Jamo D830 (Concert 8) crossover

Few years ago I build Seas based speakers. (T25-001 and W17E-002). Speakers was my own design, even filter.

I was quite satisfied speakers sound to the moment when I get chance to listen original Jamo Concert 8 speakers. After that I was not satisfied anymore :bawling:


So my question is that, does anybody have Jamo Concert 8 (Jamo D830) crossover schematic?

I have seen some pictures taken from that crossover board, but component values are not clear to me.

Picture shows how components are placed to board.
Red are capacitors, white are resistor and black circles are coils.
 

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Hi I'm Ivan and I have the same problem of you, I have woofer and tweeter seas excel (the same of Jamo D830) and I wish to built the speakers so if you have some solution (crossover anb specification of bass reflex port) could you send to my e-mail.

Thank You
 
I have the D830 I bought on sale to use the boxes and possibly the tweeter. However, with the exception of the limited bass extension, I found that I like the drivers once a good crossover was in place.

I've wanted to add a page to my site detailing the re-design, but have not had time. Some time over the next few days I'll see if I can do a quick-n-dirty page to show the original crossover and mine. It's roughly a 1900Hz LR4 with trap for the woofer breakup.

I also added some stuffing to the box in a trial-and-error method because I don't care for ported systems. The result is something of a highly damped ported system. I can't even say what the actual tuning is, I just worked on that until I liked the sound.

The woofers are the 4-ohm version, so my crossover won't work with the standard 8-ohm version.

Dave
 
Hi
I have the service manual for these great speakers.
I think the drivers was made special for Jamo, both drive have 4 ohm I don’t know the exact Seas series but I know are Excel series T25?? And w17??.
If someone need the schematic please send me a message on PM with the email address
 
Hello gabrielbecheanu,

I have several new parts of Jamo speakers and I cannot find the service manual to see which boxes they are.

If you have the manuals, you could tell me which series speakers are and what crossover to use (number or schematic)?

These are tweeter with the same appearance:
20143
20145
20449
21452

These are woofer with the same appearance:
20154
20155
23154
23155
23156
24154

This marked a woofer of 4 ohms, with apparently equal to the above:
23153

If any other member of the forum has this information, we will stay very grateful if I can provide.

Thank you very much,
mdb502
 
Hi
These are the series of speakers from the service manual
For tweeter is 20531
For woofer is 20525

Some one tells me that is almost impossible to buy those speakers from the market. These are available only on service replacement. Seas made these speakers especially for Jamo.
If you want the service manual send me an email
 
Thanks gabrielbecheanu for your reply.

I would like if you can send me the manual, unfortunately I cannot see your mail to send a message because my account is under moderation. If you can go to my profile, there is my mail.

Do you have the manual E8 Series (E850 and E870) where appear the number part of speakers and schematic of the crossover to use?

Best regards,
mdb502
 
Sorry for bringing this out of the depths of hell but I too have recently acquired a d830 in mint condition and was wondering..

what is the main reason why a lot of people have been modifying the crossover on this speaker?

Is it a relatively easy process? Does anyone have a guide on how to mod d830's / concert 8's to perform their best as so many people have said?
 
I have D830 for a while, currently I am interested in making new serial crossover for these speakers.

Did anyone tried to make new crossover, it might save me a lot time ;)

It's possible to do other things :

1. Go to a 12/12 modify the tweeter crossover :
Easy just by pass the 10uF.
Perhaps the 1ohms 4.7uF on the woofer should be removed.

2. Go to a 18/18 modify the woofer crossover (better option) :
Easy just insert between the networks (1ohms 4.7uF and 0.22mH 4.7uF) a 0.33mH inductor. And increase the 4.7uF to 22uF in the network (1ohms-4.7uF). The 1ohms could be removed.
The tweeter must be inverted. It will be in opposite polarity

Have Fun
 
Concert 8

Hi Dave, I am very curious to see your crossover upgrade. If I am well informed the original crossover is 2500 Hz. My intention is to improve only the caps with Janzen Z caps. Those are designed in Danmark but produced in Poland which explains their modest price. I assume that your intention with LR4 trap is to tame the magnesium membrane (very hard)by mid/bass driver. I can hear some distortions in the crossover area but have no idea if this is caused by the tweeter or the mid/bass driver. Anyway I would appreciate the desription of the (original) crossover parts.

Regards,
Nikola





QUOTE=dlr;1669793]I have the D830 I bought on sale to use the boxes and possibly the tweeter. However, with the exception of the limited bass extension, I found that I like the drivers once a good crossover was in place.

I've wanted to add a page to my site detailing the re-design, but have not had time. Some time over the next few days I'll see if I can do a quick-n-dirty page to show the original crossover and mine. It's roughly a 1900Hz LR4 with trap for the woofer breakup.

I also added some stuffing to the box in a trial-and-error method because I don't care for ported systems. The result is something of a highly damped ported system. I can't even say what the actual tuning is, I just worked on that until I liked the sound.

The woofers are the 4-ohm version, so my crossover won't work with the standard 8-ohm version.

Dave[/QUOTE]
 
I am a new member and posted my question (for Dave) two days ago while I have no idea how long moderators approval takes. My question was if someone can describe the crossover components by Concerto 8. I am in particular interested in the caps values because I intend to upgrade with Jantzen superior Z caps.

Regards,
Nikola
 
Jamo Concert 8 crossover,

I was not able to find any usable info about the crossover and even posted my
questions on Audiogon ''speaker forum'' without, alas, any reaction. So I decided to
see for myself and opened the speaker by removing the mid/bass driver. I was surprised to see an huge crossover plate fastened to the (bi-wire) connectors from inside. As far as I know the parts in the crossover suggest 4th order (24 dB ) for both drivers. The crossover ''plate'' is loaded with high grade parts so I abandoned my inicial idea to substitute the caps with Jantzen superior Z caps. Those are are about 10 x larger in comparison and would be very difficult to solder in place where the old one are. To my mind the crossover as is , is to complex to mess with. For the
brave among us I think the the only way to pull the crossover out is to unscrew the
connectors form outside , disconnect the wire from the drivers , and then pull the
crossover out.
 
Jamo Concert 8 crossover,

I was not able to find any usable info about the crossover and even posted my
questions on Audiogon ''speaker forum'' without, alas, any reaction. So I decided to
see for myself and opened the speaker by removing the mid/bass driver. I was surprised to see an huge crossover plate fastened to the (bi-wire) connectors from inside. As far as I know the parts in the crossover suggest 4th order (24 dB ) for both drivers. The crossover ''plate'' is loaded with high grade parts so I abandoned my inicial idea to substitute the caps with Jantzen superior Z caps. Those are are about 10 x larger in comparison and would be very difficult to solder in place where the old one are. To my mind the crossover as is , is to complex to mess with. For the
brave among us I think the the only way to pull the crossover out is to unscrew the
connectors form outside , disconnect the wire from the drivers , and then pull the
crossover out.
Hi Nikola,

I just came across your posts. I never went further with the design, too busy with other things to build new crossovers. My testing was all done using the Digital Filter in SoundEasy to audition designs. The system has been put aside for a long time now. One of the reasons is that I did not consider the bass to be good enough to want to finalize them. If they were used with a sub-woofer matched with them, then that would be different, but I never had plans to do that. My other systems are better for full-range, so they went to the storage shelf where they are today.

What else I can recall is my impression that the midwoofer breakup was very difficult to handle. I was never fully satisfied, even with the breakup farther down in level than the OEM crossover placed it. It was improved, but still had a rough edge to the sound that I believe was associated with the breakup.

Dave