[Image of an Original COT 50 Pedal]
EDIT - Demo video (Not me playing!) of the Clock of Tone 50 circuit ; http://www.youtube.com/watch?v=PFBIZkjEw34 :
EDIT 2 - Here is another sound sample, it's got a master volume (470k pot at the end of the circuit) and a pot controlling the clipping threshold of the diodes (if I remember correctly a 10k pot worked pretty well..). It's the "Electric Church Pedal". http://skipregan.com/archives/535/electric-church-pedal/
I tried a COT50 booster the other day - nice tone, I thought, but it could be better! So I got my breadboard out and modified away until I was happy! More bass response was a must so I changed th input and output caps from 47nF and 100nF to 56n and 120nF, only a slight difference but it's enough to give your tone an extra thickness. Also I wanted to alter the clipping response slightly, it seemed a little harsh to me. I swapped out the 1N60 diodes used originally and went for some 1N270 Ge diodes, this softened up the top end a little. You can also see the 47nF cap in parallel to the diodes, this acts as a highpass filter and removes unwanted sizzle - no more "Icepick". If you want those extra highs reduce the value of the 47nF cap :-)
Finally, as always, I wanted more versatility. This is where I came up with the "Nature" control to accompany the already present "Structure" control. The Nature control allows you to blend between a full on thick boost and a rangemaster style treble boost, a nice feature to add I thought. The Nature knob is fairly interactive with the Structure knob, for example with the Structure knob at min and the Nature towards treble boost you get a pretty high treble boost but with the Structure at min (and Nature still towards treble) the treble boost is much less pronounced and it just takes away a little bottom end from you tone and prevents a muddy bottom end.
Well with those mods the COT50 became a useful little pedal... Just got to send the finished article back to my buddy now, see if he likes it ;-)
Here is a great vero layout for the Clock of Tone 50 from Torchy :-)
Here's a mojotastic tagboard layout by IVIark of http://tagboardeffects.blogspot.com:
EDIT - Here's a sound sample provided by AndreGarcia57 and it shows the differences in tone between transistor types BC108 and 2N5088, on low, medium and full gain settings:
"COT50 BC108 - 0 - 0s
COT50 BC108 - 5 - 21s
COT50 BC108 - 10 - 30s
COT50 2N5088 - 0 - 56s
COT50 2N5088 - 5 - 1:10s
COT50 2N5088 - 10 - 1:29s"
Here's the sample: http://www.4shared.com/audio/XB5sVR9Y/DRIVE50.html
COT50 BC108 - 10 - 30s
COT50 2N5088 - 0 - 56s
COT50 2N5088 - 5 - 1:10s
COT50 2N5088 - 10 - 1:29s"
Here's the sample: http://www.4shared.com/audio/XB5sVR9Y/DRIVE50.html
Hi
ReplyDeletegood job
I'll try it asap
by
Hot
Just built it last night, works great! I'm suprised at how quiet it is, (background hiss). It seems a little less gainy at full than the clips of the COT 50 I've heard, which is nice. Thanks for posting this circuit, I've wanted to get one, but didn't have the coin.
ReplyDeletePhydauex
Howdy just finished a proper COT with better parts. Love it, I could see this as something that gets left on all the time.
ReplyDeletePhydauex
Hi, great circuit and mods!
ReplyDeleteI don't have 1N270 but 1N276, what you estimate the difference will be?
From specs, the only diff. is fwd current (1N270 200mA vs 1N276 40mA. The 1N60 has a few more diff.)
I didn't expect it to sound different with 1N270 instead of 1N60, so I ask...
I built the COT yesterday, and it sounds pretty good. I didnt have the 1N270s but still thought it was a sure fit in my lineup. I should be getting the diodes today so I will put them in. I am considering putting them on a switch bc I really like how the pedal sounds now. Thanks for the circuit and mods.
ReplyDeleteI just built one of these and like it very much. Both the structure and nature knobs work nicely, but are very subtle (almost too subtle, sorry). One question / issue I have is that it does not seem to have a good volume range. I think it blends well in my pedal chain and does give me a boost, but shouldnt there be a volume control? Thanks.
ReplyDeleteTry all sorts of diodes they will alter the sound a lot with different clipping thresholds and speeds - I settled with BAT46 in mine.
ReplyDeleteThe original COT50 has no "volume" control - but you can add one by placing a 500ka pot on the end of the circuit wired as standard.
I built the pedal, I love the sound, but I have one question. One of the comments (complaints?) I have heard about the original COT50 is that there is a significant volume boost when the pedal is engaged. My pedal is barely louder than the bypassed sound, which works for me, I just wondered if that might be a sign that something is wrong or if that is how it is supposed to work. Thanks.
ReplyDeleteI can't seem to find the 2N5088 where
ReplyDeleteI'm living. Can I use a BC550C instead?
And, if so, will I be able to use it as a direct replacement or should I change any of the other components' values?
Any high gain NPN transistor will work, make sure you check the pin out though!
ReplyDeletehttp://www.youtube.com/watch?v=PFBIZkjEw34
ReplyDeleteHere is a Demo video of the Clock of Tone in action :-)
what should the bias on the emitter be with the gain/bias knob all the way up?
ReplyDeletesorry i meant to say the collector!!
ReplyDeleteI'm sorry, I never checked that value and I don't have one around to test it for you at the moment :-(
Delete