Small Clone->Chorus Tremolo Tutorial

[expanoncolin]

UPDATE - I no longer recommend doing this mod, it can have some nasty (thumping) results.  A new phototutorial has been made here:  viewtopic.php?t=1578

Click here to listen to a demo.

One day I opened up a Small Clone to do a few mods to it, and somehow managed to make this thing into a Tremolo.  It's quite an easy mod, and chorus and tremolo sound brilliant together, so let's get started, shall we?

Before we get started, here's the necessary "If you break your Small Clone, it's not my fault".  You can always mess up, and I try to make this as safe for you as possible, but if your small clone stops working, it's not my fault.  I'll help you fix it, but I'm not going to be held responsible.



Here we have the parts that we need.  You only need the pot and knob if you've already done the super-high speed mod, available at Moosapotamus's webpage.  On my personal small clone, I did all of the mods at his site (except for the stereo one).  For this particular pedal I'm modding today, he only wanted the tremolo mod, so I'm not going to need the pot.  Basically, the pot serves as a "ramp" knob.  When there's no resistor there, it thumps at lower speeds, but with a resistor there on the super speed, the ramp is too fast and it cancels itself out.  So, basically, if you're going to do the super speed mod as well, you need the 1k pot instead of the 1k resistor, otherwise, just use a 1k resistor.



Here we have the thing opened up.  Note that I undid all of the nuts from it so that I could mode the circuit board away from the case-this is a good safety procedure for drilling.  Yeah, just do it, you'll be super mad if you drill into your pedal and tear a hole through the MN3207.



These are the 2 points you're going to want to connect.  Shown here we have the 1k resistor, instead of the pot, because there's no high speed mod.  If you have already done the high speed mod, just put a 1k pot there instead.  Be sure to put this resistor here, otherwise it will thump unpleasantly.  Don't forget to try this thing out to make sure it works BEFORE YOU DRILL.



Here's how I mounted the switch. I used a super sub mini ultra small super tiny mega small mini SPST, so I could fit it in there with all the components.  If you're using a bigger one, try putting it somewhere else, and check to make sure it will fit there BEFORE you drill.



And here's the finished product.  I put the switch right in the middle of the "O".  How cute, eh?

-Colin

[the mitchell]

cheers colin. did this mod to mine and its sounding pretty nice. like it a lot for fast harsh tremelos.

[nonio]

Hi ! This could be a brilliant mod for me and I admit I bought the Small Clone mainly to have it modded as a tremolo pedal, just like I read here.

However, I AM UNABLE to grap (from the pictures posted here) where on the board is one to solder the 1k resistor.

I can figure out where one of the resistor´s ends goes to but not the other one.

Please help ? ?? ! !!
:unsure:

[the mitchell]

Just pm'd you . Basically its the top 2 wires coming into the 3rd image down. the 2 points you need to solder are pretty much right next to each other. hope this helps

[nonio]

Mitchell, you´re such a STAR !

I got it just by looking at the markings on the pic you sent !

[the mitchell]

not a problem dude. hope it works as well for you as it does me. tis a damn sexy tremelo. nice and harsh just how i like my tremelo

[nonio]

As an experiment, for the time being I just soldered the resistor in, just to see if it worked and I didn´t (yet) install the switch (which is a piece-of-cake to do).

However, when the pedal´s On/Off switching used to be silent, now, everytime I switch it, there´s a huge "THUMP" coming out of the amp.

Has any of you noticed this as well or is it just me ? What could be in the origin of this ? ??

[the mitchell]

i did have this problem at first with mine. When the tremelo was turned on it would begin to make the speaker thump at the speed the tremelo was set tobut strangely this stopped as soon as i rearranged my board plus im using totally different power supply now. I was using one of the simple acdc power blocks but im using a diago one now (which may i add are awesome http://www.diago.co.uk). I think i remember being told i higher resistor stops this thumping but i couldnt remember now at all and my electronic mind wouldnt be able to work it out tbh. I think colin may be able to help though when he comes online.

[nonio]

[expanoncolin]

Try soldering a large resistance, maybe 1meg-2m2 resistor between the lugs of the switches.

-Colin

[nonio]

Try soldering a large resistance, maybe 1meg-2m2 resistor between the lugs of the switches.

Done ! Case solved

[expanoncolin]

Try soldering a large resistance, maybe 1meg-2m2 resistor between the lugs of the switches.

Done ! Case solved

I don't remember the high-speed mod...  However, a bunch of people discuss mods in the comments on the tonepad page (such as the highspeed mod and the depth switch->pot mod):

http://tonepad.com/buildReports.asp?projectID=8

-Colin

[danoisefactory]

Hi Colin,

Thanks for finding the link. I got mine working, but it still needs more. The link is a great help.

So thanks!

Michiel

[expanoncolin]

Some of you may have noticed I have been doing a bit more complex mods to the small clone lately...  I have been doing the trem-chorus in a different way too, that I think works better.  I figured I would record what I have been doing before I forget, and so that you all can do these mods too.

The first is a chorus/vibe knob.  This is a 50k pot.  Lift one end of the 33.3k resistor on the right side of the PCB and wire it to the center lug of the 50k pot.  Wire the other lug to the PCB.  To be honest, I think this mod would be better with an SPST switch instead of the pot, as the sounds in between aren't super unique, but it's still fun to have an extra pot.

The next is an extra depth selection switch.  This is a DPDT center off switch.  It works kind of funky, but it makes sense in the end.  What it does is add a capacitor in parallel to the clock's capacitor for more depth, nothing, or short out the clock's cap to disable the chorus effect while making sure that the clean signal is connected, for "no-chorus, trem only" mode.  Wire the center lug of one side to one end of the clock's cap.  This is a 150pf cap, right to the left of the biggest chip on the board.  Wire the top lug in this column to one end of a 100pf cap, and wire the other end to the other side of the clock cap.  Now, the buttom lug of this column wire to the top.  On the other column, wire the center lug to one of the lugs of the pot/switch from above.  Then wire the bottom lug to the other end.  This is so that when it's in the "no chorus" position you are ensuring that the clean signal is there.

The final mod is the improved chorus/trem mod... the previous one was a rather brute method to do it, this is a bit more safe.  The old mod can mess up the bias.  This one is a bit more complex, though.  First find the 10k resisotr right near the 33k resistor from above, it should be going perpendicular to the other one.  Remove it completely.  In it's place, on the trace side of the PCB, wire a photocell, with a range of maybe 5k-200k or more.  Anything lower than 10k works for the "light" range.  Then, get a 5k pot.  Wire one side lug to a 1k resistor to lug 1 of the LFO op amp-this is the one near the pot.  Wire the other side lug to a 10k resistor, th en to V+.  It doesnt' matter where, you can wire it on the DC jack or where the wire from the DC jack hits the circuit board.  Wire the center lug to the long end of a superbright LED.  Wire the short end of the LED to ground, anywhere.  Then optocouple them, with hot glue.  If you want a trem on/off switch instead of this pot, I woudl recommend an SPST, center lug to 2k2 to pin 1 of the op amp, other lug to the LED's long end.

My apologies that these mods are a tad bit more vague, but they are a bit more difficult... if you're confused, feel free to ask, but as I said, these are a bit more of an undertaking.

-Colin

[chout]

The first is a chorus/vibe knob.  This is a 50k pot.  Lift one end of the 33.3k resistor on the right side of the PCB and wire it to the center lug of the 50k pot.  Wire the other lug to the PCB.  To be honest, I think this mod would be better with an SPST switch instead of the pot, as the sounds in between aren't super unique, but it's still fun to have an extra pot.

I'm new here, this site rules...I tried this vibrato mod today using an SPST switch...couldn't get it to work - the pedal would just turn off when I'd switch it over.  I thought I had the right resistor, but maybe not...could someone help a modding noob find the right resistor???
Thanks!  Looking forward to modding the hell outta my small clone.