# Please Recommend Parentheses Octave Diode Options



## adaptid (Nov 13, 2021)

Hey folks!

I have a Parentheses working pretty well after a lot of inspection and diode swapping in the octave circuit. I have a serviceable octave up using 1N4739A, but it's a little sparse and splatty. I'm hoping someone can recommend something that might give me a little more body. Here are some of the diodes that didn't give me an octave:

Cheapo 1N34A that were probably actually Schottkys. Did basically nothing.
NTE109, a 1N270 substitute, Also basically no effect.
1N5817, gave a noticeable gain boost but no octave.
1N914, little boost.
1N4148, not much here.
I'm looking at some different Germanium diodes, including low leakage 1N34A, 1N69 and another variety of 1N270. Maybe I should try another Zener since the 1N4739A worked? I'm a bit of a dummy when it comes to the technical side of things, so if anyone can aide me in making a couple selections I'd really appreciate it!


----------



## TGP39 (Nov 13, 2021)

The popular solution is to use 2 germanium diodes with matching Forward voltage.  1N34a and 1n60 are my favorites.  Interestingly, Mark Hammer talks about using Schottkeys in the Foxx Tone Machine circuit.....






						Pleasing tweak of a Foxx Tone Machine
					

Pleasing tweak of a Foxx Tone Machine



					www.diystompboxes.com
				




I‘ve always used the germanium, but perhaps better options are out there.


----------



## adaptid (Nov 13, 2021)

I'm optimistic about the use of a genuine 1N34A. I ordered a small assortment of germaniums and I'm hoping they'll come through. Thanks for the link, that's some interesting info. I love the Foxx. I need another fuzz like I need a hole in the head but I'll probably build one of those soon.


----------



## jeffwhitfield (Nov 14, 2021)

I tried two different sources of 1N34A's from Pedal Hacker. Here's the ones I got:

10 Pack 1N34A NOS Germanium Diode 1N34 Green Stripe Unizon
10 Pack 1N34A NOS Germanium Diode 1N34 ITT House Marked
Both work really well and the price for 10 packs is pretty good. I used the green stripe Unizon's in my batch of Parentheses pedals. Used the ITT ones for a bunch of other things including a Rat pedal, which is what the Parentheses is based on anyways.


----------



## manfesto (Nov 14, 2021)

jeffwhitfield said:


> Used the ITT ones for a bunch of other things including a Rat pedal, which is what the Parentheses is based on anyways.


Well, not the octave section of the Parentheses, which is a Green Ringer.

The original EQD used matched pairs of Russian D9s (I think D9Ks?).


----------



## jeffwhitfield (Nov 14, 2021)

manfesto said:


> Well, not the octave section of the Parentheses, which is a Green Ringer.
> 
> The original EQD used matched pairs of Russian D9s (I think D9Ks?).


True, but the clipping is similar anyways. D9E's would work too. Pretty much any of those particular Germanium diodes are all in the same ballpark and should work well. If you match them it'll just make the octave part work a bit better with a more prominent effect.


----------



## manfesto (Nov 14, 2021)

jeffwhitfield said:


> True, but the clipping is similar anyways.


Not really, the diodes in the Green ringer chunk of the Parentheses circuit are a full-wave rectifier, the diodes in the Rat chunk of the Parentheses are hard clippers to ground.

The exact part number of your germanium diodes doesn’t matter as much as how well they’re matched; the closer they are the better the full-wave rectification is and the stronger your octave.

EQD most likely went with D9s of some sort because they work for the application and are *super* cheap - I got 200 D9Ks from eBay for about $12 shipped and have *plenty* of matched pairs I was able to suss out.


----------



## adaptid (Nov 14, 2021)

I think I'll pick up some Green Stripes and D9Es, match'em, and see how it goes. Promising leads thanks!!


----------



## Teddeeh (Nov 14, 2021)

I use 1n5817’s in mine. I feel its a more stable and true octave effect. You must have done something if you werent getting an octave effect with them.


----------



## PoppaAdat (Nov 14, 2021)

I've read that the BAT41's are good for octave, but I'm not done with this build myself so I can't say for certain. But those are what I am planning to try. Obviously gonna socket everything.

Related: can anyone help me identify which diodes are the octave diodes on the schematic/PCB?


----------



## adaptid (Nov 15, 2021)

PoppaAdat said:


> Related: can anyone help me identify which diodes are the octave diodes on the schematic/PCB?


D1 and D2 are the octave diodes. Let me know how the bat41s work out! From all I've read, and my experience, this build is a bit of a bear! Have fun!


----------



## PoppaAdat (Nov 15, 2021)

adaptid said:


> D1 and D2 are the octave diodes. Let me know how the bat41s work out! From all I've read, and my experience, this build is a bit of a bear! Have fun!


Ok cool that's what I thought. So D8 and D9 are just alternate clipping diodes? What did you use for those?


----------



## jeffwhitfield (Nov 15, 2021)

PoppaAdat said:


> Ok cool that's what I thought. So D8 and D9 are just alternate clipping diodes? What did you use for those?


If you use a rotary switch in the build, D8 an D9 become an extra_ option for clipping the distortion. Great for adding a GE option _


----------



## adaptid (Nov 15, 2021)

PoppaAdat said:


> Ok cool that's what I thought. So D8 and D9 are just alternate clipping diodes? What did you use for those?


I didn't go with the GE option for the Distortion circuit, but I've liked 1N34As in previous builds.


----------



## adaptid (Nov 15, 2021)

Teddeeh said:


> I use 1n5817’s in mine. I feel its a more stable and true octave effect. You must have done something if you werent getting an octave effect with them.


I've checked and double checked my C and R values in the debug process, everything seemed within tolerance. I built a Green Ringer clone from another company's PBC recently and had no problem with the octave. Comparing schematics appears to show some differences in the clipping section. What is it in this circuit that makes it so finnicky?


----------

