SOLVED Byzantium calibration questions

[eh là bas ma]

Hello,

I am calibrating the byzantium and i m not sure how to set the Clock. The other 2 trimmers are easy to figure out, but Clock calibration is a bit more tricky for me.

Madbean has a similar project, so i checked the instructions to calibrate my build.

https://www.madbeanpedals.com/projects/_folders/FilterMod/pdf/Fraudhacker24.pdf

It says the clock need to be set at 50 kHz when all the pots are CCW.

I am experiencing some cyclic whistling noises at some settings, with this 50kHz setting. They appear mostly when manual is in the first half of its rotation, and depth on high settings. I guess they come from the clock ? I can't dial these noise away with the other trimmers, unfortunately.

While searching the forum for some clarifications about the byzantium calibration, i found this post :

S

Thread 'How do I use my multimeter (it has hz setting) to measure the clock frequency on the Byzantium Flanger?'

Feb 19, 2024

I understand that I am supposed to set the clock to 40khz using TP1. But, how do I actually measure it? Put the black probe on ground and the red probe on the test point? Both on test point?

Pity me for being so ignorant.

• squirrelboy
• Replies: 1
• Forum: General Questions

The clock is supposed to be set at 40 kHz, according to Boss user manual.

I tried 40kHz but the background whistlings are the same or even worse. For example, if Depth and all controls are fully CCW, Clock set anywhere between 35 and 47 kHz, there is a steady whistling noise, the pitch of the noise goes up and down, similar to the auto-oscillating noise, but quieter.

At 53 kHz, the noise almost completely disappears, only some dimed cyclic high pitched noise remains on some settings. It disappears if Manual is set in the second half of the rotation, or if i lower the Depth.

I wonder if there is a way to completely get rid of the cyclic noise on the byzantium build ?

Could it be related to the signal chain, or the power supply ?

When I tried to calibrate the byzantium there was another flanger circuit connected after it in the signal chain. Lectric fx's Flintlock (A/DA flanger), it also has some whistlings at some settings, and Flintlock's whistlings are suddenly more noticable with the byzantium connected before it.

I wonder if there is some simple explanation to understand why ? 2 BBD flanger circuits can't coexist peacefully in the same signal chain, or it's all about the electrical environment (power supplies, long signal chain, etc) ?

Having a similar issue with the Flintlock, i spent time trying to fix these whistlings and 2 things came into light :

The voltage pump made it worse, removing the voltage pump IC and using an 18V power supply made the circuit almost completely quiet.

The pcb designer (or maybe some forumite, i cant remember) said the whistling issue probably came from the circuit layout, some trace or some part being too close to each other.

Could it be the same cause with the Byzantium ?

I couldn't find any post or comment about these cyclic noises, am i the only one ?

Every suggestions and observations are welcome !

 

[eh là bas ma]

Found this on diystompboxes, from M. Hammer :


"Flangers are inherently noisy pedals, but there are a few things you might do.

1) IC1 (the 4558 closest to the connecting wires side of the board) is *always* on, so it provides the constant hiss background against which flanger/delay-path noise is added on. If you can get in there and replace this chip without damaging anything do it (and I would suggest adding a bit of solder to each pin on the copper side before you attempt to unsolder it, making sure to wait a bit for it to cool down in between heating each pad for solder removal and doing the next pin). A commonly available replacement might be an NE5532 or LM833, although there are other higher-priced chips with better noise specs like an OP-275. None of the other chips will have any impact on noise levels when in bypass mode.

2) There are a number of resistors that are also in the signal path and *always* so, whether in bypass or effect mode. You could consider swapping these for lower-noise metal film ones if you are desparate for even more hiss reduction. These would include: R1-through-6, R28, R30-through-32.

3) It is possible there is a lower noise replacement for Q1 (2SC732) but I don't know what it would be.

4) If you are assured that you will never ever feed this pedal with something that has a DC offset, you can remove C1 (.047uf) and replace it with a fixed wire link. That will also reduce some input noise.

5) If you don't mind some loss of high end, you can also consider upping the value of feedback capacitors C4 and C22 from 100p (which gives a rolloff at 33khz) to 330pf, which will give a rolloff around 10khz. That will trim some hiss as well. If that's too much treble to sacrifice, add another 150pf cap in parallel to what's there already. A combined parallel capacitance of 250pf in each spot gets you a rolloff at around 13.5khz which still retains as much crispness as electric guitars are likely to require. This will have an impact on both effect and bypass mode. "

https://www.diystompboxes.com/smfforum/index.php?msg=115515

It's not exactly about clock noises, but i'll try replacing the 4558...

 

[Nostradoomus]

i set everything at noon, it sounded good enough to adjust from there

having two flangers inline probably isnt helping, it's an inherently noisy circuit...just turn it off if you don't need it on

 

[eh là bas ma]

i set everything at noon, it sounded good enough to adjust from there

having two flangers inline probably isnt helping, it's an inherently noisy circuit...just turn it off if you don't need it on

Thanks for your reply !

I think the clock noises were triggered by a Black Eye (distortion with real tubes running internaly at 170V) which was connected to the same power supply.

I removed the Black Eye from the signal chain and it's perfectly silent for now.

From my experience, it looks like some BBD effects and voltage pumps don't get along too well, even if the voltage pump is in an other effect in the signal chain ?

 

[Nostradoomus]

they all add up to more noise in your chain