somewhat cryptic), to build a new pedal from ground up, using cheap pedal's schematics, and modding them to make 'em better. initally i thought it would suffice to replace parts for others that have the same values but are more expensive (eg, using film caps instead of ceramics), but ive been already told it will do no good, or at least not enough. so now i proceeded to plan B: changing caps and resistors values. but how? and will it not explode if i change them arbitarily?

so far what i thought was changing the output cap to a higher value (im thinking about 10uf) in the hope that this will give me a fuller tone, with more bottom and highs.

@EATyourGuitar, i thought about the 1M pot because of EHX's signal pad, it may be better than a 250k for passing the treble.. but i have no idea, do you think the 250k is better? summing up, my 'problem' is the following: when i hear my PM7's sound, it sounds a bit like brass, with lots of mids and few highs and bass frequencies, if it had a 7 band graphic eq itd be this:

5                             x      x                            
4                     x       .      .                  
3               x      .       .      .                    
2               .      .       .      .       x          
1       x      .      .       .      .       .      x        
       1      2     3      4      5      6      7

there's a lot of mid-range, but few lows and fewer highs. it's like an elevator radio. and i think most cheap pedals sound like that, thats why i thought it had something to do with caps quality. but if its in the circuit, how can i restore the original sound (taking out these high pass filters i guess)? the small stone is a phaser that doesnt do this, it has a fuller tone. the tonelok series (PM7's series) all have this "elevator" sound, a shhh similar to sand falling with a very narrow width of frequencies. i could ramble a bit more on metaphors to the sounds, but this video probably shows it better:

tonelok SM7 http://www.youtube.com/watch?v=oCbO5W_XBsc
tonelok PM7 http://www.youtube.com/watch?v=PfdHAVOW03U

its almost a trademark sound for cheap pedals.

thanks again for your patience and happy holidays!

EDIT: thanks a lot for the tonestack app!!! it proved me right in some prejudices against fender and marshall, and made me want to try the big muff tone control on the PM7. my only worry is that it may lower the overall sound, and instead of increasing the high or bottom end, like i wanted to, it will just make everything quieter and give me, for example, instead of louder high frequencies just a quieter mid/bass-range (that would highlight the mid/treble). i hope im being clear, you can ask me anything you want, im sorry if this sounds confusing!