6h5c said:
Or a noisy tube or FET ??
I would also be tempted to play with the values of the 620pf caps ?? The original circuit has more filtering - a passive filter may also be an answer??
Andy
It's for the analog section.
Absolutely no noise, just music!
Gerald Gessner is selling his modifications, so I am not allowed to publish the exactly circuit.
It is really just a LC filter, 1mH in series with the signal, 10 nF to ground.
And: no output cap!
When I use this player with my DC coupled PL519 amp, then I have absolutely no cap in the signal path after the DAC chip.
Franz
Hi 6h5c,
Sorry - just a couple more questions!
I have just breadboarded my version - not connected to the cd-p yet. Nothing went BANG !!!
Did you use ecc88?
What B+ did you use?
Did you check the current through the FET?
What voltage did you get at the A-K junction.
Andy
Sorry - just a couple more questions!
I have just breadboarded my version - not connected to the cd-p yet. Nothing went BANG !!!
Did you use ecc88?
What B+ did you use?
Did you check the current through the FET?
What voltage did you get at the A-K junction.
Andy
Morning.
Just a little update on my player.
I used sound deadening material on cdp and amp and I am very impressed with the out come. The bass is deeper and the treble is more controlled, I knew it would help but not this much 😀
I have also changed the 7918 for a 7912 for a dimmer display.
I have now finished my reg pcb fully, I now have an Audiocom super reg for the +5V clock reference on the DAC.
Here is a pic of reg and of pcb......dont know where the tube stage will go. lol
Just a little update on my player.
I used sound deadening material on cdp and amp and I am very impressed with the out come. The bass is deeper and the treble is more controlled, I knew it would help but not this much 😀
I have also changed the 7918 for a 7912 for a dimmer display.
I have now finished my reg pcb fully, I now have an Audiocom super reg for the +5V clock reference on the DAC.
Here is a pic of reg and of pcb......dont know where the tube stage will go. lol
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
I have just taken off the bottom plate of the KI and bonded it with Aluminium paste (used to repair gearboxes etc). I wont come off now. lol
I did this has I felt it was not making the best contact across the whole chassis as it could so damping was suffering.
I did this has I felt it was not making the best contact across the whole chassis as it could so damping was suffering.
rowemeister said:
Hi.
One thing I noticed, about my '63SE, was that the bottom plate when hit really rattled!!!!!!!!! I suggested, earlier in the thread, that glueing it down was a good idea also a 12mm mdf 'plate' glued to the underside adds to the chassis damping and stiffness.
Andy
Biskit said:
Mu-metal is the dogs for shielding EMI isn't it? Won't you be better off getting this custom toroid though?
poynton said:
poynton said:
Hi Andy!
Well, I know a bit more now. The remaining noise is not coming from a tube or the FET.
I measured in my CD63 to compare the results, and it too has this noise at the output 😱.
Would you, or somebody else with a scope be so kind to verify this on his player? With the player in stop-mode and no muting circuit and HDAM installed, I can measure allmost 20mVpp.
For Thorstens circuit I used ECC82 on a B+ of about 220V. I didn't have 4k7 around for the PSU series resistor, so I gave each channel a 6k8. I upped the B+ a little so the voltage behind it reaches the desired 190V. The A-K voltage should be about 100V. The voltage over the FET is less than expected, because the DAC's 2,5V DC voltage is divided by the 10k-22k combination. The current through the FET is about 4mA. The FETs are not very equal....
Regards,
Ray.
Franz G said:
Thanks Franz. I think the noise is there, but you'll have to set your volume to max. to hear it. The tubestage's amplification is less, so I noticed it when I turned the volume up.
rowemeister said:
Thanks Brent, for measuring so fast
!Thank goodness i'm not the only one, apparently this is normal for this player.
Regards,
Ray.
Hi Ray,
Just popped in to say this is indeed a cool thread...!!! Plenty of co-operation. And a lot of interested people.....gotta get me an old Marantz somewhere..😉
So is the tube stage all you dreamed of?
Regards,
Bas
Just popped in to say this is indeed a cool thread...!!! Plenty of co-operation. And a lot of interested people.....gotta get me an old Marantz somewhere..😉
So is the tube stage all you dreamed of?
Regards,
Bas
Bas Horneman said:
Hi Bas!
Thanks for the compliments! How's your PP project?
I haven't had time yet to put your chokes in my amp, but PSU designer shows it's a good thing. Been busy with this tubestage...
Maybe next week, I'll let you know what the results are.
I've got a CD63 for you, but it's already modded....
Regards,
Ray.
6h5c said:
Thanks Franz. I think the noise is there, but you'll have to set your volume to max. to hear it. The tubestage's amplification is less, so I noticed it when I turned the volume up.
Thanks Brent, for measuring so fast
Thank goodness i'm not the only one, apparently this is normal for this player.
Regards,
Ray.
HI.
To find the source of the noise and so reduce / eliminate it, you need to measure earlier preferably just after the dac.
Andy
Haven't started yet...maybe tonight
NO hurries mate.
Thanks...but that would be a waste of a great sounding CD player..since I'll would probably end up using it as a transport for my RAKK DAC.