Aion Electronics Lab Series L5 Build

[bsas]

teemuk, I love you

My circuit was correct all along! I was just miss adjusting and miss using it!

After your explanation I was able to measure it with my oscilloscope and properly adjust the trim pots, and now everything sounds great!

My main issue was that I was trying to use the limiter with the "Limit" knob almost all down, around 9:00. This is why the volume drop was so drastic. After your excellent explanation I checked online a picture of the original amp limiter knob, and I finally understood it properly.

Now setting it to "0", or around 2:00, sounds awesome!

Thank you all!!!

[yuka42]

Ha!!  What an explaination!!  Fantastic. Glad you got it sorted. Have fun!

[jstone]

I've been thinking a little more about my issue - too low voltage output on pin 6 of IC10.  I checked the values of the trimpot (20k) and all of the nearby components on the schematic. Everything seems to check out. I'm getting the correct V+ and V- measurements on pins 7 and 4. So I should be getting somewhere close to the right output out of pin 6, no?  If this is the right analysis, can I conclude that I have a bad IC?

[bsas]

The first thing I always do is replace critical ICs just to be sure. Doesn't hurt to try
I would put a known sine wave in the input of the pedal and measure all opamps and OTAs in and outs too check if something is odd...

[jstone]

The first thing I always do is replace critical ICs just to be sure. Doesn't hurt to try
I would put a known sine wave in the input of the pedal and measure all opamps and OTAs in and outs too check if something is odd...

Do you mean just take a 1/4 cable and plug it straight into the input of the pedal with a sine wave on it?

[bsas]

Do you mean just take a 1/4 cable and plug it straight into the input of the pedal with a sine wave on it?

Yep! With a multimeter you can check if the sound wave is going over the spots. And if you want to be fancy, you can use an audio probe too

[yuka42]

+1 for the audio probe.  Here's a good link.

http://www.diystompboxes.com/pedals/debug.html

It's a great learning tool.  Follow the circuit with it and hear what components are doing.  Invaluable. 

[jstone]

Hi everyone,

I'm embarrassed to say that I think the reason I was not measuring the right voltages on IC10 is because I'm a n00b and just wasn't measuring it correctly. When I applied the sine wave to pin 2, I was just using a lead from the tip of my headphone cable and I had disconnected the ground connection from the sleeve. Apparently that was the problem, because when I hooked up a lead from the tip AND the sleeve to the test pads and then connected the common test lead from my DMM to another ground on the pedal, I was suddenly able to measure the correct voltages on pin 6. What a relief.

Unfortunately, I'm still a beginner and learning as I go. Anyway, thanks for all your help and patience!

Also, on bsas's and yaka42's advice, I went through my build with an audio probe. Everything seems to be working properly, which is what made me think that I wasn't measuring correctly.

[EBK]

Unfortunately, I'm still a beginner and learning as I go. Anyway, thanks for all your help and patience!

Learning is a positive thing.  There is no need for the word "Unfortunately" in this context.  Even though I didn't personally help on this one, I'll risk overgeneralizing:
We help because we enjoy helping, and we're patient because...  well...  it's the same darn reason! We enjoy helping.   

[bsas]

Unfortunately, I'm still a beginner and learning as I go. Anyway, thanks for all your help and patience!

Learning is a positive thing.  There is no need for the word "Unfortunately" in this context.  Even though I didn't personally help on this one, I'll risk overgeneralizing:
We help because we enjoy helping, and we're patient because...  well...  it's the same darn reason! We enjoy helping.   

No shame on learning man! It is part of the fun
For me, my build was perfect since the beginning but I unsoldered the C38 and solder something else and bounced my head over and over just because I didn't understood the limiter.

[MikeA]

The thing is that I found a 400mA adapter that is very small and white.
I like that it is white because then I will not mix with my DC adapter and burn my other pedals. And I like the size because of portability. I just want to know if 400mA is enough, I am not worried about price (specially on this build).

This is probably too late to help you, bsas, but I just finished a build, and measured the current draw @ 370 mA with the load resistors in place (RX3 and 4), or 322 mA without them.  This is with Channel 2 active, Channel 1 draws about 5 mA less, and I'm using low-current LED's (around 1mA each).

Regards,  Mike

[Tutorial]

Hi, Sorry to revive a dead thread but I'm having similar issues to those stated above (like the seemingly low voltages coming from pin 6 of IC10) but wasn't sure if I should make a whole new topic since this might help someone else who is as dumb as I am.

I originally had somehow fried a CA3080 when calibrating for the first time and had to wait a weekend for new ones to come. I swapped out the old for the new and everything seemed to work fine (including the compression) until I tried to calibrate it again and found that the voltages coming from PIN 6 of IC10 were really low. After taking a break for a bit i come back to find that the compressor is doing the same thing that bsas' originally did (with the compressor basically popping and muting and then slowly coming back)

Voltage wise I'm getting the same readings as bsas for IC9-12 and Q2 and Q3, but my 2n5457 is pretty different

I'm wondering if there is something wrong with my phone's output (im getting voltage readings that vary based on +/- dBs but It's never higher than 10-12). I'm using an iPhone 7->dongle->headphone cable with a piece of wire from the tip going to the + pad on near IC10 and a piece of wire from the sleeve that I've connected to both my cheapo DMM black lead and the ground on the pedal. The trimpot does change the voltages on pin 6 but it starts way too low in the first place. I've checked the resistors in the circuit, swapped some of the ICs and transistors for new ones, and tried to verify all the caps in the area of the circuit. I've been pulling my hair out over this one, w/o compression everything sounds amazing, but I just can't the compressor to work.

I'm hoping that I'm just making some incredible newbie error (went in over my head with this one) and that someone might be able to kick me in the right direction.

[Semilog]

Another apology for exhuming an old thread.

I've finished my L5 build, and everything is working first try. It does run a bit hot so I need to put in some lower-current LEDs, but that's NBD.

Here's my question. I dialed in the clipping trimpot as described in the docs and on this thread but it occurs to me that the 4.4V target on IC10 pin 6 is not specified as RMS or peak-to-peak. I used RMS and it sounds reasonable, but I'd be interested to know what others have done.