Author Topic: Glasshole bypass LFO tick  (Read 3837 times)

jpier2012

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Glasshole bypass LFO tick
« on: February 26, 2021, 03:11:38 PM »
Hello! I recently built the Glasshole and am getting LFO tick, both with the effect on and in bypass.

Does anyone have experience with this? I'm hoping I can just add another cap to the LFO circuit to take care of any transient spikes.

Thanks!

James
« Last Edit: February 26, 2021, 03:16:57 PM by jpier2012 »

danfrank

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Re: Glasshole bypass LFO tick
« Reply #1 on: February 28, 2021, 09:35:57 PM »
I had this also and I fixed mine by moving the 2 jumper wires on the PCB closer to the case and away from the 470nf cap that is close by. That cap does not like those wires close to it.

geetarm@n1

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Re: Glasshole bypass LFO tick
« Reply #2 on: April 07, 2021, 02:23:34 PM »
Hello.

I've got the same problem with mine, but the LFO ticking is only present on the 6 and 8 stage settings, is not something that is made more or less present with higher/lower Depth and Feedback settings, it's not made more or less present with a buffered effect before or after it and also is not bleeding thorough in bypass.  Not affected in any way by moving the short flying leads.  No more or less present whether it is in the enclosure or out of it.   It's simply a very consistent tick that is of a tolerable volume - at least in slow settings (not any less present, just fewer of the ticks trying to tick me off) - but loud enough that it is pretty much unusable at higher rates of speed.   It's not louder than the guitar when picking/strumming, but letting a chord die out is going to reveal the problem within seconds (as soon as the guitar level starts to drop).

But it's quiet as a mouse in 2 and 4 stage mode, and fortunately, the higher speed settings are more useful to me with fewer phase stages anyway, so if I can't get this resolved I'm still going to be extremely happy with this build. 

What I've done so far:

a) Checked voltages - everything is in line with the published voltages.   Grounds at jack are good.  Grounds from board are good (or I'd not be phasing, presumably).

b) I've tried moving the two jumpers by C18 as suggested.  Mine were originally both very short an on top of the board.  I've tried very short ones under the board (without success), then tried longer (2") loop under the board, giving me something that can be moved around.   Moving them around makes no difference.

c)  I've now disconnected the leads connecting the jack's tip to the board and board to switch and replaced them with shielded straight runs from jack to switch (shielding connected at the jack sleeve lug).   Moving them around makes no difference. 

Overall, the build seems super stable to me - I guess I'm used to building gain devices where you get all kinds of noise/radio/squelchy stuff with the back plate off, while poking around inside and moving wires (and where I can fix things like this by doing so - I've never resorted to using shielded wire in a build).   This thing is completely silent and stable in or out of the box and moving wires or putting my hands on the board don't seem to affect it adversely at all.  Other than the tick, it's as clean/clear as anything I've made.

Being that I'm not at all at the level to understand this circuit, I've now exhausted my knowledge on how to fix it.  So with brain failing me, I've resorted to using my eyes and I see that:

1) my 470nf cap C18 itself is larger than ideal (both of them, actually).  It's a 100v cap and has one leg bent inward/under it to reach the hole and the cap is therefore extended further out toward the light shield than it would be if I'd used a smaller cap, but since moving those jumpers and tipping this cap forward/backward don't show any indication of a change for better or worse, I expect my issue is not here.  I'll order a smaller caps anyway and see what happens.

2) I did use the four non-essential/visual-only LEDs for the "stage" indicators, each a different color (all diffused) and I notice that the blue LED used for the 6 stage setting doesn't ramp on/off as smoothly as the rest - it comes on and drops off a little more abruptly and is brighter than the rest.  Given that this LED is not on when the ticking is present on the 8 stage mode leads me to believe this is a non-issue.

Regarding components:   I used all 1/4 watt resistors standing on end where required.  One small ceramic and maybe 15% of the resistors are carbon film.  Most of the 6n8 caps were greenies purchased from Jameco on a whim and I've not tested them.  Everything else was the normal "good stuff" from Smallbear or the specific items from Mouser listed on the BOM.

Any suggestions would be most appreciated.


So enough of the complaining/troubleshooting for a minute.   Let me give a big thanks to Brian and bangerang101 for making this project available.  I foolishly sold my own Mutron Phasor II many (many) years ago and this is by far the closest I've come to replacing it and closer than expected.  I've been building pedals for years but haven't really advanced my electronics too far.  As such, I can still believe in magic when it comes to gear and the Phasor II is a magical thing to me and I expected this build to result in a working phaser that was cool and worth building (as all phasers are), but without any expectation that it would hold a candle to my recollection of how it felt playing the real deal at loud levels with the sound filling the room.   Well, it definitely does (hold said candle).  The quality of sound of this build is fantastic.  I had a chance to A/B it against my brother's Phasor II while tuning mine and found it to be very similar.  Not quite as loud and a bit less roomy/spacious sounding as the original - didn't seem to inhale the guitar as much (not quite as much headroom maybe?) - so the feel is different, but the sounds the Glasshole produces are somewhat more clear/refined sounding overall and the richness and smoothness of the sweep plus the (controllable) vowel-y content are beautiful and exactly what I'd hoped it to be.   I can now kick myself a little less vehemently for selling my original.

madbean

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Re: Glasshole bypass LFO tick
« Reply #3 on: April 07, 2021, 06:02:05 PM »
I'll get mine out tomorrow and take another listed to see if I can hear any ticking.

It's not unusual to get some "pulsing" in analog modulation pedals. This is unavoidable since amplitude changes will carry the noise floor of the circuit to the output. However, there should not be any kind of hard transient (like a click) with that and certainly not in bypass. There are some steps to take but let me listen to mine again to see if I can identify a problem.

geetarm@n1

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Re: Glasshole bypass LFO tick
« Reply #4 on: April 15, 2021, 02:30:10 PM »
I just reread my original post and I mentioned that it was a "continual" ticking and should clarify.    That is only the case at higher speeds.  When at slow speeds I hear two tick/thumps - one at the peak of the sweep (peak of the indicator LED brightness) and once at the bottom of the sweep (well after the indicator LED has turned off).


I've also spent some more time today listening to it with the amp up loud but without a guitar in hand - just listening.   The tick/thump is absolutely not present at all on the 2 and 4 stage settings.

The volume of the tick/thump is a little less than what I get when switching between the different stages with the rotary with the effect active (neither are sounds that worry my in terms of speaker health - unlike the pop from engaging either of the Phase 45s I've built, but that's another discussion altogether). 

The overall hiss (and its low end content) and the click/pop when engaging the effect are all very negligible.   In other words, it is hard to believe that I've miswired something, used an incorrect part value or that I have a bad solder joint as everything really seems to be working as expected other than the tick at the top and bottom of the cycle of stages 6 and 8.

If there is any reason to think that the ICs are to blame I can swap them around but I'd prefer not to pry them out of the socket arbitrarily.


madbean

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Re: Glasshole bypass LFO tick
« Reply #5 on: April 23, 2021, 01:59:01 PM »
Circling back to this an apologies for taking so long. You are absolutely right there is ticking in bypass. For me, I had to turn my amp to full volume to hear it. The ticking is quiet but it is there and that's not acceptable. Also, I can hear it no matter what stage is selected so this is coming directly from the LFO.

So, I'm going to look for a solution. It might be through using a different IC for the LFO or using shielded wire on the I/O jacks. The extra flashing LEDs could be an issue. I'll work on it today and report back soon.

madbean

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Re: Glasshole bypass LFO tick
« Reply #6 on: April 23, 2021, 03:03:33 PM »
Okay I think I've identified the problem and solution. It's the proximity of the Rate control to the I/O connections at the top of the board. This was a bad design decision on my part and it became obvious after I realized the issue. So the solution appears to be re-routing the tip connections directly from the jacks to the 3pdt (grounds can be left as they are). I couldn't hear any ticking after doing that.

Unfortunately, while I was messing around with my build my little expression jack contacted the enclosure and I fried the whole goddam LFO somehow (there was smoke). So I need to pull the board out, repair it then put everything back together before I can sign off on the rewiring being the only thing needed (pretty sure that's the case but I won't jump the gun). I'll do that as quickly as possible.

jimilee

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Re: Glasshole bypass LFO tick
« Reply #7 on: April 23, 2021, 04:17:40 PM »
Wow, magic smoke.


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madbean

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Re: Glasshole bypass LFO tick
« Reply #8 on: April 23, 2021, 05:41:55 PM »
Wow, magic smoke.

Indeed. I actually did blow up the entire LFO. I had to replace the two diodes, LED and 2n4401! When you start moving hardware around on a powered pedal you are asking for trouble.

Anyway, I have confirmed the solution 100%. It just needs the tip of the Input and Output jacks rewired directly to the 3pdt. No ticking whatsoever now. I will update the doc tomorrow with the correction, make a new wiring diagram and update the build pic.

jimilee

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Re: Glasshole bypass LFO tick
« Reply #9 on: April 23, 2021, 06:21:34 PM »
Wow, magic smoke.

Indeed. I actually did blow up the entire LFO. I had to replace the two diodes, LED and 2n4401! When you start moving hardware around on a powered pedal you are asking for trouble.

Anyway, I have confirmed the solution 100%. It just needs the tip of the Input and Output jacks rewired directly to the 3pdt. No ticking whatsoever now. I will update the doc tomorrow with the correction, make a new wiring diagram and update the build pic.
Yep, I did that to a GGG phase 100, never did get it working again.


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geetarm@n1

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Re: Glasshole bypass LFO tick
« Reply #10 on: April 26, 2021, 02:21:15 PM »
I took another listen to mine again today and found that with the amp cranked fully (low watt amp) I could indeed hear some clock noise in bypass after all (mine already has straight runs from the tip of the input/output jack straight to the switch with shielded cable) but this was only when it was in the middle of a long chain of DIY effects powered by a single One Spot, two of which have charge pumps in them.  Asking a lot from the One Spot for sure.  When I took half of the downstream effects out of the picture the clock noise in bypass became very negligible but still there.  When I reduced the chain down to where the Glasshole was the only thing being powered by the One Spot and it was the only thing between my guitar and the cranked amp there was no clock noise at all on any of the various "stages" settings (again, in bypass).   So in that way I'm good to go.

However, I still do have the issue of the clock noise in non-bypass mode on the 6 and 8 stage settings.  Testing for this issue has primarily been done with the Glasshole isolated - alone on the One Spot, no other FX in the chain, but of course it is also present when it was in the chain as well.  The clock noise present across multiple amps, multiple guitar cables.  Also present when powered by a 9v battery rather than the One Spot I mentioned earlier.  I'm sure that some of my tests are no more than shots in the dark and have nothing to do with the actual issue, but I figured that I'd rule out what I could before posting again.   Let me know if you have any recommendations of what I should try in order to track it down and lessen or eliminate it.

geetarm@n1

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Re: Glasshole bypass LFO tick
« Reply #11 on: May 12, 2021, 01:36:18 PM »
Bump    :)

Zerro

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Re: Glasshole bypass LFO tick
« Reply #12 on: May 12, 2021, 05:22:07 PM »
My tip: IC4 that creates trigger of LFO - block it at power pins 4 and 11 with some little cap 47-100nF against ground. Straight at PCB side, at very pins output.

I would like to know too, if that negative power supply IC5 LT1054 has sufficient current output for those circuits attached there. Maybe is too weak to hold it.
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geetarm@n1

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Re: Glasshole bypass LFO tick
« Reply #13 on: May 14, 2021, 04:47:04 PM »
Thanks for the reply Zerro

I tried what you suggested with a pair of 100nf caps and it didn't help, unfortunately.

I also tried a few other things:

a) Disconnected the rate status LEDs from the offending stages (6 and 8).  No difference.

b) Replaced my large size C18 with a smaller, lower voltage version of the same (thinking that the large one was acting as an antenna).  No difference.

c)  Wondering if my plastic light shield's tie-down harness (thin metal wire) was acting as an antenna, I removed it and held the light shield in place.   No difference.   

d)  I then removed the light shield and the ticking stopped.  Of course, my swooshing also stopped.    I can make it fade in/out by blocking the light that reaches the LDRs and if I do this after first strumming the guitar, the instrument's signal is completely audible, just without any phasing (or ticking) until I start bringing in the light shield.   

Also, for what it's worth, I ended up using a diffused green LED for the lamp as it was my closest in value to the 520 nm mentioned in the build doc.

So the ticking is audible only when Phasing is audible.   Does that narrow it down to any particular set of components?


And again, my issue in is non-bypass mode only.  I clarify that again as it doesn't match the Subject line of this thread.  Let me know if it is more appropriate to open a new thread rather than convoluting this one further.

Thanks

geetarm@n1

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Re: Glasshole bypass LFO tick
« Reply #14 on: May 14, 2021, 05:57:35 PM »
I just tried a few more shots in the dark one at a time, all without success.

Repositioned the power lines away from the rate pot temporarily

Tried a different LT1054

Swapped the positions of the TL074s in IC1 and IC4

Re-flowed the solder on the components in the neighborhood of IC1 and IC4 and the LDRs

Played with the trimmers - sweeping these around had no effect on the amount/level/quality of the ticking.

Putting my finger on the Rate pot lug 3 (connects to IC4 pin 1), the quality of the ticking does not go away or even really drop in volume, but it does change in quality (less full-frequencied, cuts some low end out of the signal).


Admittedly, that's some willy nilly troubleshooting and definitely where I draw the line today or I'll end up breaking something irreparably.


Also possibly of note:  I used all 1/4 watt metal film resistors, so I have very few resistors lying flat to the board.   All of the resistors running alongside IC4 have their tall end up in the air right next to IC4 and the flush-to-board end is therefore on the side by the  Depth pot.