Re: 22mV AC signal at output
Hi Geoff,
I wouldn't worry too much about it. Normally this signal is not visible because it is shunted to GND by the muting transistors (assuming you got rid of them). It's probably residue noise of the D/A-converter, which is normal, or stuff that radiates into your scope probe. Did you use the standard long-GND-wire-with-alligator-clip? Anyway, this noise is very high frequency and probably won't even make it through your interconnect.
Here's an interesting TI/BB article that covers the out-of-band noise.
Regards,
Ray
geoffgjones1 said:
Hi Geoff,
I wouldn't worry too much about it. Normally this signal is not visible because it is shunted to GND by the muting transistors (assuming you got rid of them). It's probably residue noise of the D/A-converter, which is normal, or stuff that radiates into your scope probe. Did you use the standard long-GND-wire-with-alligator-clip? Anyway, this noise is very high frequency and probably won't even make it through your interconnect.
Here's an interesting TI/BB article that covers the out-of-band noise.
Regards,
Ray
Thanks all for your speedy and usefull replies. I will post pics soon of my CD63, I am currently adding an external supply for the opamps (or descrete output stage later) with a 225VA transformer. Currently using a 6VA internally. Will let you know the difference when I have it up and running if you would like to know....
Cheers,
Geoff.
Cheers,
Geoff.
6h5c said:Not adding anything??
Well, in that case: you need at least three separate low-pass filters with separate Tx and regulators to get rid of this noise.
Ray
You should see inside his player now!! More metal in there now...
geoffgjones1 said:
Hi Geoff,
I like the choice of massively oversized transformer. I actually just tried uprating my preamp's tx from 15va to 80va and it only had a subtle effect on sound quality. Positive though (bass mainly) so I will be keeping it in there.
I very much liked the improvements gained from putting my clocks and the DAC on separate large transformers.
Please do keep us informed.
Simon
Yes, keep us posted. I wanted to build a large off-board psu, but my wife won't agree to yet another box
I seem to remember that somebody built a valve output stage (Ray?), does anyone have a schematic? A mate is very interested in getting me to build one, which is good cos I'm skint.
Lee.
I seem to remember that somebody built a valve output stage (Ray?), does anyone have a schematic? A mate is very interested in getting me to build one, which is good cos I'm skint.
Lee.
Yes it will.
On our upgrades we now add a 2X18V 15VA tx for the opamps. And even on the KI the audio is improved somewhat. This is all Naim do with their Snaps, Hi Cap psu. They supply the opamps.
also
I have just fitted a 15VA to run my DAC regs and am upping the clock and decoder txs to 7VA each.
I have a sneaky feeling the total cdp weight may break the 9Kg barrier hehe
Brent
On our upgrades we now add a 2X18V 15VA tx for the opamps. And even on the KI the audio is improved somewhat. This is all Naim do with their Snaps, Hi Cap psu. They supply the opamps.
also
I have just fitted a 15VA to run my DAC regs and am upping the clock and decoder txs to 7VA each.
I have a sneaky feeling the total cdp weight may break the 9Kg barrier hehe
Brent
The main reason why I am going for a large Tx is that it will have a lower output impedence, and be more immune to noise etc.
I will also have room in the box for some pretty serious decoupling caps. Feeding schultz regs (like the AWLSR regs) do depend on low impedence supplies for better performance, so this Tx could just pay dividends.....
However, with the small amount of current pulled off the Tx, regulation will be poorer.
An experiment is clearly required!
If it does not do well in this context, I will use it to power my PM17KI's pre-amp through a couple more regs. So nothing lost at the end of the day
Cheers,
Geoff
I will also have room in the box for some pretty serious decoupling caps. Feeding schultz regs (like the AWLSR regs) do depend on low impedence supplies for better performance, so this Tx could just pay dividends.....
However, with the small amount of current pulled off the Tx, regulation will be poorer.
An experiment is clearly required!
If it does not do well in this context, I will use it to power my PM17KI's pre-amp through a couple more regs. So nothing lost at the end of the day
Cheers,
Geoff
transport cdr whine
hello
is there a consensus opinion on the CDR playing issue on these CD63's?
i've searched this thread and found some interesting explanations - especially the particular type of CDR burnt by a DVDR drive..
My CD63, I've just started to mod, reads the TOC of all discs perfectly but always whines when playing the 1st track of CDR's burnt from a DVDR drive. After a couple of minutes the CDP gives up and stops - error 10 - radial error... I have no problem playing commercial CD's.. and strangely playing tracks further into the CDR is fine - then when going back to track 1 - it's ok??
I'm not able to test a CDR from a CDR drive yet..
I've tweaked the torx screws on the rear of the transport but found no sweet spot yet. I've also cleaned the hardened grease from the rails.. is it possible this player will never play CDR's burnt from DVDR drives?
thanks adrian
hello
is there a consensus opinion on the CDR playing issue on these CD63's?
i've searched this thread and found some interesting explanations - especially the particular type of CDR burnt by a DVDR drive..
My CD63, I've just started to mod, reads the TOC of all discs perfectly but always whines when playing the 1st track of CDR's burnt from a DVDR drive. After a couple of minutes the CDP gives up and stops - error 10 - radial error... I have no problem playing commercial CD's.. and strangely playing tracks further into the CDR is fine - then when going back to track 1 - it's ok??
I'm not able to test a CDR from a CDR drive yet..
I've tweaked the torx screws on the rear of the transport but found no sweet spot yet. I've also cleaned the hardened grease from the rails.. is it possible this player will never play CDR's burnt from DVDR drives?
thanks adrian
Mine seems to work burnt from any drive!
How old is your laser?
Also when the dvd drive burns the discs does it leave visible lines on the disc? Do you burn at the slowest possible speed?
Oh hang on. A whine is often caused by the spindle motor and shaft due to the crap disc clamp. Add a 10p/2p coin, some hot glue or blu tack to the top of the disc clamp as this all adds mass. See if this cures it.
Brent
How old is your laser?
Also when the dvd drive burns the discs does it leave visible lines on the disc? Do you burn at the slowest possible speed?
Oh hang on. A whine is often caused by the spindle motor and shaft due to the crap disc clamp. Add a 10p/2p coin, some hot glue or blu tack to the top of the disc clamp as this all adds mass. See if this cures it.
Brent