Hi guys, take a listen to the clip - https://drive.google.com/file/d/0B--6F_4JB7SYSnI2aVI4eGhSTHM/view?usp=sharing
and tell me that this amount of distortion is normal for the Harbinger.
As you know, this is a part of my Supavibe build, and so far I've pretty much only used it with the fuzz that's in the same box right, but lately I've been enjoying the clean toanz and noticed more distortion than I'd like.
Bummer.
I am aware that the design introduces some dirt in the toan but I think this is too much.
Can't get the file to play, but distortion in the audio path could be caused by an incorrect resistor in the dry through portion. I had the same problem on one of my builds (used a wrong value).
Is it distorting in both the Modern and Vintage modes? Have a second look at R1 - R14, and esp. R4, R9 and R10.
It is distorting in both modes, it is less noticable in the Vintage mode of course.
You cannot get the file to play? Can you download it? You should be able to.
I will take a close look at the values of those resistors, I've made a big mistake with that already with the 3k3/33k mixup :facepalm:
Ah, okay I downloaded it and got it playing.
Sounds like a transistor out of wonk. It's got that buzzing/misbiased thing happening. But, I can't tell where it is coming from in the circuit just by the audio clip. You may have to temporarily disconnect the phaser portion from the dry audio and probe just the dry audio first. This would help narrow down where the distortion is occurring.
But, re-check those resistors first. If you need help on the second part let me know and I will write out some instructions.
Will do!
All of the 2n5088s are from Tayda and I've had some of them that were weird before, it might be it. Definitely something off here, I'm glad I wasn't trippin' and now I have the confirmation from you.
Will check the resistors and maybe post some voltages from the transistors that are in this section - http://prntscr.com/5i7its
The problem has to be there, R4, R9 and R10 are all here. Damn.
all right...so I've checked all of the resistors and all looks okay to me.
voltages in the preamp section:
Q1
e - 1.06
b - 1.43
c - 2.13
Q2
e - 1.55
b - 2.14
c - 4.46
Q3
e - 3.86
b - 4.47
c - 13.66 oscillating to 13.77 (wtf)
are these normal? Q1 and Q2 look fine to me, but Q3, I am not so sure, what do you guys think?
So guys these voltages for Q1-3 look okay to you? Just wanna confirm with someone before I start looking at other things
I've check voltages on my build and they are very close to yours (Q3 collector is also oscillating)
I'm just starting to put mine together now. I'll let you know what I see when I get to that point if you haven't figured it out by then. The caveat is that mine's starting to shape up as not being very normal. Still, I think the transistor voltages should be about the same as a stock build and I hope I'm not doing anything that'll add much distortion.
Yeah we'll have to cross check voltages. I did use tantalums in a few placea but I don't think they're in the audio path though.
Quote from: Cortexturizer on December 20, 2014, 05:29:43 PM
Yeah we'll have to cross check voltages. I did use tantalums in a few placea but I don't think they're in the audio path though.
Right now, I'm going through the layout figuring out cap orientation so I can sub in 10µF caps all over the place.
Ok, I have narrowed it down regarding where the distortion is being introduced to the circuit. Everything up to Q10 I have a full and nice signal that's stronger than my bypass signal but without distortion, the last place in the circuit where I can hear that kind of signal is the colector of Q9. The signal degradation occurs at Q10. I tried replacing it - the same thing. I measured
Q10:
0.55
1.06
17.77
and remembered to measure R35- bingo! I had 4.7K there instead of the 47K. I have realized that every time I make a resistor value mistake (and I do that very very rarely) it is because I have trusted an old electronic components shop owner to color code read them and then bag em for me. I will NEVER make that mistake again. This has been very taxing with the Harbinger but at least now I have it working perfectly. It is great sounding and I am so proud of this one.
Of course, it couldn't end there, now I have a slight buzzing sound in the modern mode that's not there in the vintage mode, but this is neither in the audio nor in the phase path it comes from my preamp stage somehow, will look into that later. The important thing is that now I have a fully working uni-vibe that sounds fantastic. Thanks Brian so much.
Rob, I am looking forward to your experiments with this one, it will without a doubt be interesting.
Okay, good to know about the resistor. Sorry, I did not check back in sooner.
On the buzzing in modern mode....are you using active pickups or something? You mentioned a pre-amp stage.
no I was referring to the input stage on the harbinger, sorry. the buzz is constant, it doesn't occur when I play the guitar, I mean it does, but it's not dependent on the incoming audio, it is everpresent, weird. my pickups are passive.
also I haven't had this buzz prior to changing that resistor, lol. weird, very very weird. vintage mode is dead quiet, and as soon as I engage the modern - here it is, and it stays put even if I roll my guitar volume to zero.
dunno what to do, it wasn't there before I am positive of it.
the voltages on the FET are
0.00
0.26
17.7
Quote from: Cortexturizer on December 21, 2014, 04:00:43 PM
the voltages on the FET are
0.00
0.26
17.7
.26 for the source?
That's crazy low.
Hm I cross checked those with brejna on facebook and he has the same voltages basically.
I just finished mine and it's working.
I measured the voltages at the JFET and mine read
9.4mV
326mV
17.49V
I did use a different JFET, the FJN598J.
Quote from: Cortexturizer on December 21, 2014, 04:00:43 PM
the voltages on the FET are
0.00
0.26
17.7
Hmm. Maybe try bumping R51 from 4k7 to 10k or 22k?
I have same readings with and without FET..
just got from over to a friend's...plugged the pedal, and no buzz on the modern mode whatsoever. harbinger works in mysterious ways it seems. weird. dead quiet now. I did open it prior to plugging it in - preparing for the troublshooting session. obviously something was touching the chassis that now is not after I've allowed the board to wiggle in there a few mm. closed it, and still working fine. oh well, with tight builds like my multi here, it is to be expected. will not open it soon again for sure. loving loving loving this pedal. definitely a fav modulation effect ever. it can never sound out of place like a phaser can, that's what I like best about it.
Glad you got it working and it's (almost) solved. This is a really nice effect. Now if I can only figure out where to calibrate it to. The problem is, it sounds good everywhere for the gain and offset trimmers and I've got no idea where to set them to be ideal! I need to find a factory calibration manual or something.
Well pretty much everybody says that you should set the offset so the lamp never goes fully off. I've set my gain knob so that when my Intensity knob is on full I get too much throb - that situation is only good if you have your speed knob almost all the way down. The design makes the lamp shine brighter when increasing the speed, so that's kind of...unfortunate.
I would say work on having your lamp never go off, the best settings are to be found tinkering with the offset trimmer and not the gain trimmer. I have the gain trimmer on 60-70 percent from full and it sounds spot on.
Quote from: Cortexturizer on December 22, 2014, 05:25:55 PM
Well pretty much everybody says that you should set the offset so the lamp never goes fully off. I've set my gain knob so that when my Intensity knob is on full I get too much throb - that situation is only good if you have your speed knob almost all the way down. The design makes the lamp shine brighter when increasing the speed, so that's kind of...unfortunate.
I would say work on having your lamp never go off, the best settings are to be found tinkering with the offset trimmer and not the gain trimmer. I have the gain trimmer on 60-70 percent from full and it sounds spot on.
Thanks for the info. I'll give that a shot. I need to get the sound pretty optimal before I start subbing in new caps to see how it changes things.