Poogeing the SACD: The Pioneer 563A

[Nic.M]

David,

In reply to your question regarding the decision to use the same dac chip on a new board, here are some reasons:

-flexibility-- I might want to double up on the dacs and run them in mono in the future as on pg 31 in BB spec sheet. It would also make it easier to change to a completely new dac if nature tempts me.

- space-- the new board had to be built for the subregulators anyway and this would give me the chance to experiment with the grounding scheme, decoupling ps pins with fancy caps, etc.

- short run from the dac to the output section. See caution in BB specs regarding this.

- ability to run the output of the dac without a reference voltage(hopefully) and with output op amps using complementary inputs with a true +/- supply obviating offset.

The pictures I'll post as soon as I can get the forum to accept them. I've tried already. No go.

Nic.

[Nic.M]

David,

Here is the picture of the transformer and initial regulation board
I hope it posts

[Nic.M]

David

Here is the second picture of the unfinished dac output regulator board. This has +\-12 volt Sulzer supplies and +3 and +5 for the dac

[KBK]

I need some regulator boards for my Behringer 2496 six channel ouptut buffer box. I'm going to use my brand new 'mod squad line drive' I've been hauling around, NIB for the past 8 years. I picked up some OPA 637's and some 2604's and some 2132's etc... but I need the regulators!!!

Sticking ot the thread in hand here, I need to know which DSD chip is the better, I belive they have identical pin outs. Is it the 1791 or the 1793. I have a few (5) of the 1793's and want to know if it is worth the swap effort...

[net-david]

Nic,

Looks nice. I agree with your reasons for replacing the dac, but since I'm lazy, I'm just going to do the power supply and analog output. I plan to blatantly copy the spec sheet reference design, but throw a BUF634 at the output.

I need to check with Victoria Magnetics about getting a transformer wound for the power supply. I should just need +-15 for the analog and +5 for the dac analog.

Keep us updated on your progress, I just got the other popular machine for mods, the Philips 963SA.

David

[Nic.M]

Hello David,

Just thanks for your thoughts. As a matter of fact, while building up the output board, I too have decided to use buffers (LT1010 in my case which I already have). In addition, I will use opa604 single op amps, rather than the dual 2604. I have always found that the single chips offer better results, so why not use them in a new project? In addition, the singles have offset compensation trim pins (1 and 5) that can compensate for ~50mv. This feature could be potentially useful.


As for KBK question about regulator boards, we need more specifics to make suggestions. What type of regulators?
3 pin fixed, 3 pin variable, discrete regulators, single voltages, dual?

I took a quick look at the specs for the dsd1791 and 93 on the TI web site. Although the dacs look pin compatible, some of the pins seem to have different functions, 6 and 28 for example. I don't know enough about this stuff to advise any further. It must be nice to have so many interesting chips to play with.

Bye for now, Nic.

[Nic.M]

Hi all

-after replacing the caps on the power supply and the analog board with Panasonic FC a la Vinnie, I did some listening and noticed much better control of sibilance on female voices in particular(Diana Krall -when I look into your eyes sacd, Patricia Barber cafe blue SACD). More depth, better harmonics all round, etc.

- then I replaced the stock output op amp to opa2604. Muuuch better still. More of the same, but cleaner highs and noticeably better bass control. This change is really worth the effort.

- then I replaced the 47uf output caps with Black Gates 47uf NX when they arrived. This also improved the smoothness, particulary in the highs!

-then I removed the Black Gates and rigged up a pair of 4.7uf Rifa polypropylene caps. I also removed r241 and r236, changed them to 220K 1/8 w metal film resistors to keep the time constant the same. WOW! This really put the icing on the cake.

- must stop now. I going back to enjouy more music.

Nic.

[BritishSpy]

Hi, I'm new to this forum.

I think your (all) contributions are very interesting. Very nice forum indeed.

Well, I also bought the 565A and changed all caps to Elna/Panasonic, some of them bypassed. The output caps were changed to Solen 630V/10mF, bypassed with 0.01 Jensen paper in oil for smoothing the Solen with their only fault: A slightly nervous top. I also replaced the rectifiers (23ns ultrafast 600V 25A).

Next step:

1. Tube output stage with tube/choke PSU (2xEL34 & 2xECC81).

2. Complete removal of the case. The new case will be out of 10mm aluminium on all sides (15kg).

3. Decoupling of the drive, this is extreme important!

4. Complete new PSU for the DAC with a capsulated torodial transformer.

5. Cardas RCA sockets.

6. Rewiring of all PSU, digital & signal lines with 99,99% pure silver
wire.

7. Extensive mains filtering.

8. Ceramic feets for the case.

9. Switch for turning off the display.

10. Pure silver mains cable with ferrite clamps.

Salute

[BritishSpy]

After intensive listening tests I found out that the major problem with the Pioneer is the treble, it is not very clean, somewhta smeared. But after a look into the PSU the source of this problem seems clear, no transformer means normally smeared highs.

The 565A managed to beat a Sony CD Player from the QS range with chip and tube outputs! The Pioneer offered much more space and detail, the timbres of natural instruments seemed more natural with more textures and managed a wonderful body and bass to the music. The heavily modified Sony will be kicked out now, the 565A offers much more capacity for further tweaking.

[blank527]

Hi,

Here is my modified pioneer dv-747a.
Secondary tranny.. 1x6 V supplies the analog powersupply of the dac.
And +/- 12V for the sacd-enhancer from ultranalog for surround. (not connected)
And currently building the CD-enhancer II for the front output.