Feeler: ez760 - Compressor/Limiter/Expander/Gate

[shabtek]

@redmojosteve
the hairball meter is 8027-B

 

[redmojosteve]

That's great! Thanks. I guess I'll need to use a resistor around 1K for R202 as the meters use LEDs.

Regards
Steve

 

[Biasrocks]

Ribbon cables!!

I've ordered a set of 10 ribbon cables as specified in both BOM's here, which don't fit. Thinking I got it wrong the first time I re-ordered and got the exact same thing.

2.54-inch pitch to match the connectors specified.

http://ca.mouser.com/ProductDetail/Molex/25001-1006/?qs=%2fha2pyFadugnFqBk08L9qS3imTJirGlB%252bjAyttauyNKDc5LBC7ix0w%3d%3d

The problem, the cable is too wide to fit!

What the hell am I missing??

 

[0dbfs]

I used these connectors:
http://www.mouser.com/Search/ProductDetail.aspx?R=09185107324virtualkey61720000virtualkey617-09-18-510-7324
http://www.mouser.com/Search/ProductDetail.aspx?R=7810-0000PRvirtualkey51750000virtualkey517-7810-0000PR

I think this cable will fit:
http://www.mouser.com/Search/ProductDetail.aspx?qs=IOh0O5QtZ92VWnFEwLTckA%3d%3d

I seem to remember having the same prob and using a 10 conductor flat/ribbon cable harvested from a computer or something. I may have even taken a wider cable and separated just the 10 conductors similar to something you would find in a motherboard/chassis for a serial cable connector.

Cheers,
j

 

[Biasrocks]

Okay, so I'm not losing my mind.  :

It looks like the cable you linked to is .050 pitch which I assuming will work because it's a double row .100 connector.

Can someone confirm this.

Regards,
Mark

 

[Slenderchap]

You need 1.27mm pitch cable...

The connector is 2.54mm pitch, but because there are 2 rows the cable is half the pitch.

Colin
www.audiomaintenance.com

 

[Biasrocks]

You need 1.27mm pitch cable...

Alright, I've ordered the cable that 0dbfs has recommended, looks like that one has the proper spacing.

Beware, the 2 BOM's posted here both have the incorrect part for this project.

PS. I've got 20 surplus ribbon cables if anyone needs the 2.54mm type.

Regards,
Mark

 

[tonycamp]

anybody got one of these finished? I'm very curious to hear thoughts on performance and sonics?

thanx

 

[tonycamp]

nice work Collin

I would really like to see one in the 51X formfactor  ;D
compressor only would be fine ...

I think the 500 series/compressor only would be a big hit actually. I'd be all over it!

 

[tonycamp]

anybody got one of these finished? I'm very curious to hear thoughts on performance and sonics?

thanx

Rhummpa bump bump?

 

[tonycamp]

anybody got one of these finished? I'm very curious to hear thoughts on performance and sonics?

thanx

Rhummpa bump bump?

Bahh rhummpa bump bump?

 

[tonycamp]

anybody got one of these finished? I'm very curious to hear thoughts on performance and sonics?

thanx

again...

 

[redmojosteve]

The first EZ760 has gone together easily thanks to the superb instructions. I wish I could say the same for the setting up! I have clearly got something wrong. I spent all of today checking for dry joints, solder bridges (I must admit that my soldering is OK and I don't usually have much of a problem with this). All the semiconductors are the correct type, in the correct place and the right way round and I tested the value of each resistor before I put it in. Similarly for the capacitors too. I have started running through the set up procedure and not got too far as nothing is quite right.  For example with 0.775 Vrms input @1kHz I am only getting 0.27V at the output which seems low, similarly with the system "in" I measure around 0.123V which again seems low. At step 14 I was getting 0.48V at the bases of Q36 and Q37 until I realised I'd left the compressor Threshold switch at -20dB. Turning it to 0dB dropped the volts to about 20mV. Q13  and Q14 similarly have nothing much to measure at their bases. Sadly the LED in 18 hasn't illuminated at all. I have checked the LED and it is in the correct way round and is not a dud! Voltages are responding to increasing or lowering the input level so things are sort of working but not as they should. It's probably not worth going any further until I get the basics resolved. Any clues would be much appreciated such any obvious places I could have cocked up!
Cheers
Steve

 

[shabtek]

wonder about bad solder joints, the pads are small and are corroded on my board, had to clean them. also suspicious of vias\thru hole plating.

@red steve: you will have to trace signal from in to out and find out where its dropping out, did you socket the cards; what is voltage on gate of Q1

 

[redmojosteve]

Hi Shabtek
Thanks for the reply. I usually socket most things but I didn't do this when mounting the daughter boards to the main board. I will do this for the second one I am building. I may desolder them and socket them anyway.
The voltage at the gate of Q1 is 1.0V dc.
Cheers
Steve

 

[shabtek]

if you pull q1 that may narrow it down a little--that is the shunt element that does the squashing I believe

 

[shabtek]

applied power to my build today,did not go through calibration, passes signal, limit light flashes but dynamics affect is lacking--does provide gain with all cards except in and out pulled--if that helps you narrow it down

 

[redmojosteve]

Thanks Shabtek. I am away for a couple of days but I'll give it a try and see what happens.
Cheers
Steve

 

[Dr Gris]

I really should focus on getting other DIY projects finished, but have been lurking this thread a long time now,
and it' s so quiet....
I' m really interested to hear what anybody has to say about this very cool puppy, 'cause I wanna try this build
myself in the future if it' s still available then....
Any successful builders out there???

Cheers
Magnus

 

[redmojosteve]

Finally got some time to get back to the EZ760. I went through a few more checks. It seems to pass signal and the led's now work correctly. The meter does what I expect it to do. Removal of Q1 certainly raises the voltages at Q36 and Q37. Before I removed it I checked the voltage at the gate of Q1 and it was still around 1V. I admit that I don't understand everything that's going on in the circuit, some bits I do and others remain not so clear. (I am a Mechanical Engineer by profession and I am quite happy on matters of entropy and vibrating systems analysis!). If this is squashing the signal then what sort of voltage would I expect? Is this suggesting that something around the FET bias circuit on the compressor board isn't doing it's job properly? Any views would be much appreciated.
Regards
Steve