Ray I've been testing properly at home for the last 36 hours with all the changes and I have to say it is superb. I do believe it is very linear sounding now (without the ccs inparticular) and the other transistors have brought realism and that analogue sound.
Now it is offering better bass control with a small amount of extra depth. Mid range is slightly cleaner and the very uber levels of upper treble detail I used to get has improved that little bit extra too.
Ok I've had issues with this Dos but for me once some parts are changed this is the best dos pcb to date.
Ray I hope you get the same improvements I found by changing those few things. Also it is a good thing you mentioned the transistor pin out as I forget not everyone knows these things ;-)
Brent
Now it is offering better bass control with a small amount of extra depth. Mid range is slightly cleaner and the very uber levels of upper treble detail I used to get has improved that little bit extra too.
Ok I've had issues with this Dos but for me once some parts are changed this is the best dos pcb to date.
Ray I hope you get the same improvements I found by changing those few things. Also it is a good thing you mentioned the transistor pin out as I forget not everyone knows these things ;-)
Brent
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I must say this! I have another marantz sa-7s1 in and of course it is a very nice cdp. It sounds superb but compared to the uber 63 it sounded very much a cheaper player. Which of course pleased me. Lee from red hill audio heard the diff and could not believe the difference especially as he really likes 7s1 (I do too)
Brent
Brent
I also seem able to run the cdp at higher volumes which would also suggest lower distortion. That would also back up why I have these gains. Right on time for my new amp in two weeks for bi-amping
Brent
Brent
That's beautiful! So this is with the 1k8 resistor, right? Any chance you'd try a LED CCS there, which I described earlier?
I'm still wondering why the BC560's sound so different from the 2SA's then. I had a look at the datasheet and can't find any obvious differences.
Martin, maybe you have an idea?
I guess that SA-7 needs a DOS 😀. I'm planning to get a SA-11S2 in the future.
Ray
I'm still wondering why the BC560's sound so different from the 2SA's then. I had a look at the datasheet and can't find any obvious differences.
Martin, maybe you have an idea?
I guess that SA-7 needs a DOS 😀. I'm planning to get a SA-11S2 in the future.
Ray
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Hi Gareth,
Ok, just post them and we'll have a look. I saw the 4007 circuit before, can't recall who it was that mailed it to me. Both use CMOS gates and I don't think they are specifically low-jitter, because it looks a lot like the inverter-oscillator that is originally used in the player. But they can be built dirt-cheap, so you can give them a try and see what it sound like.
Ray
New chips arrived and I soldered it in and did the point-to-point corrections. Switched it on and no output on RO. I know I said before that the issue was with LO but maybe I got it wrong before, anyway now not sure whether the issue was with the chip or not😕
Investigated a bit further and found a dodgy connection between pin 26 and +ve of CD16, lifted trace. Re-soldered and it's working again.
Didn't really check all the pins on the dac that when I first had the problem as I assumed if it was a power issue the whole channel would go not just half.
So, in hindsight maybe I didn't need to replace the chip but it was good practice to do and I'm chuffed that I managed it to do it.
Still think it's odd that an issue with one of the main power caps on the chip only causes an issue on half a channel, but it's worth knowing for the future.
And the players working again.
Regards
Pete
PS in the meantime I picked up a faulty 67 mkII from ebay, haven't recieved it yet but looks to be clean with just a knackered laser. Longer term it probably makes sense to think about transferring the parts to that, hopefully I'm experienced enough now not to raise so many tracks this time (I know I said that last time I did it😉)
Ray.
Yes I'm using the 1k8 rc55y resistor. I've not tried the led way but I can imagine it sounds better than a transistor. The difference between the transistors audibly is quite staggering.
Brent
Yes I'm using the 1k8 rc55y resistor. I've not tried the led way but I can imagine it sounds better than a transistor. The difference between the transistors audibly is quite staggering.
Brent
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I feel a bit like I'm cheating here guys! I've got all the parts available but once again due to the invaluable info published by the jolly nice folks on this thread, I'm able to short cut directly to the improved version! Anyway a big thanks all who have contributed here.
Not long now and I'll have something running to compare to the audio aero!!! Now with a spot of luck, that will be very interesting!!!
Not long now and I'll have something running to compare to the audio aero!!! Now with a spot of luck, that will be very interesting!!!
Couple of minor set backs!!!
1st, the 10K RC55Y's were missing from the Farnell parcel :-( FOC replacements now on the way YAY!!! and I seem to have mislaid???? one of my 220uF Black Gates grrrr. How on earth does that happen. Needless to say, 3 BG's on the PSU are of little use to me.....
Now I'm just working out what I should do with respect to replacement.
1st, the 10K RC55Y's were missing from the Farnell parcel :-( FOC replacements now on the way YAY!!! and I seem to have mislaid???? one of my 220uF Black Gates grrrr. How on earth does that happen. Needless to say, 3 BG's on the PSU are of little use to me.....
Now I'm just working out what I should do with respect to replacement.
Three wheeling Ian? Hope you can find that f***** cap wich may have fallen behind those unmovable crates... 😉
I'm getting there..........slowly!!!!
Looking good Ian. Although the 680pf caps don't look like they are positioned correctly.
Brent
I drilled new holes in the board and connected the legs underneath as I couldn't make them fit diagonally in the original holes. ;-)
😱 Those caps are monstrous! Why didn't you use polystyrenes? They have less piezo-microphonics as well 😉
Ray
Ray
Ray I tested mine with some high quality Vishay polyester caps, polystyrenes and Silver mica. I the end I used those big mica. I found they offered better bass and more air around the mids and treble. But found no draw backs.
Brent
Brent
I've found silvered mica to be more transparent in the signal path. I've used them for ages in the filters on various TDA implementations and prefer them over styrene (although I do have styrene to try here too!!!) I've never tried mica that big before tho 😉