# Abyss - LDRs - 2 ?'s



## BeeSharp (Sep 2, 2020)

I recently built the madbean glasshole, which is a mu-tron phaser.  Those instructions say to mount the LDRs flat.  I was looking at the Jam pedals Retrovibe and some other folks' builds and I see the LDR's standing up instead of flat.  Which is correct for the Abyss? and what LED to use?  I know that 620nm is Red, so does the Tayda clear red 5mm work ok?  Thanks!


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## Cybercow (Sep 2, 2020)

The angle of the LDR is just a personal preference. Considering the whole thing will be enclosed in the case when done, any light bleed at that point would be negligible.  The use of the yellow reduces the "efficiency" of the LDR's reception by a given percentage and I believe that is by design. Perhaps by being prepared to swap out a red LED for the specified yellow LED will give an opportunity to hear any difference. Though I doubt any real difference will be heard. Just my 2¢.


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## music6000 (Sep 2, 2020)

This is how I installed, used Tayda, Works Great!








						LED 5mm Yellow
					

Get It Fast - Same Day Shipping




					www.taydaelectronics.com
				











						Photo Conductive Cell  Resistor LDR 650nm 10KΩ to 20KΩ RADIAL KE-10720
					

WAITRONY - Get It Fast - Same Day Shipping




					www.taydaelectronics.com
				








Here's my Build Report :





						Abyss
					

Awesome Vibe Pedal! Mods: Battery Clip & Stereo Input Jack.



					forum.pedalpcb.com


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## Ratimus (Sep 3, 2020)

I did mine with the LDRs pointing straight at the LED and it sounded awful. I think the resistance was going too low at full brightness. I backed them off a ways and everything sounded much better and had a more useable range. So "maximum efficiency" isn't necessarily what you want here. If you point the LDRs straight up, you'll get the bounce from the inside of the enclosure (assuming it isn't matte black on the inside), so that would probably work too.


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## zgrav (Sep 3, 2020)

I built the Glasshole recently and really like it.  I used Tayda LDRs and stood them up in a circle around the LED.


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## blackops (Jan 1, 2021)

Just want to check something - 
I can't track down an LDR with the same dark/light specs as the Tayda KE 10720.
Best I can locate locally via Jaycar hits the dark resistance (0.5M), but the light range is 2.8K to 8.4K.  Will this be suitable, or am I waiting for a delivery from Tayda or Altronics?

Also, can't locate MPSA18 locally, would BC5089 or MPSA13 be suitable?


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## Danbieranowski (Jan 2, 2021)

blackops said:


> Just want to check something -
> I can't track down an LDR with the same dark/light specs as the Tayda KE 10720.
> Best I can locate locally via Jaycar hits the dark resistance (0.5M), but the light range is 2.8K to 8.4K.  Will this be suitable, or am I waiting for a delivery from Tayda or Altronics?
> 
> Also, can't locate MPSA18 locally, would BC5089 or MPSA13 be suitable?


5089s are usually swappable with MPSA18s. Socket and test of course.


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## music6000 (Jan 2, 2021)

blackops said:


> Just want to check something -
> I can't track down an LDR with the same dark/light specs as the Tayda KE 10720.
> Best I can locate locally via Jaycar hits the dark resistance (0.5M), but the light range is 2.8K to 8.4K.  Will this be suitable, or am I waiting for a delivery from Tayda or Altronics?
> 
> Also, can't locate MPSA18 locally, would BC5089 or MPSA13 be suitable?


Where are you located?


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## blackops (Jan 2, 2021)

music6000 said:


> Where are you located?


Canberra, Australia


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## music6000 (Jan 2, 2021)

MPSA18's





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						MPSA18 - NPN Darlington Transistor - AUD $0.35 : diyguitarpedals.com.au, A shop for all diy guitar pedal enthusiasts!
					

diyguitarpedals.com.au MPSA18 - NPN Darlington Transistor - MPSA18 - NPN Darlington Transistor Brand: Fairchild Package: TO-92



					www.diyguitarpedals.com.au


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## blackops (Jan 2, 2021)

music6000 said:


> MPSA18's
> 
> 
> 
> ...


Hot damn.
AND proper pcb mount pots, AND cheaper than Jaycar.


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## music6000 (Jan 2, 2021)

blackops said:


> Hot damn.
> AND proper pcb mount pots, AND cheaper than Jaycar.


The 9mm pots are not suitable for PedalPCB builds.
I thought you would have known PedalParts Australia:




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						TRANSISTORS : Pedal Parts Australia, DIY Guitar & Effect Pedal Parts
					

Pedal Parts Australia : TRANSISTORS - SWITCHES KNOBS ENCLOSURES CONNECTORS POWER CABLES POTENTIOMETERS LED's & BEZELS WAH PARTS BOSS PARTS GUITAR PCB GUITAR PCB KITS GIFT VOUCHERS IC'S TRANSFORMERS RELAYS SEMICONDUCTORS CAPACITORS RESISTORS OPTOCOUPLERS ACCESSORIES CLEARANCE ecommerce, open...




					www.pedalpartsaustralia.com
				




https://www.pedalpartsaustralia.com/index.php?main_page=index&cPath=12_114


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## blackops (Jan 2, 2021)

No.  Have been out of the game for a few years but getting back into things.  Thanks for the heads up re. 9mm pots not being suitable.


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## Danbieranowski (Jan 2, 2021)

blackops said:


> No.  Have been out of the game for a few years but getting back into things.  Thanks for the heads up re. 9mm pots not being suitable.


Welcome back to the shit.


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## blackops (Jan 2, 2021)

Danbieranowski said:


> Welcome back to the shit.


Hah. Thanks. 
Does anyone have any input on the LDR question?


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## BurntFingers (Jan 2, 2021)

blackops said:


> Hah. Thanks.
> Does anyone have any input on the LDR question?



Chances are it'll be fine.


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