i'm looking at these, too.
Geteilt durch zwei ehemaligen board level elektronische Linkwitz Rayleigh teiler in CPI Leistungselektronik Pre-teilen Platine Beschreibung: Uns Platte Referenz Frequenz unter ESP Desig aus Potentiometer auf AliExpress.com | Alibaba
as i have use for those in a mono mobile system with 9v batteries and i would remove the psu-parts anyway and i as i would change the x-o parts, they are too expensive.
does anybody know where to get pcb's only with a layout for 4th order sallen key filters?
Geteilt durch zwei ehemaligen board level elektronische Linkwitz Rayleigh teiler in CPI Leistungselektronik Pre-teilen Platine Beschreibung: Uns Platte Referenz Frequenz unter ESP Desig aus Potentiometer auf AliExpress.com | Alibaba
as i have use for those in a mono mobile system with 9v batteries and i would remove the psu-parts anyway and i as i would change the x-o parts, they are too expensive.
does anybody know where to get pcb's only with a layout for 4th order sallen key filters?
Can you go balanced using 2 boards?
Interesting board, I am between PLLXO and active this is so cheap that it is worth a try.
I need to do a rough filtering to bi-Amp mi Fast OB.
- Wondering if you can go balanced using 2 boards as my amps have both SE and balanced inputs.
- and wondering if you can go 1st order with some mods as that might be the way to go.
I will use MiniDSP to find out the best XO point and to find out how much I need to attenuate the FR (at least that is what I expect).
Interesting board, I am between PLLXO and active this is so cheap that it is worth a try.
I need to do a rough filtering to bi-Amp mi Fast OB.
- Wondering if you can go balanced using 2 boards as my amps have both SE and balanced inputs.
- and wondering if you can go 1st order with some mods as that might be the way to go.
I will use MiniDSP to find out the best XO point and to find out how much I need to attenuate the FR (at least that is what I expect).
I've just tried simulating this circuit in Ltspice, because it does look rather elegant and well it does work. The bad news is that the filter frequencies are all wrong if I did the simulation correctly. These will have to be recalculated.
Note: the model has to be renamed to ne5532.301
It is very unlikely that both channels will need the gain of 2times (+6db) at the outputs.
You could remove either R11, or R22, to convert the output opamp to a +0dB Buffer.
The resistor pads would be left empty.
You may find that the louder channel needs the attenuator. This is usually the treble channel. You can remove the attenuator and the Buffer from the quieter channel.
If you know the bass unit needs more drive then leave that output of that channel unpopulated and take the output from U6. And fit the attenuator to the treble channel.
You could remove either R11, or R22, to convert the output opamp to a +0dB Buffer.
The resistor pads would be left empty.
You may find that the louder channel needs the attenuator. This is usually the treble channel. You can remove the attenuator and the Buffer from the quieter channel.
If you know the bass unit needs more drive then leave that output of that channel unpopulated and take the output from U6. And fit the attenuator to the treble channel.
There is a discussion on correcting the error from a filter.
I can never remember whether it's the low pass or the high pass that has the error, but I guess it's the low pass since I seem to recall seeing the plot falling to -60db and then levelling off.
It seems the cure for this error is to move the tapping point for the output to before the unity gain stage. This would need to be done for both opamps in that channel.
See if you can find this and incorporate the changes into your .asc before you commit to a PCB.
I can never remember whether it's the low pass or the high pass that has the error, but I guess it's the low pass since I seem to recall seeing the plot falling to -60db and then levelling off.
It seems the cure for this error is to move the tapping point for the output to before the unity gain stage. This would need to be done for both opamps in that channel.
See if you can find this and incorporate the changes into your .asc before you commit to a PCB.
I'm afraid my post wasn't that clear. I've used the schematic and component values from the post here: http://www.diyaudio.com/forums/analog-line-level/289754-cheap-chinese-active-x-o.html#post4683842
The filter frequencies are just wrong. (see attached plot)
I assume the reason behind this is that the schematic was a 3-way crossover at some point and somebody removed the bandpass part. Although I don't see any harm in having a gain stage as an output buffer, because as you've stated it can be converted very easily to +0dB by removing R11/R22 and fitting a piece of wire instead of R8/R19.
The filter frequencies are just wrong. (see attached plot)
I assume the reason behind this is that the schematic was a 3-way crossover at some point and somebody removed the bandpass part. Although I don't see any harm in having a gain stage as an output buffer, because as you've stated it can be converted very easily to +0dB by removing R11/R22 and fitting a piece of wire instead of R8/R19.
Attachments
I used this to calculate the filter parts:Pronine Electronics Design - Sallen-Key Active Low Pass Filter Calculator
You can input two values to get the third.
And this one:http://sound.whsites.net/project09.htm#download_esp_lr
It works better than the first one if you only want to calculate the frequency with standard component values.
You can input two values to get the third.
And this one:http://sound.whsites.net/project09.htm#download_esp_lr
It works better than the first one if you only want to calculate the frequency with standard component values.
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Just removing R11/12changes it to +0dB. You don't need to remove R8/9.
Keeping R8/9 in place makes it very easy to convert it back to +6dB
Just have a 0.1" two pin connector that takes a shorting plug to connect in the old R11/12. Remove the shorting plug and it is back to +0dB
How can you power that board with DC?
I want to use this PCB in a portable system which of course operates on batteries. I find a little complex to create another level of power to convert 12vdc to 18vac. How did you manage to use the two 9v bateries?
I want to use this PCB in a portable system which of course operates on batteries. I find a little complex to create another level of power to convert 12vdc to 18vac. How did you manage to use the two 9v bateries?
The picture and AliExpress seller link are not working. But I think that it is the same as this:
"HIFI Electronical 2 Way Crossover PCBA ClassA Power Linkwitz-Riley filter 4-Channel Output Crossover-point 2.2K Hz Free Shipping"
I've bought two of these with X-O points at 80 and 100hz for use with sub-woofers for my single driver MTLT systems.
Having frequencies down to a measured 30hz adds a subtle but valuable fullness to some music.
I used MathAudio's free plug in for FooBar to flatten out the peaks in my systems.
Anyway... Has anybody done testing on these $30 active X-Os?
Does the design look OK? 'Seems so inexpensive... less than passive X-Oers.
Thanks, Mack
Linkwitz-Riley 2-way Frequency Divider Stereo Preamp Board Treble Bass Crossover | eBay
It is a good quality board. I replaced the 5532 with LME49720 from DigiKey in US to assure genuine opamp IC's. The 5532 work ok too, but have a slightly higher noise level which can be heard if you have sharp ears. It crossover from my bookshelf to a sub at 100Hz. The sensitivity are close enough that trimmer pot is not needed.
I later made the bookshelf an active 2 way too. I need level adjustment because the tweeter has much higher sensitivity than the midrange. I use this at 2800Hz.
Latest Linkwitz-Riley Electronic Crossover 2-Way Frequency Divider preamplifier | eBay
DonVK did very extensive analysis and testing of the 3-way version from the same manufacturer. Many of his finding can be applied to your 2-way board.
Modular active 3 way - work in progress
If a power supply starts with a bridge rectifier it will run on DC or AC, cheap eBay boost converter board will get 12V upto the 25V or so needed to mimic the 18Vac peak voltage - note this is not isolated however.
Sorry I linked to the wrong thread that DonVK started. This is the correct one on his work on crossover board from e-bay.
Budget active 3 way crossover - buy, eval, mod