DIY biamp 6-24 crossover

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allhifi

Member
Joined 2018
Fixed Resisor Values

FrankCox said:
There are no dedicated test points. The 10k series resisters are directly above and below the pots so that gives you one end of each pot. For high pass there's a plated through hole next to P1 and for P2 you can use one end of the bias resister. For lo pass I used the caps but if you can't get under them you can use resisters leads too as you can see in the schematic.
Click to expand...

Hello Frank: If you know, I'd like to set-up the 6-24 as a sub/mains x-over:

LP/HP @ 45 Hz. (LR 24 db./octave).

Ideally, if I could have a gang-switch (4-6 position) to select 45,50,55, 60 and/or 80Hz that would make the 6-24 much easier to select/experiment with crossover frequency. Could that be incorporated/ in the 6-24 design?

If not, is there a slope calculator I could use to determine the (fixed) resistor values required for 45 Hz. LP/HP setting ?

Thank you,

pete
 
T

TboneAK

Member
Joined 2012
cubicincher said:
Two possibilities for a linear regulated powersupply:


LV-Regulator
The σ11 regulated power supply


and many more....


Perhaps the DIYAudiostore could think about offering boards?
single polarity and a symmetrical one? :rolleyes:




Greets
Dirk
Click to expand...

Dirk,

Thanks description of your psu's and for the links. I was digging through my stuff and stumbled on a pair of Simple Cap-Mx Regulated Low-Noise PSU from XRK-971. Impulse buy along with some other bits... :rolleyes: Anyway I think one of these will do the trick.

Did you ever get your second 6-24 hooked up to a Subwoofer?

I'm planning a tri-amped, two boards, build. The third amp will be for a subwoofer and I am curious how it worked out.

The plan is: Board #1 would have a XO at say 100hz. The LP output signal would drive the sub amp. The HP output signal would feed the input of board #2. This would create a band pass between the two boards for the LF driver in my 2-way speakers. Correct?

I'm thinking that I could use a 3 pole, 2 position, 2 deck switch to switch board #1 in/out of the signal path to board #2. This wayI can remove Board #1 out of the signal path when the sub is not needed, and leave the LF drivers in my speakers with only the LP signal from board #2. It's not always "Dance Club" time at the house according to my wife.:cop:

Does this sound feasible?
 
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cubicincher

Member
Joined 2016
to TboneAK

Hello TboneAK,

my second 6-24XO board is stuffed and ready to play. I bought a case
from Modushop Italy and some more stuff to complete the build. But it
is not finished yet. So the Subwoofer has to wait a little bit till it gets 'feed'
by the 6-24XO for sub.
Your idea with the switch between the two 6-24XO-boards should work.

And: are there really girls/wifes who don't like the 'danceclub'??? :D

Greets
Dirk.
 
T

TboneAK

Member
Joined 2012
Hi Dirk,
My wife does indeed like the dance club idea, but doesn’t want the thump when it’s quiet time. That’s why I’m considering the switch. My 8” drivers do a good job, but I really like the sub sound when it’s disco time. Turn on the DJ light, fog machine and turn up the bass. We have one of these hanging in the corner, it’s a bit over the top.:D

Kinta FX | CHAUVET DJ

Looking forward to seeing how your build turns out. I’m in the planning stages right now. But will post some pics once I start building.

Regards
Tbone
 
F

FrankCox

Member
Joined 2020
allhifi said:
Hello Frank: If you know, I'd like to set-up the 6-24 as a sub/mains x-over:

LP/HP @ 45 Hz. (LR 24 db./octave).

Ideally, if I could have a gang-switch (4-6 position) to select 45,50,55, 60 and/or 80Hz that would make the 6-24 much easier to select/experiment with crossover frequency. Could that be incorporated/ in the 6-24 design?

If not, is there a slope calculator I could use to determine the (fixed) resistor values required for 45 Hz. LP/HP setting ?

Thank you,

pete
Click to expand...

Pete, What you want to do is certainly possible. I don't know of a calculator app where you put in the crossover point and get component values for the 6-24 design. Creating one would be similar to making the one we have.

I'd probably just try to zero in on the values by trial and error in the secret labs app or in microcap. Tedious I know, but once you get one the rest should be easy.
 
F

FrankCox

Member
Joined 2020
allhifi said:
Pete, What you want to do is certainly possible. I don't know of a calculator app where you put in the crossover point and get component values for the 6-24 design. Creating one would be similar to making the one we have.

I'd probably just try to zero in on the values by trial and error in the secret labs app or in microcap. Tedious I know, but once you get one the rest should be easy.
Click to expand...

My Strategy for Adjusting the Filters

Expanding on my last post: Since Pete wants to use 24 dB/octave and Nelson says in the manual:

"... the classic L-R alignment will result from P2 potentiometers to be at around 1/2 the resistance of the other pots".

While that sentence my be open to interpretation I take it to mean that you can just run P2 from it's lowest value to half it's range and then set P1 to double that. Also, I believe both stages of a 24 dB/Oct LP or HP will be the same for maximum slope, so basically you can have just two variables to tweak. One for HP and one for LP. All the other R values follow.

I could be wrong in some of my assumptions so please correct me. I can say I successfully used the above method on my 6-24 when tested with REW. I'm waiting for my second amp before I can do listening tests.
 
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cubicincher

Member
Joined 2016
to RogerGustavsson #649

It depends on the Opamp you want to use.


Greets
Dirk
 

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PaulInWA

Member
Joined 2021
I haven't been able to find a build guide for the DIY biamp 6-24 crossover. Nelson mentions that 6L6 was going to do one but I can't find it. Does one exist? I'm a novice builder so the project is daunting without more detailed instructions than a parts list and labels on a circuit board.
 
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cubicincher

Member
Joined 2016
PaulInWA #654

Most important to read and understand (I hope you did?):


https://www.firstwatt.com/pdf/art_diy biamp_6-24_ crossover.pdf


Till now there is no pictured build guide. You can build this active crossover in so many ways (6- / 12- / 18-/ 24-dB-slope and you have to calculate your resistor- and cap- values (in the filters) on your own - for your special requirements = crossover points/range your speakers demand).


Greets
Dirk
 
D

Decker

Member
Joined 2004
Still wondering how to translate the resistors R1 through R4 in the Mike Rothacher crossover program to P1 and P2 of the first stage and P1 and P2 of the second stage of the crossover. Is R1 = P1 first stage, R2 = P2 first stage, R3 = P1 second stage, R4 = P2 second stage. Have I got this right?
 
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FrankCox

Member
Joined 2020
Decker said:
Still wondering how to translate the resistors R1 through R4 in the Mike Rothacher crossover program to P1 and P2 of the first stage and P1 and P2 of the second stage of the crossover. Is R1 = P1 first stage, R2 = P2 first stage, R3 = P1 second stage, R4 = P2 second stage. Have I got this right?
Click to expand...


Kind of confusing. The default values in the app have R1 half the value or R2, and so on... The manual recommends that P2 be "around" 1/2 P1 (at least for 24db/oct) so that's how I remember which is which. Note that the resisters in the app include the 10k series resister so it's not just the value of the pots -- Maybe that's part of the reason they aren't labeled P1 and P2... r1 and so on also seems to be the HTML/javascript variable names so there's that too...

So I think you have it, R1 = P1 and R3 = P1 and so on
 
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cubicincher

Member
Joined 2016
translate NP-schematic to MRcalculator (6-24XO)

Hello 6-24XO-builders,


it seems that many builders are confused how to translate the part-numbers in
the schematic of Nelson Pass to the Mike Rothacher - calculator.
Believe me, I also was stretching my brain alittle bit.....:rolleyes:
Please be patient with me, because I am not an electronic engineer and no teacher!


Let's start with a simple 6dB high pass filter (in the Nelson Pass-schematic):




9k=

And now the MRcalculator:


2Q==

The value of R2 (MRcalc) corresponds to the value of P1(0 Ohm up to 50kOhm-how you adjust it) + the 10kOhm resistor (NPschematic).
If you adjust P1 to 12,5kOhm +the 10kOhm resistor inline you get 22,5kOhm (22500Ohm).


To make the confusion perfect:


In the MRcalc is the second stage bypassed = in the NelsonPass-schematic is
the first stage bypassed!


I hope I made no mistake! :confused:



Greets
Dirk :D
 
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