Byzantium Flanger not Flanging

T

Twinningses

New member
Hi Folks,

Newish builder here and encountering an issue I haven't come across before: I've built the Byzantium Flanger but there's no effect.

Pedal bypass is working fine. When engaged, LED lights up, I get sound, but it's the exact same sound as when the effect is off. The knobs don't alter the sound at all, the trim pots don't alter the sound at all, etc.

I read another thread where people encountered this issue from using the wrong ICs and transistors, but I'm using all the ones to spec.

Interestingly, I don't even here any noise from the ICs that I would expect. Absolutely zero affected signal.

And... forgive my lack of low-profile caps here. I didn't have them for this build and so used what I had and just bent the caps so they still fit between the boards. I've been fairly meticulous to make sure their legs aren't touching things they shouldn't be, so I don't think that's what's causing my issue.

Any and all help very much appreciated.

WhatsApp Image 2026-07-14 at 10.09.06.jpeg
WhatsApp Image 2026-07-14 at 10.09.05.jpeg
WhatsApp Image 2026-07-14 at 10.09.06 (2).jpeg
WhatsApp Image 2026-07-14 at 10.09.06 (1).jpeg
 
Sort by date Sort by votes
Woof. This one can be an intimidating trouble shoot, but I would start by using the continuity function on your meter to verify that the board connections have continuity from one side to the other. Put one probe of the meter to the solder pad of one of the connectors and the other probe to the back side of its mating component on the other board.

Then, verify that each leg of each IC has continuity to its solder pad by touching one lead of the meter to the IC's leg and the other to the back side of the solder pad.

Check that the ground connection exists between both boards.
 
Upvote 0 Downvote
jwin615 said:
Some of your joints look cold and stressed especially on the 100v caps. the 100u on the top left of the pot board may be shorting it's legs when the boards are squeezed together.
Click to expand...
Cheers I'll check those particular caps.

For cold joints, you know what my eye for them is not good ever since switching solders. When i was using leaded solder it was super obvious to me when there was a cold joint, but now that I'm using lead-free, I find every joint looks dull and cold.
 
Upvote 0 Downvote
falco_femoralis said:
Woof. This one can be an intimidating trouble shoot, but I would start by using the continuity function on your meter to verify that the board connections have continuity from one side to the other. Put one probe of the meter to the solder pad of one of the connectors and the other probe to the back side of its mating component on the other board.

Then, verify that each leg of each IC has continuity to its solder pad by touching one lead of the meter to the IC's leg and the other to the back side of the solder pad.

Check that the ground connection exists between both boards.
Click to expand...
Great thanks, will do connectivity checks across everything.

And yea this is a weird one. When I've head connectivity issues before, it's resulted in weak/no signal when engaged... not strong signal with no effect as is currently happening.
 
Upvote 0 Downvote
Twinningses said:
Hi Folks,

Newish builder here and encountering an issue I haven't come across before: I've built the Byzantium Flanger but there's no effect.

Pedal bypass is working fine. When engaged, LED lights up, I get sound, but it's the exact same sound as when the effect is off. The knobs don't alter the sound at all, the trim pots don't alter the sound at all, etc.

I read another thread where people encountered this issue from using the wrong ICs and transistors, but I'm using all the ones to spec.

Interestingly, I don't even here any noise from the ICs that I would expect. Absolutely zero affected signal.

And... forgive my lack of low-profile caps here. I didn't have them for this build and so used what I had and just bent the caps so they still fit between the boards. I've been fairly meticulous to make sure their legs aren't touching things they shouldn't be, so I don't think that's what's causing my issue.

Any and all help very much appreciated.
Click to expand...
1784063619154.jpeg
This one looks like there's not enough solder, other pads also look suspicious to me.

Might be an issue with your soldering technic.

Set the iron around 380 or 400°C, get the tip of the iron in contact with both the pad and the component's leg in order to simultaneously heat both of them for 2 or 3 seconds.
Then put some solder on the pad and remove the tip of the iron upward, along the component's leg, in order to form a nice dome.
You need the right amount of solder, not too much but enough to fill the pad.
If you do it wrong on a pad, use the desoldering pump to start again.
Take your time and give it time to cool down to avoid overheating your pads, and clean the iron's tip often on some piece of dry old sponge, slightly wet.
 
Last edited:
Upvote 0 Downvote
falco_femoralis said:
Woof. This one can be an intimidating trouble shoot, but I would start by using the continuity function on your meter to verify that the board connections have continuity from one side to the other. Put one probe of the meter to the solder pad of one of the connectors and the other probe to the back side of its mating component on the other board.

Then, verify that each leg of each IC has continuity to its solder pad by touching one lead of the meter to the IC's leg and the other to the back side of the solder pad.

Check that the ground connection exists between both boards.
Click to expand...
Ok thanks for the first set of advice:

I confirm that I have continuity through every leg of the board connections.
I confirm that I have continuity through each IC leg.
I confirm that the ground connection exists between both boards.

I have also reflowed all joints as per @jwin615 's recommendation, as well as checked every cap's legs to ensure they are not shorting.

One thing I did notice by happenstance is that both pins on the left board connector (circled in green) have connectivity to ground, where as neither pins on the right board connector (circled in red) have any connectivity to ground. The other three board connectors each have one connection to ground. I need to check the trace to see whether that makes sense but it's now 1am and I've got to call it!

The only other thing I could think of is that where one IC location calls for a "TL022" I have used a "TL022CP" but from what I read that shouldn't make a difference.

Any other advice would be super welcome, thanks in advance!

1784099257013.png
 
Upvote 0 Downvote
If you are sure about your soldering joints and checked with a continuity test all suspicious pads, you can try to narrow it down with an audioprobe.


You can find the signal path by drawing the shortest line from IN to OUT on the schematics.
Circuit powered and switched on, feed the circuit with a signal source connected to the IN jack.
Then probe the pads at various location on the signal path, following the schematics until you found a spot where the signal stops.
Check all connections with continuity tests, make some visual inspections, check components values and orientation, and reflow all pads related to that spot, according to schematics, until you restore the signal path.

You can also make some voltage readings on your transistors and ICs, to make sure they are getting the right voltages.
You can post your readings here if you have some doubts : pin1 = ?,
pin2 = ?, etc.
1784124826338.png
For transistors : E = ?, B = ?, etc.
1784126234611.png

EDIT: i cant find the schematics for the Byzantium, does someone have them ?
 
Last edited:
Upvote 0 Downvote
red : quick path that doesnt explore the full circuit, probing here and there will help you locate where the signal stops
and find suspicious aera.

green : quickpath to check if the signal is going in the BBD and Resonnance parts of the circuit, and comes back correctly.
1784127340141.png
 
Upvote 0 Downvote
You might try removing the top board from the bottom one and see if there is a change in sound. Leave them both wired to the footswitch, audio in/out, and power/ground, but separate them from each other (but add a ground wire to the solder pad next to the IN pad and run it to the other board)
 
Upvote 0 Downvote
You must log in or register to reply here.
Back
Top