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Old 13th February 2002, 02:29 AM   #1
SteveG is offline SteveG  United States
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Default Is it worth moding?

I have an older (1992) technics CD player (SLPG100). It has the one bit MASH converter. Is this worth modifying, even just for the experience? I have taken a peak inside, and the transport looks really cheap- flimsy plastic. The power supply looks primitive and cheap. Oddly enough, I can't find any op amps! I can't seem to locate the crystal either. As you can tell, I'm really new to this kind of stuff. Should I just focus on modifications to my Sony SACD instead? This thing is just sitting here gathering dust, but I don't want to throw away my money either.
Steve
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Old 13th February 2002, 10:54 AM   #2
Helix is offline Helix  United Kingdom
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if you are gonna mod a expensive SACD player, you might as well practice on something cheaper to start off with. You have to be really stoopid to break anything permanently, but still be careful!

This would teach you a few 'mod tricks' you can use later
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Old 13th February 2002, 01:17 PM   #3
SteveG is offline SteveG  United States
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It's not that I need experience with electronics so much. I have been soldering and changing IC's etc. every day for the last 10 years! I just want some experience with CD players. I'm not sure what needs to be changed, etc. Obviously the power supply and output stage could use some help, but I don't know a lot about the digital section. I have read that an improved clock helps a lot. I guess my question is does this have any relevance to the newer players- will it help me figure out what to do to a newer better player.
Steve
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Old 13th February 2002, 02:32 PM   #4
tvi is offline tvi  Australia
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Technics use up to 8 1 bit dacs per channel and then sum the differental outputs through a heap of opamps usually quad opamps at that.

What opamps are in the SLPG100?


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James
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Old 13th February 2002, 03:09 PM   #5
SteveG is offline SteveG  United States
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James,
I did a quick look inside last night, and I didn't see any op amps- just 4 square surface-mount IC's that I assumed were D/A chips, etc. I'm thinking that this may be too integrated to do anything with. Thanks for the info.
Steve
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Old 13th February 2002, 03:33 PM   #6
Helix is offline Helix  United Kingdom
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Have a go at getting the service manual!
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Old 15th February 2002, 07:40 AM   #7
hifiZen is offline hifiZen  Canada
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yep, service manual would be handy. Also try looking for datasheets online for the ICs you see connected to the audio outs.
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Old 13th March 2002, 01:17 PM   #8
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The small SMD type IC is a dual Op Amps
and Technics usually used 4558 from Fairchild Semicon. You can make some mod with your CDP. I have also Technics SL-PG350 and made some mod, now it sounds great.
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Old 13th March 2002, 05:34 PM   #9
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Default Easy Jitter Fix

Hello SteveG and all,
A fast and relatively easy way improve things is to replace electros throughout with modern good quality SMPS grade caps.(RS Components, Farnell etc.).
A point worth noting is that for a given capacitance value, a higher voltage rated cap will give lower ESR value than a lower voltage rated example of the same make and type, so it is worth the price penalty of fitting the biggest physical size caps that are a comfortable fit - pay attention to conserving lead spacings, or be prepared to drill a few small pcb holes.
Also need to (must) add and a big benefit is to be had by fitting multiple parallel lower value types down to surface mount or tubular types.
This will help to give infinitely fast power supplies.
Have also found an RC network accross power supply caps to give blacker blacks.
Also there is much benefit to increasing the value ( double or triple value and more etc) of shunt caps, and also in increasing value of coupling caps to lower -3dB point.
Quote:
I have been soldering and changing IC's etc. every day for the last 10 years!
This should be easy for you then !
A quick and easy way to improve/change the jitter perfomance is to simply add a thin earth wire ( I use stripped fine silvered wire wrap wire ) to connect the can of the oscillator crystal to
1: to a close by ground.
2: or to either connection of the crystal at either of the two shunt capacitors.
This fine wire will fit down the pcb hole next to the component lead, so no drilling etc required for this.

This will give three slightly different sounds - You get to choose which one !
Also worth looking at is beefing up earth runs.
I hope this can help you to both practice and get a result that you can enjoy - good luck.
Please give us all a report of your results........

Regards,Eric.

BTW - My experience of MASH ( Panasonic noise shaping ), despite the above improvements, is that it gives an initially impressive sound with much detail, but with extended listening can prove to be false detail that can become a little grating even.
Good for nitpicking monitoring but not so good for comfortable easy listening - IMHO.
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Old 13th March 2002, 06:00 PM   #10
SteveG is offline SteveG  United States
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Eric,
I find the same fatigue happening when I listen to the mash players. I don't really think that this thing is worth modifying- it's just too cheap. I may look into finding a decent cheap player to mess around with. The only problem there is to find a single tray player anymore! I hate the fact that everyone is going to multi-disk players. This couldn't be good from a jitter standpoint, could it? Thanks for all the good suggestions. I will look into using them in something that is worth the time to modify.
Steve
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