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Thread: Impulse H2 Speakers Crossover help please?

  1. #1
    Join Date: Nov 2011

    Location: Seaton, Devon, UK

    Posts: 13,242
    I'm Adrian.

    Default Impulse H2 Speakers Crossover help please?

    I have been considering hopefully improving the sound of my lovely Impulse H2 speakers. Initially I thought I would replace the capacitors in them as they are probably getting a bit old in the tooth by now. H2 builds varied quite a bit over the years I believe, mainly the siting of the crossover. Mine has the crossover on the inside mounted on a board that is secured to the rear of the cabinet by 6 screws, on the outside of this board is where the 6 speaker posts are. It is quite straight forward to get the board off but with limited movement due to the length of the internal leads to the speakers.

    I removed and have examined the crossover circuit which looks quite straight forward, two large capacitors and one smaller one, all are black and I think oil filled ones but I could be wrong, by the way I have limited electronics knowledge. I examined the capacitors carefully looking for markings to indicate what voltage and microfarads they are rated as with a view to ordering high quality replacements. Unfortunately they seem to be completely unmarked .

    I have searched the internet for crossover wiring diagrams for the H2's but can find none, I did find some pictures of a redesigned crossover for an upgraded pair and also a pair of Taus (the last version of H2's that look slightly different). But in both cases the circuits look a bit different, probably I believe due to the tweeters being replaced and I suspect an upgrade to improve the top/mid range crossover point.

    If anyone has any info or could guide me in the right direction it would be appreciated. I was hoping to do the simple capacitor swap myself, and then to look at making a minor mod to the circuit to improve a 450hz dB drop (I believe this is a standard tweak).
    Listening is the act of aural discrimination and dissemination of sound, and accepting you get it wrong sometimes.

    Analog Inputs: Pro-Ject Signature 10 TT & arm, Benz Micro LP-S, Michel Cusis MC, Goldring 2500 and Ortofon Rondo Blue cartridges, Hitachi FT5500 mk2 Tuner

    Digital:- Marantz SA-KI Pearl CD player, RaspberryPi/HifiBerry Digi+ Pro, Buffalo NAS Drive

    Amplification:- AudioValve Sunilda phono stage, Krell KSP-7B pre-amp, Krell KSA-80 power amp

    Output: Wilson Benesch Vector speakers, KLH Ultimate One Headphones

    Cables: Tellurium Q Ultra Black II RCA & Chord Epic 2 RCA, various speaker leads, & links


    I think I am nearing audio nirvana, but don’t tell anyone.

  2. #2
    Join Date: Sep 2011

    Location: Kilmarnock, Ayrshire, Scotland

    Posts: 533
    I'm stuart.

    Default

    Here you go. Have a look at http://www.acoustica.org.uk/ for lots of info on Impulse. I had H2's and Taus for many years, loved them.


  3. #3
    Join Date: Sep 2011

    Location: Kilmarnock, Ayrshire, Scotland

    Posts: 533
    I'm stuart.

    Default

    After loads of experimenting I used a Jantzen Superior Zcap in the tweeter and a Clarity Cap TC Poly in the mid and changed all the inductors for Jantzen air cores. Might be worth speaking to Paul at Reference Fidelity Components as he developed a completely new crossover which is supposed to be very good.

  4. #4
    Join Date: Nov 2011

    Location: Seaton, Devon, UK

    Posts: 13,242
    I'm Adrian.

    Default

    Quote Originally Posted by killie99 View Post
    After loads of experimenting I used a Jantzen Superior Zcap in the tweeter and a Clarity Cap TC Poly in the mid and changed all the inductors for Jantzen air cores. Might be worth speaking to Paul at Reference Fidelity Components as he developed a completely new crossover which is supposed to be very good.
    Hi Stuart

    That's very helpful, at least I know the values of the Caps, resistors and inductors, so I can decide what to do. Yes I have spoken with Paul some time ago but I am on a limited budget and his prices are too much for me, plus I think I would like to try myself. I have also spoken with another chap who has worked on several H2's and has told me the crossover can be improved with better components and the addition of a resistor to get rid of the mid-range dip at 450hz. So I will price the parts up and decide what to do.

    By the way why did you replace the inductors with air cores, is it because they are more stable?

    Many thanks

    Adrian
    Listening is the act of aural discrimination and dissemination of sound, and accepting you get it wrong sometimes.

    Analog Inputs: Pro-Ject Signature 10 TT & arm, Benz Micro LP-S, Michel Cusis MC, Goldring 2500 and Ortofon Rondo Blue cartridges, Hitachi FT5500 mk2 Tuner

    Digital:- Marantz SA-KI Pearl CD player, RaspberryPi/HifiBerry Digi+ Pro, Buffalo NAS Drive

    Amplification:- AudioValve Sunilda phono stage, Krell KSP-7B pre-amp, Krell KSA-80 power amp

    Output: Wilson Benesch Vector speakers, KLH Ultimate One Headphones

    Cables: Tellurium Q Ultra Black II RCA & Chord Epic 2 RCA, various speaker leads, & links


    I think I am nearing audio nirvana, but don’t tell anyone.

  5. #5
    Join Date: Sep 2011

    Location: Kilmarnock, Ayrshire, Scotland

    Posts: 533
    I'm stuart.

    Default

    I changed them because I thought they improved the sound - i thought the air core inductor in the bass gave much better control. As I said, I experimented with lots of components and built my final crossovers with what I thought sounded best.

  6. #6
    Join Date: Nov 2011

    Location: Seaton, Devon, UK

    Posts: 13,242
    I'm Adrian.

    Default

    Quote Originally Posted by killie99 View Post
    I changed them because I thought they improved the sound - i thought the air core inductor in the bass gave much better control. As I said, I experimented with lots of components and built my final crossovers with what I thought sounded best.
    That makes sense from what I read about ferrite core ones, I believe the air core should be better. Thanks
    Listening is the act of aural discrimination and dissemination of sound, and accepting you get it wrong sometimes.

    Analog Inputs: Pro-Ject Signature 10 TT & arm, Benz Micro LP-S, Michel Cusis MC, Goldring 2500 and Ortofon Rondo Blue cartridges, Hitachi FT5500 mk2 Tuner

    Digital:- Marantz SA-KI Pearl CD player, RaspberryPi/HifiBerry Digi+ Pro, Buffalo NAS Drive

    Amplification:- AudioValve Sunilda phono stage, Krell KSP-7B pre-amp, Krell KSA-80 power amp

    Output: Wilson Benesch Vector speakers, KLH Ultimate One Headphones

    Cables: Tellurium Q Ultra Black II RCA & Chord Epic 2 RCA, various speaker leads, & links


    I think I am nearing audio nirvana, but don’t tell anyone.

  7. #7
    Join Date: Sep 2011

    Location: Kilmarnock, Ayrshire, Scotland

    Posts: 533
    I'm stuart.

    Default

    here's a pic of the xo's I built, note £1 coin to give an idea of the size!


  8. #8
    Join Date: Nov 2011

    Location: Seaton, Devon, UK

    Posts: 13,242
    I'm Adrian.

    Default

    Quote Originally Posted by killie99 View Post
    here's a pic of the xo's I built, note £1 coin to give an idea of the size!

    Thanks, that looks good, am I right that the brown is tweeter, blue is mid and red is bass? I see you kept the inductors as far apart as possible and at 90 degrees to each other to minimise interference. I can see from the size it's not very practical to fit inside the speaker, and presumably heavy with the air core inductors.

    Thanks again

    Adrian
    Listening is the act of aural discrimination and dissemination of sound, and accepting you get it wrong sometimes.

    Analog Inputs: Pro-Ject Signature 10 TT & arm, Benz Micro LP-S, Michel Cusis MC, Goldring 2500 and Ortofon Rondo Blue cartridges, Hitachi FT5500 mk2 Tuner

    Digital:- Marantz SA-KI Pearl CD player, RaspberryPi/HifiBerry Digi+ Pro, Buffalo NAS Drive

    Amplification:- AudioValve Sunilda phono stage, Krell KSP-7B pre-amp, Krell KSA-80 power amp

    Output: Wilson Benesch Vector speakers, KLH Ultimate One Headphones

    Cables: Tellurium Q Ultra Black II RCA & Chord Epic 2 RCA, various speaker leads, & links


    I think I am nearing audio nirvana, but don’t tell anyone.

  9. #9
    Join Date: Sep 2011

    Location: Kilmarnock, Ayrshire, Scotland

    Posts: 533
    I'm stuart.

    Default

    Yes that's correct with the colours and I put coloured speaker connectors on the speakers and used coloured heatshrink on the cables linking the crossover to the speakers to minimise the risk of connecting things up wrong! The bass inductor was very heavy, think it weighed about 700g. The crossover boxes weren't too big, you can see them here beside the speakers:


  10. #10
    Join Date: Mar 2009

    Location: Nottingham

    Posts: 625
    I'm Ian.

    Default

    Quote Originally Posted by AJSki2fly View Post
    Hi Stuart

    That's very helpful, at least I know the values of the Caps, resistors and inductors, so I can decide what to do. Yes I have spoken with Paul some time ago but I am on a limited budget and his prices are too much for me, plus I think I would like to try myself. I have also spoken with another chap who has worked on several H2's and has told me the crossover can be improved with better components and the addition of a resistor to get rid of the mid-range dip at 450hz. So I will price the parts up and decide what to do.

    By the way why did you replace the inductors with air cores, is it because they are more stable?

    Many thanks

    Adrian
    HI Adrian, how did this work out in the end, was it worthwhile?, what parts did you use?. I am thinking of doing the same Ian

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