Upgrades for D1

[sixty9]

Hi,

I'm new to the forums and was looking for a little help.

I'm getting the pass labs d1 (non-upgraded) soon and was hoping for some tips on what i can do with the D1.

1. Does anyone know what parts and process are needed to upgrade the dac for 24/96 functionality. I understand so far that i have to upgrade the receiver chip and swap the dac chips.. but i'm looking for more details.
2. Can someone email me the service manual? sixty9 @ gmail dot com
3. WHat other upgrades can i do? For instance i've heard people have upgrade the cable for the volume control?

thanks!

Byron

[spzzzzkt]

From what I've been able to deduce the 24/96 upgrade consisted of:

- each PCM63 replaced by a 2 x PCM1704 module

- Daughter board replaced with following changes
-- CS8412 -> CS8414
-- SM5842 -> DF1704
-- added relay to select between 96/44.1 operation

- a cable between Front panel board and the daughter board - presumably to control the added relay.


If you don't have a pressing need for 24/96 I suggest you consider leaving the dac "as is". Wayne Colburn has expressed the opinion that the PCM63/SM5842 combination is the superior choice for 16/44.1 playback.

One upgrade that would be worth making is replacing the electrolytic caps around the DAC's and I/V with Elna Silmic II's. Wayne's personal D1 is built using these caps and they seem to be a favorite of Nelson's also.


Paul

[sixty9]

thanks for the manual!

I don't have the dac yet but here are some pics the seller sent to me (http://www.flickr.com/photos/22969753@N07/) hope they help.

Yeah, seems to me that i'll keep it at 20 bit for the time being. From my correspodence with Pass Labs it looks like the 24/96 upgrade also requires a new power supply.

I'll look into the electrolytic caps upgrade.

How about replacing the pcm63K with the pcm63Y? I've heard it's supposed to be better. Also how about replacing the CS8412 -> CS8414? would i get better jitter rejection?

[spzzzzkt]

I'm not sure if the new PSU is required. From the pics I've seen the 24/96 version uses different rectifier diodes (4 pin bridge vs individual diodes) to the 16/44.1 version. There are also a couple of extra caps near the I/V stage which could be PSU related, and there is a line filter on the mains inlet but that appears to be the extent of the changes.

Based on some tests posted over at diyhifi.org the CS8414 should have better rejection of data correlated jitter, so it could possibly be worthwhile. However, the recovered clock from the CS8412/4 is only used to clock data into the SM5842 DF. The DF itself runs from the clean clock generated by the VCXO so I'd expect the gains to be minimal.

If you can get genuine Y's it could be worthwhile trying. Bear in mind that the PCM63P-K in the D1 were matched for linearity and distortion using a custom test rig hooked to a Audio Precision Two. It may be the benefits of matched pairs swamps the potential improvements from unmatched Y. If do you pull the chips make sure you make note of where they were originally installed.

Thanks for sharing the pics, it's really nice looking bit of kit

[JeffCullen]

As a layman, casually comparing these photos to my upgraded unit, it looks like you have it right Paul (assuming this small yellow plastic canister thing is the extra relay...). The white cable from the receiver board to the front panel board is just to light up the 96KHz light!

I'd love to have one of the original receiver boards to try a PMD100 with an adapter........................... well a PMD200 would be even more fun but hard to implement and harder to find :P I have always felt the DF1704 is the only weak link in this thing. I have a Sonic Frontiers SFD-II Mk.III which uses PMD200/PCM1704 and it smokes my D1 in most aspects, despite using OPA627APs for I/V and t00bs...

I guess there were a handful of factory 24/96 units made... check this out: http://cgim.audiogon.com/cgi-bin/vs....89&viewitem&o2
notice "24/96" silkscreening near volume control...

[spzzzzkt]

My relay theory is incorrect it seems. It looks like on the 24/96 versions the jumpers on the motherboard are set to the 96/88khz position. The upgraded receiver board has 74VHC74 and 74VHC157 which handle divide by 2 and switching between divided and undivided clock rates respectively. Quite a neat solution.

[sixty9]

For those of you who are interested, i've posted my impressions of the Pass Labs D1 vs Emm Labs Dcc2 vs Weiss Minerva

http://www.audioasylum.com/cgi/vt.mp...gital&m=145592

[spzzzzkt]

Nice review! Good to see the D1 performs so well on redbook compared with more recent DACs.

[tiefbassuebertr]

Originally Posted by JeffCullen

As a layman, casually comparing these photos to my upgraded unit, it looks like you have it right Paul (assuming this small yellow plastic canister thing is the extra relay...). The white cable from the receiver board to the front panel board is just to light up the 96KHz light!

I'd love to have one of the original receiver boards to try a PMD100 with an adapter........................... well a PMD200 would be even more fun but hard to implement and harder to find :P I have always felt the DF1704 is the only weak link in this thing. I have a Sonic Frontiers SFD-II Mk.III which uses PMD200/PCM1704 and it smokes my D1 in most aspects, despite using OPA627APs for I/V and t00bs...

I guess there were a handful of factory 24/96 units made... check this out: Audio Virtual Systems
notice "24/96" silkscreening near volume control...

I don't understand this term:
...and it smokes my D1 in most aspects...

[qusp]

you bumped a 2yr old thread to ask for clarification of english slang?

the term is derived from racing cars, where a car that leaves the competition long behind from the start, smokes the tyres off the start line in a convincing manner.

so he is said to have 'smoked them'