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Using the AD844 as an I/V
Using the AD844 as an I/V
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Old 13th July 2016, 10:39 AM   #1741
esgigt is offline esgigt  Netherlands
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Join Date: Dec 2013
Quote:
Originally Posted by Torchwood421 View Post
Hi esgigt, Keep us posted on your progress.
So I will.

Yesterday I finally found the time to perform surgery on my CD player, a CD880.

Among the NE5532 opamps I exchanged for the AD826's (and sockets!) also other work was done. Decoupling by chokes instead of resistors, increased caps (Vrefs of the TDA1541A S1 now have 3300uf muse gold caps) and a DEM-mod (thanks to the excellent thread by John of ECdesigns).

I choose the approach of listening, implementing a single mod and listening again and kept record of my findings.

Work sequence:
1) SAA7220 powersupply modded. Cleaned up some mess and relaxed the soundimage somewhat.
2) DEM-mod. Added more subtility and detail to the soundimage.
3) Power supply TDA. Losing some of the harshness and a more coherent sound image.
4) AD826. Game changer... soundimage now is dynamic, relaxed and "analogue", no harshness at all.
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Old 13th July 2016, 03:15 PM   #1742
Torchwood421 is offline Torchwood421  United States
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Join Date: Jul 2011
Location: Prior Lake, MN
Thumbs up CD upgrades...

Quote:
Originally Posted by esgigt View Post
So I will.

Yesterday I finally found the time to perform surgery on my CD player, a CD880.

Among the NE5532 opamps I exchanged for the AD826's (and sockets!) also other work was done. Decoupling by chokes instead of resistors, increased caps (Vrefs of the TDA1541A S1 now have 3300uf muse gold caps) and a DEM-mod (thanks to the excellent thread by John of ECdesigns).

I choose the approach of listening, implementing a single mod and listening again and kept record of my findings.

Work sequence:
1) SAA7220 powersupply modded. Cleaned up some mess and relaxed the soundimage somewhat.
2) DEM-mod. Added more subtility and detail to the soundimage.
3) Power supply TDA. Losing some of the harshness and a more coherent sound image.
4) AD826. Game changer... soundimage now is dynamic, relaxed and "analogue", no harshness at all.
Hi esgigt, That is excellent. Make a change and then a listen. That is what I do as well. John ECDesign's has done use all a great service. I use his decoupling method. John actually moved away from locking the DEM to the bitclock. Myself I use 120 pF between pin 16 and 17. That puts the DEM at 705 Khz, and that will sync up with the bitclock. However there is nothing wrong with his earlier DEM mod. Power supply is critical because the SAA7220 is actually rather poor. Sadly the only game in town in a CD player. AD826's are an excellent choice. I'd let things kind of settle in before making any other changes. Enjoy!
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Old 13th July 2016, 03:49 PM   #1743
esgigt is offline esgigt  Netherlands
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Quote:
Originally Posted by Torchwood421 View Post
I'd let things kind of settle in before making any other changes. Enjoy!
That's the plan, Torchwood... later the TWTMC will join the setup.. but I'll have to make some arrangements for it's power supply. Also the mute-transistors will go, but I didn't like to disassemble the machine yet, otherwise I can't reach them.

Had to demolish the 5532's too because they were hard to desolder.

In the meantime i'll have to solve a grounding hick-up in the pre-amp
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Old 13th July 2016, 06:37 PM   #1744
Torchwood421 is offline Torchwood421  United States
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Join Date: Jul 2011
Location: Prior Lake, MN
Talking TWTMC?

Quote:
Originally Posted by esgigt View Post
That's the plan, Torchwood... later the TWTMC will join the setup.. but I'll have to make some arrangements for it's power supply. Also the mute-transistors will go, but I didn't like to disassemble the machine yet, otherwise I can't reach them.

Had to demolish the 5532's too because they were hard to desolder.

In the meantime i'll have to solve a grounding hick-up in the pre-amp
TWTMC? Yes... The easy way is to clip the op amps out and unsolder each pin one at a time, that will prevent the traces from lifting as well. A 5532 isn't by today's standards state of the art so don't sweat that. Sorry to hear about the grounding issue. I have been there.
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Old 14th July 2016, 08:41 AM   #1745
didiet78 is offline didiet78  Indonesia
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Join Date: Mar 2007
Location: Bandung
SD Card Wav Player + AD1860 + DDNF
Attached Images
File Type: jpg Wave DDNF.jpg (329.7 KB, 212 views)
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Usb I2S + AK4490 / WM8805+ESS9023 / SDHC Card I2S audio player + AD1860
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Old 14th July 2016, 08:51 AM   #1746
sumotan is offline sumotan  Indonesia
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Join Date: Oct 2013
Nice Didiet
May I ask is the SD card player a diy effort ?

Thks
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Old 14th July 2016, 09:03 AM   #1747
didiet78 is offline didiet78  Indonesia
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Join Date: Mar 2007
Location: Bandung
Quote:
Originally Posted by Jaffrie View Post
Nice Didiet
May I ask is the SD card player a diy effort ?

Thks
Yes, it diy. Its based on Koon player. He make a thread about it.
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Old 14th July 2016, 06:24 PM   #1748
Torchwood421 is offline Torchwood421  United States
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Join Date: Jul 2011
Location: Prior Lake, MN
Thumbs up Very nice...

Quote:
Originally Posted by didiet78 View Post
SD Card Wav Player + AD1860 + DDNF
Something I should look into as well. SD card storage is rather interesting. Thanks for posting your player. Nice work!
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Old 15th July 2016, 03:05 AM   #1749
Torchwood421 is offline Torchwood421  United States
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Thumbs up Found it...

http://www.diyaudio.com/forums/digit...scillator.html A low jitter clock.
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Old 16th July 2016, 10:57 AM   #1750
giro1991 is offline giro1991  Scotland
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Eh, I think the point was missed completely.
When transistor is overdriven, the wave clips (approaches squarewaves).
I presume VFB OpAmps do this. What about current mirror section on 844 OPAmps though? Does it show 'gradual' non linear distortion when driven to extreme, similar to some certain tubes do? Apologies I was not clear enough earlier in my question.
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