Tyrian - Whistling on Volume above 12 o'clock and when Blue/Red Mode engaged - possible issues?

[HippoPippo]

Hi all,
first post here, hope I am doing this correct without missing any important information. Setup is:

Tyrian plugged into my Audio Interface, running AmpHub just with an IR for soundtesting sake.
I have an issue with my Tyrian build, that when I push the volume above a certain threshold, should be around 12 (have no Pot-caps to fully determine this, so roughly guessing) I get a unbearable whistle which does not go away. I also have this whistle kind of permanently when I switch one of the modes on.

When I leave the volume below a certain threshold on the "normal" mode, then I can kind of get away even with gain even very high, but as soon as I turn up the volume.
The whistle shifts as I turn the EQ knobs, especially the treble knob highly influences it.
The whistle is somewhere around the range 1kHz to 3 kHz, I would guess (based on swiping through with an online frequency generator to "find the whistle tone).

I do have an oscilloscope at my disposal, so I could measure stuff (although I would have to work myself into it again, since last time I used one is 10+ years ago), but no signal generator, so the things which I basically checked:

- Clipping LEDs tested with a multimeter, on the LED checker setting they light up when Anode connected to + pin and cathode connected to com pin.
- The ICs show in the right direction as far as I can tell
- Elko Condensers show in the right direction
- All diodes in correct direction from what I can tell
- Wiring should be fine as well

Do you see anything else based on the pictures? Or any recommendations on certain voltages to check etc.?
Let me know if a video is needed.

Thanks a lot in advance for any help!

Cheers
Phil

 

[HippoPippo]

I also uploaded a video showing the issue (sorry for the mess I am, just woke up kind of), and also be careful with your ears! The high pitched frequency is really piercing, and way louder than the spoken word volume!

https://drive.google.com/file/d/1-NAStpvqRDEVDYlTDetInBEsqVjWKA8H/view?usp=sharing

(Note to future viewers - If you check this link after the issue has been found/project has been given up, could potentially be the videolink is not available anymore).
Hoping for any insight/idea from anybody, thanks again!

 

[HippoPippo]

Another finding: Disengaging the Hi-Z function on the interface input drastically shifts the threshold at where the whistling starts to my benefit, meaning if I use a line input impedance, then I can only get whistling when I really crank volume, gain and treble fully on the pedal, therefore basically pushing the input into clipping. So it seems that the issue especially is prone to happen on Equipment which would have a Hi-Z input - which is a problem I guess, since most pedals to follow after will have a Hi-Z input, but might give somebody more sophisticated on troubleshooting get a better picture on what's happening.

Still appreciate any input from others, just updating as I progress for all to read.

 

[HippoPippo]

Hi all,

I think I got way closer to a solution by now! I was trying around different boosters in front of the Tyrian, when Gain pedals were engaged, even more gain was introduced, no whistle, but once bypassed, whistle came back. So I ended up now plugging in a buffer in front of the Tyrian, and it seems ot be the solution I so desperately needed - no more whistle with any kind of booster (in my case a Ibanez TS7, which works similar to Boss Pedals without true bypass and a buffer instead).

So my curiosity is now haunting me - can anybody explain what is happening, that a buffer get's rid of the whistle? Because I think the whistle will be some sort of oscillation going on, but where will that most likely be coming from? Is there still an issue, which I am unaware of, or is it just the nature of things?

Thanks for reading, and highly appreciate any input still on the matter from more knowledgeable people than I am.

Cheers
Phil

 

[HippoPippo]

So, I finally found my solution:

Either you use a buffer, or you do not twist the cables like I did. After checking in on the German forum of Musikding, a DIY-Kit reseller, I got the hint to untwist and trim the cables both to the Power supply and especially to the footswitch. Done that, closed the enclosure - no signs of that annoying whistle anymore!



So this is how the PCB now looks, and it works wonderfully: with Gain, Volume and Treble maxed out completely in Red mode, there is no annoying whistle, only natural feedback occuring - but that is to be expected.

Yes, if I then blast the mids, I get back into whistle territory - but these are anyways levels on which my interface is desperately screaming for mercy because it is clipping as hell. Backing down volume again leaves headroom for it to not whistle, only good punchy, natural saturation and harmonic feedbacks - what an awesome pedal!

So to all of you out there: keep your cable management tidy and short, it will pay off!

Thanks for reading until here, hope this helps somebody else!

 

[kylewetton]

Hmmm so this is my problem right now, one of my footswitch wires is soldered onto the top instead of through the hole (desoldering could not get rid of the previous botched wire I mounted in there). I'm wondering if this is the problem. I may also buy a bag of heat shrink to really insulate as much as I can on future builds

 

[Barry]

Great job troubleshooting, you should mark your post solved

 

[flemming]

My Tyrian whistled like crazy until I used shielded wire for the input jack.

 

[kylewetton]

My Tyrian whistled like crazy until I used shielded wire for the input jack.

I followed your suggestion and changed my input jack to shielded wire, no change in the whistle. Would you recommend I try the output as well or would that not really matter?

 

[flemming]

I followed your suggestion and changed my input jack to shielded wire, no change in the whistle. Would you recommend I try the output as well or would that not really matter?

I now realize that I think your problem is with a different pedal and that you just popped into this thread since it seemed similar. You can always try the output as well, but in my case with the Tyrian it was unnecessary. Other people have built the Tyrian and not had the same issue so .

 

[Elijah-Baley]

I heard, sometime, about the squeal/whistle/oscillation problem in the Tyrian or more than else with a diy replica of the Revv G3 pedal using different board, like veroboard. Maybe protoboard not.
I never built it, but I think that a signal track longer than G4 (Sanguine version), the mid boost added and the layout of the PCB/board make the difference. (Once I solved this issue on a Dr. Boogie veroboard layout just making a track a bit shorter without moving anything).
There are two veroboard version of it in the web, but in both this issue come up, even if not for everybody. I'm not sure if the components make the difference, or the PSU, wires, guitars and amps... But I think that in this pedal the issue is around the corner.

In these days I have to make an experiment. I have on veroboard the G4 version (and it works fine) and I will add the extra mid gain stage of the G3 version
Considering that the G4 has a bit of more gain than the G3 version and the G3 mid stage is on breadboard, I expect anything really good, but it's an experiment.