Musical Fidelity A5CD

[betty boop]

As part of the A5 range musical fidelity brought out the A5CD player. Cosmetically in build a match for the A5 integrated and pre-pwr. It was however a limited edition release ... due to a couple of little factors that made it unique....in the the muvista 6112 mil spec valves....these reside in the output stage of the player (mf have a long tradition of using valves on the output stage of the dacs and players. These in particular are extreme long life valves and quoted in this configuration to last 100,000 hours or essentially fitted "for life"

 

spec on the 6112 are here,

http://frank.pocnet.net/sheets/137/6/6112.pdf

 

and yep its mil specs mean it will handle 450G's impact, 1000G 's uniform acceleration, 220 DegC and an altitude of 60,000 ft !  

 

as per the spec "The premium subminiature type 6112 is a high mu double triode having separate cathode connections for each section, it is intended primarily for use in low level audio circuits, and is designed to provide dependable service under conditions of severe shock, vibration and high temperature and altitude. The 6112 is manufactured and inspected to meet the applicable MIL-E-1 specification for reliable operation"

 

so yeah valve failure certainly not something to be bothered with

 

anyways a few pics

 

Front and back,

 

 

 

 

 

under the lid,

 

 

and with shield over the dac section removed,

 

close up of the dac and analog output stage,

 

and there can see the couple of 6112 valves... one for each channel

[Addicted to music]

Nice pics Al,

 

if you can kindly identify the markings of IC101-103 and the type of BB (Brown Burr) D/A converter would be great

Edited June 15, 2014 by pchan

[firefly0071]

Valves look small

[betty boop]

Nice pics Al,

 

if you can kindly identify the markings of IC101-103 and the type of BB (Brown Burr) D/A converter would be great

 

theres 6 off them, would appear 3 per channel ? IC 101-103 and 201-203

 

marking on them,

 

54A8K1M

NE5532AP

 

these I believe

http://datasheet.octopart.com/NE5532AP-Texas-Instruments-datasheet-150397.pdf

 

 

re the dac used its a 24 bit delta-sigma DAC, 8X oversampling and 192KHz up sampling and is the burr brown 1792 

 

http://www.ti.com/lit/ds/symlink/pcm1792.pdf

 

Valves look small

 

yep as I quoted from the spec I linked to from sylvania "The premium subminiature type 6112 is a high mu double triode….."

[Addicted to music]

FWIW,

 

there's nothing wrong with the NE5532 great opamp, manufacturers like Rotel and the like have been using them for years.

 

My 1st DAC was a Gigaworks $70US that consists of a BB 1798 which is pin compatible to the 1794.  The 1798 produces a rich tones and grains in the sound that the ESS or the WM just cannot match, it inspire me to get into DACs like Bhobba.        I'd like to hear a 1794 one day as this is regarded as the top spec of BB D/A without going to 32bits.  To have these in place + valves that provide an "musical organic" presentation...its no wonder you like MF gear...

[Darren69]

There's an A5CD currently for sale at Len Wallis, second hand for under $2k.