DIYstompboxes.com

Well, I decided to scrap it and start over with a new board - was extra careful/slow this time around and it worked the first time I plugged it in! Thanks for the help all. The pedal sounds great.

Hello masters of the DIY Stompbox world. I seem to be having some trouble getting my DIY aurora build up and running. This is only my third build so there is likely an easy answer. As of yet it hasn't presented itself to me, but it might present itself to the infinite intelligence of the internet 

Here is a picture of my work


Here is the checklist:
1. What does it do, not do, and sound like?
Effect (circuit) not working : Audio does work when effect is not engaged/bypassed

2. Name of the circuit => Aion Electronics Aurora 125b Dyna/Ross Compressor

3. Source of the circuit (URL of schematic or project) =
https://www.dropbox.com/s/2hd9ujnxndb9fe5/aurora_documentation.pdf?dl=1

4. Any modifications to the circuit? No

5. Any parts substitutions?
Electrolytic Capacitors (C3, C4, C7, C9, C14, C19) are tantalum capacitors
Film Capacitors (C1, C10, C11, C12) are polystyrene capacitors
RPD = 2.2M Yageo

6. Positive ground to negative ground conversion? No

7. What is the out of circuit battery voltage? => 9.43 v
Voltage at the circuit board end of the red battery lead => 9.36 v
Voltage at the circuit board end of the black battery lead => 0v

Q1
C = 7.12
B = 2.43
E=2.013

Q2
C= 6.87
B= 2.775
E= 2.25

Q3
C = 8.92
B = 0.221
E= 0.0

Q4
C= 8.90
B= 0.0
E= 0.0

Q5
C = 9.1
B = 8.92
E = 8.6

Q6
C = 6.88
B = 2.788
E = 2.254


IC1 (or U1)
P1 = 1.172
P2 = 0.053 (Begins to fall as the leads contact)
P3 = 4.725
P4 = 4.726
P5 = 2.792
P6 = 0.000
P7 = 0.005
P8 = 1.10 (Starts out here, but begins falling quickly as the lead contacts) Stops falling at 0.86
P9 = 6.12
P10 = 0.015
P11 = 9.06
P12 = 0.002
P13 = 0.000
P14 = 0.000
P15 = 0.000

D1
A = 9.33
K = 9.13

D2
A = 0.0
K = 0.0

D3
A = 0.0
K = 0.257

Thanks in advance for the help!

ok, so i found some problems, fixed some others and re-drew the whole thing as it sits now.

i still don't really get how the power supply thing works. i had drawn it WRONG, of course. for the life of me, i don't understand why this thing just wouldn't run off a plain old 9volt battery. is the voltage divider thing really necessary? doesn't seem to do anything or be hooked up to anything.
that said, without it? circuit won't fire.


and apparently this has a ground AND a - 9v connection, even tho the -9v of the battery  and ground connection are to the same place on the power supply jack.

standard tip/ring/sleeve on/off input jack.

but dig this.... if ya connect the - side of the 9v supply DIRECTLY to ground, it will NOT fire. even tho its connected at the ring of the input jack!!!

weird weird weird.

but it sounds pretty good. i will try n get more video tomorrow, my family is probably ready to kill me.

still can't get the octave part as loud as the fuzz. may add a simple boost stage hacked in there somehow.

changed the diodes in the rectifier. one side is pink led, the other 1n34 and pink led in series. if ya want it to swell, use two 1n34's in series on both sides, and run a fuzz face into this thing. holy cow.
if ya want this to clean up with volume pot on guitar, ge is the way to go. i opted for the ge/led combo in search of more balls on the fuzz, which stock is fairly anemic. two leds makes the octave two spitty, and no possibility of turning your guitar down.

changed the 10k bias trimmer on q1 to 50k. it makes a huge diff on the volume of the octave. i was reading 23k with one side disconnected, so 22k should be ideal.

i ditched the cap bypassing pin 2 to ground on u1. it sounded cool, but not worth keeping in the end. it really made the octave pop out more... but... the big problem with this and switching from fuzz 1 to fuzz 2 is that each wants opposite settings on the gain pot.

the fuzz wants the gain/sustain pegged. when ya go to the octave, it wants it off. what to do?

well, i used the same footswitch connections i had used for the cap, and simply ran wires to the pot.. the wiper, and the unused side, so when the footswitch is in octave mode, it automatically shorts the pot off. huge improvement. trying to find a happy medium meant a splatty jawari-esque octave and a gated buzzy fuzz. now ya can just crank the thing up full and get a decent sound out of each. some folks may like the gain down a bit for more velcro-y sounds.

as it turned out, i totally dropped the ball on the power supply, and i apologize for that. i'm still confused on it.

i checked today, i had thought the - of the battery/power supply was jumpered to the junction of the two 10k resistors and the 33u cap, but that node is connected to nothing. the cathode of the cap is to ground along with the low side of the voltage divider. the 33u cap comes off the junction of the two resistors, but it doesn't seem to be connected to anything else. without it? won't run right, tho it makes some really amusing envelopey sweepy weird noises, particularly with the tone knob on the guitar down.

weird weird weird.
ok, that it for changes. for sure, for real, THIS is what i got running. all hacked onto that cheezy graymark kit board





so the billion dollar question.... why the hell is -9v different from ground on this? or is ground floating somewhere between ?

like... i am confused more by the minute. or is it really somehow
its running at +/- 4.5volts with ground in the middle somehow?

i don't get it at all.

this thing sounds great with a fuzzface driving it, too. holy crap. it compresses like crazy, then releases when ya play legato and automatically swells in. its sick!

OR i messed something else up.   

One thing that may become an issue is the interelectrode capacitance.  Not only is it higher than tube capacitances, it varies significantly with collector / drain voltage, so you may have a distortion mechanism built in.  In a grounded-source gain stage, the Miller capacitance which is the gate to drain capacitance times ( 1 + gain).  One way around this is cascode amplifiers which hold the drain at a near constant voltage.  This allows the input capacitance to be the gate-to-source capacitance plus the gate-to-drain capacitance and the fixed voltage means no variation in capacitance.

Large FET's have a higher transconductance than small ones but large bipolar transistors tend to have lower gain than small-signal devices unless you go with Darlington transistors.

Check out all the device specs and build it if you think you can tolerate the non-linearities.  You will either find it is what you want or you will find out why not many other people have done it before.

How much "creepage" is in a pedal?

Why would they use a One-Ton package for a moped-load device?

Just do it. Gus is correct that strays may be significant. But that may not be bad.