tonedude

Re: Feeler: ez760 - Compressor/Limiter/Expander/Gate
« Reply #360 on: August 31, 2014, 02:25:25 PM »
Hi fellow ez760 diy'ers!   :)

 - I bought Gustavs ez760 and had to redo the calibration becouse I changed the meters to the Hairball 1mA gainreduction meters. Calibration seems to work out fine except for expander calibration part, and also the part below (the one in the attached photo...), and I wonder if it's a typo in that section or if I misunderstand anything... If I chose a 2:1 comp ratio I get approximately 20dB of compression, if I chose 20:1 I get far more...

 - And I seem to have a problem getting through the expander calibration, is there a way to "pre-trim" the trimpots to get me through that part? As it is right now I'm kind of lost at 114), because I cant trim the FET law to -8db (it's not possible to lower it, just raise it from -20 db and on...), as it is right now I'm stuck with a non functional expander section....  :(
« Last Edit: August 31, 2014, 02:30:03 PM by tonedude »


Re: Feeler: ez760 - Compressor/Limiter/Expander/Gate
« Reply #361 on: August 31, 2014, 03:21:56 PM »
Hi fellow ez760 diy'ers!   :)

 - I bought Gustavs ez760 and had to redo the calibration becouse I changed the meters to the Hairball 1mA gainreduction meters. Calibration seems to work out fine except for expander calibration part, and also the part below (the one in the attached photo...), and I wonder if it's a typo in that section or if I misunderstand anything... If I chose a 2:1 comp ratio I get approximately 20dB of compression, if I chose 20:1 I get far more...

 - And I seem to have a problem getting through the expander calibration, is there a way to "pre-trim" the trimpots to get me through that part? As it is right now I'm kind of lost at 114), because I cant trim the FET law to -8db (it's not possible to lower it, just raise it from -20 db and on...), as it is right now I'm stuck with a non functional expander section....  :(

I dont understand 100% what you're saying, but in case you did not catch it - all trimmers are "mirrored" compared to Colins guide (CCW = CW, CW = CCW). So as a first step, it would be nice to know if you noticed that. Its not a problem with colins guide, but just reversed trimmers on my build.

And since I hit a snag when I reached the expander portion on my first few attempts - http://groupdiy.com/index.php?topic=40274.msg720876#msg720876 I know you dont have a VU scale, but maybe you calibrated to the wrong 0 point on the meter? (Just worth checking).

I would have thought you could simply calibrate the two meter trimmers replacing the meters, so you wouldn't have to do the whole procedure!?

Gustav
« Last Edit: September 01, 2014, 08:37:33 AM by Gustav »

tonedude

Re: Feeler: ez760 - Compressor/Limiter/Expander/Gate
« Reply #362 on: September 01, 2014, 08:03:03 AM »
Thanx Gustav, I think I got one channel with expander calibrated and working just fine. Starting with the other one in about 30 minutes...  :)

One more question regarding trimpot R87, input threshold on the comp PCB, cant find any instructions regarding how to pre trim that one? (in the middle, about 10k... ?)
« Last Edit: September 01, 2014, 08:06:23 AM by tonedude »

tonedude

Re: Feeler: ez760 - Compressor/Limiter/Expander/Gate
« Reply #363 on: September 02, 2014, 12:50:42 AM »
And..... done!!!   :)

Matching the expander for stereo linking was a tough one,,, for sure...  :o

But there is instructions on how to do it in the Q2 Compex manual, link below:

www.musictoolz.pl/pliki/instrukcja-obslugi-344.pdf

Thanx!


Re: Feeler: ez760 - Compressor/Limiter/Expander/Gate
« Reply #364 on: September 02, 2014, 05:22:13 AM »
And..... done!!!   :)

Matching the expander for stereo linking was a tough one,,, for sure...  :o

But there is instructions on how to do it in the Q2 Compex manual, link below:

www.musictoolz.pl/pliki/instrukcja-obslugi-344.pdf

Thanx!

Awesomeness!

Gustav

dustbro

Re: Feeler: ez760 - Compressor/Limiter/Expander/Gate
« Reply #365 on: July 14, 2015, 09:28:11 PM »
I'm finding a bunch of discrepancies between the original schematic and the one Colin provided.  Have these been noted yet?

Potato Cakes

Re: Feeler: ez760 - Compressor/Limiter/Expander/Gate
« Reply #366 on: September 26, 2015, 12:53:09 AM »
Hello, everyone!

I know this thread has been inactive for some time, but I have 2 EZ760 boards that I'm going to build out later this year. I read that the meters shown on Colin's example are no longer made. I would like to know what suitable substitutions there are that would fit the holes that are cut out on the .FPD file that is on Gustav's website as I would like to just have a panel made as is with redoing the file.

Thanks!

Paul

deadpoet

Re: Feeler: ez760 - Compressor/Limiter/Expander/Gate
« Reply #367 on: January 03, 2016, 09:50:58 AM »
Hi everyone,


A happy 2016 for everyone. Finishing up my build of this monster and I though I'd share it here for those interested.


About me: I have built all-in-one kits before (SeventhCircleAudio, SoundSkulptor, ShadowAudio/Serpent and PCB Grinder) so this was a little harder.


Got the PCB's (and PSU board) from Gustav @ pcbgrinder, front and case from Dan DDT, meters from Hairball, transfo's/switches/pots from Colin @ audiomaintenance.
Parts I got from Mouser and Farnell (this was fairly new to me, spent a incredible amounts of time on those websites trying to figure out what I really needed). Including 2 extra orders because I missed something or ordered a wrong part  ;D
Knobs are from a Guitarpedalsite called Newtone.nl - when they arrived I got scared they didn't look 'real' enough but assembling the unit just now they turn up quite good.

The 'missing' transistors I got from UTSource.net - they're the only part still missing, should be here somewhere next week and then I can start wiring up and doing all 116 steps of calibration, yaay  :P

I will report back when it's assembled and tested.


Next up: rehousing/fixing/modding 4x D&R Comp/Limiters and probably a NetEQ - I'm hooked  :)

Herwig

Potato Cakes

Re: Feeler: ez760 - Compressor/Limiter/Expander/Gate
« Reply #368 on: May 22, 2016, 10:50:54 PM »
Where did you get those panel mount LEDs? I've been looking for something like that.

Thanks!

Paul

jazzyjoepass

Re: Feeler: ez760 - Compressor/Limiter/Expander/Gate
« Reply #369 on: February 23, 2017, 07:12:22 PM »
I'm looking for the rack case for this project. Is the maker of the rack case still in business and has them ??? Who is it anyway ???


Potato Cakes

Re: Feeler: ez760 - Compressor/Limiter/Expander/Gate
« Reply #370 on: February 24, 2017, 01:08:01 AM »
I'm looking for the rack case for this project. Is the maker of the rack case still in business and has them ??? Who is it anyway ???


Frank does. He made mine. It's nice

https://www.frontpanels.de/miscellaneous-frontpanels/ez760/


Thanks!

Paul

jazzyjoepass

Re: Feeler: ez760 - Compressor/Limiter/Expander/Gate
« Reply #371 on: February 25, 2017, 07:03:44 PM »
THANKS !!!!

Potato Cakes

Re: Feeler: ez760 - Compressor/Limiter/Expander/Gate
« Reply #372 on: December 18, 2017, 03:01:17 PM »
Hi, everyone!

I've been going through and debugging my build that has been sitting waiting to be finished, and I am able to calibrate all the way to the FET Law trimmer, then I get stuck. I am having the same issue as other guy who couldn't get the meter to go lower than -20dB. For a test, I wired in a 100k pot (I don't have any trimmers higher than 25k) and was able to two the last two adjustments and found that the resistance needed to do was 40k. I had tried recalibrating several times and everything worked great right up to this point, so I decided that there wasn't enough resistance and found increasing the value of R76 would allow me to complete the calibration procedure. Does anybody know if this will mess anything up? I don't see the other leg connected to anything so I figured changing this value would be fine.

After the new year I hope to build a single channel version and document the process with some tips to make building one of these less daunting. It does seem to be very straightforward, but it does require a much higher than average amount of paying attention to details. Definitely not for anyone who is starting out or new to the DIY scene, and definitely not for anyone who can not troubleshoot their own builds.

Thanks!

Paul

Potato Cakes

Re: Feeler: ez760 - Compressor/Limiter/Expander/Gate New
« Reply #373 on: January 31, 2018, 10:53:07 PM »
All righty,

After going through the mess I did fixing all my mistakes and finding bad parts, I feel the need to compile and share all the tips I had to figure out to help others here who are struggling with this build to get it off of the bench and into the studio. It's a great sounding compressor and definitely worth the effort.

First, it's not an insanely difficult build since there is minimal off board wiring, but it is not something for a beginner as there are heaps of parts with varying values and keeping track of them and their orientation can become overwhelming. Plus, chasing down traces and comparing them to the schematic will make your eyes cross as the connections are highly condensed on the individual daughter boards and is very easy to loose track of what is going where.

Also, don't forget that with these boards, the trimmers are to be turned opposite of the calibration instructions per Gustav.

With all of that aside, here we go, in no particular order:

- 1/4W resistors are fine to use in place of the 0.6W as listed on the BOM
- Unless you have a verified source of NOS transistors, use only modern equivalents. I had a bad batch of BC182B's that didn't know were faulty. Here are the ones I used - BC184C=MPSA18(backwards orientation), you can also use BC550C, BC182B=BC550C, BC212B=BC560C, BC212L=PN4355 - B and C legs have to be crossed, the PN4355 should be angled downward (towards the main board when the daughter card is connected) to ensure the crossed legs are not touching - just double check this, BC184L=2N3417
- The LC Network (CL1,2) are not on the BOM. I used this part:
https://www.mouser.com/ProductDetail/Bourns/EMI101T-RC/?qs=%2fha2pyFaduiDbeIvXMFHbA4Jqa4pQl60iVMLBFv8s0M%3d
- Stereo matching the expander section:
www.musictoolz.pl/pliki/instrukcja-obslugi-344.pdf
- Use this link to calculate between RMS and dBu:
http://www.sengpielaudio.com/calculator-db-volt.htm - It's helpful to calculate all of the dBu values to VAC(RMS) and write them down so that following along with the calibration process is easier.
- For the compressor input threshold, there is no mention of it in the calibration process. I ended up on having 8k5 ohms resistance between the wiper and the bottom leg as viewed when installed. I don't know if that is correct but I started there and everything seems to work out.
- When you get to Step 11 of the calibration, make sure that FET Bias and Inverter Set are turned all the to where you have most level you can get from those trimmers. If both trimmers are about halfway when you start, and you turn the FET one way, the output level will change. Same with the Inverter Set. My notes say full CCW for FET Bias and full CW for Inverter Set. I think that is correct, but I am not willing to double check it as my build is all buttoned up and finished after what seems to be more than a dozen calibration attempts. You're output signal should be closer to 0.69VAC when both trimmers are all the way in their correct starting positions. I think that makes sense.
- My Target Value A was 1.07VAC
- Start with the Compression Ratio full CW
- I changed the FET Law trimmer (R78) to 50k as I found that I needed more resistance to do the procedure. However, I also found that I needed to start with the trimmer set so where the wiper and the bottom leg that connects to the Control VPositve needs to be around 1k, because any lower the meter bounces around and looks like something else is wrong when you start the expander calibration. After this discovery, I thought that maybe 20k would be fine, but I had already installed the 50k trimmers so I just left them. If you want to be safe, you can use 50k. This may have something to do with using the modern equivalent transistors.
- The LED for the expansion indicator did not come on for me until about -3dB of reduction and not as the calibration instructions say. Again this may have something to do with using the modern transistors. I tried to adjust the values of R86 and R85, but nothing changed as far as the LED indication was concerned, so I left it as is.
- If you can find sockets to connect the daughter cards to the main PCB that will greatly aid you in the event you need to troubleshoot. If you can't find the correct size sockets (as in my case) then I would install the Input and Output cards first and check to make sure you are getting audio to pass with the front panel PCB connected. You should be able have a functioning Input and Output controls when the System is set to In. Then one at a time, install the Compressor card, Limiter card, and then the Expander card in that order, checking signal and the relevant calibration steps each time you install a card. Once you see that everything is working, then you can start the full calibration.
- Put a marker of some sort on a printed copy of the Initial Setup Procedure as you go through each calibration step. There are sections that are repeating a series of steps and if you have been working on this for a long period of time or if you are calibrating for the 10th time, it becomes easy to lose your place and/or skip over a step that will adversely affect the final outcome and you will have to start over. Again.
- Don't put the wrong part in the wrong place. After desoldering many connection points, my growing impatience caused me to break some to of the solder pads and then I had to trace where the connection was supposed to be going and solder jumper in place. So just stuff the boards correctly the first time. And then solder them correctly. Just like we all try to do when we start building any project. Seems easy enough...
- The large majority of these solder pads are very tiny and some of them are very close together. Make sure you have quality, thin gauge solder and fine solder tip. The iron temp should be set to at least 700F and the solder should effortlessly melt and flow into place. If your soldering skills do not land in the scale of really good to exceptional, then you will probably be in for a rough ride sorting out cold solder joints and bridges. Also, I would definitely clean the solder pads before starting this guy just to be certain.

These are all things I landed on after a massive number of attempts ending in failure and frustration. These are by no means the absolute true methods of doing this project, but if you follow the Colourbook and use these tips in conjunction with it, you will have a working unit.

On a side note, I was able get what seemed to be proper metering responses using a VU, 1mA, and a cheap DC type. My build wound up using a 1mA.

Here a link the process I had to go through when I started debugging my initial build. It may have some more information that someone may find helpful.

https://groupdiy.com/index.php?topic=67481.0

Thanks!

Paul
« Last Edit: February 25, 2019, 01:01:55 PM by Potato Cakes »


 

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