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Buffalo II

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In the measurements we see a slight improvement. Use a Hiface in measurements. It would be interesting to see if there are improvements in general with all kinds of transport. The same I've tried it with Aune DAC and Gigawork DAC, worsened jitter in both.

The pulse transformer is not very special. It's just a small ferrite toroid with two copper coils like any other pulse transformer.
 
I would like two output stages behind the Buffalo II DAC. LEGATO stage and another stage output valves. I like the legato but I want to use the valves according to the type of music.
I am studying if I can do without compromising too much sound. I see two possibilities:
- A low signal relay PANASONIC TQ2-5V type just behind the DAC output. With the minimum cable. The relay signal derived from one or another stage.
- Connect the two stages at once without relays in the signal path and steps on or off via relays. The two stages would NEVER on.

Is it feasible or forget about it?, I'm no expert and maybe this is an impossible
 
As mentioned...

here by Russ; I would like to see someone attempt to design a CFP style tube output stage for the B-II/III. I know nothing of circuit design for these, but I assume Russ believes that a (legato style) CFP tube output stage could achieve the low input impedance preferred by the ESS 9018. I wonder if this kind of design could be done fairly simply with a pair of dual triodes...
I know Russ has considered doing a TPA tube output stage, but it appears he is really too busy to take on a completely new project... Any low level tube I/V experts out there...
 
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Thanks Russ, but the information arrives a little bit later, I bought the B3 & sold my B2:mad:
Why bitter? From what Russ writes it seems to me that BIII will do higher sample rates than BII so you did the right move!
I'm sitting here looking at the BIII with just a few components and full of holes like a swiss cheese:worried:
Anyway, Russ thanks for the information.
Cheers,
Nic
 
For all-tube I/V:
1. What is the recommended shunt to use the Sabra chip in current mode?
2. What is the recommended High Frequency roll-off (what frequency to have -3dB attenuation)?

1. For tubes some have had good success with an I/V resistor of 21-47 ohms depending on the gain of the tube stage. To be correct this is not exactly current mode, but it will work well.

2. I would aim for 40-60khz but some people like to go even higher. It really depends on the output stage and your personal taste.
 
1. For tubes some have had good success with an I/V resistor of 21-47 ohms depending on the gain of the tube stage. To be correct this is not exactly current mode, but it will work well.

2. I would aim for 40-60khz but some people like to go even higher. It really depends on the output stage and your personal taste.

Thanks.
What value resistor is needed for the DAC chip to operate at current mode?
 
There is no hard cut off for "current mode". :)

Any resistance will modulate the DAC outputs which is what causes some distortion.

What you need to remember is that the lower the impedance at the DAC output the better the performance. So the best answer is as low as your stage can manage. :D

For example both Legato and IVY-III impedance are just fractions of an ohm.
 
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Question:

I am trying to switch between spdif and I2S with the arduino. So, at the moment I have both sources permanently connected and the spdif switch on. I have a pulse input transformer, but I leave the termination to the board.

The problem is that the I2S module is always on, and gives a signal out. This prevents the spdif to work. If I switch the I2S module off, then it works.

Is it possible to do what I am trying to do ? How ?

Thanks,

Davide
 
Question:

I am trying to switch between spdif and I2S with the arduino. So, at the moment I have both sources permanently connected and the spdif switch on. I have a pulse input transformer, but I leave the termination to the board.

The problem is that the I2S module is always on, and gives a signal out. This prevents the spdif to work. If I switch the I2S module off, then it works.

Is it possible to do what I am trying to do ? How ?

Thanks,

Davide

At the least you need to switch D1 between I2S and SPDIF as it is shared. In addition, if you want to leverage the on-board comparator you will need to cut the trace of the comparator to D1. Then you take the output of the comparator to the switch in D1
 
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