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Old 20th November 2012, 11:23 PM   #18771
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Hi to all:-)

From another tread I read a post from Ergo where he stated that there is a lot of crap outside the audio band in the output of the CD67 DACs. I remember to measure a PWM signal in the DAC with five Volts amplitude and five MegaHertz, which arrive at the operational amplifier (OK.... an integrated Op Amp or a HDAM but still an operational amplifier) after a simple RC filter, which does not eliminate the 5 MHz signal.

I do not like the idea of having this .3 Volt (after the RC) in the differential inputs..... with the delays of the circuit and the high gain of the Op Amps there will be a lot of inter modulation.

Does anyone has a good approach for this?

Thanks
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Old 21st November 2012, 05:44 AM   #18772
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Originally Posted by bull041161 View Post
Hi have tried a few and i think the screened ha ones sound the best
I noticed there is a modded CD63 in the UK eBay and may be you can consider this rather than doing all the major mods by your own. You can change other better caps if you wish at a later stage.
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Old 21st November 2012, 07:11 AM   #18773
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Default re op amps

[UOTE=bull041161;3249722]Hi have tried a few and i think the screened ha ones sound the best[/QUOTE]

For some reason the metal cased ones sound better the specs are the same tho,
they are free off the samples program @ national.
cheers guys alan
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Old 21st November 2012, 08:52 AM   #18774
Chivvyp is offline Chivvyp  United Kingdom
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Originally Posted by higlander View Post
I noticed there is a modded CD63 in the UK eBay and may be you can consider this rather than doing all the major mods by your own. You can change other better caps if you wish at a later stage.
Depends who did the modding and how neat they were. I wouldn't recommend anyone making any further changes to some of the machines that I've modded in the past

Pete
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Old 21st November 2012, 10:07 AM   #18775
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Originally Posted by Chivvyp View Post
Depends who did the modding and how neat they were. I wouldn't recommend anyone making any further changes to some of the machines that I've modded in the past

Pete
Basically I agree with you. BUT there is no harm just to swap some of the caps that are of higher quality. Of course more extensive modifications by unskilled hands could do more HARM than GOOD
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Old 21st November 2012, 01:07 PM   #18776
UV101 is offline UV101  England
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Originally Posted by Chivvyp View Post
Depends who did the modding and how neat they were. I wouldn't recommend anyone making any further changes to some of the machines that I've modded in the past

Pete
Lol. Some of my early ones fall into the same category too! Fortunately I've learned from my mistakes and the ones I do now are far far better!!!

That KI on eBay has some of Brent's work, but I'd say looking at it, it's also got some "other" stuff done that's not part of the original upgrade he did.
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Old 21st November 2012, 04:27 PM   #18777
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Originally Posted by UV101 View Post
Lol. Some of my early ones fall into the same category too! Fortunately I've learned from my mistakes and the ones I do now are far far better!!!

That KI on eBay has some of Brent's work, but I'd say looking at it, it's also got some "other" stuff done that's not part of the original upgrade he did.
@UV101: Good observation and I noticed that there is a remark at the end of the description that some of the works were not carried out by Brent
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Old 21st November 2012, 04:56 PM   #18778
UV101 is offline UV101  England
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Didn't notice that comment in the listing.

Looking at it again, I'd say come caps on the board, C2 clock, clock psu and spowers are all Brent's work. The untidy stuff, long wires caps on vero etc are not.

I thinks it's a bit of a liberty claiming a professional upgrade. At the very least it devalues Brent's work.

I list players I've done a couple of times a year and mine look immaculate compared to that!!!! I wonder why there is vero attached to the spowers on for the audio power??????

Assuming the additional work hasn't cocked things up, it will be good. I know of I was asked to look at it, I'd strip the crappy work out and start adding properly on top on Brent's work!!!
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Old 21st November 2012, 05:27 PM   #18779
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Originally Posted by UV101 View Post
Didn't notice that comment in the listing.

Looking at it again, I'd say come caps on the board, C2 clock, clock psu and spowers are all Brent's work. The untidy stuff, long wires caps on vero etc are not.

I thinks it's a bit of a liberty claiming a professional upgrade. At the very least it devalues Brent's work.

I list players I've done a couple of times a year and mine look immaculate compared to that!!!! I wonder why there is vero attached to the spowers on for the audio power??????

Assuming the additional work hasn't cocked things up, it will be good. I know of I was asked to look at it, I'd strip the crappy work out and start adding properly on top on Brent's work!!!
TBH I have no idea on Brent's original upgrade work but from those photos I can agree with you that the layout and wiring could have been done better. Like you I have no idea on the actual use of the vero

My workmanship is not that good when compare with yours but at least I will do my best to make them tidy and good looking which you can judge from some of my uploaded photos
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Old 21st November 2012, 05:56 PM   #18780
UV101 is offline UV101  England
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To be fair, it does look like there are multiple regs on that vero at the front and although its not that tidy, it will be better. Even lots of std 7805's will be better than 1 single one!!! Did this a few years ago in a Philips cd850 mki
I think that's 11 regs on the dac board lol!!
Click the image to open in full size.

I'm not sure about all that screening tho. Why not just connect it to the top layer screen rare than wire all round the player.
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