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Passive Overdrives


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The Black Ice is two diodes in parallel, but with opposite polarities. Diodes in series means higher breakover voltage equals less clipping. For more clipping, try Germanium diodes.

germaniums won't clip anymore than any other diodes.. they will only do it later in regards to siganl threshold. if you are going passive with a black ice type device as in this thread then germaniums would give you more headroom than the shotckys so you would need super hot pickps to make them crunch.. personally my last setup would have cause them to really spank a set of germnaiums .51v into a .3v germanium would have really made shotckys have a bad day. but would n't even conduct a silicon unless i really hit the strings hard. but then again i do play hard, and with 16 on the high E and a 75 on the low E i think i could do it. lol

but in the world of stompboxes it goes like this.

schotkys on input for an octave type effect. or on a simple 1 transistor booster

germaniums for a buzzier sound more fuzz like

silicon for basic crunch

leds for higher threshold and more tube like sound

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I just read on a newsgroup or someplace that the "black ice" passive distortion designs actually lower your guitar's output. That kind of made me want to forget about it. Now I'm thinking of a stomp box that sounds less 'heavy metal' that a tube screamer, and more like " tweed amp crunch" which is what the "black ice" claims to do.

maybe you ideas about the different diodes are just the kind of info that needs to be considered on stomp box units.

You got me thinking LEDs are the way to go for what I'm after.

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if you truely want a tweed amp type style you need to look at the sansamp gt-2 schematic and rip out all the high gain stuff, and just use their fender section.. it would be pretty easy to do. if you need me to email you the schematic let me know.

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germaniums won't clip anymore than any other diodes..  they will only do it later in regards to siganl threshold.  if you are going passive with a black ice type device as in this thread then germaniums would give you more headroom than the shotckys  so you would need super hot pickps to make them crunch.. personally my last setup would have cause them to really spank a set of germnaiums .51v into a .3v germanium would have really made shotckys have a bad day. but would n't even conduct a silicon unless i really hit the strings hard. 

What schottky are you using? I couldn't find one with a forward voltage drop lower than a germanium 1N60.

but in the world of stompboxes  it goes like this.

schotkys on input for an octave type effect. or on a simple 1 transistor booster

germaniums for a buzzier sound more fuzz like

silicon for basic crunch

leds for higher threshold and more tube like sound

Not according to Aron Nelson:

Change the clipping diodes to different types to get different "shades" of distortion. LEDs give more crunch and buzz. Silicon diodes (1N4148, 1N914) are crisper (harsher?) than germanium (1N34a). Germanium (Ge), Silicon (Si), FETs and MOSFET transistors also have diodes in them that you can use as clippers. Try different types in your circuit.

Buzzwords: Ge = "squishy", "tubey", "compressed".

Si = "sharp", "focused","tight", "precise"

FETs/MOSFETs = "Tube-like", "Crunchy"

LEDs = "Crunch", "Buzz", "Less Compressed"

Please don't get the idea that i'm trying to start a war here, but what you've said doesn't correspond to what i've been taught, so I'm just trying to get some clarification here. I personally prefer a well-designed tube preamp with several cascaded triode stages for really smooth distortion even at high gain, but that ain't gonna fit in my Strat. :D

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ok no problem here, aron, just like myself and everyone else in teh diy world has different terms of descrbing fuzz. i dont' use fets very much, so i didnt' put them in as i am sure there are different levels of diyer here, as there is on any forum, but i tend not to post about what i dont' play with that much.. kind of like this.

if you drove a lamborgini would you take it to be repaired by mr goodwrench.

anyway i have only found one design that i coudl tell a diference in tath used fets or mosfets. and thats joe davissons amberdrive

"What schottky are you using? I couldn't find one with a forward voltage drop lower than a germanium 1N60."

i won't say as this isnt' my project i am working on it is brians so if he wants to post the diodes he showed me then cool till then its kind of like ZVEX schematics. i have some but i dont' share out of respect for him.

couldnt find a 1n60 datasheet, could you post a link. casue i am not sure what the forward is on it.

for shotckys on the input you should check out TIM escebedo's rambler

there is a good highvoltage, solidstate, tube emulator but i dont' konw where it is. it uses jfets and mosfets in parrallel acting like a tube.. real sweet i did a low power version in a pedal.. sweet............. but yeah i like tubes better myself, but its amazing what uses diodes in the clipping circuit..

JCM900 anyone?????

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quite a bit, i have done several little plexi clones that i do lower wattage output section.. what do you need to konw.

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2 things i was wondering

1 is quite simply how do you go about making or getting chassis for them?

second thing is id like to know if there is a half decent program that i could use for designing them?

i probablly have enough electronics knowledge to build a decentish amp but i dont wanna have to learn by trial and error lol

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2 things i was wondering

1 is quite simply how do you go about making or getting chassis for them?

second thing is id like to know if there is a half decent program that i could use for designing them?

i probablly have enough electronics knowledge to build a decentish amp but i dont wanna have to learn by trial and error lol

theres a couple the ax84.com is a great page to get started.. personaly i would start out with doug hamonds firefly its a great preamp uses ready availbale parts and is pretty cheap to do, and sounds about as loud as a20 watt solidstate amp.

it is about 1.5-2.5 watts depending on what tube and transformer you use.

http://home.cfl.rr.com/dbhammond/ff.htm

read this page it is very helpfull. and it is very easy. its a plexi clone with a twist a reverb driver type tube for your outptu tube.

as far as a program to do it for you, hmm i am not sure.. i haven't heard of one. if you tell me what you are looking for, i could draw up something for you. it all depends on the sound you wish to acheive.

i do mostly high gain - medium gain stuff. but i also do some squeaky clean things as well.

how much wattage do you need , i am currently working on a nanohead type amp in a bigger box, with an extra tube, and an extra gainstage with and eq section.

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also a chasis well it depends on how big you need it. personally can make a tube amp in the 50watt range in a hammond D box if i had to ..

i already do a 8 watt tube amp,(loud enough to spank your ears and the drummers) in a hammond S box

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