01-19-2024, 07:29 PM
(This post was last modified: 01-19-2024, 08:17 PM by Tim Curtis.
Edit Reason: Add paragraph breaks
)
10 years! It is a good time to donate again!
A couple of items:
I recently added a FifiPiMa re-clocker and I am so far pleased with the results. There were a few stumbling blocks though. Hopefully my errors will help anyone attempting the same.
Firstly, the GPIO on the FifoPiMA provides only 3.3vdc to the power pins of the Protodac. I use a Salas DIYAudio linear supply and am feeding the FifiPI through the RPi so far. I needed to disconnect the pwr supply pins to the ProtoDac using the header with pins 2&4 removed as suggested by someone earlier in this thread and feed directly yo yhe through holes provided on the dac board. These were jumpered to the terminal strip on the MA. This worked fine!
Second - I tried to feed the MA and RPi through this terminal strip but it would not boot properly if I connected everything and then started the power supply. Apparently the startup routine of the MA is quicker than the pwr supply startup and it gets confused. So I had to add a switch in the supply line so that the power supply could be up and running before switching everything on. It worked!
Thirdly: I had first to remove 2 bypass caps on the bottom of the Protodac board (0.1uf , Vishay MKP) to fit physically before adding the extra header. I was interested to perceive that there was a difference after they were re-installed. Just a little "sweeter" - whatever that means!
Lastly there has been some discussion on this thread and seemingly forever elsewhere about the effect of absolute polarity. I have always found that switching polarity made a difference , but that difference was very much recording dependent. From some experience in recording control rooms, admittedly some years ago, polarity between mic feeds was always a consideration, but absolute polarity was never mentioned. And how would this be determined in a multi track, isolation booth type environment? A minimalist/natural recording can take this into account but I don't know that it actually is done.
It seems to me preference in this is often a matter of taste/personal preference/system characteristics.
I often wonder if what I/we hear is just a non-linearity in our systems that we tailor to our own preferences? As nelson Pass has demonstrated, positive going 2nd harmonics added to a signal increase spaciality and warmth while negative going does the opposite.
In any event, be sure to Enjoy the Music!
MG
A couple of items:
I recently added a FifiPiMa re-clocker and I am so far pleased with the results. There were a few stumbling blocks though. Hopefully my errors will help anyone attempting the same.
Firstly, the GPIO on the FifoPiMA provides only 3.3vdc to the power pins of the Protodac. I use a Salas DIYAudio linear supply and am feeding the FifiPI through the RPi so far. I needed to disconnect the pwr supply pins to the ProtoDac using the header with pins 2&4 removed as suggested by someone earlier in this thread and feed directly yo yhe through holes provided on the dac board. These were jumpered to the terminal strip on the MA. This worked fine!
Second - I tried to feed the MA and RPi through this terminal strip but it would not boot properly if I connected everything and then started the power supply. Apparently the startup routine of the MA is quicker than the pwr supply startup and it gets confused. So I had to add a switch in the supply line so that the power supply could be up and running before switching everything on. It worked!
Thirdly: I had first to remove 2 bypass caps on the bottom of the Protodac board (0.1uf , Vishay MKP) to fit physically before adding the extra header. I was interested to perceive that there was a difference after they were re-installed. Just a little "sweeter" - whatever that means!
Lastly there has been some discussion on this thread and seemingly forever elsewhere about the effect of absolute polarity. I have always found that switching polarity made a difference , but that difference was very much recording dependent. From some experience in recording control rooms, admittedly some years ago, polarity between mic feeds was always a consideration, but absolute polarity was never mentioned. And how would this be determined in a multi track, isolation booth type environment? A minimalist/natural recording can take this into account but I don't know that it actually is done.
It seems to me preference in this is often a matter of taste/personal preference/system characteristics.
I often wonder if what I/we hear is just a non-linearity in our systems that we tailor to our own preferences? As nelson Pass has demonstrated, positive going 2nd harmonics added to a signal increase spaciality and warmth while negative going does the opposite.
In any event, be sure to Enjoy the Music!
MG
ProtoDAC, Rpi4, TD146, Mayware, Ortophon Blue, Schitt M1, Pass B1,Ayima, Luxman, MarkAudio OB
