Diode substitution

[stompboxmaker]

I have a project that requires this( 1N4001 ) or a similar diode

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=1N4001FSTR-ND

Can I replace them with 1N4004

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=1N4004FSTR-ND

I saw a build report of someone using the 1N4001 diodes to build the mxr dist plus can I use the 1N4004 instead?
Are there any characteristics that are desirable in diodes for distortion boxes?

Thanks.

[R.G.]

I have a project that requires this( 1N4001 ) or a similar diode
Can I replace them with 1N4004

Yes. The 1N400x family is a family - all 1A forward current average, everything else very similar. They differ primarily in the reverse withstanding voltage. 4001 is 50V, it goes up to 100, 200, etc. to the 1N4007, which is 1000V. They're all about the same size, so many people buy the 4006 or 4007 and use them for all power rectification applications.

I saw a build report of someone using the 1N4001 diodes to build the mxr dist plus can I use the 1N4004 instead?

Yes.

Are there any characteristics that are desirable in diodes for distortion boxes?

Yes, but you'll get as many opinions as you can count noses for which ones are best and why. Use of various diodes is a neverending source of fun for DIY effects makers and an article of (sometimes false) pride for boutique effects makers.

Generally, a person reads here, learns to make a stompbox or two, and within a couple of weeks after that has opened his internet boutique effects making business, talking very knowledgeably about the subtle differences between this, that, and the other in HIS stompboxes instead of those other useless imitations. 

It happens fast. 

[jrem]

how about substitutions in the Octavia?  After the transformer.  I have one breadboarded and it doesn't sound right.  I don't think I had any 1N34A's and used something else, it sounds nasty and doesn't ring. 

[solderman]

As clipping diodes, my experience is that there is a quite noticeable differens between different types of diodes but no differens within one type.

-No audibly differens between normal switching diodes like 1N400X, 1N4148, 1N914 etc as they clip at almost the same voltage.

-No audibly differens between different colours of LED:s as they also clip at almost the same voltage and sound alike.

-1N34A is a Ge and no audibly differens between different Ge diodes however they clip at a much (was it lower ?) voltage than Si.

So in your case the Ge 1N34A are probably essential for the sound.

[stompboxmaker]

Thanks for all of your input. This is my first project and I didn't want to kill my amp by using higher rated diodes.

[JKowalski]

-No audible difference between different colours of LEDs as they also clip at almost the same voltage and sound alike.

Different color LEDs often use different semiconductor materials to make the different colors. These different materials all have their own voltage drops, and the typically used types have a range from 1.6V to 4.4V.... Thats alot of difference, so I would say different color LEDs may have a significant effect on the sound.

Of course, my opinion is that all diodes sound the same - the strength of the signal into them makes the same amount of difference as the voltage drop. It's just a matter of which one you want to change, the diode or the signal strength. Sure there may be subtle differences but it's not worth thinking about IMO

[Mark Hammer]

Different color LEDs often use different semiconductor materials to make the different colors. These different materials all have their own voltage drops, and the typically used types have a range from 1.6V to 4.4V.... Thats alot of difference, so I would say different color LEDs may have a significant effect on the sound.

Which is why the vast majority of circuits that will use LEDs as the clipping element use red LEDs, since their forward voltage of around 1.5v is not so outrageous as to requre a huge change in gain structure.

Note that the impact of diode type will have different sorts of impacts depending on whether the diode is in series with the signal (as they are in the Octavia) or go to ground.  If they go to ground. then the signal still has a means to find its way to the output, and all that happens is that the signal is clipped at a different amplitude.  If the diode is in series with the signal, that signal is going nowhere unless it exceeds the forward voltage of the diode.  Use of a diode type with a higher forward voltage than a germanium unit will inevitably cut off both the initial attack and tail of notes unless massive amounts of gain are applied.

Regardless of what kind of diode you use in which context, they show individual variation, so it is always advisable to measure their forward voltage with a meter, and make a decision that is appropriate for the circuit based on the actual properties of the diode, rather than what the datasheet/catalog says it is.

[jrem]

So in your case the Ge 1N34A are probably essential for the sound.

didn't mean to hijack the thread but thanks for the info.