Hello,
i tried to debug this pedal i built more than a year ago,
with no success.
after i built it the first time, it produced no sound.
but at this time, i had a solder iron with a too thick pointer, and i think it's not impossible that i made a few
short cuts on the pcb.
so i got a new board, and started all again with a thinner solder iron.
of course, before soldering it again, i checked all the components values(resistors, capacitors, the pinout of the NPN and PNP transistors)
The only thing i couldn't check were the 5 IC (CA3080).
I read on another thread here that the CA3080 could die instantly if it's pin5 received more than 1ma; with my first attempt
with this effect, i think this may have happenned !
So, if someone could confirm the CA3080 are dead (or better, that i missed something obvious !), it would be nice...
1.What does it do, not do, and sound like?
2.Name of the circuit
3.Source of the circuit (URL of schematic or project)
4.Any modifications to the circuit? Y or N
5.Any parts substitutions? If yes, list them.
6.Positive ground to negative ground conversion? Y or N
1- output is either the same as input, or just mute (i think it depends if i turn the rate/depth pots)
2- piedrita (like EH small stone phaser)
3- http://www.tonepad.com/project.asp?id=11
4- Yes : just replaced R42 (4k7) a 2k resistor in series with a 5k lin pot (adding a depth pot)
5- No
Measurements:
Voltage on the power supply = 9.10V
Voltage at the circuit board + = 9.10V
Voltage at the circuit board - = 0V
i also made some tests with an audio probe, out of the CA3080 or the transitors, but all i could hear (if i could hear something) was a very weak, saturated sound)
IC 1 to 5 are CA3080
IC1 :
pin1 : 0
pin2 : 0.74
pin3 : 0.74
pin4 : 0
pin5 : 0.74
pin6 : 1.82
pin7 : 5.39
pin8 : 0
IC2 :
pin1 : 0
pin2 : 0.74
pin3 : 0.74
pin4 : 0
pin5 : 0.74
pin6 : 1.79
pin7 : 5.39
pin8 : 0
IC3 :
pin1 : 0
pin2 : 0.63
pin3 : 0.74
pin4 : 0
pin5 : 0.74
pin6 : 0.49
pin7 : 5.39
pin8 : 0
IC4 :
pin1 : 0
pin2 : 0.85
pin3 : 0.74
pin4 : 0
pin5 : 0.74
pin6 : 5.39 (!)
pin7 : 5.39
pin8 : 0
IC5 :
pin1 : 0
pin2 : 1.17
pin3 : 1.17
pin4 : 0
pin5 : 0.67
pin6 : 2.61
pin7 : 5.39
pin8 : 0
Q1 : (NPN)
e : 0.29
b : 0.71
c : 5.37
Q2 : (PNP)
e : 5.39
b : 5.36
c : 0.7
Q3 : (NPN)
e : 1.29
b : 1.79
c : 5.36
Q4 : (NPN)
e : 0.73
b : 1.29
c : 5.38
Q5 : (NPN)
e : 1.27
b : 1.76
c : 5.36
Q6 : (NPN)
e : 0.72
b : 1.27
c : 5.38
Q7 : (NPN)
e : 0.29
b : 0.46
c : 5.38
Q8 : (NPN)
e : 0.29
b : 0.29
c : 5.38
Q9 : (NPN)
e : 4.87
b : 5.38
c : 5.35
Q10: (NPN)
e : 4.25
b : 4.87
c : 5.38
Q11: (PNP)
e : 1.77
b : 1.14
c : 1.76
Q12: (PNP)
e : 1.77
b : 1.14
c : 1.73
Q13: (NPN)
e : 1.87
b : 2.58
c : 1.88
Q14: (NPN)
e : 1.13
b : 1.87
c : 1.14
(http://img560.imageshack.us/img560/7179/20120910182755.th.jpg) (http://imageshack.us/photo/my-images/560/20120910182755.jpg/)
(http://img802.imageshack.us/img802/2940/20120910182810.th.jpg) (http://imageshack.us/photo/my-images/802/20120910182810.jpg/)
(http://img338.imageshack.us/img338/3589/20120910182825.th.jpg) (http://imageshack.us/photo/my-images/338/20120910182825.jpg/)
Though it won't sound qute as robust with 3 instead of 4 stages, you might consider jumpering and bypassing a stage at a time to see if it is just that one 3080, or something more generalized.
hi, and thanks for the reply!
Quoteyou might consider jumpering and bypassing a stage at a time to see if it is just that one 3080, or something more generalized.
it seems to be a clever idea, i'll just have to find out how to do that... :icon_redface:
i suppose the 4 stages are from ic1 to ic4, and if i want to bypass stage2 i cut the connections marked in red :
(http://img694.imageshack.us/img694/7578/bypassstage2.png) (http://imageshack.us/photo/my-images/694/bypassstage2.png/)
i'll do that tomorrow, it's the evening in france...
I can't see the drawing here, but you would want to isolate the input of each stage from the output of the previous one. That cut can be easily bridged again once you have identified the stage that has the problem.
C'est l'après-midi içi.
Hello again,
i tried to bypass the stages , no changes (no phasing effect)
i finally removed the 5 CA3080, and the sound is exactly the same as it is with them all ! :icon_eek:
i guess they are all dead ?
QuoteC'est l'après-midi içi.
nice ! you speak french ? (but you would write "ici" , the "ç" is for sounding like an "s" in cases it would sound like "k", for example :"ça ne marche pas !")
J'ai toujours des confusions avec la cédille. Comme fonctionnaire je dois parler et écrire les deux langues officiels, mais je ne suis pas parfaitment bilingue Tout de même, j'essaie.
The Piedrita has MANY transistors. Are you certain they are all oriented properly?
QuoteJ'ai toujours des confusions avec la cédille. Comme fonctionnaire je dois parler et écrire les deux langues officiels, mais je ne suis pas parfaitment bilingue Tout de même, j'essaie.
you speak very well ! you're doing more than trying !
yes 14 transistors is a lot..
i remember testing them all for checking the pins (ebc) with my multimeter before putting them back on the pcb.
(just in case the pinout would be different from one brand to another, but i don't even know if it's possible)
anyway, i had no surprises, and then i put them just like on the drawing from the pdf file.
i don't know if you still can't see the pictures, but i posted one of my board, orientation is the same as on the pdf.
and after reading the build reports on tonepad, there seems to have no mistakes on the pdf...
I made one, using BC550 and BC560. It worked fine, however the BC550 has the opposite pinout to the 2N5088.
Je comprend que c'est mathématiquement impossible, mais avec 3 jambes il y a au moins 823 moyens de faire un erreur! :icon_lol:
:icon_biggrin:
well, you sure are right, but what troubles me is that i only used 2N5088 and 2N5087 as written on the pdf...
so the orientation should be the same as on the drawing, right? (and i checked their pinout before putting them on board)
anyway, i'll check again... (but i'm pretty sure, it's ok)
maybe the best thing to do is to buy some other CA3080 to be sure...
thank you very much for your time anyway !
The CA3080 is becoming rare AND expensive, while the availability and cost of the 2N5952 are becoming more favourable. It may be wiser to attempt a clone of the Ross phaser (which is a Small Stone using the cheaper and more available LM13600 and op-amp input and mixing stages), or to buy a small pile of 2N5952 and make a Phase 90. You can buy a small handful of 2N5952 for the same cost as a CA3080, and an LM13600 (= 2x3080) can also be purchased for very little.
you are right again, i already considered giving up with this fx, and starting a new phaser like the phase 90.
the thing is i already built like 10 guitar/bass fx, and a 12ax7 guitar preamp that all work perfect,
and it's kind of frustrating staying on a failure !
but you are right, i'd better stop with this one and try another model...
thanks!
Well, don't stop trying to de-bug this build. You already have the money invested in the CA3080s, and the problem may not be those chips but something simple elsewhere in the circuit. I just don't think it is wise to throw money at buying more 3080s unless you really need them (e.g., to repair a well-loved synth).
However, sometimes it is is faster and easier to just build something new than to figure out why something already built isn't working. I wish it wasn't that way, but sometimes it is.
If you are really tired by this one, build DynaComp (or RossComp*) meanwhile, it's an easy build, nice compressor and you can use it as CA3080 tester :) T.
* I may even offer my own verified layout (http://www.diystompboxes.com/smfforum/index.php?topic=91107.0) ;)
QuoteWell, don't stop trying to de-bug this build. You already have the money invested in the CA3080s, and the problem may not be those chips but something simple elsewhere in the circuit. I just don't think it is wise to throw money at buying more 3080s unless you really need them (e.g., to repair a well-loved synth).
However, sometimes it is is faster and easier to just build something new than to figure out why something already built isn't working. I wish it wasn't that way, but sometimes it is.
yes, you're right.
i'll stop spending money on that one for now unless i find out what's wrong with it.
QuoteIf you are really tired by this one, build DynaComp (or RossComp*) meanwhile, it's an easy build, nice compressor and you can use it as CA3080 tester
* I may even offer my own verified layout
i love the idea of building that comp as a CA3080 tester ! :icon_biggrin:
i checked your link, and :icon_eek: , this thing is crazy, and superb !
i downloaded your pdf, i think there's everything i need to build that comp (modded by the same "Mark" who's posting here ?)
thanks for sharing !
Btw, i just rechecked all transistors for their pinout by measuring their hfe with my multimeter (is it the right way to do it ?)
everything seems ok...
Okay, that's one less thing to wonder about.
One of the things I like to do is find points in the circuit where I can measure AC voltages to assure myself they are in an appropriate range. You can do that without having to cut any traces.
The first place to begin is to measure the output of the input stage (the 5088/5087 pair), on the negative side of that 10uf cap.
By the way, do you get bypassed sound? Do you know that the switch works?
ok, i just measured the negative side of C3 (10uf) : 2.83v
i didn't put any bypass switch yet (i usually check if the fx works ok before i do that).
Is that with a guitar signal or without any input at all?
it's without any input.
just checked with an input, it's the same....
The Emitter voltages for Q1 and Q2 look wrong - Q2's Emitter should be sitting around 9v as it's coupled to the power rail. Can you check your power supply is functional? What's causing the rail to be clamped around 5 to 6v - have you been using VBias where the power rails should have been? Q4,6,8 and 10 have the same issues on their emitter and 3,5,7 and 9 should probably be sitting a volt or 2 higher than they currently are.
When this has been resolved and other problems persist: check continuity between the input resistor and the input side of the capacitor, check the capacitor is in correctly, check between the otherside of the cap and the base of the transistor. Check between the emitter of the transistor to the base of the 2nd transistor, then both transistors emitters to the 4k7 resistor etc. etc. and see if there's a point in the signal path that's not connected.
After just testing those and a couple of O/P resistors we should see if you can get the clean half of the output. The phased half should then be checked by the same means - if the signal path is solid then it's back to step 1.
Quote from: alesk on September 12, 2012, 11:55:23 AM
QuoteIf you are really tired by this one, build DynaComp (or RossComp*) meanwhile, it's an easy build, nice compressor and you can use it as CA3080 tester
* I may even offer my own verified layout
i love the idea of building that comp as a CA3080 tester ! :icon_biggrin:
Great then! :)
Quote from: alesk on September 12, 2012, 11:55:23 AM
i checked your link, and :icon_eek: , this thing is crazy, and superb !
Oh, thanks, I'm glad you like it! :)
(so my self-promo did work! :icon_mrgreen:)Quote from: alesk on September 12, 2012, 11:55:23 AM
i downloaded your pdf, i think there's everything i need to build that comp
Should be, let me know (in that thread, not here) if not.
Quote from: alesk on September 12, 2012, 11:55:23 AM
(modded by the same "Mark" who's posting here ?)
Yep, that would be him :)
Quote from: alesk on September 12, 2012, 11:55:23 AM
thanks for sharing !
My pleasure, good luck! T.
QuoteThe Emitter voltages for Q1 and Q2 look wrong - Q2's Emitter should be sitting around 9v as it's coupled to the power rail. Can you check your power supply is functional? What's causing the rail to be clamped around 5 to 6v - have you been using VBias where the power rails should have been? Q4,6,8 and 10 have the same issues on their emitter and 3,5,7 and 9 should probably be sitting a volt or 2 higher than they currently are.
thanks, the power supply is functionnal (although it's a DIY one), it powers my other pedals with no problem.
i measured again it's output : 9.06v
i have 9.06v on the board before R2 (470R) , and 6.54v after it, (i should be the same all along the power rail on the board, because of R2 that is between the power input and the power rail on the board, i think !) and so 6.54 again at Q2 emitter. (and 2.07v at Q1 emitter)
but i noticed voltages changed when it moved the depth pot i added (mod).
so i'm going to remove that mod, put R42 like it should be, and measure all the voltages again on transitors and ICs.
i'll post that when done...
Quotehave you been using VBias where the power rails should have been?
hum... i'm not sure i understand the question! my electronic skill are weaker than my english level (that is not really great!) :icon_confused:
if that's what going to pin3 of IC1 to 4, i had the same voltage everywhere!
but i'll measure that again and let you know.
Thomeeque : yes your self promo did work ! :icon_biggrin:
about "the" Mark, i just remembered i saw his name on a few projects i built !
i guess it's kind of he's fault i began DIY , and partially he's fault i'm stuck with this one ! :icon_mrgreen: (just kidding!)
ok, so i removed the "depth" mod, and restored the 4k7 R42.
(i wish i could modify my first post , but it seems like i can't...)
new measurements :
Voltage on the power supply = 9.07V
IC1 :
pin1 : 0
pin2 : 2.74
pin3 : 2.70
pin4 : 0
pin5 : 0.7
pin6 : 5.03
pin7 : 6.54
pin8 : 0
IC2 :
pin1 : 0
pin2 : 2.61
pin3 : 2.70
pin4 : 0
pin5 : 0.7
pin6 : 0.56
pin7 : 6.54
pin8 : 0
IC3 :
pin1 : 0
pin2 : 2.73
pin3 : 2.70
pin4 : 0
pin5 : 0.7
pin6 : 6.41
pin7 : 6.54
pin8 : 0
IC4 :
pin1 : 0
pin2 : 2.72
pin3 : 2.70
pin4 : 0
pin5 : 0.7
pin6 : 0.68
pin7 : 6.54
pin8 : 0
IC5 :
pin1 : 0
pin2 : 2.02
pin3 : 2.02
pin4 : 0
pin5 : 0.68
pin6 : 1.89
pin7 : 6.55
pin8 : 0
Q1 : (NPN)
e : 2.13
b : 2.57
c : 5.95
Q2 : (PNP)
e : 6.55
b : 5.94
c : 3.94
Q3 : (NPN)
e : 4.53
b : 5.04
c : 6.52
Q4 : (NPN)
e : 3.93
b : 4.53
c : 6.54
Q5 : (NPN)
e : 1.14
b : 0.56
c : 6.54
Q6 : (NPN)
e : 1.15
b : 1.14
c : 6.55
Q7 : (NPN)
e : 6.01
b : 6.41
c : 6.52
Q8 : (NPN)
e : 5.40
b : 6.01
c : 6.54
Q9 : (NPN)
e : 0.61
b : 0.68
c : 6.54
Q10: (NPN)
e : 0.61
b : 0.60
c : 6.54
Q11: (PNP)
e : 2.67
b : 2.03
c : 2.65
Q12: (PNP)
e : 2.67
b : 2.04
c : 2.65
Q13: (NPN)
e : 1.38
b : 1.89
c : 6.51
Q14: (NPN)
e : 0.77
b : 1.38
c : 2.04
Quote from: Jazznoisecheck continuity between the input resistor and the input side of the capacitor, check the capacitor is in correctly, check between the otherside of the cap and the base of the transistor.
it's ok with that.
Quote from: JazznoiseCheck between the emitter of the transistor to the base of the 2nd transistor,
you probably meant the collector of Q1 to the base of Q2 ? it's ok
Quote from: Jazznoisethen both transistors emitters to the 4k7 resistor
you probably meant the emitter of Q1 and the collector of Q2 to R42 (4k7) ? it's ok
Quote from: Jazznoiseetc. etc. and see if there's a point in the signal path that's not connected.
mmm, i'll need a few days/weeks to do that ! :icon_redface:
(http://img834.imageshack.us/img834/8756/capture1ny.png) (http://imageshack.us/photo/my-images/834/capture1ny.png/)
That's o.k, my English is better than my electronics and mon francais est vraiment merde. :P
I assume your depth pot was instead of the 27k and 30k resistors before the output? I find the voltage drop across the 470 odd. Is it a 470 and not a 4K7?
Please check if there's a signal coming from the 30k resistor after Q2 - just hook it up to a jack and play through it! If it works, then all of the transistor stages should work.
Quote from: jazznoiseI assume your depth pot was instead of the 27k and 30k resistors before the output?
no, it was instead of R42 (4k7) connected to the emitter of Q1 and collector of Q2 (in orange on the picture above)
Quote from: jazznoiseI find the voltage drop across the 470 odd. Is it a 470 and not a 4K7?
i just rechecked, and althought it's violet ring looks more like brown, it's a 470R , yes!
Quote from: jazznoisePlease check if there's a signal coming from the 30k resistor after Q2 - just hook it up to a jack and play through it! If it works, then all of the transistor stages should work.
ok, just did it : between Q2 and the 30k (R8), the signal is much stronger than it is on input.
and after R8, it's weaker.
thanks for your time !
(btw, is your signature related to sonic youth? "♪ ♪ We're gonna kill the California girls...♪ ♪")
(btw n°2, i hope Mark isn't in a bad mood because of my horrible humor!)
Pas de problème. Peau épais. :icon_wink:
ouf ! déjà que je suis nouveau ici, que j'ai un humour un peu bizarre et que la traduction n'aide pas, j'ai douté à un moment ! :icon_redface:
blague à part, internet est formidable, et c est grâce à des personnes comme toi que j'ai commencé à faire des effets !
Merçi de ta gentillesse. :icon_smile:
"Ouf" est un mot très peu rencontré ce coté de l'océan! Peut être dans un livre d'Asterix ou Tintin, mais pas dans la conversation typique.
But back to a language more here can understand....
It looks like jazznoise is successfully guiding you through the trouble shooting.
Haha, "the milk maid maidenhead!"! :icon_lol:
That makes sense. So we know your input transistor works. Now take the same wire from the jack and stick it after the 10uF cap before the first OTA. And then to the output of your OTA. Ca marche ou ca marche pas? C'est la questionne!
..I'll stop. And you don't get off that easy, Mark, you don't know how much I don't know about OTA's! :P
Quote from: JazznoiseNow take the same wire from the jack and stick it after the 10uF cap before the first OTA. And then to the output of your OTA. Ca marche ou ca marche pas? C'est la questionne!
so after the 10uF cap (C3), the sound is ok.
then after R25, it's a lot weaker.
then after IC1 (pin6), it's a bit stronger than on IC1 input (but seems to have more high freq, and it's still weaker than after C3)
strange thing (?), the sound is the same on emitter and collector side of Q3. (is this normal?)
Q4 : sound on emitter side only, weaker and more "dirty"...
if i quickly probe the outputs of IC2, IC3, IC4 the sound is weaker and weaker (to barely audible)
seems like more i go on on signal path, weaker and more dirty is the sound...
Yes, it's the same current being drawn through emitter and collector so the signal should be the same unless something naughty is happening.
Do you mean dirty as in, distorting or just noisey? I actually just simulated those little longtailed amps using a pair of 2N5088's and the gain of each stage is about 0.5 (Meaning or signal is 1/16th or -24dB of itself upon output) I had to change the 10k resistor going from ground to the 47k resistor to 100K to get near unity gain (well, 0.9). But that's no good because after 4 stages we've gone from, say, 1 volt to 0.66 volts which is close to 6db.
So I say take out the 10k resistor in the first stage and see if that makes it better. If yes, do it on every stage!
by dirty, i meant distorting.
Quote from: JazznoiseSo I say take out the 10k resistor in the first stage and see if that makes it better. If yes, do it on every stage!
So i removed R31 (10k) , unfortunately no audible change...