The HiFi chat, build and modification thread!

[apache]

Still have my Akai 4000D sitting waiting for finishing. Had one years ago and it was lovely, in the same way it's lovely to watch vinyl spinning even though you know it's not quite right...

 

[legrandefromage]

Trouble is with 'claims' about frequency responses is that you have no idea what it was mastered/ authored at. It has to be released into the wild as a hi resolution recording. Most of what is available is compressed with a piss poor top end.

Am looking forward to hi resolution stuff. It will work perfectly well with old amps but I'm not sure about speakers as the crossover allows roll offs at around 22kHz. Headphones can go way higher which seems to be the market aim with this stuff.

 

[apache]

As someone who struggles to hear above 14kHz (thank god for tone controls!), I can state that there is plenty of information in midrange and lower to enable one to pass judgement on sound quality

 

[grumpycommuter]

As someone who struggles to hear above 14kHz (thank god for tone controls!), I can state that there is plenty of information in midrange and lower to enable one to pass judgement on sound quality

Pardon

New laser fitted by our trusty 'site' electrician who also did it for free and the CD63 is now silky smooth. And even better, it is heading down to Dr Apache tomorrow for a spot of re-engineering. I genuinely cannot wait....

 

[legrandefromage]

Re:

Found one of these down the tip

Sadly not as good as the picture but exquisite all the same. CDM mechanism too!

 

[apache]

Good for eBay only I would suggest. Why does my tip never find me anything??

 

[apache]

Karl's CD player. As standard...

The CPU treated with proprietry EMC absorber. Reduces the amount of processor noise radiating into the rest of the circuitry.

The DAC clock crystal can grounded and glued to the board. Crystals can be microphonic - this one isn't anymore.

The DAC clock components relocated to reduce track lengths and parasitic reactances, should produce a useful reduction in jitter and increase clock accuracy.

All those discrete components make up Marantz' HDAM circuit, which is basically a marketing exercise because audiophiles think discretes are better than a laser trimmed high accuracy low drift op-amp. No telling some folk. Anyway, best we change the old I-V converter op-amps for arguably the best audio specific op-amp on the market, the LM4562 (it's electrically identical to it's rebranded LME brother), dispense with all that excess discrete junk and simplify the analogue chain drastically!

HDAM power removed, and signal from output of I-V converter taken directly to O/P sockets. Have left the HDAM circuitry on the board, it's completely isolated though.

Other stuff done - small EMC filters fitted in power lines to op-amps, larger reservoir caps fitted for analogue power, headphone amp isolated.

Currently hooked up in my system making some very nice noises indeed. Very immediate, full of attack and life. It rocks!

 

[grumpycommuter]

Re:

Oooooooooo i may have to go for a stiff walk

 

[legrandefromage]

Just picked one of these up(well, not quite the same, mine's got rotary pitch control and a fader) . "It's dead" is the fault. Sure enough, doesn't power up so I'm hoping it's something very simple like an internal fuse. Will get it apart tonight and have a look. Tell you something though, it's built like a bloody battleship!

guess what I've got...

Doesnt read CD's yet though.

 

[apache]

Re:

Mine doesn't read cds either. Impossible to get circuit diagrams for the SL-P1200 'B' variant it seems.

If you decide to get shut, might take it off you if it has a different fault to mine! Would love to get it going.