Hi all. I'm a new member and this is my first ever forum request!
Anyway, I have owned an Assemblage DAC 2.6 for 15 years and finally want to upgrade it (very late I know). I can source the op amp upgrades easy enough and I have a blank daughter board for the DF1704 upgrade.
My problem is that I don't know what goes on to the DF1704 daughter board apart from the DF1704 itself. Does anyone have detailed photos or parts list or schematic by any chance.
Yours, hopefully!
Anyway, I have owned an Assemblage DAC 2.6 for 15 years and finally want to upgrade it (very late I know). I can source the op amp upgrades easy enough and I have a blank daughter board for the DF1704 upgrade.
My problem is that I don't know what goes on to the DF1704 daughter board apart from the DF1704 itself. Does anyone have detailed photos or parts list or schematic by any chance.
Yours, hopefully!
I did a quick search and the upgrade is to ditch the Pacific Microsonics HDCD filter and substitute a DF1704? Sounds like a step backwards to me rather than an upgrade. What's the rationale behind this?
Here's where I learned of the details - http://www.soundstage.com/revequip/assemblage_dac26.htm. In this article they say -
It should be pointed out that over the years, reviewers have been trying to tell us that the HDCD filter is one of the best-sounding filters you can use for CD playback. That may have been true a while back, but the DF 1704 filter change here indicates that 24/96 filtering sounds significantly better than 16/44.1-based filtering, even HDCD.
Doesn't make any sense to say 'that may have been true a while back' as if the design of the two filters has changed in the meantime.😕
Here's where I learned of the details - http://www.soundstage.com/revequip/assemblage_dac26.htm. In this article they say -
It should be pointed out that over the years, reviewers have been trying to tell us that the HDCD filter is one of the best-sounding filters you can use for CD playback. That may have been true a while back, but the DF 1704 filter change here indicates that 24/96 filtering sounds significantly better than 16/44.1-based filtering, even HDCD.
Doesn't make any sense to say 'that may have been true a while back' as if the design of the two filters has changed in the meantime.😕
Thanks for replying abraxalito. That is the same article that I read. Apparently the Assemblage people also thought it was a good idea to upgrade the PMD100, but to be honest, my knowledge isn't enough to know the reasons why.
I thought that if I could get hold of the upgrade then I could see for my self whether it is better or not. I don't mind spending some cash in doing so.
I thought that if I could get hold of the upgrade then I could see for my self whether it is better or not. I don't mind spending some cash in doing so.
The DF1704 allows operation at sample rates of 96K with 24 bits, the PMD100 allows operation to only 48K and 16 bits IIRC..
I own an Assemblage 3 with the PMD100.. Thinking also of getting a DF1704 to allow operation at 24/96. (The 3 definitely supports 24 bit operation, not sure about the 2.6)
I own an Assemblage 3 with the PMD100.. Thinking also of getting a DF1704 to allow operation at 24/96. (The 3 definitely supports 24 bit operation, not sure about the 2.6)
Thanks ihear21khz! That looks very hopeful. I have emailed them and asked about compatibility with the Assemblage 2.6. I'll report back when I know more.
The DS for the PMD100 I downloaded says the input's good for up to 24bits, but yes the input sample rate's limited to 55kHz max. Running the input at 96kHz though means the output's going to be revving rather highly (768kHz) and I can only think of downsides to running the PCM1704 so fast.
The SQ improvement could be down to the fact that the DF1704's far more frugal in its power draw and hence creates a lot less PSU noise than the PMD. Myself I'd improve the power supplies to both the filter and the DAC chips before swapping out the digital filter. Removing the digital filter entirely in order to run non-oversampling might also be a SQ win.
@Designamp - my comments weren't intended to discourage your own experimentation into what sounds best 🙂
The SQ improvement could be down to the fact that the DF1704's far more frugal in its power draw and hence creates a lot less PSU noise than the PMD. Myself I'd improve the power supplies to both the filter and the DAC chips before swapping out the digital filter. Removing the digital filter entirely in order to run non-oversampling might also be a SQ win.
@Designamp - my comments weren't intended to discourage your own experimentation into what sounds best 🙂
Thanks abraxalito. I really appreciate your advice. That gives me lots of food for thought and guarantees more time with Mr Google. What I might do then is upgrade the op amps to OPA627 first and see how that goes while I dwell on the other upgrades. PartsConnexion did offer a significant upgrade package for the DAC 2.6 years ago but I'm I bit late and trying to recreate that is proving hard!
Plenty of ceramic caps (10uF/35V 1206 sized) across the supply pins work wonders for removing opamp 'glare' I've found. A much cheaper and probably more effective upgrade than rolling to another opamp. I don't think such compact low-ESR capacitor technology existed when DACs like this one were designed.
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