A NOS 192/24 DAC with the PCM1794 (and WaveIO USB input)

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leif christensen

Member
Joined 2005
hi again
have run a tes cd from my nas via fifopi and into the dac
measured vac directly on both dac outputs between pin 2 and 3 on XLR simultaneously with 2 DMMs
the left is mostly stable at aound 2,34 vac
the right is about 2vac on 20Hz and rises slowly til it reaches same as left ch at about 80Hz
then RC rises to about 2,37vac
at 2 K the RC is back to 2,34vac
at 5K 2,29 vs 2,21/LC-RC
10K 2,12 vs 1,8
16K 1,82 vs 1,26
20K 1,57 vs 0,9
22K 1,44 vs 0,84

something is obviously not correct

best
Leif
 
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leif christensen

Member
Joined 2005
hi
only DMMs
balanced cables have been swapped to rule out that
nothing else than load resistors which I just resoldered to be certain....AN 2 watt tants
don´t have any caps or output x-formers since I drive TVC direct
I´ll repeat test with DMMs on pos and neg to gnd..but tomorrow...now I´m fed up and listen to Keith Jarret Køln concert on my new Garrardzilla approach
Thxs so far
 
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Robin De Wolf

Member
Joined 2019
3kes said:
Hi Johan,

My setup is a single deck dddac (tent edition), stock dddac p/supp, Pass B1/Amp Camp, IMF TLS50 speakers (so no high end stuff) and experimented with different streamers.

- Rpi - Allo Isolator - higiberry digi plus.
Sounded okay for me and had it running for almost a year.
- Rpi - Isolator - Kali
Sounded better in my ears, more transparent, better overall soundstage
- Rpi - Ian fifopi with stock clocks
No better than the Isolator/Kali combi.

When I ordered the figopi I also did order the Accu Silicon clocks but didn’t installed them at first time to hear the difference between the Kali and the fifopi.

Installing the Accu Silicon clocks was a real step forward. Sounded in my setup so much better than the stock clocks. More detail, more transparency, better image. I can recommend the Silicon’s.

Never heard the Andrea Mori clocks but I can imagine this will be another great step forwards.
Click to expand...

Very useful for my next upgrade! How did you power the Rpi? I assume you used your 5v doede Psu for the FiFoPi?
 
dddac

dddac

Member
Joined 2003
blog.dddac.com
Paid Member
leifchristensen said:
hi
only DMMs
balanced cables have been swapped to rule out that
nothing else than load resistors which I just resoldered to be certain....AN 2 watt tants
don´t have any caps or output x-formers since I drive TVC direct
I´ll repeat test with DMMs on pos and neg to gnd..but tomorrow...now I´m fed up and listen to Keith Jarret Køln concert on my new Garrardzilla approach
Thxs so far
Click to expand...

Hope the music will get you going again Leif ;-)

next step: make sure to have disconnected the transformers before you measure POS and NEG to common DC between POS and NEG. And of course with signals again between POS/Common and NEG/Common.... than you know if it is the TVC or the DAC. and if it is one side of the DAC (POS or NEG)

oh, are the DMM the same model? if not swap both to rule out any readings based on different RMS AC chips. Or just swap anyway to make 100% sure you are not reading differences because of the DMM - 100% deduction so to speak
 
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leif christensen

Member
Joined 2005
only DMMs directly on outputs
not same models..will swap pos /neg DMM next
swapped meters on pos neg leg and FLUKE is stable....Meterman is drifting more vs frequency
RCH...63 frequencies from 20Hz to 22K
both leg start at 1,18 and by
10 K it´s 1,04
16K it´s 0,9
22K its 0,7

LCH
identical......displayed difference Fluke and Meterman at 22 K: 0,7 vs 0,42vac!

all voltages from psu´s are dead on
12 to dac
5 to raspberry pi3
5 to reclocker
next suggestion?
 
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