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Need a actual Synthrotek EKO schematics
MUFF WIGGLER Forum Index -> Music Tech DIY  
Author Need a actual Synthrotek EKO schematics
JohnnyThorj
Hello! I have enthusiasm to assemble Synthrotek EKO schematic on bread board for educational purposes. So I've check this scheme from official page:

http://www.synthrotek.com/wp-content/uploads/2014/07/Synthrotek-ECHO-S chematic.png

…and I think this is a not actual scheme — I don't see here some components, like R22, R23, C9, C18-21, D1-3, U2, maybe there is something else… Pins for TL074P, ok, I know is for +/– 12V maybe, but I don't see it on scheme. And I see on PCB +12 and -12 on the one side, but schematics talk about +5 and GND…

So, gentlemans, anybody have an actual scheme for this module?
pre55ure
Looks like there is probably supposed to be another page that has all the power stuff on it.

Probably not too hard to put together. You can find euro schematics with power lots of places. Just notice that you'll need +5v for the echo chip, so either get that from your case or use a 5v regulator.
JohnnyThorj
pre55ure wrote:
Looks like there is probably supposed to be another page that has all the power stuff on it.


Yes, I think about it too.

pre55ure wrote:
Probably not too hard to put together. You can find euro schematics with power lots of places. Just notice that you'll need +5v for the echo chip, so either get that from your case or use a 5v regulator.


Maybe you can give advice for some examples?
basicbasic
Whenever I perfboard anything for Euro I check the schematics on the CGS site for the power stuff eg. http://www.cgs.synth.net/modules/cgs26_analogic.html

You'll need to deal with the 5v somehow. I would use a voltage regulator IC myself eg https://www.sparkfun.com/products/107
JohnnyThorj


Here I've try to build this module power looking back for PCB (http://www.synthrotek.com/wp-content/uploads/2013/11/Synthrotek_ECHO_ PCB_and_Panel_Combo.jpg)

Do I've do something wrong?
JohnnyThorj
basicbasic wrote:
You'll need to deal with the 5v somehow. I would use a voltage regulator IC myself eg https://www.sparkfun.com/products/107


Yeah! I got this lil'boy
JohnnyThorj
Any opinions?

pre55ure
Ok, Some quick thoughts.

I'm not sure why your using the 1N5817 Diodes there.
If your going for reverse power protection then you want to use something like 1N4001's
Also , the diode on the +V side is backwards, It won't conduct that way (Might just explode w00t )
Or if your just using it yourself for experimenting or whatever, you don't even need the diodes at all.

I usually use ferrite beads where you have the 1 ohm resistors, or I'd maybe make them slightly higher value, like 10ohm.

I think you can eliminate the diode around the 78L05, I've never used one there and never had a problem.

They aren't shown on the schematic but I imagine the PCB has bypass caps around the IC's?

After you get the diodes worked out or eliminated it looks like it should work.
JohnnyThorj
pre55ure wrote:
Ok, Some quick thoughts.

I'm not sure why your using the 1N5817 Diodes there.
If your going for reverse power protection then you want to use something like 1N4001's
Also , the diode on the +V side is backwards, It won't conduct that way (Might just explode w00t )
Or if your just using it yourself for experimenting or whatever, you don't even need the diodes at all.

I usually use ferrite beads where you have the 1 ohm resistors, or I'd maybe make them slightly higher value, like 10ohm.

I think you can eliminate the diode around the 78L05, I've never used one there and never had a problem.

They aren't shown on the schematic but I imagine the PCB has bypass caps around the IC's?

After you get the diodes worked out or eliminated it looks like it should work.


Thank you! I've just made some work on mistakes in scheme now:




Now I've got -12/+12 and +5 that show me +4.5V on multimeter:





But I have a question — do I need this dotted block if I have +5 bus on my 4MS Power Row? Maybe this stuff it can be more simple?
pre55ure
Ok, a few things.

On the schematic where you have the +12 and -12 Labels connected to the 22uf capacitors - those labels should be Gnd. You want to take the power for the circuit from between the 1ohm resistor and the 22uf cap.

Second - if your case or PS provides 5v, then no. I would still use the 10u and 100n caps, but where you are connecting to the VO on the regulator could just be connected directly to the power headers 5v connection.

So to sum it up - delete the regulator, what used to be Vinput to the regulator is now your +12v rail.
What was connected to Voutput of the regulator can now connect to pins 11/12 of the power header.

Hope that makes sense.
mskala
The diode around the 7805 is to protect the regulator in the case where it's supplying a large filter capacitor. When you turn off the circuit in such a case, the input of the 7805 drops to 0V but the output is held up by the filter capacitor. That drives current backwards through the regulator, and can kill it. For that reason people sometimes put a diode there to protect the regulator, and you'll see it in some schematics. This may or may not be explained in the data sheet for the 7805 depending on which manufacturer's data sheet you're looking at. But in this case, where the output capacitor is only 10uF, there's probably not enough energy stored to damage the regulator, so the diode is unnecessary.

1N5817 diodes are Schottky - which is kind of nice in the reverse-protection role because they will drop much less forward voltage than 1N4001 type. However, I wouldn't use 1N5817 because they're only rated up to 20V, and reversed Eurorack power is 24V (even if all of that would not normally appear across a single diode); I would use 1N5818 type, which are rated up to 30V.
wotwot
I built both EKO and DLY as 4HP modules from original PCBs and panels and did not find more than the schematics mentioned above in total.
Means I had to reverse engineer the power part for both modules like you people did too as this is missing in the schematic.
FWIW, I asked on their website for DLY schematics without an answer.
On both dly and eko the values of most caps and resistors are exactly like in the application notes of the PT2399 datasheet. hmmm.....

Having built more than 50 modules myself, I did not find these builds particularly difficult but as I found the need to puzzle this out for myself I for sure am not going to recommend syntrotek PCBs to beginners.
whoop_john
JohnnyThorj wrote:


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