I was going to remove the analogue regs completely as I won't be using opamps in the output stage; just audio transformers.
The analogue part of the DAC uses the 5V supply right? I'm going to try separating the analogue and digital pins of the DAC though as per Ray's instructions.
Ordered that 50VA for the servo
Thanks guys!
The analogue part of the DAC uses the 5V supply right? I'm going to try separating the analogue and digital pins of the DAC though as per Ray's instructions.
Ordered that 50VA for the servo
Thanks guys!
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+1. I also use independent 5V regulated supplies to the sero; the decoder and the DAC. Total 6 low noise regulators are used.
I have a separate Nuvotem encapsulated transformer for each 5v chip, with separate secondaries for analogue and digital. I don't have special low noise regs yet; just 'off piste' LM317s with green LEDs. However, in addition to the isolated supply, each regulator has a 22,000uF Mundorf before and a 470uF Black Gate FK (analogue) or NX (digital) after, right at the load. Despite chronic itchy finger syndrome up til now, I'm pretty happy with this arrangement.
Edit: I actually have the DAC channels broken out separately like this, so the DAC has 2 transformers, 4 22,000uF smoothers, 4 regs, etc.
Edit: I actually have the DAC channels broken out separately like this, so the DAC has 2 transformers, 4 22,000uF smoothers, 4 regs, etc.
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Haha I guess that's why you have three CD player cases to house all of this!
Hello,
I've fried my sm5872bs ... anybody here having a spare for sale ?
Why not search eBay for one.
Sorry Ben; confusing you with another member there!
At some stage, does having too many trannies close to each other (and close to noisy IC chips) offset the benefits of dedicated supplies to each chip?
An externally hosted image should be here but it was not working when we last tested it.
Very cool! Do those output transformers properly sum the output of the DAC?
Hey, no fair, your transformer mounting bracket is copper plated. Mine isn't. I always thought that was an oversight.
I don't know for sure about the separate transformers causing interference, but I have no reason to think that they do. There's no audible difference having them inside the case that I can tell.
Hey, no fair, your transformer mounting bracket is copper plated. Mine isn't. I always thought that was an oversight.
I don't know for sure about the separate transformers causing interference, but I have no reason to think that they do. There's no audible difference having them inside the case that I can tell.
Yup straight from DAC out to RCA. They sum the signals, convert from PWM to analogue, remove quantisation noise and separate digital and analogue ground loops in one go!
The transformer and chassis are stolen from my old CD6000KI. All the regs and clock etc are from that player that I modded years ago. I went for a cd67 recently because it only uses one DAC chip where as the 6000 uses two of them, so I always had to use a pair of opamps to sum the signals once then the transformers to sum them again. I always hated that I was forced to keep opamps in the output signal path
They also block DC too...forgot that one ha
Mine are from Audio Consulting (via Audiocom) pure silver wire wound 1:1 but you can buy cheaper pairs from Sowter in the UK or Lundahl I believe.
Here's a useful page from the Sowter website:
SOWTER DAC I/V TRANSFORMERS
The DAC in the CD63/67/6000 is 'voltage out' so you don't need a resistor between signal and ground on the RCA sockets, and you don't need amplification from the turns ratio (hence you want a 1:1 like the Sowter 3575 - http://www.sowter.co.uk/specs/3575.htm).
Thanks for the positive feedback Ray! Its entirely thanks to you that I thought of this CD67 / 6000KI hybrid project in the first place!
I still have my toroid TX for the servo to install and bitumen damping material for the chassis and lid and haven't hooked up these output TXs yet (just have the HDAMs bypassed with stock opamps and filter). Even with no damping and the PCBs not even screwed down, the sound quality at this point is better than my modded CD6000KI ever was! I can hear details of instruments I never even knew were there in some very familiar CDs of mine. All that clever decoupling of noise from each chip certainly works wonders!
Very excited about the servo TX and damping since others have mentioned this is the biggest improvement they have made!
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Hi Ray,
I finally got around to having a go at this. It seems to work (the relay switches when there is sound), but with an issue: when the CD player powers down, the relay loses its ability to mute and I get the pop and crackle I was hoping a muting relay would block.
I haven't bypassed the HDAM on my system, but have some RCA sockets waiting. Is there a way of wiring this up through the relay that will cut the signal to the RCA sockets and stopping the noise when the CD player is powered down? That was my main goal when using the relay.
Best,
Peter