So I'm looking at this board of the Electra Distortion 500D / Mysto Dysto / Boston / Nadine's etc. Not sure of these diodes, but they are of Japanese make I'm guessing (based on the origin of the board used in those pedals). I know old soviet germaniums are reversed, but don't know about 1980s JDM fare. Is it safe to say the blue band is the cathode?
https://rvb-img.reverb.com/image/upload/s--rRQGl2K7--/a_0/f_auto,t_supersize/v1692070464/qvskslkl74w2but2qdfx.jpg
I'm planning on following the advice of the FSB post breaking down the Mysto Dysto, and putting in some 4148s, unless anyone has a better suggestion :)
Thanks
I always measure to be sure. Here are three quick ways to verify diode anodes:
If you have a diode test setting on your multimeter, it will read voltage (Vf) when the red (+) lead is on the anode, and no voltage when the red + lead is on the cathode.
If you don't, use the ohms setting on your multimeter, it will read a resistance (1k to 100k) when the red + lead is on the anode, and a much higher resistance (megohms) when the red + lead is on the cathode.
Connect a battery to an LED thru the diode. In one direction (anode to +V) the LED will light up, in the other direction (cathode to V+) it won't.
Quote from: mauman on December 29, 2023, 03:21:05 PM
I always measure to be sure. Here are three quick ways to verify diode anodes:
If you have a diode test setting on your multimeter, it will read voltage (Vf) when the red (+) lead is on the anode, and no voltage when the red + lead is on the cathode.
If you don't, use the ohms setting on your multimeter, it will read a resistance (1k to 100k) when the red + lead is on the anode, and a much higher resistance (megohms) when the red + lead is on the cathode.
Connect a battery to an LED thru the diode. In one direction (anode to +V) the LED will light up, in the other direction (cathode to V+) it won't.
Sadly I don't have the board on my possession to actually check it :/
Oops, sorry.
no worries
perhaps?
https://www.retroamplis.com/epages/62070367.sf/en_GB/?ObjectPath=/Shops/62070367/Products/DI-1S1588
(https://www.retroamplis.com/WebRoot/StoreES2/Shops/62070367/4EBA/9EB8/87EA/B93F/CB33/C0A8/29BB/9D1D/1S1588.jpg)
I'm going to go with that as the use and assume it follows the JP-NA pattern of the band being the cathode mark, and orient the footprints to match that.
As an additional data point, I got these from Retroamplis:
(http://derevaun.com/images/out/IMG_2662.JPG) (http://derevaun.com/images/out/IMG_2664.JPG)
Quote from: derevaun on December 29, 2023, 10:23:23 PM
As an additional data point, I got these from Retroamplis:
Super! Thanks for that.
As long as they're facing opposite directions, it won't matter how you put them in.
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Quote from: jimilee on December 30, 2023, 01:08:50 AM
As long as they're facing opposite directions, it won't matter how you put them in.
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Totally sure for the clipping pair. Those two other ones were doing something else that I didn't quite grasp. Maybe in the buffer? ¯\_(ツ)_/¯
I'm just a little persnickety atm heh
Not final yet, but I'm just redoing the board as a single -sided homage/replica.
Maybe so, do you happen to have a schematic?
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Quote from: jimilee on December 30, 2023, 03:04:25 AM
Maybe so, do you happen to have a schematic?
https://forum.pedalpcb.com/threads/electra-distortion-500d-600d-schematic.20134/
someone traced it on FSB, and another traced from a vero by mirosol on tagboardeffects. I tried both on the breadboard multiple times (granted, without the buffer, so I might've mucked that up), and I'm so bloddy sick of it not working I'm going to just mimic the danged board from the original hahah. if that doesn't work, well, I'll cross that bridge eventually.
I might've messed up on the removal of the buffer, but I also couldn't get the reverse-vero schematic (sans buffer) to work, either. But that could still be my fault.
Traced from the board c/o FSB:
(https://i.imgur.com/LosJEtr.jpg)
My edit in Eagle (PDF attached):
(https://i.imgur.com/QU5h4fN.png)
Now I'm thinking about it, are those NPNs even necessary anymore, since the drive from the circuit comes from the 4558? Do I need to remove the NPNs completely; i.e. were they part of the buffer, too? Hooray for swiss cheese knowledge :P
side note it's wild to me there were so many localizations of the 500D. Same board! Thank goodness Reverb listings occasionally have some gut shots, like the one in the OP.
(https://i.imgur.com/1LkDAyC.jpg)
Ah perfect, thank you. Looking at the second schematic, the diodes are clipping, so as long as the are facing opposite directions, it doesn't matter which way they are oriented. The NPNs are a buffer, so you can go without them, if you want.
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Quote from: jimilee on December 30, 2023, 03:59:12 PM
Ah perfect, thank you. Looking at the second schematic, the diodes are clipping, so as long as the are facing opposite directions, it doesn't matter which way they are oriented. The NPNs are a buffer, so you can go without them, if you want.
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Awesome, thanks, Jimmy!
So would a more better modified schematic look like this? I.e. if I wanted to prep this for true bypass?
(https://i.imgur.com/RJH7N9v.jpg)
I chopped it based on what I see on the the OD250.
Quote from: jessenator on December 30, 2023, 04:29:17 PM
Quote from: jimilee on December 30, 2023, 03:59:12 PM
Ah perfect, thank you. Looking at the second schematic, the diodes are clipping, so as long as the are facing opposite directions, it doesn't matter which way they are oriented. The NPNs are a buffer, so you can go without them, if you want.
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Awesome, thanks, Jimmy!
So would a more better modified schematic look like this? I.e. if I wanted to prep this for true bypass?
(https://i.imgur.com/RJH7N9v.jpg)
I chopped it based on what I see on the the OD250.
(https://uploads.tapatalk-cdn.com/20231230/9e06d510bb87fee040fc23730df8d498.png)
More like this.
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Cool cool. Thanks, I'll breadboard that config later today
Quote from: jimilee on December 30, 2023, 04:34:32 PM
More like this.
Yeah! That's got it. Thanks, man.
It's definitely a bit anemic on the output volume side. Nixing components connected to pin 2 of LEVEL and putting pin 1 to ground makes it behave more like the output on an OD-1. Could make it toggled with a DPDT, I think.
(https://i.imgur.com/PcP9FZQ.png)
Quote from: jessenator on December 30, 2023, 09:03:29 PM
Quote from: jimilee on December 30, 2023, 04:34:32 PM
More like this.
Yeah! That's got it. Thanks, man.
It's definitely a bit anemic on the output volume side. Nixing components connected to pin 2 of LEVEL and putting pin 1 to ground makes it behave more like the output on an OD-1. Could make it toggled with a DPDT, I think.
(https://i.imgur.com/PcP9FZQ.png)
Interesting. Removing the buffers should have made it loud. Using GEs would have that effect. 1n914s or LEDs should bring it back to life.
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Ope. I did something screwy. Plugging it into a real amp and not my desktop jobbie got me no sound. Switching R19 from VB to GND made it work. It's also got more output now.
I can still get a little bit more from bypassing R16 C15 and R19, routing LEVEL pin 1 to ground. I'll have to play more and hear if it's worth it to keep the switch in it. Oh, I also had DIST wired backwards in my initial redraw, so that's fixed now.
edit: my fog brain is acting up again. New post and demo incoming. It's not moar volyoom, it's something else.
It's like the clipping is more pronounced. It's after the clipping section, but it just sounds more bright. Might just keep it with a switch.
https://www.dropbox.com/scl/fi/tzqc75e2p85oaun5ylz7v/500d-two-outputs-med.mp3
renamed thread...
One thing I've been thinking about is the FSB drawn schematic, and while there's talk about TBP vs buffered for everything, I'm wondering about why it wouldn't work the first time(s) I breadboarded it.
For some reason, it shows a PNP in this portion of the buffer:
(https://i.imgur.com/Njc19YF.png)
I'm looking at the OD-1's schematic as a sort of reference point (LED indicator section) and wonder if the fixed "drawing error" in the final version of the traced Mysto-Dysto schematic missed that, or if it was the correction? Not throwing shade, just curious.
The parts list/board pics of the Mysto-Dysto in the OP on FSB has all NPNs (2SC1815) listed, with two JFETs (2SK30A). Who knows, maybe the ID of the parts was wrong, but part of me wants to replicate the original board (mostly), just for kicks.
Did it Illustrator first, because I thought I would etch again:
(https://i.imgur.com/pkSQHB6.png)
Thought better of that and did one in Eagle (it's weird doing a board sans schematic...):
(https://i.imgur.com/MgwAItol.png)
I mean, at the end of the day, thanks to jimilee, I've got a usable TBP schematic. This part is just for fun.