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Old 21st September 2007, 10:24 AM   #21
SimontY is offline SimontY  United Kingdom
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The DAC is SAA7320. The chassis is solid and there's space for power supplies etc. so I look forward to modding it. Hopefully the one-note bass and indistinct treble can be remedied.

I'll write no more off-topic posts now, Sorry Lee.
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Old 21st September 2007, 10:33 AM   #22
Thomo is offline Thomo  United Kingdom
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Quote:
Originally posted by SimontY
The DAC is SAA7320. The chassis is solid and there's space for power supplies etc. so I look forward to modding it. Hopefully the one-note bass and indistinct treble can be remedied.

I'll write no more off-topic posts now, Sorry Lee.

LOL. If you read my posts on the cd63 thread, you may find most are off topic!

I'll be having another go at the little Marantz later on today and will let you know the progress. I'll add an extra tx and isolate the supply rails to the dac and SAA7220.

The transport in this thing is a cdm2 btw. The whole mech floats on its own rubber suspension, totally decoupled from the rest of the (**** plastic) chassis.

All the chips seem to be philps Phil.

Lee.
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Old 21st September 2007, 10:34 AM   #23
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Yeah. Sorry Lee.
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Old 21st September 2007, 11:17 AM   #24
awpagan is offline awpagan  Australia
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Quote:
Originally posted by Thomo
Hi Allan.

I think it's very similar to the Philips CD160 also. Thanks for letting me know, it may be easier to find some mods for the CD65.

Have you done any mods to yours? I am curious about the potential of these players after having heard so much good about the TDA1541.

Don't suppose you know what the little board is do you?

Cheers, Lee.

Hi Lee
i havn't done anything to it at all........!!!
absolutely standard.
I must admitt, in standard form, it has a very analogue sound too it.
Nowhere near the detail of my modded cd67, but better than a standard cd67.

From what "philpoole" and others have said...
Clean up the Saa7220 filter psu and clock.
As for opamps? Look for Nelson Pass's D1 discrete output.
It was going to try it on this player, just never got around to it.

allan

General question for anyone.
The Rotel's used BG cap's standard.
How long does a BG electrolytic last?
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Old 21st September 2007, 11:34 AM   #25
SimontY is offline SimontY  United Kingdom
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Quote:
Originally posted by awpagan
The Rotel's used BG cap's standard.
How long does a BG electrolytic last?
Good question! My player must be 16-17 years old. I've no doubt these old caps contribute a lot to the mellow, smoothed over sound.
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Old 21st September 2007, 11:36 AM   #26
Thomo is offline Thomo  United Kingdom
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Default Now we are getting off-topic!;)

I once read that a BG lasts much longer than a standard elco. The writer said around half again as many years, so by my estimation that makes ~15 years. I am not sure about this, it may just have been marketing blurb. I think it depends on how close to the maximum voltage you run them also.

Saying this, BC Aerovox say their caps will sit on a shelf for well over ten years with no detrimental effects. I have two very old, 6800uF 100v Aerovox's which I used for a while on my Gainclone and they were fantastic. They're a similar size to Brents Silmics btw Simon!

If you are talking about the Rotel, I think it has a filter built into the dac and this may limit the performance along with the power supply.

Lee.
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Old 21st September 2007, 03:42 PM   #27
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Hi Thomo,

Sorry I was being off thread - I thought Simon's was a CDM4.
CDM2 - blimey! How old is this player?
Have you got any photos of the CDM2?

So, I doubt the little board is a converter then if its all Philips chips. The plot thickens. Can you get a side shot of it? Maybe we'll be able to spot the odd component?

Cheers,
Phil
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Old 21st September 2007, 04:15 PM   #28
Thomo is offline Thomo  United Kingdom
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Hi Phil. It's OLD. lol. Doesn't even have a remote sensor!

Component side:

Click the image to open in full size.

Trace Side/Pinout

Click the image to open in full size.

Both transistors are labeled c548b.

Pin 7 of 7220 is subcode data?

Lee.
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Old 21st September 2007, 06:42 PM   #29
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I'm sober at the moment, so its tricky, but, I think the little board is an AND gate.
I think.
I take it the black wire is one of pin 33 and pin 38, and the other is just a through hole?

I reckon, although I don't know what a mab8441 is (is it a microcontroller?) that one pin is the subcode data, and the other is an enable line for the subcode data.
Maybe it was an irreversible error in some software in ROM, and this is a cheap workaround (a handful of resistors and transistors probably is cheaper than a quad AND gate IC - especially back then)?

That's my best guess so far, I've got a rough sketch of the circuit, but I'm sort of guessing the pinout for the transistors.

Does this have a digital output? And (if its like my CD624) does it have a digital output enable button? Maybe this is the disable circuit?
With the SAA7220, I know that if the subcode clock (and/or data) is left constant at a level, then it is disabled. And subcode stuff is only used after the digital filter for SPDIF (It doesn't do anything for I2S) as far as I know.

However, I may well have completely the wrong end of the stick.

Cheers,
Phil
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Old 22nd September 2007, 11:04 AM   #30
Thomo is offline Thomo  United Kingdom
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Quote:
Originally posted by philpoole
I'm sober at the moment, so its tricky, but, I think the little board is an AND gate.
I think.
I take it the black wire is one of pin 33 and pin 38, and the other is just a through hole?

Phil
Nope, sorry. The leg on the left centre connects to these pins

Anyway, I've fitted a couple of extras now and the results have been very good.

I've fitted an extra tx (2x15vac 3.2va), 2 x Schottky bridges, 4 x 560uF 50v Panasonic FC's.

One winding supplies 560uF FC - 7805 - 100uF Black Gate = 5v to SAA7220.

The other Supplies +5v Audiocom Invisus - TDA1541 +5v.

This little player just keeps on suprising me, it's now within a whisker of my CD67. I admit it's not quite as clean, top and bottom are a little ragged compared. But with one 7915 reg feeding both the dac and the opamps that's not surprising. Detail is very nearly as good, just lacking separation.

I'll add another tx to supply +/-15v to the opamps when I get chance, and beef up the caps to more suitable BG's.

Cheers for all your help guys.

Lee.
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