Marantz CD63 & CD67 mods list - Page 897 - diyAudio
Go Back   Home > Forums > Source & Line > Digital Source

Digital Source Digital Players and Recorders: CD , SACD , Tape, Memory Card, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 3rd February 2008, 02:50 PM   #8961
diyAudio Member
 
Join Date: May 2005
Location: TN
Quote:
Mauro

My observation was not directed to criticyse your fine work.

I am not a professional so I must rely on others experiences before I try anything.

I was just testing the forum to see if anyone had already tryed your technique and maybe get some practical advise.

Folowing your previous comment i understand that with your modd I will get lower noise and not affect the audio response.

I will try this modd and report back to you.
Tanks, Ricardo.
Now I understand your thought....
I had sensed that the reasons for modify could not be well understood.
The important thing is that you know the reason for this change, then is not mandatory that you make the change or you like it, this is a subjective choice.

Good work.

ciao

Mauro
  Reply With Quote
Old 3rd February 2008, 03:24 PM   #8962
RCruz is offline RCruz  Switzerland
diyAudio Member
 
RCruz's Avatar
 
Join Date: Sep 2006
Location: Wallis
Blog Entries: 1
Quote:
Originally posted by mauropenasa

The pass band amplitude, phase, and group delay it's one problem, and my modify have on this one limited impact (some like bessel filter solution), but the problem it's the attenuation over 300khz, some Ineffective in the bessel or "group delay correction" and dozens dB in my propose.
This reflected in low side band harmonics (audio band).
Hi Mauro

I am sorry if I caused some misunderstanding.

Just tryed your mod with a 390pF Silver mica and the sound became more clear without the treble "fizz" that sometimes makes voices and guitars to be edgy.

I find your modd very important.

Can I use a 330pF Silver Mica instead of the polystyrenes you indicated ?

Thank you for the very good advise.

Ricardo
__________________
RC
  Reply With Quote
Old 3rd February 2008, 04:11 PM   #8963
diyAudio Member
 
Join Date: May 2005
Location: TN
Thank you for your test, Ricardo.

I used a 330pF silver mica on my prototype, during the tests.
I think we can also use this type of material, or COG ceramic multilayer...

As shown in the graphs, and also noted Ray, It's better not go beyond 330pF if you do not want to attenuate at 20Khz.

In some cases you can do a value between 220pF and 330pF ...
(Especially if you are using a modified output filter or with not original
shape....)

ciao

Mauro
  Reply With Quote
Old 3rd February 2008, 04:14 PM   #8964
diyAudio Member
 
Join Date: Jul 2005
Location: italy
I think that what happens with this new filter is : before there was only music coming out from source. Bi-dimensional
Now, there is'nt a question about HF or Low, or meddle, really, but what appears are musicians with their instruments.Music happens..
IN the past for this mod i did use cog caps. But i think that polistirene 1% are the abosolutely best choice. But, the important is the final effect on sound, no material. There wil be the time.
  Reply With Quote
Old 3rd February 2008, 05:11 PM   #8965
RCruz is offline RCruz  Switzerland
diyAudio Member
 
RCruz's Avatar
 
Join Date: Sep 2006
Location: Wallis
Blog Entries: 1
Thank you again.

I will settle with polystyrenes and report when the mod is done.

Regards

Ricardo
  Reply With Quote
Old 4th February 2008, 09:14 AM   #8966
diyAudio Member
 
Join Date: Oct 2006
Location: Cleveleys, Lancashire
Morning guys.

I have 2 questions

I bought some 1N4937 fast recovery diodes for the PSU section and they appear to be able to handle big voltages etc (420v RMS and600v peak reverse voltage). Ray advised recently that Schottky's would be better. Would I find much difference using these as they are so over-specced?

Second
I did the filter mods from Ray's list using the Farnell components specified. My SMD soldering isn't that brilliant, and when I was checking the components for dry joints before powering up I noticed that I measured different values of resistance in the circuit to those before soldering. Have I fried the resistors or am I likely to be seeing the influence of other parts of the circuit?

If I've been ham-fisted with the iron (too much heat) what's the best option? Is there a trick with SMD or should I just use normal sized resistors?

Cheers,

Jim
  Reply With Quote
Old 4th February 2008, 09:53 AM   #8967
Thomo is offline Thomo  United Kingdom
diyAudio Member
 
Thomo's Avatar
 
Join Date: Nov 2006
Quote:
Originally posted by jimh0612
Morning guys.


Have I fried the resistors or am I likely to be seeing the influence of other parts of the circuit?

Jim

I would check for broken tracks, solder bridges etc. I would also measure each resistor cos I managed to put them in the wrong places a few times. I have never managed to destroy/damage a resistor with a soldering iron, though I reckon it's possible.

Lee.
__________________
/\/\/\/\/\/\/\/
  Reply With Quote
Old 4th February 2008, 10:05 AM   #8968
diyAudio Member
 
Join Date: Oct 2006
Location: Cleveleys, Lancashire
Yeah that's what I did. Sorry, didn't make it too clear.

I measured each new resistor once I'd soldered it in and the readings were different to the values out of the circuit, before applying the heat.

Thing is, not all the values were different!

I seem to remember reading somewhere about carbon films changing value if overheated but these are the Vishay metal film 1% jobbies.

Any clues??
  Reply With Quote
Old 4th February 2008, 10:11 AM   #8969
diyAudio Member
 
Fidelity Audio's Avatar
 
Join Date: Dec 2005
Location: Doncaster England
How different are the reading?

Brent
  Reply With Quote
Old 4th February 2008, 10:36 AM   #8970
diyAudio Member
 
Join Date: Oct 2006
Location: Cleveleys, Lancashire
Hi Brent

This is embarrassing. When I did the work a couple of weeks ago I'm pretty sure I got a big difference, like 18k became 15k or similar.

Now it's all run in, with the opamps back in and resistors across the opamp pins to bias into Class A, R601....604 read 26.6k which is quite close to the 27k spec, and R607/608 read 17.7k, close to the 18k specified.

Dunno whether it's cos its all settled in or because I've put the opamps back in (I'd taken them out of the sockets for safety!!).

Should have checked before posting!

PS do you have a view on the diode question
Quote:
I bought some 1N4937 fast recovery diodes for the PSU section and they appear to be able to handle big voltages etc (420v RMS and600v peak reverse voltage). Ray advised recently that Schottky's would be better. Would I find much difference using these as they are so over-specced?
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



New To Site? Need Help?

All times are GMT. The time now is 09:10 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2