rebuild 0a-4: Visaton W200S + OT-57-148, act. cross-over

[schdrag]

Hi there
Sorry, that I do not write in Swedish, but I have never learnd Swedish.
Recently I have bought a pair of Sonab 04-4 type 2 with three 16 ohm peerless (on every one 16 ohm is printed). With the help of the people of visaton.de I want to repair the sonab's (one Philips Philips 9710M/01 and two Peerless MT20HFC are damaged). I have bought several OT-57-148 https://www.pollin.de/shop/downloads/D640600D.PDF and I will buy a Visaton BG 20 as well. Now the guys are setting up a crossover, see http://www.visaton.de/vb/showthread.php?p=416567&posted=1#post416567.
I wonder whether or not there are 2x air-core 0.5 mH inductors (I can see a 1x 6.8 uF and a resistor according to the photo) because I would like to use as much existing parts as possible. In this thread http://www.diyaudio.com/forums/multi-way/174894-sonab-oa-4-crossover-tweeter-impedance.html the user UrSv recommended to ask a question in the section "Carlsson Illuminati".

[kvaal]

I guess you will find the answer here: http://www.carlssonplanet.com/en/

[schdrag]

I have also asked on carlsson planet: they couldn't tell me, whether or not the value is the same like the coils from OA5: 0,2 Ohm and 0,510mH, see http://www.troelsgravesen.dk/sonab_files/sonab_AO5-mkII_crossover_1.GIF
Because someone from Visaton Forum helps me to develop an active crossover, I'm changing the setup to an active closed box wit 4xOT-57-148 and Visaton 200S plus amplifier moduls tpa3118.
I will keep you informed.
I

[Perfector]

Hi there
Sorry, that I do not write in Swedish, but I have never learnd Swedish.
Recently I have bought a pair of Sonab 04-4 type 2 with three 16 ohm peerless (on every one 16 ohm is printed). With the help of the people of visaton.de I want to repair the sonab's (one Philips Philips 9710M/01 and two Peerless MT20HFC are damaged). I have bought several OT-57-148 https://www.pollin.de/shop/downloads/D640600D.PDF and I will buy a Visaton BG 20 as well. Now the guys are setting up a crossover, see http://www.visaton.de/vb/showthread.php?p=416567&posted=1#post416567.
I wonder whether or not there are 2x air-core 0.5 mH inductors (I can see a 1x 6.8 uF and a resistor according to the photo) because I would like to use as much existing parts as possible. In this thread http://www.diyaudio.com/forums/multi-way/174894-sonab-oa-4-crossover-tweeter-impedance.html the user UrSv recommended to ask a question in the section "Carlsson Illuminati".

According to my crosssover table it seems to be 2x 0.5 mH coils, providing the woofer is 8 ohm.
The high crossover seems to be 3000 Hz 12dB/Octave and the woofer 6 dB slope.
If the woofer is 4 ohm then thecrossover is 1500 6dB slope that will give a big dip between the two.
My own Component list can help you determing what it is.

[chrisss]

Hi there
Sorry, that I do not write in Swedish, but I have never learnd Swedish.
Recently I have bought a pair of Sonab 04-4 type 2 with three 16 ohm peerless (on every one 16 ohm is printed). With the help of the people of visaton.de I want to repair the sonab's (one Philips Philips 9710M/01 and two Peerless MT20HFC are damaged). I have bought several OT-57-148 https://www.pollin.de/shop/downloads/D640600D.PDF and I will buy a Visaton BG 20 as well. Now the guys are setting up a crossover, see http://www.visaton.de/vb/showthread.php?p=416567&posted=1#post416567.
I wonder whether or not there are 2x air-core 0.5 mH inductors (I can see a 1x 6.8 uF and a resistor according to the photo) because I would like to use as much existing parts as possible. In this thread http://www.diyaudio.com/forums/multi-way/174894-sonab-oa-4-crossover-tweeter-impedance.html the user UrSv recommended to ask a question in the section "Carlsson Illuminati".

According to my crosssover table it seems to be 2x 0.5 mH coils, providing the woofer is 8 ohm.
The high crossover seems to be 3000 Hz 12dB/Octave and the woofer 6 dB slope.
If the woofer is 4 ohm then thecrossover is 1500 6dB slope that will give a big dip between the two.
My own Component list can help you determing what it is.

Sorry Perfector but that table is useless for designing crossovers for real drivers with:

limited bandwidth
rising impedance
different distance to the LF & HF drivers

In rare occasions it might produce decent (not terrible) result if you are lucky

[Perfector]

Hi there
Sorry, that I do not write in Swedish, but I have never learnd Swedish.
Recently I have bought a pair of Sonab 04-4 type 2 with three 16 ohm peerless (on every one 16 ohm is printed). With the help of the people of visaton.de I want to repair the sonab's (one Philips Philips 9710M/01 and two Peerless MT20HFC are damaged). I have bought several OT-57-148 https://www.pollin.de/shop/downloads/D640600D.PDF and I will buy a Visaton BG 20 as well. Now the guys are setting up a crossover, see http://www.visaton.de/vb/showthread.php?p=416567&posted=1#post416567.
I wonder whether or not there are 2x air-core 0.5 mH inductors (I can see a 1x 6.8 uF and a resistor according to the photo) because I would like to use as much existing parts as possible. In this thread http://www.diyaudio.com/forums/multi-way/174894-sonab-oa-4-crossover-tweeter-impedance.html the user UrSv recommended to ask a question in the section "Carlsson Illuminati".

According to my crosssover table it seems to be 2x 0.5 mH coils, providing the woofer is 8 ohm.
The high crossover seems to be 3000 Hz 12dB/Octave and the woofer 6 dB slope.
If the woofer is 4 ohm then thecrossover is 1500 6dB slope that will give a big dip between the two.
My own Component list can help you determing what it is.

Sorry Perfector but that table is useless for designing crossovers for real drivers with:

limited bandwidth
rising impedance
different distance to the LF & HF drivers

In rare occasions it might produce decent (not terrible) result if you are lucky

Then I and Visaton and Monacor have been lucky for more than 25 years and they never complaint over the results.
Perhaps you should try it out and see what it really does instead of nagging.

[Prozac]

Hi there
Sorry, that I do not write in Swedish, but I have never learnd Swedish.
Recently I have bought a pair of Sonab 04-4 type 2 with three 16 ohm peerless (on every one 16 ohm is printed). With the help of the people of visaton.de I want to repair the sonab's (one Philips Philips 9710M/01 and two Peerless MT20HFC are damaged). I have bought several OT-57-148 https://www.pollin.de/shop/downloads/D640600D.PDF and I will buy a Visaton BG 20 as well. Now the guys are setting up a crossover, see http://www.visaton.de/vb/showthread.php?p=416567&posted=1#post416567.
I wonder whether or not there are 2x air-core 0.5 mH inductors (I can see a 1x 6.8 uF and a resistor according to the photo) because I would like to use as much existing parts as possible. In this thread http://www.diyaudio.com/forums/multi-way/174894-sonab-oa-4-crossover-tweeter-impedance.html the user UrSv recommended to ask a question in the section "Carlsson Illuminati".

Hi Schdrag

When I read the your text I understand that you will have one speaker with BG20 and one with Philips 9710? I Think you need to replace both bass units if one of them is damaged (or find another 9710). I agree that a crossover should not be designed from a list of standard values due to the reasons mentioned. However its Always fine to try different combinations and for that the list can be useful.

As a start for your Project, I think a crossover frequency of approx 3000hz will work fine. 6 db for the bass and 12 db for the tweeters. Due to different impedance (depending on how you design your Circuit and depending on your replacement speakers), you will need to adjust the Component values accordingly. I have built with BG20 in a OA4 and used a coil of 1.2 mh, because of the rising frequency response in BG20, so it needs to be tamed somewhat. With a 6db bass filter at 1500hz BG20 will still produce a lot of midrange, which is ok since you will listen to them off axis in OA4 with reflections. The tweeters can be divided at approx 3000 hz with 12db and maybe you can use the old coils there if you want.