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Thread: Digital Amplifiers

  1. #1
    Administrator Mr. Widget's Avatar
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    Digital Amplifiers

    I have been hearing a bit of chatter about the new digital amplifiers. Jeff Rowland has come out with one that is highly regarded by vinyl playing audio tweaks and others are coming onto the scene.

    Here is a link to a company that makes OEM digital amp modules. One version seems to be very interesting for those of us prone to designing our own speakers.

    http://www.d2audio.com/dynimages/XS-1074637885.pdf

    Check it out and then snoop around the rest of their site.

    Widget

  2. #2
    Senior Member pangea's Avatar
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    Power supply for class D amps

    Hi!

    It seems class D amps are on the move.
    Recently I stumbled upon The Dutch company Hypex, now releasing a couple of small Hi-End modules, 100W and 200W 8 Ohm, at very low prices, for DIY purposes.

    However they do not provide power supply.

    I was thinking of building one 200W 8 Ohm, (400W 4 Ohm)module for the two paraleled 2215H I have.
    For this I will build a 500VA, +/- 60VDc power supply, with quite a few caps. I think it was you Mr. Widget, who said there can't ever be too many caps!!!

    Then I would build a Stereo amp also with two 200W modules, like a dual mono amp. for the 2225H's I have.
    For this I would also take one 500VA transformer with 2 x +/- 60VDc to support the two channels.

    Finally I would build two stereo amps, (each amp driving the mids and highs on the same channel) using two 100W modules in each amp, driven by one 200VA transformer with 2 x +/- 45VDc in each amp, also with a few large caps of course.

    For protection I would include fusing and a small cap on the main switches.

    Does anyone know if this sounds reasonable and also does anyone know what components I would need?

    I do know that the transformers secondary voltage has to be multiplied by 1,4141 to get the Dc voltage required.

    But I don't know why most transformers have two separate secondary wirings. Is it to support two channels in the amp and to provide for better channel separation? Do I need one or two rectifiers, one for each channel?
    Is it possible to parallel the two secondaries to get more power, when using it for mono use?
    If I'm using both channels on the same side, does that mean channel separation has no bearing, i.e. making it OK to use only one transformer for both channels?

    Can anyone please help me with this and perhaps even show me a schematic on the wiring?

    Grateful as always for any help.

    BR
    Roland

    PS: I think this topic might become quite sought after in the future, as the D amps are becoming more widely spread out there. DS.

  3. #3
    Senior Member pangea's Avatar
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    Re: Digital Amplifiers

    Originally posted by Mr. Widget
    I have been hearing a bit of chatter about the new digital amplifiers. Jeff Rowland has come out with one that is highly regarded by vinyl playing audio tweaks and others are coming onto the scene.

    Here is a link to a company that makes OEM digital amp modules. One version seems to be very interesting for those of us prone to designing our own speakers.

    http://www.d2audio.com/dynimages/XS-1074637885.pdf

    Check it out and then snoop around the rest of their site.

    Widget

    Do you know what the XS250 amps cost and what the SPEQ option cost and do you know if the SPID option is awailable for JBL pro drivers?

    I've mailed them but haven't got any reply.

    Thanks BTW for telling us about the D2 Audio company. VERY interesting stuff!

    BR
    Roland

  4. #4
    Administrator Mr. Widget's Avatar
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    I haven't researched them yet... a friend pointed me in their direction and I thought it looked interesting with the DIY speaker enthusiast in mind.

  5. #5
    Super Moderator Hofmannhp's Avatar
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    Re: Power supply for class D amps

    Originally posted by pangea (shorted by HP)
    Hi!

    ................For this I would also take one 500VA transformer with 2 x +/- 60VDc to support the two channels......
    .......Does anyone know if this sounds reasonable and also does anyone know what components I would need?

    I do know that the transformers secondary voltage has to be multiplied by 1,4141 to get the Dc voltage required.
    But I don't know why most transformers have two separate secondary wirings. Is it to support two channels in the amp and to provide for better channel separation? Do I need one or two rectifiers, one for each channel?
    Is it possible to parallel the two secondaries to get more power, when using it for mono use?
    If I'm using both channels on the same side, does that mean channel separation has no bearing, i.e. making it OK to use only one transformer for both channels?

    BR
    Roland
    Hi Roland,
    it's not as you wrote.....first:
    never couple the transformer sec winding in parallel !! little differences in the voltages and currents will produce leakage currents in the transformer. Use them separately.

    When you need two voltages for the amp stages, you have to know if they need bridged power supply, that means two mirrored voltage sources.
    They need to be connected serial. The middle is now your new ground base, so you have a + and a - source.
    You need only one rectifier but an also serial pair (or more) caps. The middle of the caps are the same ground base for your power supply.
    When you need i.e. +/- 60VDC for the amps, you have to divide through 1.414 for the transformer voltage (please calculate with 1.4).
    Example: for +/- 60VDC you need a transformer with 2 x 43 to45 VAC.

    HP
    Please help us save more info about the vintage systems. Let us register your speakers and drivers.

  6. #6
    Senior Member pangea's Avatar
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    Re: Re: Power supply for class D amps

    Originally posted by Hofmannhp
    Hi Roland,
    it's not as you wrote.....first:
    never couple the transformer sec winding in parallel !! little differences in the voltages and currents will produce leakage currents in the transformer. Use them separately.

    When you need two voltages for the amp stages, you have to know if they need bridged power supply, that means two mirrored voltage sources.
    They need to be connected serial. The middle is now your new ground base, so you have a + and a - source.
    You need only one rectifier but an also serial pair (or more) caps. The middle of the caps are the same ground base for your power supply.
    When you need i.e. +/- 60VDC for the amps, you have to divide through 1.414 for the transformer voltage (please calculate with 1.4).
    Example: for +/- 60VDC you need a transformer with 2 x 43 to45 VAC.

    HP

    Vielen Dank HP!!!

    I realize that I probably would have made a blunder there.

    Do you by any chance have some drawings on a good power supply, or know where to find one, perhaps with some sophisticated filtering, if that would improve the sound in any way.

    Do you think a few Volts over the target, could pose a problem that needs adjustment with a resistor in series, or isn't that critical, you think?

    BR
    Roland

  7. #7
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    Re: Re: Re: Power supply for class D amps

    Originally posted by pangea
    Do you by any chance have some drawings on a good power supply, or know where to find one, perhaps with some sophisticated filtering, if that would improve the sound in any way.
    Hello,

    You will of course need a good transformer, good bridges (single or twin) and capacitors!

    It is not because you will use the best of the best that the amplifier will sound good.

    As some of you know, I am working on a studio amplifier for more than 2 years now and it is still on the bench.

    What I can say:

    The way the transformer is winded changes the sound quality (more or less shinny, lack of mids and low mids).

    Same for the capacitors from one brand to another, once again you will have a different sounding amplifier.

    Same for the bridges.

    BTW I honestly doubt that a class D amplifier will sound as good as a class A or AB amplifier.

    I know this will not help you.

    Unless you want to build an amplifier by your own, why don’t you look for a ready to use amplifier (ask ALLBA to lend you one from my own, hope you will enjoy it as much as ALLBA does!).

  8. #8
    Senior Member pangea's Avatar
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    PSS amps

    Hi Yuri!

    Thanks again for your kind offer, but I simply don't have that kind of money to spend. (Prices starting at 1200$)
    Borrowing one of your amps, will only make it very hard for me to part from it when returning it, I'm sure.

    I would love to have a few of your amps, as I'm sure they are absolutely awesome, but paying twelve hundred $ for two channels, has to be compared to what I will get if I spend the same amount on a DIY project, using for instance the new Hypex class D blocks and building my own power supply.
    The DIY project will set me up with, three 200W 8 Ohm 400W 4 Ohm channels for the 2215's and the 2225's, as well as four 100W 8 Ohm channels for the mids and highs, all drivers active.

    Since my financial capabilities are quite restricted I really have to try to squeeze as much as possible out every single buck at all times. This is unfortunately the only way I can afford this hobby of mine.

    BR
    Roland

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    Re: PSS amps

    Originally posted by pangea
    ... but I simply don't have that kind of money to spend. (Prices starting at 1200$)
    Where do have this price?

    Witch model are you talking about?

    Please let me know as I do know the export prices but I am not aware of all retail prices in each country...

  10. #10
    Senior Member pangea's Avatar
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    Re: Re: PSS amps

    Originally posted by PSS AUDIO
    Where do have this price?

    Witch model are you talking about?

    Please let me know as I do know the export prices but I am not aware of all retail prices in each country...
    Hi Yuri!

    I was referring to the PSS600, 2 x 300 W, 4 Ohm RMS, which cost 8900 SEK VAT included and that translates roughly into 1200 USD or 970 Euro.

    BR
    Roland

  11. #11
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    Re: Re: Re: PSS amps

    Originally posted by pangea
    I was referring to the PSS600, 2 x 300 W, 4 Ohm RMS, which cost 8900 SEK VAT included and that translates roughly into 1200 USD or 970 Euro.
    Gorgeous!

    What is the VAT rate in Sweden?

    Compared to other brands, how expensive is a PSS amplifier?

    In a word, from what you know and feel, what do you think about the marketing of PSS amplifiers in Sweden?

    In France, with a 19.6% VAT, a PSS600 amplifier is sold less than 600 Euro.

  12. #12
    Senior Member pangea's Avatar
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    Re: Re: Re: Re: PSS amps

    Originally posted by PSS AUDIO
    Gorgeous!

    What is the VAT rate in Sweden?

    Compared to other brands, how expensive is a PSS amplifier?

    In a word, from what you know and feel, what do you think about the marketing of PSS amplifiers in Sweden?

    In France, with a 19.6% VAT, a PSS600 amplifier is sold less than 600 Euro.
    Hi Yuri!

    Tax in Sweden is 25%.

    In comparison with other amps sold elswhere, the PSS amps are quite expensive.

    The QSC RMX 850, 2 x 300W 4 Ohm, is sold for under 6000 SEK (650 Euro) elswhere.
    The Samson S700, 2 x 350W 4 Ohm, is also sold under 6000 SEK.
    The Samson F800, 2 x 400W 4 Ohm, is sold for 5500 SEK (600 Euro).
    The Omnitronic P500, 2 x 504W 4 Ohm, is sold for 5000 SEK (540 Euro).

    What marketing?
    I can't remember ever having seen any ads about PSS in Sweden.

    If I where you, I would try to find a new representative, like:

    Ljudia AB
    Box 221
    S-542 23 MARIESTAD

    HiFikit, Elektronic AB
    Box 23098
    104 35 STOCKHOLM

    Or simply sell them via the Internet to Swedish customers, Like Musikhaus Thomann Cyberstore, in Germany does, placing some (English) ads in assorted publications and delivering from a central warehouse. That way I think they might be sold for under 500 Euro in large numbers, with a healthy margin still intact.

    BR
    Roland

  13. #13
    Senior Member pangea's Avatar
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    About PSS amps

    Hi Yuri!

    I forgot, I would also offer the customers low shipping and handling costs, as well as a special/extended warranty deal, like including one prepaid free shipment back to factory, within 5 years, to make it real attractive and simple for the customer.

    BR
    Roland

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    Re: Re: Re: Re: Re: PSS amps

    Originally posted by pangea
    In comparison with other amps sold elswhere, the PSS amps are quite expensive.
    Very interesting!

    Do you know that ALLBA sells about 100 PSS amplifiers a year in Sweden... It seems to be quite pretty for the number of habitants!

    They are enthusiast with them, as their customers!

    And they give a better ranking than all the brands you just spoke about.

  15. #15
    Senior Member pangea's Avatar
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    Re: Re: Re: Re: Re: Re: PSS amps

    Originally posted by PSS AUDIO
    Very interesting!

    Do you know that ALLBA sells about 100 PSS amplifiers a year in Sweden... It seems to be quite pretty for the number of habitants!

    They are enthusiast with them, as their customers!

    And they give a better ranking than all the brands you just spoke about.
    Hi Yuri!

    And I'm sure the numbers could be higher if they were better known in Sweden and if the price was more competitive.

    Also, I'm sure that some amps are bought from abroad already, with that kind of differences in price.

    It would be interesting to know how many pro-amps Ljudia sell each year. I'm sure it's much more than a hundred items.

    BR
    Roland

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