Feeler: ez760 - Compressor/Limiter/Expander/Gate

[Gustav]

(temp) Ghetto Style

Very cool.

Have you finished the calibration procedure yet?

Gustav

 

[MountCyanide]

Not yet. Just wrapped on getting it all together. Shall do in couple of days, on my next binge.

 

[salomonander]

so one problem i have is the 3pdt switch. it its physically higher than the other toggle switches. so not alligned properly in terms of depth when put at the front plate. i ordered the one on the bom. what am i doing wrong? cheers

 

[Gustav]

so one problem i have is the 3pdt switch. it its physically higher than the other toggle switches. so not alligned properly in terms of depth when put at the front plate. i ordered the one on the bom. what am i doing wrong? cheers

I don't think you're doing anything wrong. The switch will peek out a little more than the others when you secure the control PCB to the panel via 22mm studs, but for the actual mounting, it won't be in the way.

Gustav

 

[salomonander]

Don't know why they are missing from the parts list...

The ferrite beads F1 & F2 are Farnell 9265236

The 3 terminal capacitors are Rapid 26-6182

However, they are only their to comply with EU EMC regulations (which don't apply outside the EU.... or for anything built for personal use).... so you can simply fit wire links instead.

The pots are LA20BU's.... they came in stock the other day (along with the Lorlin switches)... just haven't made it into the store yet.... they will be in a "kit" along with the output transformers (which are expected on Friday).

Colin
www.audiomaintenance.com

anyone know a part number for the 3 terminal caps at farnell? rapids shipping rate is way too high....
is this part correct:
http://de.farnell.com/murata/dsn6nc51h101q55b/kondensator-3-terminal-100pf/dp/9527354
its only 50v but should do i guess?

 

[groovetubes]

Hi guys,

I'm constructing a stereo EZ760 and I have a little problem when calibrating my left channel (step 8/9)...

In fact, when system is OUT, I have about 3 Volts at the output when sending a 0,775 mV at the input... instead of +/- 795 mV (+ 0,2 dB) at the output (following Colin's procedure). And when system is IN, I measure about half the tension 1,4 Volts (+/-6 dB drop) at the output...

So, does anyone have an idea where to start looking at?
For info, It's not coming from the front panel because it works fine when connected at the right channel's motherboard (Yeah, fortunately, right channel works fine
So, the problem has to come from the left channel's motherboard.
I already double check my solders on it and they are good, so....???

PLEASE HELP!

In advance, THANKS!

Franky

 

[Gustav]

Hi guys,

I'm constructing a stereo EZ760 and I have a little problem when calibrating my left channel (step 8/9)...

In fact, when system is OUT, I have about 3 Volts at the output when sending a 0,775 mV at the input... instead of +/- 795 mV (+ 0,2 dB) at the output (following Colin's procedure). And when system is IN, I measure about half the tension 1,4 Volts (+/-6 dB drop) at the output...

Hi Franky.

I came here thinking I had an answer for you after spending time with the calibration procedure, but I had it wrong (I remembered it as if you were seeing +3dbu at the step where you needed to see -1, which would have been "ok" according to my findings).

Since you have a working channel, you could probably trace the signal and compare!?

Gustav

 

[salomonander]

hey

i need help here. my first build that doesnt work at all
basically i get no signal whatsoever. i do get loud pops when inserting the output card. so that seems to work. i also hear something when touching the solder joints on the comp card.
i get no such sounds from the limiter or input card.
also, my leds aint working and the expander card gets way too hot when connecting J29. something really wrong there.

so im wondering how to go about troubleshooting this. how can one find the problem? i sawpped the expander card - same problem.
swapped the connecting cable. same problem again. can one somehow bridge the cards to find out where the error lies?


ps: the expander card gets hot around the PL9 plug which leads to J29. i double checked all transistors and the seem fine....

thanks alot

 

[salomonander]

or maybe my 10way cables are the wrong way around? i did it like gustav on his pic a few pages back...

 

[0dbfs]

Could be x-over'd ribbon cables.

Good thing is that you have a working channel so you can compare.

I would test, check, and compare continuity and DCR between pads on each unit while powered down so you don't run the risk of causing components to fail if something is mis-wired or if you have stuffed a wrong component in one unit.

On some autoranging DMM's 120r, 1k2, 12k, or 120k may appear very similar when you check/confirm values before stuffing/soldering. I have had that happen before (and stuffed the wrong value) and was pulling hair till I identified what I had done.

Hope that helps!

Cheers,
jb

 

[salomonander]

Could be x-over'd ribbon cables.

Good thing is that you have a working channel so you can compare.

I would test, check, and compare continuity and DCR between pads on each unit while powered down so you don't run the risk of causing components to fail if something is mis-wired or if you have stuffed a wrong component in one unit.

On some autoranging DMM's 120r, 1k2, 12k, or 120k may appear very similar when you check/confirm values before stuffing/soldering. I have had that happen before (and stuffed the wrong value) and was pulling hair till I identified what I had done.

Hope that helps!

Cheers,
jb

thx JB

im afraid i dont have a working channel. its all malfunctioning at the moment. i did measure that the two pins to the far right on PL18 connector is getting 24 volts. is that normal. there is a resistor (r188) between the 24volt line and the pins. but my diode tester gives me a beep. not shure if its because the resistance is so low (5r6) or the resistor is bad. i have the same "problem" on the connector of the output card. gives a beep to my main 24v line....

id need some voltage points to get anywhere im afraid. i have no clue what voltage is supposed to go where.....


but thx anyways!

 

[touane]

Hello,
would it make any sense to try at calibrating the unit if the VU meter is not connected? 

Cheers,
M.

 

[mutterd]

An update on this.

Waiting for proper standoffs and a few other bits to finish up.

Gustav

Hey Gustav - thats really nice - I like the stereo pair in the 1 enclosure…

did you just stack the PCB's with the standoffs? You remember the height by chance???

and no problem with spacing of the front panel PCB's?

very classy!

 

[salomonander]

can anyone who built this succesfully please tell me where pin one of the 10way ribbon cables is supposed to go on the front panel pcb?
there are no clues in the manual and basically its a 4-way gamble. im shure this is where the problem lies.

so looking at the front panel from the front (pots aiming at me).... where does pin one go?
this info should really be in the colourbook...... maybe im just stupid

thx!

 

[Gustav]

can anyone who built this succesfully please tell me where pin one of the 10way ribbon cables is supposed to go on the front panel pcb?
there are no clues in the manual and basically its a 4-way gamble. im shure this is where the problem lies.

so looking at the front panel from the front (pots aiming at me).... where does pin one go?
this info should really be in the colourbook...... maybe im just stupid

thx!

If you are using the IDC connectors specified, you should be able to see it in the guide. Alternatively, you can see the correct wiring it in the picture here - http://groupdiy.com/index.php?topic=40274.msg716274#msg716274

Gustav

 

[Gustav]

Hello,
would it make any sense to try at calibrating the unit if the VU meter is not connected? 

Cheers,
M.

I had to use a 1ma DC meter...

And some of the later calibration steps require you to use the meter. (learned the hard way )

Gustav

 

[touane]

I had to use a 1ma DC meter...

And some of the later calibration steps require you to use the meter. (learned the hard way )

Gustav

Thanks for the info Gustav! I was hoping that I could just stick a 600ohm resistor between Meter Positive and Meter Negative, since that is the internal resistance specified for the suggested VU meter. Am I completely off with this assumption?

 

[Gustav]

I had to use a 1ma DC meter...

And some of the later calibration steps require you to use the meter. (learned the hard way )

Gustav

Thanks for the info Gustav! I was hoping that I could just stick a 600ohm resistor between Meter Positive and Meter Negative, since that is the internal resistance specified for the suggested VU meter. Am I completely off with this assumption?

I guess it depends on the load (or maybe not, I don't know much )

Gustav

 

[salomonander]

hey

so my problem was wrong setup of the 10pol connectors. the unit seems to "work" now. meter is moving but i dont hear any compression yet (although i see lots). hope this will be fixed during calibration.

 

[Gustav]

hey

so my problem was wrong setup of the 10pol connectors. the unit seems to "work" now. meter is moving but i dont hear any compression yet (although i see lots). hope this will be fixed during calibration.

You wrote previously you followed my wiring, and I can verify that its 100% correct.

Finished unit, calibrated and measuring perfectly.

Objective parameters check out - haven't checked the subjective side of things yet though (aside from the looks)

Gustav