Same here, at customs since the 25th. Maybe they start wondering what's in all these Twisted Pear Audio packages and if they have to start charging import taxes. Let's hope not
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A few questions for Russ or Brian:
1) -the Metronome has a very good onboard regulator, would it do any good to use a placid to feed that regulator ? current?
2) - In the manual it is stated that the Metronome eliminates (almost) any incoming jitter.
So upgrading the clock/regulators from my CDPRO2M is therefore useless ?
3) -The Volumite uses a 5k lin pot, can i use a 10k LIN Alps ?
4) - I'm a little confused about the powersupply for the IVYIII.
If I don't install j1~j4, do I need 3 BP placids (pwr1/pwr2/pwr3) to power the IVY ?
5) 3x +/- 15V at what current must i set the placids ?
6) - The BuffaloII can work with 3 single placids by removing L6/L7/L8, at what current ?
7) Why are VD pads still there ? Can I still use the AVCCshunt in this situation ?
I hope these questions are worth answering and could help others.
1) This is purely your call. Is it required? No. Will it sound better. No right answer here.
2) See answer #1
3) Yes but I would not use more than 10K. The pot is not critical in the least.
4) Well yes, you would need 3 bipolar supplies of some sort.
5) about ~50 per supply. The placid work best at about 100ma or above so I would never use less current than that.
6) Technically yes, but you would need to change the placid circuit a bit, practically I would never suggest it. I will plublish current specs for these later. I just can't remember off the top of my head. But I do know that none use more than about ~60ma. So the 100ma suggestion above would hold.
7) VD pads are there so that you can use the VD power supply to feed the local regulators if you choose. You don't have to use them, but there is no harm in doing so.
You can always use the AVCC shunt regardless of what you do at the other three spots.Now to explain how you *could* use placid for both 3.3V and 1.2V.
For 1.2V you would need to replace the opamp with a low voltage R2R input and output opamp. Then you would need to use two schottky diodes as a reference, or one silicon diode and one resistor. You would also not use the NPN on the shunt, and short the emitter resistor on the PNP (or use something like 1R). This limits you to shunting < 40ma or so. I have actually done this and it works fine. The opamp I used has a max supply voltage of 5.5V. Be aware of such things. This is not something someone who does not understand the circuit should try.
You can do the same thing for 3.3V. Or you can usually use the supplied opamp and one LED and one silicon diode for the VREF.
It's not a trivial thing to do. Is it worth all the trouble? I just don't know.
I do have a nice little 3 pin regulator coming for both 3.3V and 1.2V that is tailor made for the application. I would much prefer that to trying to use placid at each spot.
Cheers!
Russ
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Thanks Russ,
I know about the pot, but i use a big knob and need more momentum.
I don't know how you say that in English.
"I do have a nice little 3 pin regulator coming for both 3.3V and 1.2V that is tailor made for the application". Good, i will wait for that.
btw, if I replace the 2 green leds with ones with Vf 1,65V, that would work
to get 3.3V ?
Before selling any single Placid, could you tell me what type of supply i need for the upcoming Counterpoint II ?
Best regards, Erik.
I know about the pot, but i use a big knob and need more momentum.
I don't know how you say that in English.
"I do have a nice little 3 pin regulator coming for both 3.3V and 1.2V that is tailor made for the application". Good, i will wait for that.
btw, if I replace the 2 green leds with ones with Vf 1,65V, that would work
to get 3.3V ?
Before selling any single Placid, could you tell me what type of supply i need for the upcoming Counterpoint II ?
Best regards, Erik.
If you want 3.3V with no other changes I would just substitute a silicon diode for one of the LEDs. Simple as that.
The counterpoint II will work very well with either Placid BP or LCBPS with the preference toward the placid BP.
Cheers!
Russ
Only if you have an PCM source that does not output 64fs I2S.
Many people who have CDPro units are using metronome to convert the PCM so that the Buffalo will accept it.Cheers!
Russ
Why convert S/PDIF to I2S when the Buffalo takes S/PDIF directly ?!?
If you have optical S/PDIF (i.e. Toslink) you can get a Toslink-> S/PDIF converter from TPA for less than 20$ (and probably many other places). No need to convert to I2S whatsoever.....
Nic
Ok, sorry to confuse you guys, I didn't knwo TOLINK was SPDIF. But I already hooked up the SPDIF to the Buffalo, but I've read opinions that optical might sound better, so I am trying to get a Optical input socket for the Buffalo, but I can't seem to find optical/i2s jacks? If you guys can tell me how to get one or get something to work with the Buffalo, I would appreciate it.
From the B2 manual:
"Each analog output at 0DBFS is equivalent to a voltage of approximately 92.4% of AVCC in series with 195 Ohms. So given 3.3VDC AVCC it will be about 3.05Vpp across 195 Ohms. The output will be DC biased at AVCC/2. This works out to about 16ma peak to peak at each output. The amount of bias current will depend of the voltage of the virtual ground."
Thus, 16mA AC peek-to-peek riding on a DC current for each phase (L_HOT, L_COLD, R_HOT, R_COLD) when in stereo mode (ie 4 differential DACs in || per left and right channel) when AVCC = 3.3VDC. A bit more current when AVCC=3.5 VDC. That is, each DAC phase delivers 16/4 = 4 mA AC p-p riding on a DC current.
Regards,
"Each analog output at 0DBFS is equivalent to a voltage of approximately 92.4% of AVCC in series with 195 Ohms. So given 3.3VDC AVCC it will be about 3.05Vpp across 195 Ohms. The output will be DC biased at AVCC/2. This works out to about 16ma peak to peak at each output. The amount of bias current will depend of the voltage of the virtual ground."
Thus, 16mA AC peek-to-peek riding on a DC current for each phase (L_HOT, L_COLD, R_HOT, R_COLD) when in stereo mode (ie 4 differential DACs in || per left and right channel) when AVCC = 3.3VDC. A bit more current when AVCC=3.5 VDC. That is, each DAC phase delivers 16/4 = 4 mA AC p-p riding on a DC current.
Regards,
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