Sproing Deluxe

[Erik S]

I’m behind a couple on build reports, but I finished this one yesterday and I’m really happy with it. I sold the first one of these I built and I’ve missed it ever since. The reverb in this is my favorite of any of the ones I’ve built or bought. Sounds just as good as I remembered.

 

[The Gator]

Wow. Super clean build! That looks really great!

 

[steviejr92]

Well dang this is just crazy slick!

Great job on how clean it is inside too!

 

[jaredguitarbud]

That looks great!
Forgive me if this has been addressed elsewhere or if I'm simply being ignorant. I'm new to pedal building. I'm interested in building a sproing deluxe, but the build documentation isn't yet available. How do I go about getting a BOM for this so I can order the appropriate components? Thanks!

 

[Erik S]

How do I go about getting a BOM for this so I can order the appropriate components? Thanks!

Thread 'Sproing Deluxe'
https://forum.pedalpcb.com/threads/sproing-deluxe.13580/

For projects that don’t have build docs posted, a search on the forum will usually turn up a BOM. The values are printed on the boards too, so you could technically work from that, but it is nice to be able to pre-order your parts.

 

[jaredguitarbud]

Hey thanks so much for the help! I searched, but I couldn't find it. I figured they'd be on the board, but you're right about being able to preorder components ahead of time. Thanks again, Erik! I'm really glad to be a part of the community.

 

[Justin Mariner]

Thanks for posting the build report! The BOM doesn't list the specs for the LDR. Can I ask what you used?

 

[Erik S]

Thanks for posting the build report! The BOM doesn't list the specs for the LDR. Can I ask what you used?

I checked my notes, but I didn’t write it down. Maybe KE-10720? Definitely something from tayda.

Whatever you use, mount the led/ ldr combo in a way where you can adjust the gap. Slight changes there make a big difference if I remember.

 

[Justin Mariner]

This is really helpful, thanks! I noticed that the Moonshot and Trembling Loon call for the GL5516 LDR, which has lower light resistance values than the LDRs on Tayda, so it's good to know you had success with one of these. Adjusting the gap might be a key to making this work, so that's a great tip!

 

[Erik S]

This is really helpful, thanks! I noticed that the Moonshot and Trembling Loon call for the GL5516 LDR, which has lower light resistance values than the LDRs on Tayda, so it's good to know you had success with one of these. Adjusting the gap might be a key to making this work, so that's a great tip!

From a search for "Sproing LDR" I came up with this:

DEMO - Sproing Deluxe (PPCB + J. Rockett Boing) - Demo Added

After my spasm of overdrives I needed to step away from the pipe and do a modulation build. This project is the brainchild of our resident reverse engineer @Robert adding an optical tremolo circuit to the original Sproing project (J. Rockett Boing). The Sproing is a simple one knob Belton...

forum.pedalpcb.com

Good bet that without a part number on the BOM, I would have searched the forum and used the LDR @MichaelW had luck with.

 

[kinkinaudio]

Do y'all think I could use P9203 LDR for this build? I have a couple spares from building a couple of Uni-vibes. A quick google comparing P9203 and KE-107020 came up with no results!

 

[Erik S]

Do y'all think I could use P9203 LDR for this build? I have a couple spares from building a couple of Uni-vibes. A quick google comparing P9203 and KE-107020 came up with no results!

I’m not familiar with that part. Were you able to find a data sheet for each? Any big differences in the specs?

 

[kinkinaudio]

Upon further digging I think KE-107020 is actually KE-10720.

Here's what I'm finding:

P9203 (https://stompboxparts.com/leds-bezels-optoelectronics/9203-cds-ldr/)
Dark Resistance: 5MΩ minimum
Illuminated Resistance: 20kΩ (+/- 10kΩ)
Rise Time: 60ms
Fall Time: 25ms

KE-10720 (https://www.taydaelectronics.com/photo-conductive-cell-resistor-ldr-650nm-radial-ke-10720.html)
Spectral peak Max(nm): 650nm
Maximum Voltage: 100VDC
Photo Resistance at 10LUX: 10KΩ-20KΩ
Dark Resistance Min: 0.5MΩ
Power dissipation: 35mW

According to this thread the KE-10720 is now labeled as 5528, and the specs for those are:
Spectral peak (nm): 540nm
Maximum Voltage: 150VDC
Photo Resistance at 10LUX: 10-20KΩ
Dark Resistance: 0.5MΩ
Power consumtion: 100mW

Should I go ahead and order the 5528s you think?

 

[Erik S]

Looks like the resistances are in the same range, but the rise and fall times are faster on the 10720s. Not sure how much that would change the character of the tremolo.

My uneducated guess is that it would probably function. The Ldr is under the belton brick though, so swapping it out later could be a bummer.

If you try the 9203 it and it works, let us know.

 

[kinkinaudio]

I'm building two side-by-side and I'm tempted to do one of each. Either way, I'll report back.

Edit: This video explaining how LDRs work is really interesting if you're curious and have 5 mins to watch it:

 

[kinkinaudio]

Update! I just finished one Sproing Deluxe with the 5528 LDR from Tayda. Everything works! But I used the small B10K and B500K pots and don't love that they barely peek through the top of the enclosure. Has anyone tried replacing those with anything else?