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Thread: Hypex DLCP (DSP) with 6 Channel UcD Amp Project.

  1. #11
    Join Date: Mar 2008

    Location: Galashiels

    Posts: 13,669
    I'm inthescottishmafia.

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    Me either, got them from Geoff here.
    “Music has always been a matter of energy to me, a question of fuel. Sentimental people call it inspiration, but what they really mean is fuel. I have always needed fuel. I am a serious consumer. On some nights I still believe that a car with the gas needle on empty can run about fifty more miles if you have the right music very loud on the radio”

    Hunter S Thompson

  2. #12
    Join Date: Apr 2012

    Location: N E Kent

    Posts: 51,624
    I'm Geoff.

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    Those Cryslers are mega rare. I kept an eye out and I've never seen another pair anywhere.
    It is impossible for anything digital to sound analogue, because it isn't analogue!

  3. #13
    Join Date: Jan 2013

    Location: Carlisle - UK

    Posts: 1,956
    I'm Ken.

    Default Update

    I've been re thinking the amplification......

    I was going to use 6 identical Hypex UcD180, that's 180w/4ohm 120w/8ohm.

    My bass drivers are 4ohm and the mids/tweeters are 8ohm.

    Using my current lash up and 7 channel Nakamichi amp, which has identical channels, I am having to attenuate the signal a fair amount for the mid/tweeter before the power amp, to match the levels I get out of the less sensitive bass drivers.

    I know it's all about the total gain/sensitivity, but show me a high gain power amp that isn't big on watts. Apart from variations due to design/losses, for all intents and purposes, when looking at power amps, large gain = large watts. So I tend to talk in those terms, as the actual gain is usually buried in the spec somewhere.

    My concern is that if I use six identical modules (read identical gain), I am going to have to make a similar large attenuation to the mid/tweeter channels, but in the digital domain, as the Hypex DLCP functions as a digital pre amp with individual level controls on the six output channels. I don't like the idea of using so much digital adjustment.

    My proposed solution is to use the UcD400 modules for the two bass channels 400w/4ohm. Its not that I need so much power, its the benefit it gives, by having a more balanced gain structure across the channels, that will need the minimum digital attenuation to achieve the correct levels at the drivers.

    An added bonus is I will probably have power to spare in the bass, which will allow me to consider a Linkwitz transform to EQ the bass and lower the f3 point, if I feel I need to. The driver has plenty of Xmax if I were to attempt this.

    Just thinking about the pros and cons at the moment, it will still fit in the same case footprint, but not in the planned 2U case height. The UCD400 are taller and will need a 3U case, which would also allow me to use a thicker piece of aluminium, as a heat sink in the bottom of the case.

  4. #14
    Join Date: Oct 2012

    Location: The Black Country

    Posts: 6,089
    I'm Alan.

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    I like your thinking Ken, particularly the Linkwitz transform.

    Watching with interest

  5. #15
    Join Date: Jan 2013

    Location: Carlisle - UK

    Posts: 1,956
    I'm Ken.

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    Couldn't find anything about the Crystal driver Ali.
    I've looked at Alpair before, the AL12P is a full range speaker but looks like it would make a good OB midrange.
    I would have to use it in a sealed chamber. It gets good feedback from folks that have used it on diyaudio etc.
    My first test, once the digital crossover is running, is to try the Yamaha Beryllium dome mid with the Scanspeak bass and Fountek Ribbon.
    The mid and Ribbon are closed back and don't need a separate chamber, so I can just mount em OB style on a baffle board for a quick test.

  6. #16
    Join Date: Mar 2008

    Location: Galashiels

    Posts: 13,669
    I'm inthescottishmafia.

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    Yeah there's not much out there.
    “Music has always been a matter of energy to me, a question of fuel. Sentimental people call it inspiration, but what they really mean is fuel. I have always needed fuel. I am a serious consumer. On some nights I still believe that a car with the gas needle on empty can run about fifty more miles if you have the right music very loud on the radio”

    Hunter S Thompson

  7. #17
    Join Date: Jan 2013

    Location: Carlisle - UK

    Posts: 1,956
    I'm Ken.

    Default Update

    Well, I've been busy for a while on other projects, but got back to the DLCP this week and made some progress.



    I checked the Main/Aux output on the SMPS's, plus the voltage on the Standby Module and all were as expected. I wired it up to explore the menu set up and set the volume to minimum, prior to connecting to the Amp and testing the Audio.
    I downloaded the latest firmware/filter software, created a basic filter set on the laptop and uploaded it.

    I'm only using the auxiliary output from one of the SMPS's at present, to power the DSP. They are really meant for powering the Hypex Amp modules, to be fitted in stage 2 of the build, but I needed to test the pin out for the DSP standby signal, that puts them and the Amp modules to sleep. There are many ways of wiring these boards, better to understand how the plumbing works before fitting it all into the case.

    Now I need to disconnect the analogue and passive crossovers from my speakers and add a series capacitor to protect the ribbon tweeter. I should then be ready to insert the temporary Nakamichi amplifier.

  8. #18
    Join Date: Jan 2013

    Location: Carlisle - UK

    Posts: 1,956
    I'm Ken.

    Default Update

    I managed to get everything plumbed in and 50+ hours on it, to make sure everything was run in, not sure that it needed more than a few hours, but didn't want any niggling doubts.

    So how does the DLCP sound..........?
    Err, decidedly underwhelming!

    There is detail, but dynamics are down, slightly bloated and mushy bass, lost some slam compared to my analogue active, on the plus side it is a cleaner less sibilant top end, not that that was a major issue with the analogue circuit, but it has improved slightly with the DLCP. Mid range is bland, not as transparent and boring to listen to.
    Overall? I couldn't live with it, especially with a vinyl source, most definitely a backward step in its present form.

    Configuration
    I set up a basic filter set with the same crossover points 300/3200Hz and slope 24dB/Octave as the analogue circuit.
    I used the same multi channel power amp and audio sources, so it was a pretty even comparison.

    I'm not righting it off just yet, folks on various Hypex threads for other products, say beefing up the cables between boards/smps etc helps, I especially don't like the 14way ribbon cable that transfers the analogue and digital signals from the input board to the DSP board. Also, I am powering the DSP from the Aux output from their amplifier SMPS. Hypex confirmed this was possible, but I'm thinking, maybe not the best way of running it. Some DLCP specific threads have said improving their (linear) PSU regulation etc firmed up their woolly bass and Hypex do produce a custom SMPS for the DSP board. I have a high quality tracking PSU which I made for my Pro-Ject phono stage, it's the right dual rail voltage (+/-18vdc). I've ordered some connectors to make up a lead, it wont take long to see if this makes any difference.
    I can wire the input board to DSP with some dual core screened for each channel to negate the ribbon cable, there is not much else I could change. The six audio outputs from DSP to power amp are short balanced XLR leads, so nothing to improve there. The whole set up is fully differential balanced circuitry from cartridge to power amp.

    If nothing helps improve things, I'm not opposed to reverting back to an analogue crossover and using the DSP as a development tool to establish the best crossover points, slopes and shelf/notch filters. The Hypex filter design software is also the measurement software and filters can be applied to measured results to overlay a predicted outcome in a graphical form, in a before and after comparison. You can also upload changes from your laptop to the DSP while music is playing and hear the instant change, its a useful tool in its own right.

    I will keep you updated as to how it all pans out.
    Last edited by Qwin; 05-08-2017 at 16:25.

  9. #19
    Join Date: Mar 2008

    Location: Galashiels

    Posts: 13,669
    I'm inthescottishmafia.

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    That's a shame Ken, hopefully you can sort it.
    “Music has always been a matter of energy to me, a question of fuel. Sentimental people call it inspiration, but what they really mean is fuel. I have always needed fuel. I am a serious consumer. On some nights I still believe that a car with the gas needle on empty can run about fifty more miles if you have the right music very loud on the radio”

    Hunter S Thompson

  10. #20
    Join Date: Jan 2013

    Location: Carlisle - UK

    Posts: 1,956
    I'm Ken.

    Default Update

    Well, that was a quick fix.
    Not being used to some of the techniques, I had set the Q for the cascading Butterworth biquad's at the wrong level.
    I ended up with straight Butterworth cross overs with +3dB humps and not flat LR crossover points.
    This is what was causing the muddy upper bass/mids.

    Its a lot better now, bass and mids better defined and more transparent, comes across as more dynamic.

    If I'd had a suitable mic/interface and taken measurements it would have been obvious, but I just had a flash of inspiration when reading about creating LR filters and realised I had not done it correctly. It's a learning curve.

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