Looking for interest in another active filter board group buy.
Each board is a single channel. Two required for stereo 2 way, 4 for stereo 3 way, 6 for stereo 3 way.
Features:
High/Low/bandpass to 4th order.
Sallen Key equal component value topology (jumper for unity gain topology)
Balanced/Single ended input buffer with bandwidth limiting lowpass (optional) can also be configured as shelving low pass filter (baffle step compensation).
Variable attenuation for both high and low pass output buffers.
Independent of the high and low pass filters, the following can be patched into either band:
Linkwitz transform (biquad)
2 notch/peaking EQ sections
first order all pass
The board does not include a +/- 15V power supply. Power supply boards and parts are also available as part of the group buy (if there is enough interest)
Active XO Board Goup Buy WIKI
Each board is a single channel. Two required for stereo 2 way, 4 for stereo 3 way, 6 for stereo 3 way.
Features:
High/Low/bandpass to 4th order.
Sallen Key equal component value topology (jumper for unity gain topology)
Balanced/Single ended input buffer with bandwidth limiting lowpass (optional) can also be configured as shelving low pass filter (baffle step compensation).
Variable attenuation for both high and low pass output buffers.
Independent of the high and low pass filters, the following can be patched into either band:
Linkwitz transform (biquad)
2 notch/peaking EQ sections
first order all pass
The board does not include a +/- 15V power supply. Power supply boards and parts are also available as part of the group buy (if there is enough interest)
Active XO Board Goup Buy WIKI
Sorry about the typo.
Each board is a single channel configurable as either high + low pass or bandpass. We chose to keep the boards single channel to allow the other features and still keep within the free version of Eagle's size limits.
Schematic: http://www.delta-audio.com/temp_jens/Active_filter_DIYaudio.com.sch.pdf
A single board does a single channel two way, use two for a stereo two way.
For a three way you need two boards per channel - either 1 for High and Low, the other for Mid (bandpass) or one for mids up/lows and the other mids/tweeters.
Similar concept for a four way, three boards per channel.
Each board is a single channel configurable as either high + low pass or bandpass. We chose to keep the boards single channel to allow the other features and still keep within the free version of Eagle's size limits.
Schematic: http://www.delta-audio.com/temp_jens/Active_filter_DIYaudio.com.sch.pdf
A single board does a single channel two way, use two for a stereo two way.
For a three way you need two boards per channel - either 1 for High and Low, the other for Mid (bandpass) or one for mids up/lows and the other mids/tweeters.
Similar concept for a four way, three boards per channel.
I just read through most of the threads on the filter and PSU boards and must say a big thanks goes out to Bob and Jens for the time and effort that went into these excellent circuit and PCB designs.Your efforts put Hi performance active crossovers in our hands for ridiculously little money.
Great work Gentlemen.
Fred
Great work Gentlemen.
Fred
This might seem like a ridiculous question at this point, but is there a parts list? I'm assuming that because values have to be calculated parts aren't included, but is there a list with Digi-key part #'s and approximate prices?
Basically my question is, if I buy 4 boards, 1 PS kit, what else do i need before i have a functioning crossover (other than enclosure, in/out connectors)?
Basically my question is, if I buy 4 boards, 1 PS kit, what else do i need before i have a functioning crossover (other than enclosure, in/out connectors)?
A PSU kit will power four boards with no extra parts.
The parts that go with all filter boards are:
2 ea ~220-470nf caps 10 mm dia x 5 mm lead spacing
100 nf decoupling caps (2 per op amp) 2.5 x 7.5 mm, 5 mm lead spacing
Op amps 4-9 depending on features used. 5532s will work, or try your favorite dual op amp. I don't know if anyone has tried LM6172 or other very fast chip on this board. It shouldn't be a problem, but without testing you never know.
Op amp sockets good idea, but not absolutely required.
Trim Pots 1 or 2, top adjust Bourns 3296Y or equivalent.
10K resistors you buy these 1000 at a time, right?
Pin Headers 0.1"/5mm spacing, snappable (optional) for input/output and patching sections together. You may want some jumpers to switch between 2nd and 4th order, etc. Molex (or other) contacts can be used by themselves or with a connector body to make I/O connections.
mounting hardware don't forget to pick up a bunch of extra standoffs and 4-40 x 1/4 (for US builders) screws.
For the filter sections, most target frequencies can be reached using 10-100 nf caps. (5x 7.5 mm, 5 mm lead spacing) You could use 5-10% caps if you buy extras and pick out ones that are within 1-2%.
There is a manual and excel spreadsheet available on my website (button below) as well as Jens' site and in the thread (WIKI links)
It looks like there is enough interest to support a group buy. I'll offer 100 nf and 470 uf caps like last time.
I will be taking a break from technology from 21-30 July - There's no Internet access where I am going (I can't bear dial up). I'll be back to answer questions on 31 July.
The parts that go with all filter boards are:
2 ea ~220-470nf caps 10 mm dia x 5 mm lead spacing
100 nf decoupling caps (2 per op amp) 2.5 x 7.5 mm, 5 mm lead spacing
Op amps 4-9 depending on features used. 5532s will work, or try your favorite dual op amp. I don't know if anyone has tried LM6172 or other very fast chip on this board. It shouldn't be a problem, but without testing you never know.
Op amp sockets good idea, but not absolutely required.
Trim Pots 1 or 2, top adjust Bourns 3296Y or equivalent.
10K resistors you buy these 1000 at a time, right?
Pin Headers 0.1"/5mm spacing, snappable (optional) for input/output and patching sections together. You may want some jumpers to switch between 2nd and 4th order, etc. Molex (or other) contacts can be used by themselves or with a connector body to make I/O connections.
mounting hardware don't forget to pick up a bunch of extra standoffs and 4-40 x 1/4 (for US builders) screws.
For the filter sections, most target frequencies can be reached using 10-100 nf caps. (5x 7.5 mm, 5 mm lead spacing) You could use 5-10% caps if you buy extras and pick out ones that are within 1-2%.
There is a manual and excel spreadsheet available on my website (button below) as well as Jens' site and in the thread (WIKI links)
It looks like there is enough interest to support a group buy. I'll offer 100 nf and 470 uf caps like last time.
I will be taking a break from technology from 21-30 July - There's no Internet access where I am going (I can't bear dial up). I'll be back to answer questions on 31 July.
Hi Bob welcome back. Hope you had an enjoyable holiday.
Great to hear that the buy is a go.
I do have a couple of questions if I may.
I searched the manual but was unable to find info to design the notch filters and determine component values for Baffle step compensation.I am hoping there is some sort of spreadsheet for these.
Also in your sample (pg.21) using the Focal drivers the Baffle step comp indicates R12 and R16 should be 4.95K but the value of C10 is not mentioned.
This will be about the right amount of BSC needed for my project.
Thanks Bob for your help.
Fred
BTW did you fly F14'S for the US Marines?
Taking off and landing one of those babies on an Aircraft carrier has got to be the craziest but most exciting job period.
Great to hear that the buy is a go.
I do have a couple of questions if I may.
I searched the manual but was unable to find info to design the notch filters and determine component values for Baffle step compensation.I am hoping there is some sort of spreadsheet for these.
Also in your sample (pg.21) using the Focal drivers the Baffle step comp indicates R12 and R16 should be 4.95K but the value of C10 is not mentioned.
This will be about the right amount of BSC needed for my project.
Thanks Bob for your help.
Fred
BTW did you fly F14'S for the US Marines?
Taking off and landing one of those babies on an Aircraft carrier has got to be the craziest but most exciting job period.
There is a page in the spreadsheet for caclulating both notch filters and shelving filters. You'll pick some values and the sheet will calculate the rest. See my website to download it if you haven't already.
I used 100 nf for my BSC, but you could use any convenient value. I'll have to update the manual to show that.
I was a Tomcat RIO (Radar Intercept Officer) in the US Navy - the backseater with no flight controls. Some guys I flew with made landing fairly benign, others made it (landing and the language following) quite colorful
I used 100 nf for my BSC, but you could use any convenient value. I'll have to update the manual to show that.
I was a Tomcat RIO (Radar Intercept Officer) in the US Navy - the backseater with no flight controls. Some guys I flew with made landing fairly benign, others made it (landing and the language following) quite colorful
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