Diodes in series - does it matter which does first?

[Lp_man]

Hi there, I'm currently working on the next section of my site (www.geocities.com/overdrivespider) and including 4 SD-1 mods - one of them Indyguitarists Fulldrive II mod (dont worry guys, Brian has given me permission!).

Anyways, the bit I'm stuck on is where it says:
"D4 ------------Germ. And 1n4001 series"
So put a germainium and 1n4001 diode in series.

Does it matter which comes first? I.e. should I put the black stripe of the germainium to the board solder the other end to the 1n4001 diode and solder the other end of that to the board OR should I solder the black stripe of the 1n4001 directly to the board?

Thanks for your help

-Will

[zpyder]

Though my experience amounts to reading about different clipping diode layouts (until tonight when I'll be playing with different diode setups for a TS808!! stoked...), I'm pretty confident that the answer is something like "Try both ways and choose the one you like the most."

Tonight I'm going to play with different diodes for my current build (a TS 808).  I've got 1N4148's/1N914's, LED's, and one germanium.  I'm gonna try all combinations on my protoboard, pick a few to go with, and hook up a few switches for my completed build so I can select between a few options.

Best of luck!
zpyder

[Lp_man]

That was the plan if no one replied

I've experimented with NOS germainium and 1N4148 diodes in my SD-1 converted to TS808 specs. Both sound good! I have them on a switch now

-Will

[lovekraft0]

Here's what R.G. had to say about passive series strings:

If you have a series string of passive components, as long as you look at voltages and currents only at the ends of the string, not the middle connections, the order of the components makes no difference at all. The internal parts can be arranged in any order at all and you'll get the same voltage across the string and current through it. Obviously if you look at the voltages at the middle points, that's order sensitive, but at the ends, it makes no difference.

I think the same would apply here - so long as there's a simple series with no other connections, you should be able to treat it as a single component, regardless of the order of the diodes, but that's at best an "informed guess".

[Lp_man]

Ok thanks! I plan on socketing the diode anyway so it will be easy to try both ways to see any audiable difference. 

[scaesic]

i beleive this is a case where the principle of superposition applies. (i.e order should make no difference)

[petemoore]

as long as you look at voltages and currents only at the ends of the string
  The biggest difference in diode clipper configurations sounds is the voltage of the diode position, this can be measured with the DMM.
  but there are also other differences, GE's have the "OD" or softer clipping sound often attached to their use in various clippers, and LED's have a history of "Soft Crunch" or Crunch associated with their use.
  Course usin' a socket for this, maybe a switch too, start by moving the foreward voltage clipping configurations up and down in voltage [each way from SP to ground] note tones you like, see what you like.
  Say you end up with a configuration like
  >Si
  <si Si
  If you're feeling experimental @that point, measure the clipping threshold of the si SI string, and try to find 1 LED, or maybe 3 or 4 Ge configuration [or mixed Ge Si..so on] that measures the same clipping threshold, then you can more accurately' compare clipping using difference materials, everything else close to the same.
  I'ts probably worth it to put a diode config. select switch on a clipper, if you're interested in trying diodes out, then play and mess with the knobs in the signal chain including amp for a while, then swap the 2nd choice clipping configuration elements using that socket. You may want to resolder semipermanently, the 1rst choice donfig. where the wires go to the switch or whatever.
 

[Lp_man]

I didn't understand most of that post due to me being an electronics theory noob! Funny you should say though, in my SD-1 I used a switch to swap between GE and sillicon diodes, but I socketed the actual switch so if I ever got my hands on some random diodes or LEDs I'd have a quick option of switching.

The one I'm going to start work on however is a friend of mines and I havn't done the Fulldrive mod before so I thought I'd better ask. I'm also giving him some other diodes so he can experiment if he wants.

Thanks again guys!

-Will

[R.G.]

In any two-diode series chain, the order of the diodes does not matter to any significant degree.

I only put that "to any significant degree" in there because I can postulate situations with signals fast enough to make the parasitic components of parallel capcitance and ESL matter. For typical audio frequencies, the parallel capacitance and ESLs are not large enough to matter. It would matter if you put parallel resistors, caps or inductors across the diodes.

This is a very counterintuitive issue sometimes, but it is true.

[Lp_man]

Hi guys I have another question;
I have a multimeter with diode test settings, would it be benificial to tone in this case to bias the diodes? If so, am I looking for all the ones that are close together in value or furthest away? Or would there be no change in tone at all?