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Audio Action - DIY Night


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Audio Action - DIY Night

8pm Wednesday 12th December, visitors welcome.

Willis Room, City of Whitehorse Offices
Maroondah Highway (Whitehorse Road), Nunawading
Melway Map 48 Ref G9
Contact: 9437 1249

 

December's meeting is the Audio Action DIY night where those members who have built their own equipment can audition it to the club. Building your own equipment may seem daunting but there are many plans and kits available for sale on eBay and dedicated audio sites such as www.DIYaudiostore.com

 

Within the Melbourne Audio Club we have a tremendous resource of knowledge and experience, particularly when it comes to DIY. Speak to any of the Audio Action group if you are interested in doing your own project.

 

This year we are particularly lucky to have three sets of DIY speakers, all completely different, yet each with their own appeal. They are partnered with a range of amplifiers that suit each speaker's character. Source material on the night will be a mix of vinyl and CD as we have two DIY phono preamps on offer.

 

  • System #1

    LP12 Turntable with Grado MM cartridge
    Paul Seymour's "Meishu" valve phono preamp
    Alistair Webb's Class-D 70W TPA3251 based Chip Amp

     

Audio Action group's refurbished Bailey transmission line speakers Paul has been building and experimenting with valve equipment for many years, and his "Meishu" phono preamp should provide some necessary warmth to balance the solid-state amp used, Alistair's TPA3251 Class-D chip amp. This outputs up to 70W into 8 ohms, which should provide plenty of drive for the Audio Action group's refurbished pair of Bailey transmission line speakers.

 

These were donated to the group by Bob earlier in the year and we have spent the past 6 months restoring and upgrading these 40 year old KEF based speakers. Ron and Stephen have worked their magic on the crossovers and Noel has graciously provided his workshop over the winter months as a home for these large speakers as we refurbished the cabinets and drivers.

 

  • System #2

    LP12 Turntable with Grado MM cartridge
    MAC Phono Preamp with upgraded PSU
    Dave's Preamp Alistair's "Burning MoFo" Class-A amplifier
    Mark's "VoXUno - 12P" full-range speakers

     

The MAC phono preamp has been auditioned by many club members over the past year. Last year's failure to launch was a lesson in not showing DIY equipment before the gremlins have been well and truly exterminated! The unit has had a number of upgrades over the past year, which have led to a subtle but noticeable improvement in sound staging and clarity.

 

Amplification is provided by Alistair's "Burning MoFo" - the marriage of two Nelson Pass inspired circuits in the one amp! A 'Burning Amp BA3' complementary JFET front-end feeds a 'MoFo' output stage. This is an unconventional Class-A design in that it uses a large choke to increase the output power and efficiency well beyond what would normally be achieved. It produces about 15 watts of glorious Class-A power into 8 ohms.

 

The speakers are Mark's "VoXUno - 12P" with Markaudio fullrange drivers. They use a single 8" Markaudio 12P full-range driver to cover the entire audio spectrum. They may not have super-deep bass or the airy highs of titanium tweeters but they do cover an extreme range and cover it well. What they do better than most multi-driver speaker is image perfectly. They produce a believable well scaled image and with the right amp will produce 40hZ. At 92db of efficiency they work well with low power amps.

 

The boxes are about 90ltrs and are built to the design provided by Markaudio. They are a vented design, with the port coming into play below 40 Hz. The boxes are braced and dampened with bitumanised heavy Al foil and Dacron. There is no crossover, the full-range driver connects directly to the amplifier.

 

  • System #3

    All Dave's gear!
    Audio Aero La Fontaine CD/SACD player/preamp/DAC as the source.
    OAD (Open Audio Designs by Jon DeSensi) solid state amplifier.
    3-way open-baffle speakers with Focal drivers

     

Dave's DIY open baffle loudspeakers comprise Focal bass, mid and tweeters and Response 12" sub drivers. There are two subs on each panel and the Focal drivers are reclaimed from a pair of Focal In Wall speakers.

 

Alistair Webb

 

Note: As in previous years each system will be allotted 30 minutes. Each presenter will get to explain and demonstrate their gear with some music. This should see us finish up well before 10pm, allowing the members on the night to hear all the systems. It should be a great night so come and support your club.

 

Nick Karayanis , Program Co-ordinator

          

Ken Tripp
Wise and Wonderful Webmaster
Melbourne Audio Club, Inc.

http://www.melbourneaudioclub.org.au

Edited by ArthurDent
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