A. Made with:
01. Xicon resistors 1/4 watt, 1% tolerance Metal Film resistors.
02. Wima Film capacitors 5% Tolerance (10%where 5% was not
available). Where no Wima capacitor was available for a
particular value, either TDK/EPCOS film capacitors or Kemet Film
capacitors were used.
03. Nichicon fine gold/Muse electrolytic capacitors. USW series LP
7mm.
04. Kemet Multilayer Ceramic Capacitors 5% tolerance. Rated Class
1 (C0G).
05. Diodes: The exact Germanium clipping diode that was used in the
original Centaur is unknown. Some sonic testing was done and
Russian D9E diodes were thought to be an exact sonic match. What
we know for sure is that the diodes in question had a forward
voltage of 0.35v. To that end, 200 Russian D9E diodes were sourced
from Bulgaria. Each was hand tested. All 200 of them clustered
right around (+/- 0.04v) 0.25v. I made the decision to try and get
closer to the value that we were sure of, the 0.35v. Kevin from
Aion Electronics has mentioned having luck with 1n270 germanium
diodes from Tayda electronics. 100 were sourced and tested. The
forward voltage varied a great deal. ~16 were very close or an
exact match to the 0.35v value. ~20 were, "Hot Loads" with a value
greater than 0.40v. For this production run of 12 pedals the
values were in-between 0.342v and 0.372v. D9B, D9K, 1n914 and
1n60 were also tested in significant quantities.
06. Alpha 16mm potentiometers were used.
07. Pot covers from Small Bear were used to, prevent shorts in-
between the back of the pots and the PCB.
08. Gold-plated IC sockets from Mouser were used.
09. IC's: TL072 are made by Texas Instruments. TC1044scpa are
sourced from Microchip.
10. Red LED footswitches are sourced from Amplified parts.com.
11. Guitar jacks are from switchcraft.
12. DC power jacks are from Kobiconn.
Modifications:
1. c14 is changed to 6n8 to boost the treble. Many said the original,
pedal was somewhat dark. This addresses that.
2. As for the germanium diodes, see above.
3. The original centaur used a linear potentiometer as its output
control. Most people seem to favor a logarithmic taper for that
particular stage. Being as that the human ear hears or rather
appreciates sound on the logarithmic scale, that seems to make
sense. Therefore I am changing this as well, to a 10kA.
QC:
1. Resistors and capacitors: Each component subjected to physical
inspection to ensure Good condition and to ensure value needed/picked
were a match. This was verified using a HHMM (Handheld multi-Meter,
a Fluke 17B+).
2. Solder joints: Each solder joint was individually inspected
underneath a digital microscope and re-flowed if necessary.
Nicely done! I wouldn't have the patience to go to this level of detail but I applaud you for being thorough. I like the finished inside of the enclosure and the cool detail of magnets for screws. When mine look like that it means I've snapped the head off the screws ::)
Thanks. I really like those anodized aluminum enclosures except they're over 20 bucks a pop. I don't like that. There are also a lot more difficult to drill through as they are much harder than standard enclosures. As for detail, I worked in neurosurgery for many years and that's just part and parcel of the game.
-Mike
Wow. I'm impressed by the thought behind this. My approach is generally, "close enough for rock and roll!"
You could describe me in lots of ways. Belt and suspenders or thorough would be nice. To say I'm an*l would be closer to the truth. Still it works for some things.
-Mike
I like to work with all these details, always. ;)
I'm planning to build the Klon Centaur, too.
I compared some schematics, with so many options and possible mods, even if I probably settle with the closest original schematic.
Very cool! Any particular reason you didn't add the resistors on the switch board?
Sonnyboy,
Just unreasoning fear. This was the first time I had ever used the Refractor bypass board and also the first time I've used one of those new LED footswitches. I just was unsure how tt would all interact. Thinking ahead for troubleshooting, I thought it would be easier to put them in, rather than take them out.
Everything works, so now I have to decide if I should put them in.
This is why I say I'm a cook and not a chef. I don't yet fully understand why everything is done the way it's done and so I introduce a little VooDoo into the system.
-Mike
So what do you think SonnyBoy27, Any reason to not put those three resistors in?
-Mike
There's really no reason not to put them in. I believe it's just part of the switching setup. They shouldn't have a big impact on tone. They aren't in the schematic in the documentation though. From looking elsewhere it looks like they have something to do with the output section (probably impedance or something with preventing switch popping, total guess there). If it's working and you like the tone though then I'd leave it as is.
Edit: I checked Coda's breakdown of the circuit and feel slightly justified. He also says he has no idea what those resistors are for.
I assumed they were part of the buffer system/wiring. I'm going to put them in and see if the tone changes. I'll post later.
-Mike
Well, uh.
Maybe my minds playing tricks on me but the sound is not only noticeably louder, but brighter as well.
Remind me not to think.
-Mike
Quote from: Ekimneets on August 19, 2018, 07:09:29 PM
Gold-plated IC sockets from Mouser
Excellent.
Suggestion for build description: Make/Model of soldering iron/station ... details of solder used for builds ( i.e. 63/37, 60/40, diameter, ... )
Hakko-FX888D (Love)
Solder:0.7mm 60/40
Nice looking build.
But ...
Quote from: Ekimneets on August 19, 2018, 07:09:29 PM
05. Diodes: The exact Germanium clipping diode that was used in the
original Centaur is unknown. Some sonic testing was done and
Russian D9E diodes were thought to be an exact sonic match. What
we know for sure is that the diodes in question had a forward
voltage of 0.35v. To that end, 200 Russian D9E diodes were sourced
from Bulgaria. Each was hand tested. All 200 of them clustered
right around (+/- 0.04v) 0.25v. I made the decision to try and get
closer to the value that we were sure of, the 0.35v. Kevin from
Aion Electronics has mentioned having luck with 1n270 germanium
diodes from Tayda electronics. 100 were sourced and tested. The
forward voltage varied a great deal. ~16 were very close or an
exact match to the 0.35v value. ~20 were, "Hot Loads" with a value
greater than 0.40v. For this production run of 12 pedals the
values were in-between 0.342v and 0.372v. D9B, D9K, 1n914 and
1n60 were also tested in significant quantities.
People still think this? Or more to the point: Aion is still claiming this in the build doc?
Bill F said that they were 1N34A. He put it in a post on TGP for everyone to see probably 5-6 years ago now. He said he bought out all of a
particular manufacture he could find of them. Notwithstanding that any two different multimeters are going to give you two different forward voltage measurements for the same diode (so you can't usually use anyone else's numbers), 1N34A are also the only Ge diode that typically measures 0.35V.
The only people to ever claim that they were D9E were people who misunderstood what BYOC meant when they wrote that the D9E they used in the kit (which, let's be honest, just happened to be some of the cheapest germanium diodes you could buy at the time) were the closest to their reference model. The original diodes had black stripes, which none of the Soviet diodes had, and D9E had a blue stripe, so there was zero chance of them being D9E. Also, it's exceptionally unlikely that anyone was using Soviet surplus diodes in the early 90s, for any number of reasons.
Also, re the C14 mod, that mod actually
lowers the frequency affected by the treble control. Aion's a little unclear when he says the treble is "a little thin" (I'm, not really sure what that's supposed to me ...). In other words, if the pedal were too dark, increasing the size of that capacitor is going to make it darker.
Here's how that control works:
When the pot is clockwise, C14 forms a high-pass filter with R22 (the 100K). Low frequencies are blocked by R22 and high frequencies are allowed to pass.
As the pot travels counterclockwise, the capacitor begins to bypass the feedback loop gain in the last op amp stage. Without the treble control, that stage is unity gain: R22 and R24 are the same value, which in an inverting op amp stage gives you 1x gain. However, R23 and the tone pot have a resistance much lower than 100K, so along with C14 (which is in series with them), they allow frequencies above a certain point to ignore that 100K resistor. The result is that those frequencies now get much less gain, because they divide with R22, the 100K resistor.
There are some ways to brighten up the pedal, but increasing the size of that capacitor doesn't do it. I suspect the build document is meant to communicate that people think the pedal as a whole has too much treble compared with the midrange and lower frequencies, so lowering the frequency of the "treble" control gives the sound more midrange.
The resistors on the switch allow a small amount of the buffered signal to appear in the final sound regardless of where the volume control is set. Looking at a schematic that actually includes them would be helpful: http://madbeanpedals.com/projects/Sunking/Sunking2015.pdf
Thank you, I still have a vast amount to learn and am just a babe in the woods. When you post info like this I inevitably learn and I do have my disclaimer "I'm just a cook., you guys are chefs". I mean that am not an EE or even a tech for that matter and so if I make a mistake it should not be a surprise.
Now if you want to discuss 1 year survival of Glioblastoma or the relative merits of the Mayfield head clamp then I would be more in my element.
-Mike
Would this be more palatable for you?
Diodes: Bill F., has stated that 1n34a's were the original diode. The forward voltage was ~0.35. I aimed for that value. We need to also understand that a guideline as those numbers can vary a great deal with a multitude of factors including each individual HHMM. So, it is just a guideline.
Many hundreds of diodes were tested.
D9B, D9E and D9K sourced from Bulgaria.
1n34a, 1n60a and 1n914 sourced from the US were tested.
As per the build documentation, I tested some 100 1n270 diodes were sourced from Tayda in Thailand. The values of these varied a great deal including quite a few of what I call "Hot loads" that measured 0.4v or more. A number of them were an exact match or were within a few hundredths of a volt. I made the decision to use these.
As for the caps, it is painfully obvious that I have a lot more reading to do. Now, Impicked up the "Art Of Electronics" from Amazon for some light reading a couple of years ago. I can only compare it to my old immunuology textbook for induction of catatonic zombie sleep.
Can someone give me better recs for an electronics book. I don't know, Imguess I'm looking for "Basic Bear Guide to Making LED's Glow Pretty" or "Piggly Wiggly and Adventures in Resistors".
As always, any help much appreciated.
-Mike
Quote from: Ekimneets on August 21, 2018, 08:39:52 PM
Diodes: The exact Diode used in the original is generally not agreed upon.
As Jon already pointed out, Bill Finnegan has freely shared that the diodes in his Klon Centaurs were 1N34A. There is no secret and no need for debate.
Duh, I totally missed that. That's why younshouldn't Do five things at once.
Give me a minute and I'll fix it. I may not get it right the first time but I'll sure is hell keep trying.
-Mikel
All right, I made even more corrections. You're gonna help me get my crud straight One way another.
Hard to believe how much I've already learned from this thread. Keep up the good work.
-Mike
Something to note is that germanium diodes and transistors are *infamous* for wildly varying specs, even within the same component code. A 1N34A diode from one company, may sound wildly different to a 1N34A diode from another company. This is why, for example, Smallbear sell matched sets. You can't trust that any given transistor will match the "typical value" in the spec sheet. You need to measure what you have in front of you. (You can trust that a diode is a diode, and a NPN transistor is an NPN transistor, but you're on your own as far as leakage and gain are concerned.)
Don't be afraid to use your ears.
Don't believe numbers and parts are gospel and don't get hung up on using the 'right' part.
This goes double for anything made with germnaium. I've found that FV readings mean diddly poo with those and that reverse leakage is far more influential. If a FV .23 diode is very leaky, it will take a bigger signal to make it clip, rendering that .23 reading moot.
Don't sweat it. Try different diodes and use the ones you like the sound of the most.
One thing you can do is buy 2-3 PCBs of a design. Build one using lots of sockets so you can swap in and out parts. When you dial it in, slap those parts on the empty board for the final build.
Definitely do some reading. There's some 'technology of' articles on geofex and electrosmash that will help a lot.
I'm obviously a little slow on the pick up on some things. As noted in this thread. I did pick up on the fact pretty early do you need to directly measure a lot of things and that's why I took such care for measurement of those diode's.
You guys have no idea how much I appreciate all the help. I have belong to other forums for other purposes and encountered a tremendous amount of hostility for seemingly no reason whatsoever. The reception is been very different here and I really do appreciate it .
So... the 1N34As are the correct diodes? :o If I already knew it, I forgot it!
I was going to order D9E from Musikding. The 1N34As are more expensive than D9E. Or I could order a pair of 1N34A from Tayda, the low cost choice.
Now, what I have to do? ???
Cheaper D9E from Musikding, expensive 1N34A or cheapest 1N34A from Tayda?
I also have two 1N270s diodes from Tayda bought maybe four years ago.
If you want some D9E's I've got plenty. I"d be more than happy to send you a few gratis if you decide to go with that particular diode.
Just send me a PM with your addy if you decide on them.
-Mike
I just want to be sure if the 1N34As Tayda are fine and accuracy for the Klon.
Quote from: JackSkellington on August 22, 2018, 12:32:29 PM
I just want to be sure if the 1N34As Tayda are fine and accuracy for the Klon.
The part number 1N34A is pretty much meaningless. Depending on manufacturer, they could be anything.
It's like a Toyota. If someone just says they're selling a Toyota, that could mean a compact car, SUV, pickup ...
Best thing to do is socket and test with your ears.
Jack,
Form my experience the 1n34s from Tayda have tested on my multimeter have been in the 2.7/2.8 range. Could just be the batches I've received on a few occasions....good luck!
Quote from: destro on August 23, 2018, 03:41:32 PM
Form my experience the 1n34s from Tayda have tested on my multimeter have been in the 2.7/2.8 range. Could just be the batches I've received on a few occasions....good luck!
Hi destro. I'm sorry, perhaps I missed something. What do you mean? What is 2.7/2.8 range?
Quote from: jubal81 on August 23, 2018, 02:29:11 PM
Best thing to do is socket and test with your ears.
Yes, probably I'll do. It's just to know how this pedal works.
Anyway, I bought a pair of D9E from Musikding and, of course, I forgot the 1N34As from Tayda! ;D
So, I'll have wait some weeks to build the Klon and I'll socket the diodes. I'm going to try D9E, 1N270 and... what about 1N60P?
I tested some germanium diode, except 1N34A.
The couple of 1N60P and 1N270 sounds pretty similar.
But the D9Es are the best, with the highs warmer and softer, and maybe a bit less aggressive.
Meanwhile, the 1N34As are now more hard to find.
Off Topic: How you see the D9E as perfect substitute of the 1N34A? Or those sound too much different?
Quote from: midwayfair on August 21, 2018, 06:20:33 PM
People still think this? Or more to the point: Aion is still claiming this in the build doc?
The docs for that version of the Refractor are a few years old, but I corrected it on the main project page (the history writeup) maybe two years ago and it's discussed with more accuracy in the docs new version of the Refractor from this year. Should probably go back and revise the old one though just for posterity's sake.