Hi Lee,
There's just one ferrite bead separating the IC's from the rest indeed, not very impressive. I have to open my player anyway, to fit a new analog output stage, and I have a spare Tentlabs shunt here. I'll have a look at it, thanks for the tip!
Ray
No worries Ray. It made a big difference, which I expected to be honest.
That board looks tasty, I presume it's the improved DOS which I'm going to have to get me. I think I'm going to struggle to remove all the noise coming out of the dac with just the LPF section of the original output stage and a couple of cap tweaks.
Cheers, Lee.
Hi Lee
Super PSU you've got there. I like the biggie caps from Mundorf/FTCaps - one of the best around! You should be getting a night-to-day change in the 7001. Aren't you?
Arup
Hi Arup.
It certainly sounds a lot better than the standard machine, which I found quite flat, and uninvolving.
The Mundorf's are fantastic parts and I love most Mundorf products (I have a pair of their AMT's in my Jamo Concert speakers now), but I have to say that the low noise regs on the dac and splitting the psu's made more difference. The original circuit has the dac sharing the psu with the servo
Cheers, Lee.
Yep, it's the new DOS with Complementary Feedback Pair and current sink in the output section. Thanks to Steve!! I was hoping to fit the board this week, but it looks like it's not going to happen... Too many other interfering stuff.
Ray
I did this mod, and i hear a big improvement. As i understand correctly the filter has become 2 pole (originally 4 pole). I don't hear any noise, i think that a 2 pole filter is good enough for me.
Ok then, here goes:
That's the general overview of the main player. The regs and caps at the dac are going to be tidied up pretty soon, and I'll be swapping the 4 x Black Gate smoothing caps on the dac for some 22,000uF Mundorfs. (The BG's are going into my preamp when I get around to it).
Lee.
edit: sorry about the image quality, camera packed up so resorting to the iPhone.
An externally hosted image should be here but it was not working when we last tested it.
That's the general overview of the main player. The regs and caps at the dac are going to be tidied up pretty soon, and I'll be swapping the 4 x Black Gate smoothing caps on the dac for some 22,000uF Mundorfs. (The BG's are going into my preamp when I get around to it).
Lee.
edit: sorry about the image quality, camera packed up so resorting to the iPhone.
And the mods list:
http://redhillaudio.co.uk/images/lees_system/Thomo's_SA7001KI_Mods_List.pdf
Ta,
Lee.
http://redhillaudio.co.uk/images/lees_system/Thomo's_SA7001KI_Mods_List.pdf
Ta,
Lee.
I have 2 other mods... The biggest improvement in sound quality was when I bypassed the differential hdam. I'm using only one phase of the CS4397, coupled to the current LPF by a mkp capacitor and a bleeder resistor. The result is a natural warm sound. I was inspired to do this bij de Hawk Audio MP-Dac.
TNT-Audio MP-Dac:
"While the CS4390 features balanced-differential voltage outputs, the MP-DAC uses only one phase of the signal: this may compromise dynamics and internal common mode noise rejection, but allegedly the designers have tried all possible configurations of this chip, eventually settling for the solution with the best sonics. "
The second mod was inspired by my Marantz PM-17. The HDAM of the PM-17 is similar to the SA7001 hdam, but the PM-17 has a potmeter across 2 resistors. I added a potmeters to the hdams in my SA7001 and now the dc-offset is adjustable. I used to have 80mv on the output after bypassing the output capacitors. Now it is adjusted to 0mv +/- 1mv.
TNT-Audio MP-Dac:
"While the CS4390 features balanced-differential voltage outputs, the MP-DAC uses only one phase of the signal: this may compromise dynamics and internal common mode noise rejection, but allegedly the designers have tried all possible configurations of this chip, eventually settling for the solution with the best sonics. "
The second mod was inspired by my Marantz PM-17. The HDAM of the PM-17 is similar to the SA7001 hdam, but the PM-17 has a potmeter across 2 resistors. I added a potmeters to the hdams in my SA7001 and now the dc-offset is adjustable. I used to have 80mv on the output after bypassing the output capacitors. Now it is adjusted to 0mv +/- 1mv.
Hi Dennusch. A couple of years ago when I was last using this player I bypassed a lot of the output stage and found it beneficial.
However, I'm now using pretty revealing ATC speakers, a much better DIY preamp and more transparent power amp. I now find that because the whole system sounds so linear, with no real peaks or dips in the frequency response I need that full output stage in for the best sound. Without it, the sound becomes slightly bright, a tiny bit harsh and the ultimate deep bass isn't as good.
The trimpot is a great idea and is something I've been thinking about myself.
Lee.
However, I'm now using pretty revealing ATC speakers, a much better DIY preamp and more transparent power amp. I now find that because the whole system sounds so linear, with no real peaks or dips in the frequency response I need that full output stage in for the best sound. Without it, the sound becomes slightly bright, a tiny bit harsh and the ultimate deep bass isn't as good.
The trimpot is a great idea and is something I've been thinking about myself.
Lee.
Thanks Ray, nice to hear from you.
I suggest that you take a really close look at that servo board under the mech. Those standard SMT caps hold back the sound massively. If you get those swapped out for Oscon SEPC's you will certainly get big improvements.
I still have plenty of things left to do, and some more ideas to try too.
Cheers, Lee.
I suggest that you take a really close look at that servo board under the mech. Those standard SMT caps hold back the sound massively. If you get those swapped out for Oscon SEPC's you will certainly get big improvements.
I still have plenty of things left to do, and some more ideas to try too.
Cheers, Lee.
I used 5k trimpots, cheap and effective. I used the PM17 service manual to find the right way to integrate de trimpots onto the hdams.
In your mod list you mention 2 different clocks, CD 16.9 mhz and SACD 33.86 mhz. I have only replaced the SACD 33.86 for a low jitter clock. But i also heard an improvement for cd playback. Is that possible?
Thanks Lee, i'll look into that.
I see that Farnell has a wide range of Sanyo SVP in stock, are they any good? They are SMD's, and I like things to look nice and neat so i'd rather not use though-hole types on that board (I know, it's neurotic ;-)
Ray
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