Hi Jens,
would you, by any chance, have a complete circuit schematic available? In the documents you posted, there is a block diagram, and schematics of the individual blocks with part designation. But there is none of the complete circuit of one MOX board.
The reason why I ask is that I assume to build the layout you have one lying around already, and for ppl like me who will assemble several boards for 4th order 3 channel setup with some parts substitutions etc, a full diagram would help. Also, to locate jumper setup with multiple boards. Any form, pdf or gif is enough, I can then print out 4 copies per channel and assemble/draw on paper.
One error correction: in the manual's block diagram, latest edition, there are two "jumper 2" labels. The one on the right should be labeled "jumper 3".
Markus
would you, by any chance, have a complete circuit schematic available? In the documents you posted, there is a block diagram, and schematics of the individual blocks with part designation. But there is none of the complete circuit of one MOX board.
The reason why I ask is that I assume to build the layout you have one lying around already, and for ppl like me who will assemble several boards for 4th order 3 channel setup with some parts substitutions etc, a full diagram would help. Also, to locate jumper setup with multiple boards. Any form, pdf or gif is enough, I can then print out 4 copies per channel and assemble/draw on paper.
One error correction: in the manual's block diagram, latest edition, there are two "jumper 2" labels. The one on the right should be labeled "jumper 3".
Markus
Another thing I may have missed: for dicrete op amp use (it will take me some time to get there but working ahead) - where on the MOX board do you place the 4k7 for DC stability? I gather it's on the underside, but I can't find holes corresponding to it. Or is it supposed to be surface soldered?
Markus
Markus
MBK,
Jens has posted full schematics on his site. It is the first item in the list of downloads:
http://www.delta-audio.com/Active filter two.htm
Correct...there are no pads for it on the MOX mainboards, which was designed for standard opamps. An alternative to surface mounting is to use R10 on the opamp boards and connect to a nearby ground pad.
Jens has posted full schematics on his site. It is the first item in the list of downloads:
http://www.delta-audio.com/Active filter two.htm
Correct...there are no pads for it on the MOX mainboards, which was designed for standard opamps. An alternative to surface mounting is to use R10 on the opamp boards and connect to a nearby ground pad.
Hi Tiroth,
yes I have that document. It does have all the schematics, but piecemeal. It would be nice to have a larger, complete schematics, so I don't have to cut and paste the different sub-circuits together from the different pages. Of course that can be done too, but I assume to make the MOX board layout Jens already has a file with the complete circuit in one page...
Markus
yes I have that document. It does have all the schematics, but piecemeal. It would be nice to have a larger, complete schematics, so I don't have to cut and paste the different sub-circuits together from the different pages. Of course that can be done too, but I assume to make the MOX board layout Jens already has a file with the complete circuit in one page...
Markus
Jens
Are these active filters PCB's still available at the web address.
http://www.anidian.com/audio/construct/mox.shtml
Thanks
Are these active filters PCB's still available at the web address.
http://www.anidian.com/audio/construct/mox.shtml
Thanks
Sorry to have stepped out of the thread for a while... Sadly, I have been obliged to W*RK. (Moderators...sorry for the four letter word!)
Few people have really bit on this thread. It seems as the most tedius part of this project is typing in the part numbers for ordering!
I would be happy to distribute those surplus caps from Jens ( for the cost of the shipping) to all the audio junkies in North America.
Of course, I would be happy to forward Jens the money for the shipping. (Via Paypal I would assume.)
So, kick it arround.
Discrete Op-amp
I have assembled and tested the discrete opamp and all have checked out good. When the first opamp was assembled on the circuit board and power and other leads were breadboarded it oscillated. YIKS? Whats going on??. I regrouped shortened my test leads and now it works. The bandwidth of the follower with 68pF cap for C2 is 5MHz. 100pF was about 4MHz.
I have also used a P-channel MOSFET, a Zetex ZVP3310, in place of PNP MPSA 92. I used a 5K fixed resistor parallel with a 10K pot. at R3 and R4 in order to adjust for zero DC offset. The value of the drain resistance worked out to be 1850 ohms , but this value will vary depending on the ZVP 3310 used, that is if you want a low DC offset. Initially the drain resistance R3 used was 1500 ohms and the DC offset was 230 mV. I also added a 100 ohm gate resistor to the mosfet just for good measure to prevent oscillation.
I have no doubts that the circuits will work when installed in the MOX filter boards.
BDP
I have assembled and tested the discrete opamp and all have checked out good. When the first opamp was assembled on the circuit board and power and other leads were breadboarded it oscillated. YIKS? Whats going on??. I regrouped shortened my test leads and now it works. The bandwidth of the follower with 68pF cap for C2 is 5MHz. 100pF was about 4MHz.
I have also used a P-channel MOSFET, a Zetex ZVP3310, in place of PNP MPSA 92. I used a 5K fixed resistor parallel with a 10K pot. at R3 and R4 in order to adjust for zero DC offset. The value of the drain resistance worked out to be 1850 ohms , but this value will vary depending on the ZVP 3310 used, that is if you want a low DC offset. Initially the drain resistance R3 used was 1500 ohms and the DC offset was 230 mV. I also added a 100 ohm gate resistor to the mosfet just for good measure to prevent oscillation.
I have no doubts that the circuits will work when installed in the MOX filter boards.
BDP
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