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DIY Stompboxes => Building your own stompbox => Topic started by: Jonas on February 19, 2004, 06:12:12 AM

Title: Slow Gear Clone
Post by: Jonas on February 19, 2004, 06:12:12 AM
I'm planning on building a SG clone. The schem I got has all that buffer and latching thing I don't want to use since I'm going to true-bypass it.
Can anyone help me eleminating all that I will not be needing?
here's the schematic:

(http://www.generalguitargadgets.com/v2/diagrams/slow_gear_schem.gif)

I suspect all the stuff beyond R11 can go off, but I'm not sure
Cheers!
Title: Slow Gear Clone
Post by: Peter Snowberg on February 19, 2004, 06:54:38 AM
Hi Jonas,

Welcome to the forums. :D

I think you're right. It looks like you could just chop off the switching circuitry up to R11 and leave it at that. I'm guessing that T3 is off when the effect is on. If it's reversed from that, then all you would need to do would be to connect the wire running from the attack control to a 1K resistor and then two signal diodes like 1N4148 and then to ground, as to mimic the voltage drop across T3 and D3. That should do it.

Best of luck,
-Peter
Title: Slow Gear Clone
Post by: Dan N on February 19, 2004, 08:47:45 AM
Yay Peter! I have seen that question posted a few times before.

Never answered.

Jonas, please post your results!
Title: Slow Gear Clone
Post by: Jonas on February 19, 2004, 09:05:16 AM
Well... thank you very much Peter!

I'll probably test it on breadboard this weekend. I'll let you all Know the results

Cheers!
Title: Slow Gear Clone
Post by: R.G. on February 19, 2004, 09:17:10 AM
I drew the original, I guess I can update the schem to pull out  the flipflop.

(http://www.geofex.com/FX_Images/slow_gear_schem.gif)
Title: Slow Gear Clone
Post by: Jonas on February 19, 2004, 09:35:50 AM
Thank you RG

Should I consider pull down resistors on the in and output to eleminate pops when turning the thing on and off?

I see R25 on the output... Do I need to change it?[/i]
Title: Slow Gear Clone
Post by: R.G. on February 19, 2004, 12:25:13 PM
My pleasure. R25 is fine as it is. You can add between 1M and 4.7M to ground at the input on either side of R12 to get a reasonable pulldown there.
Title: Slow Gear Clone
Post by: puretube on February 19, 2004, 01:28:10 PM
P2`s "southside" is still floating; is that OK?
Title: Slow Gear Clone
Post by: R.G. on February 19, 2004, 03:41:22 PM
QuoteP2`s "southside" is still floating; is that OK?
It's not floating; it's tied to the timing capacitor, where the variable resistance determines how fast the envelope detector T8/T9 pulls down the gate of the FET that's doing signal shunting.

The gate has to be pulled low to turn the shunting JFET off so signal goes though the main path.
Title: Slow Gear Clone
Post by: Zero the hero on February 19, 2004, 04:29:42 PM
Hi Jonas, I had a bit of time for this mod.
I've drawn and built the layout on GGG, so I applied the mods suggested by RG and Peter, so I simply removed R11 from the circuit and it works well, the effect is always engaged.
Title: Slow Gear Clone
Post by: Jonas on February 19, 2004, 04:44:40 PM
I'll redesign the PCB layout for myself, I want it to fit in a small box...

It's funny... this is the first time I pick an electronics project since I left highschool 5 years ago. I have to dig out some books and notes that I have boxed.

I'll keep you up with news of this baby. I'm building a Green Ringer to...

Cheers! Thank you all for your help

PS: By the way, I'm looking for an used scope and maybe a function generator if I get them cheap... What do you think of those scopes on Uk's  and german Ebay for less that 100â,¬? I live in Portugal
Title: Slow Gear Clone
Post by: Jonas on February 19, 2004, 04:57:04 PM
:? UPS!!  Just noticed that the pot I have for P2 is 22K, not 20K... What kind of trouble am I in?
Title: Slow Gear Clone
Post by: smoguzbenjamin on February 19, 2004, 05:02:21 PM
Probably not much because most pots have a 10% tolerance anyway ;)
Title: Slow Gear Clone
Post by: Mr.Huge on February 19, 2004, 09:21:44 PM
Here's a schematic:
http://www.wayhuge.com/slowgear.pdf

Cheers,
-Mr. Huge
Title: Slow Gear Clone
Post by: Zero the hero on February 20, 2004, 05:31:56 AM
Quote from: Jonas:? UPS!!  Just noticed that the pot I have for P2 is 22K, not 20K... What kind of trouble am I in?

I'll get a longer delay in the attack when the pot is set for max resistance. Anyway, with 2k the difference is slightly audible...