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DIY Stompboxes => Building your own stompbox => Topic started by: MikeH on November 07, 2006, 04:26:49 PM

Title: I need some diode suggestions please
Post by: MikeH on November 07, 2006, 04:26:49 PM
I'm working on an distortion with a wide array of diode switching options.  I'm using a 6 way rotary switch and so far I have 5 ideas, I need 1 more, but I can't think of anything very different from my other choices:

4148/914 Symetrical
4148/914 Asymetrical
Germanium
Silicon (4001)
LED

Can anyone offer a good suggestion for a 6th option?
Title: Re: I need some diode suggestions please
Post by: Seljer on November 07, 2006, 04:31:31 PM
Mosfet as a clipping diode? search the forum for how to do it (I believe its the shakah clipping thing)
Title: Re: I need some diode suggestions please
Post by: Barcode80 on November 07, 2006, 04:44:48 PM
or mix a setup. like 1 LED and 1 41005 sounds cool.
Title: Re: I need some diode suggestions please
Post by: R.G. on November 07, 2006, 05:01:53 PM
Schottky.
Title: Re: I need some diode suggestions please
Post by: MikeH on November 07, 2006, 05:39:38 PM
Schottky diode sounds cool.  What do they sound like?  Do I use them just like regular diodes?  How would I know what voltage I would want?

Edit:  I got confused, I thought you meant Zener- what exactly is a schottky diode.  Isn't it similar to a 1N4001?
Title: Re: I need some diode suggestions please
Post by: brett on November 07, 2006, 05:41:16 PM
Schottkys are 0.35V (half of silicon).  They are "hard" edged like silicon, not "soft" like Ge.

What about Schottky/LED or any other highly asymetrical setup (e.g. 4 1N4148 one way, 1 1N4148 the other).
It produces slight octave-up tones and harmonically rich distortion.
Title: Re: I need some diode suggestions please
Post by: Peter Snowberg on November 07, 2006, 05:46:10 PM
http://en.wikipedia.org/wiki/Schottky_diode

The behavior of a fast silicon diode with the forward voltage drop of a Ge diode (well.... close).
Title: Re: I need some diode suggestions please
Post by: MikeH on November 07, 2006, 05:54:46 PM
I didn't see schottkys at small bear, where can I get them?

Edit:  Nevermind, I found them...
Title: Re: I need some diode suggestions please
Post by: Peter Snowberg on November 07, 2006, 06:01:04 PM
I use 1N5818 for most situations needing a Schottky. The 1N5817 & 1N5819 are two other related diodes with different PIV ratings.
Title: Re: I need some diode suggestions please
Post by: MikeH on November 07, 2006, 06:44:13 PM
Is it ok to have all of these diodes connected to a single trace at one end, with each pair (or group) attached to it's own lug on the 6-way switch, with the pole attached on the circuit to where the other end of the diodes would go, or should I use a 2way rotary switch and have each pair isolated?  The first way is simpler, I just don't know if it will have one sucking issues, or something like that.
Title: Re: I need some diode suggestions please
Post by: Barcode80 on November 07, 2006, 06:50:05 PM
my limited knowledge pushes me to say isolate them, but i'm fairly new to this whole game and diodes are a strange beast to me at the moment...
Title: Re: I need some diode suggestions please
Post by: MikeH on November 07, 2006, 07:07:27 PM
Perhaps this will help more than my nonsense rambling above:

Here's the two scenarios (I'm going to mount all of the diodes on a separate PCB to make it easier to fit in the enclosure).
In the second scenario, the two switches represent the different sides of the same 2 way 6 pole rotary switch.

(http://img170.imageshack.us/img170/3795/diodeswitch1qo9.gif)

(http://img166.imageshack.us/img166/831/diodeswitch2kp5.gif)
Title: Re: I need some diode suggestions please
Post by: Ronsonic on November 07, 2006, 10:27:52 PM


#1 will do fine. Having the ends of all those other diodes won't affect anything.

Actually my inner audiophilish tone-nazi says it will have some unknowable, but subtle effect. but it's a freeking fuzz-thing, so it won't hurt a damn thing.


Ron
Title: Re: I need some diode suggestions please
Post by: Izzy on November 07, 2006, 10:52:40 PM
Looks cool!
I had this weird Idea before, But I dropped it.  :D

http://www.diystompboxes.com/smfforum/index.php?topic=50722.msg379604#msg379604
Title: Re: I need some diode suggestions please
Post by: brett on November 08, 2006, 01:24:58 AM
Diode mania incarnate  :icon_eek:
Title: Re: I need some diode suggestions please
Post by: WGTP on November 08, 2006, 09:12:25 AM
http://www.elixant.com/~stompbox/smfforum/index.php?topic=38581.0   :icon_cool:

Title: Re: I need some diode suggestions please
Post by: MikeH on November 08, 2006, 10:41:27 AM
Damn.  Now I have to get a 7 way switch. 
Title: Re: I need some diode suggestions please
Post by: cacibi on November 08, 2006, 11:10:49 AM
Just get a 2-12pos rotary from smallbear - then you'll have room to expand.

I came up with 8 clipping stages for my modded TS808:

Toshiba 1S1588 - symmetrical 1:1
Toshiba 1S1588 - asymmetrical 2:1
1N914 - symmetrical 2:2
1N914 - asymmetrical 3:2
1N456 germanium - symmetrical 1:1
1N456 germanium - asymmetrical 2:1
LED - symmetrical - 1:1
LED - asymmetrical - 2:1