Thanks for the explanation. I might wait till I have a second DAC board with shunt regs before spending on posh I/V resistors.I can take this one
it depends.... higher is not good, as you will have the analog stage (the current source) in the PCM1794 clip against the positive rail, due to higher Bias voltage and also higher output voltage (I/V from Rload)
If you go lower, it is no problem, as your DC voltage goes lower, but the output AC signal voltage as well, so OK. no clipping...
Only back drop would be, that you have a bit lower output voltage. in your example only -1dB by the way.
It's interesting stuff on reducing the impedance by bypassing the 5w resistors and fuse in the 12v power supply. Got to be worth a go and small rises in the 12v output should still be well within the ranges of by the regulators on the mainboard/dac board, so it should be possible to take any bridging on and off to compare the sound quite easily shouldn't it?
Ijscobar and Leif, are you both running the standard 25va encapsulated transformers in the power supply or have you swapped out for something larger?
Also, has anyone who's using shunt regulators or similar on their DAC boards instead of the standard LF regs experimented with removing/bridging the L4 10uH chokes that sit after the 8v regs yet?
thanks,
James
I found doing the bypass yield the same findings as Leif and ijscobar.
My bass got better, more articulated and much faster. Better transparency with again darker background noises and certainly more dynamic. The sound indeed a little harsh to my ears like Leif said. I have now ordered Elna ROA 1000uf 35V to touch up this moothness.
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For someone used to have KDAC for many years, your DDDAC must be awesome! Did you also have any reg shunts installed in DDDAC, mate?
Chanh
Hey Chanh,
Don't actually have one yet, still saving for the setup with the Sowters.
After experiencing the diff the 4 pole makes on a KDac powersupply and an amp powersupply, wpuld be very interested in soneones thoughts with the DDDAC, next try for one in on the clock supply in the FIFO setup I'm currently putting together for the KDac.
Sont want to add my thoughts on their sound, would like someone to try them "virgin". Best to run them in for around the 400 hrs before critical listening though.....
Chuz,
Drew.
Don't actually have one yet, still saving for the setup with the Sowters.
After experiencing the diff the 4 pole makes on a KDac powersupply and an amp powersupply, wpuld be very interested in soneones thoughts with the DDDAC, next try for one in on the clock supply in the FIFO setup I'm currently putting together for the KDac.
Sont want to add my thoughts on their sound, would like someone to try them "virgin". Best to run them in for around the 400 hrs before critical listening though.....
Chuz,
Drew.
still thinking about 5V transformer but for 12V I actually have had 300VA connected. Btw, unsure why R1 and 2 are serving the purpose? If remove them could have other negative effects? Would appreciate Doede or anyone to shed some lights here please?good guys
I´m not senile yet then...ha-ha
250va on 12 v and 80va transformer on 5 volt
best
Leif
Many thanks,
Chanh
Hi Leif,
I have spent nearly 5hrs listening after the mod, damn it, time flys too fast! LoL!
I really appreciate the clarity and the precision imaging after these r1/2 and the fuse were removed for both 5/12V Doede's std PS. The negative for me like you said, sound is abit too much resolution, in especially in the hf, and the mid is also a touch lighter for my taste. I have order 2x Elna ROA 1000uf 35V and they are on their way to me in couple weeks. Hopefully these can help smooth out the sound and add a little more weight and body to the mid to my liking. Nevertheless, many thanks for this simple but most beneficial tweak!
Best,
Chanh
I have spent nearly 5hrs listening after the mod, damn it, time flys too fast! LoL!
I really appreciate the clarity and the precision imaging after these r1/2 and the fuse were removed for both 5/12V Doede's std PS. The negative for me like you said, sound is abit too much resolution, in especially in the hf, and the mid is also a touch lighter for my taste. I have order 2x Elna ROA 1000uf 35V and they are on their way to me in couple weeks. Hopefully these can help smooth out the sound and add a little more weight and body to the mid to my liking. Nevertheless, many thanks for this simple but most beneficial tweak!
Best,
Chanh
hi Chanh
maybe I was unclear. but the harshness was already there earlier, but were more exposed after the psu mod
what Rload s are you using?
4 decks BALANCED MODE "old" MB: I use 33R AN 2 Watt tantalums, no caps, no 100K in output into TVC
CAN ONLY CONNECT THIS WAY IF TVC nect stage!!!!!!!!!!!!
AN makes difference
Panasonic FC in last position in PSU 470µF or 1000µF will smothen things
best
Leif
maybe I was unclear. but the harshness was already there earlier, but were more exposed after the psu mod
what Rload s are you using?
4 decks BALANCED MODE "old" MB: I use 33R AN 2 Watt tantalums, no caps, no 100K in output into TVC
CAN ONLY CONNECT THIS WAY IF TVC nect stage!!!!!!!!!!!!
AN makes difference
Panasonic FC in last position in PSU 470µF or 1000µF will smothen things
best
Leif
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So, no need for upgraded size, but you believe that 1 x Panasonic FC cap is superior choice in this position (C7 and C8 of the power supply board) to the 2 x Nichicon Muse KZ caps supplied?
I have bought two Mundorf 10,000uF M-Lytic`s to replace the 4700uf`s supplied, and will be changing the two 470uf`s for two 1000uf Nichion Fine Gold capacitors.
I will keep the fuse and resistors for now but may try removing the resistors later as they are there to help smoothing in the original design which is very quiet
I will keep the fuse and resistors for now but may try removing the resistors later as they are there to help smoothing in the original design which is very quiet
I bypassed the inductors after the shunt regs. This is recommended!
The sound becomes more open and airy.
Good to see you guys you are experimenting with the power supply impedance.
I use the Salas shunt regs with elna silmic supply caps, there is absolutely no harshness in the music.
Silmic is the best choice for caps now black gate is obsolete (I am glad I still have a nice stock of BG
) anyone in for a trade of BG non polars for 500v BG WKZ types?Pet-240: thanks for the tip of the reed relays, I will check them out.
Perfect timing, thanks. I have everything out as I'm fitting my larger tx and mounting my shunt regs properly. I'll bypass the L4 chokes before I put it all back together this evening