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Thread: Lack of bass information if connecting with DX1

  1. #1
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    Unhappy Lack of bass information if connecting with DX1

    Dear all brothers,
    Does anyone knowing the DX1?
    As the title said when I connect the DX1 for the biamping system to the K2 s9500, it obviously much less of bass information than single amplifying system, I have even tried both transistor amp and tube amp but the result were the same. The present connection is Preamp -->DX1(main input) then HF(L,R)-->tube poweramp-->speaker (HF), then LF + (L,R)-->tube poweramp-->speaker (LF), LF - (L,R)-->no connection.

    Best Regards,

  2. #2
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    I would check for polarity issues somewhere in the signal path of the low frequency in your bi-amped set up. Just for a quick test reverse the + & - connections at one speaker.

  3. #3
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    Quote Originally Posted by Mike Caldwell View Post
    I would check for polarity issues somewhere in the signal path of the low frequency in your bi-amped set up. Just for a quick test reverse the + & - connections at one speaker.

    Hi Mike, thanks for your kind suggestion. I did reverse the + & - connection at one side, the bass nothing improved however the sound stage was pretty wide but not focus.
    I still guess the problem is coming from the DX1, think it filters lot of basses information from the circuit design.
    Again, does any brothers can help who may know the DX1 something.

  4. #4
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    S9500, DX-1 problem

    Quote Originally Posted by AYYK
    SNIP,,,,SNIP
    - The present connection is Preamp -->DX1(main input) then HF(L,R)-->tube poweramp-->speaker (HF),
    then LF + (L,R)-->tube poweramp-->speaker (LF), LF - (L,R)-->no connection.
    - The DX-1 used ( model specific ) crossover cards for the different speaker systems it was be used with .
    - Are you sure you have the correct crossover cards installed ? ( You'll need to open up the DX1 to check the labelling on the cards )

    - Here's a pic showing both HP & LP cards for the S9500 .


    Here's another pic showing the component values that make these cards unique to the S9500 system .


    - And finally, here's a pic that shows the bass boost the LF card gives .


    - ie; You're supposed to get more bass from the S9500 when using the DX-1 ( when it's populated with the proper crossover cards ) .

    >< cheers

    ps; here's the DX-1 schematic ( in pdf form )
    & the DX-1 Operators' Manual

  5. #5
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    Quote Originally Posted by Earl K View Post
    - The DX-1 used ( model specific ) crossover cards for the different speaker systems it was be used with .
    - Are you sure you have the correct crossover cards installed ? ( You'll need to open up the DX1 to check the labelling on the cards )

    - Here's a pic showing both HP & LP cards for the S9500 .


    Here's another pic showing the component values that make these cards unique to the S9500 system .


    - And finally, here's a pic that shows the bass boost the LF card gives .


    - ie; You're supposed to get more bass from the S9500 when using the DX-1 ( when it's populated with the proper crossover cards ) .

    >< cheers

    ps; here's the DX-1 schematic ( in pdf form )
    & the DX-1 Operators' Manual
    Dear Earl,
    Thank you very much to your valuable information of the DX1 but I don't know what my card is, so I would like to upload a pic for you to indentify.
    In addition to the last page of the sketch that I don't understand to the part on the lower right hand corner, is it a additional circuit to the cards or already exist on the main board?

    Many thanks again.
    Auyeung
    Attached Images Attached Images  

  6. #6
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    Wrong Bass Card / maybe wrong HF card .

    Hi,

    Quote Originally Posted by ayyk
    but I don't know what my card is, so I would like to upload a pic for you to indentify.
    - I can see from here that the bass card ( the one on the right in your picture ) is not correct . It's missing a bunch of capacitors and also has a few resistors in the place of the expected capacitors .

    - You need to take these cards into an electronics service center ( it doesn't have to be JBL ) & have them populate both cards with the correct resistors & capacitors ( before your DX-1 will work correctly with your S9500 ) .
    - Have them use Polypropylene type capacitors ( not mylar ) .
    - Print out the info that I posted and take it along to the electronics shop / they'll need it .

    - It doesn't really matter which speaker system your cards are presently set for / they need to be changed ( & JBL no longer sells them / so we've been told ) .

    Quote Originally Posted by ayyk
    In addition to the last page of the sketch that I don't understand to the part on the lower right hand corner, is it a additional circuit to the cards or already exist on the main board?
    - It looks to be a "recommended addendum" ( after-thought ) .
    - It could be meant for the HF input of each speaker box ( therefore, you'd need 2 ).
    - The (3.5 mH, 2.0 uF, 7.5 ohms ) is either an LCR notch filter centered at 1900 hz /or / a LCR impedance equalizer, centerd at the same frequency / ( what the LCR ultimately does depends on its' placement in the circuit ) .

    - It wouldn't exist on the HF crossover cards .

    - If it's strapped across the HF terminals outside of the speaker box it'll act as a frequency dependant impedance equalizer .
    - If it's strapped across the drivers' terminals inside the speaker & after the passive crossover components / it'll notch out a few db of response in the 1900 hz area .

    - I don't know which scenario is recommended ( 4313B might be able to find out ) .

    >< cheers



    -

  7. #7
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    Hi Earl,
    Thanks again for your helpful reply.
    Shall I re-work the cards by myself if following the component value that was given. Is the silver Mica = Polypropylene, and which kind of capacitor is better for the DX1?
    I always wonder whether the passive crossover inside the speaker be bypassed if toggle to the bi-amp position at the back of the speaker.
    For the (3.5 mH, 2.0 uF, 7.5 ohms ) connection, does it useful if using bi-amp connection.

    Thanks,
    Auyeung

    Quote Originally Posted by Earl K View Post
    Hi,



    - I can see from here that the bass card ( the one on the right in your picture ) is not correct . It's missing a bunch of capacitors and also has resistors in place of a few capacitors .

    - You need to take these cards into an electronics service center ( it doesn't have to be JBL ) & have them populate both cards with the correct resistors & capacitors ( before your DX-1 will work correctly with your S9500 ) .
    - Have them use Polypropylene type capacitors ( not mylar ) .
    - Print out the info that I posted and take it along to the electronics shop / they'll need it .

    - It doesn't really matter which speaker system your cards are presently set for / they need to be changed ( & JBL no longer sells them / so we've been told ) .



    - It looks to be a "recommended addendum" ( after-thought ) .
    - It could be meant for the HF input of each speaker box ( therefore, you'd need 2 ).
    - The (3.5 mH, 2.0 uF, 7.5 ohms ) is either an LCR notch filter centered at 1900 hz /or / an impedance equalizer centerd at the same frequency ( what it ultimately does depends on its' placement ) .

    - It wouldn't exist on the HF crossover cards .

    - If it's strapped across the HF terminals outside of the speaker box it'll act as a frequency dependant impedance equalizer .
    - If it's strapped across the drivers' terminals inside the speaker & after the passive crossover components / it'll notch out a few db of response in the 1900 hz area .

    - I don't know which scenario is recommended ( 4313B might be able to find out ) .

    >< cheers



    -

  8. #8
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    Quote Originally Posted by ayyk
    Thanks again for your helpful reply.
    Shall I re-work the cards by myself if following the component value that was given. Is the silver Mica = Polypropylene, and which kind of capacitor is better for the DX1?
    - Have a professional do the work after you've satisfied for yourself that your cards follow the same basic component layout as per my picture. A trained eye can use the pdf schematic ( with its' circuit layout for the Xover cards ) to make sure that the ones' you have conform to the electrical ( if not physical layout .
    - Silver Mica caps are sonically very very good / but I've had ( in the past ) problems with them flaking apart ( & then changing values ) / so I'd stick with MPP ( metallized polypropylene ) . One can use polystyrene caps if you can find them . They are very good also / but are more heat sensitive to a soldering iron .

    - Follow RobHs ( retracted ? ) advice to make sure your cards conform to the basic circuit layout for these cards .
    ( Perhaps he'll post pics of the backside of the cards so can can compare yours to his .)


    I always wonder whether the passive crossover inside the speaker be bypassed if toggle to the bi-amp position at the back of the speaker.
    - The schematic for the S9900 is posted somewhere on this website / I just can't find / but having said that / I'm pretty confident that most if not all of the HP network remains in place when "bi-amp" is selected by the toggle switch .

    For the (3.5 mH, 2.0 uF, 7.5 ohms ) connection, does it useful if using bi-amp connection.
    - Since I don't know where this LCR is meant to reside, I can't comment any further .

    >< cheers

  9. #9
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    Hi Earl,
    In Hong Kong is quite difficult to find professional to do the card, so I will try by myself. Does anything need to be awared when making the card?

    kind regards,
    Auyeung

    Quote Originally Posted by Earl K View Post
    - Have a professional do the work after you've satisfied for yourself that your cards follow the same basic component layout as per my picture. A trained eye can use the pdf schematic ( with its' circuit layout for the Xover cards ) to make sure that the ones' you have conform to the electrical ( if not physical layout .
    - Silver Mica caps are sonically very very good / but I've had ( in the past ) problems with them flaking apart ( & then changing values ) / so I'd stick with MPP ( metallized polypropylene ) . One can use polystyrene caps if you can find them . They are very good also / but are more heat sensitive to a soldering iron .

    - Follow RobHs ( retracted ? ) advice to make sure your cards conform to the basic circuit layout for these cards .
    ( Perhaps he'll post pics of the backside of the cards so can can compare yours to his .)




    - The schematic for the S9900 is posted somewhere on this website / I just can't find / but having said that / I'm pretty confident that most if not all of the HP network remains in place when "bi-amp" is selected by the toggle switch .



    - Since I don't know where this LCR is meant to reside, I can't comment any further .

    >< cheers

  10. #10
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    Keep Searching !

    Quote Originally Posted by ayyk
    In Hong Kong is quite difficult to find professional to do the card, so I will try by myself. Does anything need to be awared when making the card?

    kind regards,
    Auyeung
    - I'd suggest that you look harder to find someone qualified to do this work .
    - ie; Searchout a JBL representative and findout if they have the contacts in your area ( or even Japan ) to get this done .
    - Once the new parts are in the cards / & the cards are back in the DX-1 / the tech needs to run Voltage vs Frequency tests to make sure the work has been done correctly . ( ie ; Match the voltage-drive curves to what I posted above )
    - Sorry to say, but I don't believe you are qualified to get this all accomplished correctly if left to your own devices .

    >< cheers

  11. #11
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    Hi Earl,
    Since I did not think so complicated and seems it needs instrument for testing after assembling of components. So I decide to take your advise let somebody to finish my work.


    Quote Originally Posted by Earl K View Post
    - I'd suggest that you look harder to find someone qualified to do this work .
    - ie; Searchout a JBL representative and findout if they have the contacts in your area ( or even Japan ) to get this done .
    - Once the new parts are in the cards / & the cards are back in the DX-1 / the tech needs to run Voltage vs Frequency tests to make sure the work has been done correctly . ( ie ; Match the voltage-drive curves to what I posted above )
    - Sorry to say, but I don't believe you are qualified to get this all accomplished correctly if left to your own devices .

    >< cheers

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