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Buffalo II

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I have listen to the BII with and without the Bal/sie, without maybe more alive but also harsher. Now i want to try it with the BII alone(passive), I must use a 10 Ohm resistor between +out/GND to pull the DAC-out into voltage mode ?
Do I need a Coupling cap ?
I know that THD goes up, but I'm just testing my hearing.:)

-It is for me not possible to turn the volume completely down, I'm using the Volumite.
- I2S is what I use as input, together with the Metronome, is this the best method ?

Best regards, Erik.
 
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I have listen to the BII with and without the Bal/sie, without maybe more alive but also harsher. Now i want to try it with the BII alone(passive), I must use a 10 Ohm resistor between +out/GND to pull the DAC-out into voltage mode ?
Do I need a Coupling cap ?
I know that THD goes up, but I'm just testing my hearing.:)

- I2S is what I use as input, together with the Metronome, is this the best method ?

Best regards, Erik.

I tried it with output open and loaded both phase with 200R. Measurement on one phase only (not balanced).

DC output open: 1.75V
DC output loaded 0.85V

AC output open: 1.2V, THD 0.015% at 0dB
AC output loaded 0.55V THD 0.007% at 0dB (This is what I have with resistor + coupling cap)

I used also a coupling cap to avoid DC.

I have connected the Metronome to BII via I2S with short cables as you can.

Also sort possible cables between regulators & BII & Metronome & IVY III.
 
Using just one phase of the DAC output negates much of the advantage of the chip and will result in higher distortion than you would get using the DAC as intended which is balanced. :)

I am not saying this should or will be important to everyone, it's just a fact.

Of course the lower you make the output voltage swing by reducing the resistor value the less distortion you will have, but also you now have pretty bad dynamic range, so it's a trade off.

The DAC is simply a voltage source with a 195R impedance. It is not a classical current source. Any resistor after it simply forms a voltage divider.

This is why a low impedance (less than an ohm) differential input output stage is a must for getting the most out of the chip. For those of you who don't like opamps, the zero feedback Legato is almost here. :)

Cheers!
Russ
 
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I get this pretty regularly. "Russ, how come the volumite does not attenuate down to silence?"

Here is the answer:

The volumite only attenuates down to -63.5 db. This is a practical measure so that there is not as much dead zone in the pot travel. Otherwise only about half the pot travel would be very effective. if you really need to attenuate more than -63.5db you should setup the output stage for less swing.

If you want silence then turn the DAC off. :)
 
ESS 9018 in the Moon 750D

Just some short info on our beloved ESS 9018 DAC. This chip is not only used by McIntosh, but has also found its way into the new Moon 750D DAC/CD-Transport. Moon is a Canadian High End supplier and the 750D is priced at 9500 EUR in Germany (probably cheaper in the US). A review of the 750D is published in the new May issue fo the German magazine AUDIO. Their rating is the second highest in their top reference class group. Only the Accuphase DP800/DC801 combo is rated slightly higher, but at 2.6 times the price. The review doesn't say what kind of I/V stage is used.

I think it's wonderful that we can experience the sound quality of the ESS 9018 at a much more affordable price thanks to the efforts of TPA. Thanks again, Russ and Brian!

Kurt
 
Output Stage question

I am looking for another DAC and am considering the Bufallo II. I just finished modding a Valab NOS DAC and I am curious about output stage options for the Bufallo II. Seems like the the IVY III is the way to go but is it possible to use an IV resistor and capacitor as in the Valab? If not what about transformers? I am new to all this but I like the idea of keeping op amps out of the output stage.

Regards,

skibum
 
Question on usage... I'm waiting for the pre-order to open and have a question on usage.
I'd like to go for a dual mono setup with only a spdif input and I/V with a Sowter transfomer. No volume control as it will be used in a controll preamp (lo mu tube)and multiple input select before the amplifiers.
Wasn't quite sure after reading the pdf users manual... Will I need two complete Buff2's?
A block diagram with the different configurations possible would be nice to refer to.
Thanks!

Jeff Davison
 

Please stop referencing a wrong wiring schematic.
As I posted before, the diagram was already corrected by Russ.

I have a primitive question on the schematic for a "Dual Mono B-II and IVY-III" that Brain had released on TPA Support Forum before. ( Those who configure a "Dual Mono mode" must ignore the output stage wiring given on the schematic. They must reference Russ's schematic shown on this thread before instead.
http://www.diyaudio.com/forums/twisted-pear/160782-buffalo-ii-8.html#post2099315
Russ's schematic contains a correct output wiring with no phase inversion.
 
This is the correct way to wire a Dual mono Buffalo II. :)

The important thing to remember is simply that the phase of the opposite side of the DAC than is selected is reversed.

This makes wiring simple when using IVY_III or Legato.

Cheers!
Russ

Russ:

I wasn't questioning the correctness. I just don't see a L_In - on the IVY section of the schematic. I see 2 R_IN - pts.

Best

Bob
 
Dear Russ:

I think I understand why the ESS9018 wants to "see" zero impedance,
but then we also have 0 Vac output voltage, right? How does one then
measure THD (-120 dB)?


Regards,

Using just one phase of the DAC output negates much of the advantage of the chip and will result in higher distortion than you would get using the DAC as intended which is balanced. :)

I am not saying this should or will be important to everyone, it's just a fact.

Of course the lower you make the output voltage swing by reducing the resistor value the less distortion you will have, but also you now have pretty bad dynamic range, so it's a trade off.

The DAC is simply a voltage source with a 195R impedance. It is not a classical current source. Any resistor after it simply forms a voltage divider.

This is why a low impedance (less than an ohm) differential input output stage is a must for getting the most out of the chip. For those of you who don't like opamps, the zero feedback Legato is almost here. :)

Cheers!
Russ
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.