Simplest relay bypass possible - no microcontroller

PedalPCB

Admin (Robert)
Staff member
That list is for non-latching only.

This is the parts list for the latching relay version:

R1 10K
R2 10K
R3 100K
R4 10K
R5 10K
R6 10K

C1 1u MLCC
C2 100n
C3 100u
C5 100n

IC1 NE555
IC2 78L09

K1 Relay (TQ2-L-5V)

Q1 2N3904
Q2 2N3904
Q3 2N3906
Q4 2N3904

FS Momentary Footswitch
 

megatrav

Active member
Thanks!
I have a dumb question.
what’s the difference between latching and non-latching aside from the price and power consumption?
 

spi

Well-known member
Did the design for latching relay change? From the picture of the PCB on the site, it looks like either 2 transistors, or one transistor and one power regular got dropped.

I'm excited to try one or the other in the next order, but I'm not sure what extra parts I'd need.
 

GuitarBuilder

New member
Took a little longer than expected, but two versions are on the way.

This one uses a standard non-latching mini relay.
(Higher power consumption, but less expensive)

This one uses a latching mini relay.
(More expensive, but less power consumption)
Sorry about the late question! I'm a big fan of the µP-controlled bypass, so I'm having difficulty understanding why someone would want a "simpler version". My question to @PedalPCB is: does the 555 timer version suffer from mis-triggering when the foot switch is depressed for too long? The µP version appears to be flawless and fool-proof.
 

jcrhee

Active member
R1 10K
R2 10K
R3 100K
R4 10K
R5 1K

C1 1u MLCC
C2 1u MLCC

D1 1N5817
D2 1N5817
D3 1N5239B

IC1 NE555
K1 Relay (A-4.5W-K)

Q1 2N3904
Q2 2N3904

FS Momentary Footswitch
Just want to reconfirm the resistor value. On the PCB it calls for two 1k resistors. Is this correct or should I go with your parts list which calls for 10k instead. Thanks.
 

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ADAOCE

Well-known member
Sorry about the late question! I'm a big fan of the µP-controlled bypass, so I'm having difficulty understanding why someone would want a "simpler version". My question to @PedalPCB is: does the 555 timer version suffer from mis-triggering when the foot switch is depressed for too long? The µP version appears to be flawless and fool-proof.
I was posing the question because I was building a loop strip switcher and didn’t need intelligent functionality and was trying to minimize cost is all.
 

PedalPCB

Admin (Robert)
Staff member
The PCB was originally designed for 1K, which will work fine, but 10K will consume less idle current.

Go with 10K if you have them, if not, it'll function exactly the same with 1K.
 

jcrhee

Active member
The PCB was originally designed for 1K, which will work fine, but 10K will consume less idle current.

Go with 10K if you have them, if not, it'll function exactly the same with 1K.
One other stupid question, which 1K to replace with 10K? Or should I replace both with 10K? Thanks!!
 

jcrews

Member
That list is for non-latching only.

This is the parts list for the latching relay version:

R1 10K
R2 10K
R3 100K
R4 10K
R5 10K
R6 10K

C1 1u MLCC
C2 100n
C3 100u
C5 100n

IC1 NE555
IC2 78L09

K1 Relay (TQ2-L-5V)

Q1 2N3904
Q2 2N3904
Q3 2N3906
Q4 2N3904

FS Momentary Footswitch
having a helluva time finding that
That list is for non-latching only.

This is the parts list for the latching relay version:

R1 10K
R2 10K
R3 100K
R4 10K
R5 10K
R6 10K

C1 1u MLCC
C2 100n
C3 100u
C5 100n

IC1 NE555
IC2 78L09

K1 Relay (TQ2-L-5V)

Q1 2N3904
Q2 2N3904
Q3 2N3906
Q4 2N3904

FS Momentary Footswitch
I have been looking everywhere for a "L8709" variety IC chip. Is this supposed to be Q5? I'm seeing 3 leg transistors, but no IC's
 

jcrews

Member
Super cool. I ordered a bunch incase that was right because they were cheap. I ordered 5 of the relays and 5 boards for the latching.
Looking forward to getting them built and installed in a couple of things this weekend.

I know the build docs aren't out yet but the layout seems pretty simple. In and out is self explanatory, are + and - coming off the power jack?
Any tips on combining it with my informant "buffered or true bypass on a switch layout? Another user here was able to hook me up with a layout for the buffered bypass on the relay switch, but was hoping i could retain my layout.
Buffer Switch.jpeg
 
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