i have some question do you guys encounter CD63 got humming sound bcoz currently i got 2 CD63 another one is stock without modding when i play some song i put pause than i put the amp volume to maximum found the humming is quite loud compare to another stock CD63 pls help thanks
what iam done :
- remove the 4 transistor and some resistor for transistor
- bypass HDAM
- put discrete opamp and clock
what iam done :
- remove the 4 transistor and some resistor for transistor
- bypass HDAM
- put discrete opamp and clock
RCruz said:
In the Cap Comparison article, (http://gboers.xs4all.nl/daisy/home/g3/139/measure/capacitor-comparison.html), The author asks if his method is correct or not.
One thing that stood out to me, was that his frequency sweep stopped at 20kHz and while the Mundorf cap showed an obvious improvement against the others, what was happening above 20kHz?
In the TI article, ( http://focus.ti.com/lit/an/sloa069/sloa069.pdf ) the sweep goes right into RF frequencies. The initial parts of the graphs show the same form as with the electrolytics but also show what is happening higher up. A lot of RF energy gets by !!
It stands to reason, therefore, that in digital power suppies, where RF noise is of greater interest, paralleling caps of different values will spread the null points which, when combined, will reduce the RF noise over a wider spectrum. Also certain cap types are better here eg. Oscon.
When it comes to audio power supplies, yes, with caps like the Mundorf or Black Gate, you can reduce noise above about 5Khz.
But what can be done to reduce noise lower down the audio range????
Has anyone tried the "Never-Connected" type of psu?
or the shunt type which nulls out the 50/100hz residual?
Would a switch mode psu be 'better' as most of the noise should be out of the audio range?
Andy
For info :- BHC Slit Foil / T-Cap page
http://www.bhc.co.uk/slit_foil.htm
CD 67MKII SE
Hi,
I own a CD67MKII SE for ages now. Did no mods at all. When playing back a CD-R (YES a recordable!
), I usually have a problem when skipping to another song. The cd stops playing and goes back to its initial position (like when you just loaded a cd).
Maybe the question is asked before in the forum, but it's quite a big one.
Does anybody have an idea what causes this problem to occur?
Many thanks for you input on this!
Regards
Kuip
Hi,
I own a CD67MKII SE for ages now. Did no mods at all. When playing back a CD-R (YES a recordable!
), I usually have a problem when skipping to another song. The cd stops playing and goes back to its initial position (like when you just loaded a cd).Maybe the question is asked before in the forum, but it's quite a big one.
Does anybody have an idea what causes this problem to occur?
Many thanks for you input on this!
Regards
Kuip
rowemeister said:
But leaves a lot of questions too. Like what is the nichicon cap he's testing and why wasn't a "known good" industrial cap like a Pana FC/FM or Rubycon ZA or OSCON tested?
There is some interesting test data on a range of caps - including a BG standard - here:
http://diyparadise.com/web/index.php?option=com_content&task=view&id=37&Itemid=27
The comments on the second page are well worth reading.
Look for dry solder points.L700 said:
I use multimeter to test my grounding no problem
Nevertheless, we all agree that after removing output mute transistors, it is possible to hear a buzzing when the volume is full on and no music playing.
I practically cured this by replacing the output opamps by the mighty DOS.
I still can hear some hiss at full volume but now is very uniform and smooth. (The noise floor from most vinyl is much higher and still admissible)
You can make it better by using schottky diodes and better regs in the analog psu.
If it really irritates you, put the mutting transistors back on.
Ricardo