Mini Sample Hold - Transfer Layout

Mark Hammer · January 02, 2021, 12:27:05 PM

Quote from: rankot on January 02, 2021, 10:33:57 AM
Hope I didn't forget anything - also, there's a question for Mark - he noted that Bias range can be altered for bass, but didn't mention how. Help would be appreciated.

Also, what was the purpose of the filter section of the original FSH-1? I thought of possibility to make an additional filter PCB with a 3PDT switch. It will require 1590BB, but may be interesting.

And I have some bubbling sound even with no sound input (both magnet volume pots at 0), is it normal or not?

1) I think what I was suggesting was more a change of the two caps setting the filter range - 1nf & 33nf, rather than anything to do with the Bias control.
2) The FSH-1 was/is a combination envelope-controlled filter and S&H.
3) I get the "bubbling" on both my Mini S&H and my FSH-1 build. A normal side-effect.

rankot · January 10, 2021, 06:16:14 PM

I'm finalizing this one, so I took some time to test different transistors.

I have a bag of few TO-92 2N2222A transistors with hfe in 170-200 range, they are great sounding as noise generators. Also have another bag of 100 of them, and they suck. Probably fake transistors (bought from Aliexpress). Unfortunately, I can't remember where I bought the first group.

Also have some Chinese metal can 2N2222A, they also suck, and a few metal can 2N2222A bought from local store, they also suck, but if I touch their can with a finger, magic happens!

2N4401, 2N5088 and similar are not interesting in this case.

I also tried two AF 109, they are noisy as hell, but somehow higher frequency noise than 2N2222A. Sound interesting.

I might try some more in the morning, perhaps some Russian NPN Ge from my collection.

vizcities · December 27, 2021, 09:28:49 PM

Anyone have a vero layout for this? I know a vero protoype was mentioned earlier in the thread...

Eladmiz · January 29, 2022, 01:54:09 AM

Quote from: rankot on January 10, 2021, 06:16:14 PM
I'm finalizing this one, so I took some time to test different transistors.

I have a bag of few TO-92 2N2222A transistors with hfe in 170-200 range, they are great sounding as noise generators. Also have another bag of 100 of them, and they suck. Probably fake transistors (bought from Aliexpress). Unfortunately, I can't remember where I bought the first group.

Also have some Chinese metal can 2N2222A, they also suck, and a few metal can 2N2222A bought from local store, they also suck, but if I touch their can with a finger, magic happens!

2N4401, 2N5088 and similar are not interesting in this case.

I also tried two AF 109, they are noisy as hell, but somehow higher frequency noise than 2N2222A. Sound interesting.

I might try some more in the morning, perhaps some Russian NPN Ge from my collection.

Hey I know this is a year old but do you mind sharing the pcb schem/brd? I'd love to try this.

rankot · January 29, 2022, 05:21:00 AM

This is my final build schematic:

Kevin Mitchell · January 31, 2022, 08:58:14 AM

Thanks for sharing, rankot!

Quote from: vizcities on December 27, 2021, 09:28:49 PM
Anyone have a vero layout for this? I know a vero protoype was mentioned earlier in the thread...

A vero/tag board layout could easily be done based off of the original layout. However I had not drawn one up.

Transfer files are still active. I have an SMD version of the design ready for fab - just dragging my feet until I get a few other designs done. Since I've made this thread the DIP versions of the LM13700 have been announced as discontinued so that's one reason why I switched over to SMD. So for the longevity of the DIP devices I may leave the original version for the home-etchers.

Eladmiz · January 31, 2022, 09:48:17 AM

Quote from: Kevin Mitchell on January 31, 2022, 08:58:14 AM
Thanks for sharing, rankot!

Quote from: vizcities on December 27, 2021, 09:28:49 PM
Anyone have a vero layout for this? I know a vero protoype was mentioned earlier in the thread...
A vero/tag board layout could easily be done based off of the original layout. However I had not drawn one up.

Transfer files are still active. I have an SMD version of the design ready for fab - just dragging my feet until I get a few other designs done. Since I've made this thread the DIP versions of the LM13700 have been announced as discontinued so that's one reason why I switched over to SMD. So for the longevity of the DIP devices I may leave the original version for the home-etchers.

oh thats sick!
Im about to place a JLC order & was hoping to mock this up as well. If you want to send the files, i can fab it up!

Kevin Mitchell · January 31, 2022, 02:29:46 PM

Quote from: Eladmiz on January 31, 2022, 09:48:17 AMoh thats sick!
Im about to place a JLC order & was hoping to mock this up as well. If you want to send the files, i can fab it up!

Hmmm... you're asking about the SMD version? I was going to sell those on my own so that puts me in a hard place.
Maybe someone else has some gerbers of their version they could send - I know there's been two redraws of the layout but not sure if they have the files to share. Otherwise I do plan on posting here when I have my SMD PCBs which I project should be ready by April.

Eladmiz · January 31, 2022, 07:47:16 PM

oh no worries! I didnt know you were planning on selling them.
Just wanted to mock one up for myself (not a huge fan of vero).

Ben N · February 01, 2022, 04:43:21 AM

FWIW, Kevin's layout below could rather easily be perfed.

Quote from: Kevin Mitchell on November 26, 2019, 02:49:38 PM
Here's a no-fill version. I didn't do solder mask for my first one and the bridges are a nightmare. The spacing isn't wide enough to avoid bridges. I'd need a thinner solder tip for sure.

PDF link here

-KM

Kevin Mitchell · March 16, 2022, 08:33:42 AM

Thought I'd post a preview of the SMD design to gauged interest. Most DIY folks are in the though-hole crowd but I'd like to know if this is something you'd be tempted to try.
Also judge my layout! Do you see something that can be improved on?

It's a one-knob design. Pot & stomp switch would be on the back side. Q1 is the noise transistor and would be socketed.

Thanks, gang!

rankot · March 16, 2022, 08:42:48 AM

That looks cool!

Mark Hammer · March 16, 2022, 09:44:40 AM

I was just playing mine last night. I still like it a lot. Having one single panel-mounted control misses out on a lot of the beauty of this circuit. Mine has resonance, bias, and range controls as well as speed, and my own twist of a "droop" switch. All of these provide pleasing match of the filter to the requirements of a tune. I would hope that your SMD layout affords the opportunity to easily replace trimpots with panel-mount pots.

Kevin Mitchell · March 16, 2022, 11:40:34 AM

Quote from: Mark Hammer on March 16, 2022, 09:44:40 AMI would hope that your SMD layout affords the opportunity to easily replace trimpots with panel-mount pots.

That's a fine idea! I mean you could definately wire it up but with a right-angle pot there already I probably should include the footprints & layout for the others. I could rework it so the trims can be substituted with pots.

I'm glad to know you're still rockin' the pedal! Your video is a fantastic demo of what this thing can do. I'll relay to your notes and modify things accordingly.

Will return with an updated preview.

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Mini Sample Hold - Transfer Layout