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Whither Next for RJM Audio?

Posted 26th January 2012 at 01:22 AM by rjm
Updated 1st February 2012 at 09:20 AM by rjm

On the occasion of selling the 100th and last VSPS Stereo Kit, it's time to consider what direction(s) RJM Audio will take over the next little while.

A. A minor revision of the stereo VSPS board is planned. Just a point release to address feedback I received over the last couple of years. Point release on current boards (Phonoclone 3, VSPS 300, Sapphire) expected when I deplete existing stock and have to re-order.

B. Since my circuit designs are essentially modular (the voltage regulation of the Sapphire headphone amp could be used with the Phonoclone, the output stage of the Sapphire could be detached and used on the output buffer on the VSPS...) I'm going to work on bringing that vision to a concrete reality by developing "swap-in swap-out" circuit boards... like those toys where you can change out the head, body and legs of a character to make many variations.
  1. X-reg board
  2. Zener reg board
  3. basic op amp gain block board
  4. VSPS and Phonoclone boards with no voltage regulation.
  5. Diamond buffer board. (configurable for headphone, preamp, or line buffer use)
  6. Power buffer board. Unity gain transistor output stage for power amplifier. More of a long term project, concept only at this point.

All the boards will be standardized as much as humanly possible, same size and mounting, using common resistor values, etc, so a minimum number of different parts are required, and if you collect the parts for one project, you can re-use most of them on another one.


After thinking it over, the fundamental problem with the approach is the more general purpose and granular you make the modules, the bigger and more complicated the total circuit becomes: instead of one circuit board and four standoffs, you have four, and a dozen or more chassis holes to drill and a similar number of extra interconnects.

It makes more sense, I think, it to develop the modular circuit blocks, but put them together in common combinations when making a circuit board.
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  1. Old Comment
    dimkasta's Avatar
    The "lego" approach on pcbs is nice for experimenting. Which will make it more appealing for diy members who do this mostly for the sport and not just to build something and leave it.
    Especially since the boards are with standard/smallish pads that do not allow multiple recapping.
    Interconnects can be as small as a 1cm jumper with the boards side by side. Or we can stack them one on top of the other.
    And standoffs can be eliminated by using something like 1 central instead of 4 corner ones on small boards.
    Just thinking here....
    I m in the point of wanting to try different capacitors and regulators on vsps and it is a bit awkward
    Posted 29th March 2012 at 07:19 PM by dimkasta dimkasta is offline
  2. Old Comment
    I'm probably alone in this, but I'd like to see the API-2520/JE990 foot print used for the opamps.

    It could be optional as the standard DIP 8, single footprint could be used inside the 2520/990 footprint. But dual's can't be done that way.

    The reason - fairly nice opamps like Sam Groner's SGA-SOA-2 can be had in kits form for less than $20. And provide higher Class-A output drive levels.

    Companies like Whistle Rock Audio sell DIP to DOA adapters at a fair price with both DIP and SMD footprints. So if one wanted a 5534 with compensation, there's a place on the DOA adapter for the cap - no change to the main circuit board itself.

    Regardless, I do like the idea of a modular approach.
    Posted 7th September 2012 at 10:22 PM by disfunctionalshadow disfunctionalshadow is offline
  3. Old Comment
    I like the idea of phono boards without the regulator.

    How about a modular pre-amp? Phonoclone, Buffer (gainstage optional) Headphone amp, DAC and so on..All powered from the same PSU Mddule... I would build that
    Posted 13th August 2013 at 05:34 PM by MagnumOpus MagnumOpus is offline
  4. Old Comment
    Originally Posted by MagnumOpus View Comment
    I like the idea of phono boards without the regulator.

    How about a modular pre-amp? Phonoclone, Buffer (gainstage optional) Headphone amp, DAC and so on..All powered from the same PSU Mddule... I would build that
    Also, since you are a 47labs man, a gainclone to rival AudioSector, BrianGT and MyRef would be cool
    Posted 18th March 2014 at 07:21 PM by MagnumOpus MagnumOpus is offline

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