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Old 15th November 2010, 08:23 AM   #21
back is offline back  Greece
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the current output of a single buffalo II is 16ma.

guys i have one question too.

i don`t have i2s to feed the buffalo modules.

can it be done with paraled coaxial or it would spoil the 75ohm standard?

my other option is to use the 2 transformer isolated outputs from musiland.

one is with rca and the other is with bnc.

this will be for testing purpose only.

if i like it and buy a second buffalo for myself

i will change the connectors to use the same at both channels.
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Old 15th November 2010, 12:58 PM   #22
jgazal is offline jgazal  Brazil
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Quote:
Originally Posted by back View Post
the current output of a single buffalo II is 16ma.

guys i have one question too.

i don`t have i2s to feed the buffalo modules.

can it be done with paraled coaxial or it would spoil the 75ohm standard?

my other option is to use the 2 transformer isolated outputs from musiland.

one is with rca and the other is with bnc.

this will be for testing purpose only.

if i like it and buy a second buffalo for myself

i will change the connectors to use the same at both channels.
Quote:
Originally Posted by Russ White View Post
No need to buffer if you use I2S source as the impedance is pretty high. If your using any of our I2S sources the outputs are perfectly capable driving the load and are designed to do so.

If your using SPDIF the solution is similarly quite simple. Use one Buffalo II with normal SPIDF input. On the other leave the SPDIF switch open. Now connect D1 and GND between the DACs. This will make a single comparator drive D1 with TTL level SPDIF on both DACs. Something it can do quite easily. This works very well and is how I did some of my testing.

Cheers!
Russ
Is this helpful in anyway?
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Old 15th November 2010, 02:43 PM   #23
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Quote:
Originally Posted by nycavsr2000 View Post
Next question. Since you used 2 Buffalo II modules, obviously the current doubled. What did you end up changing on the Legato module in order to get 1.5V to 2V rms at 0dBfs? It's important to find out what this current is as others who would like to implement a differential I/V stage, whether tubed or solid state or transformer, will need this info to make sure their favorite I/V stage can handle this level of current.

Does anybody know what the current output is of a single buffalo II module?

Thanks,
Anand.
Hi Anand
Or even "Dzień Dobry"

Well this is really good question how Legato is reflecting double current from Buffalo side. In theory this would be 2x16ma about 30-32ma and this is definitely few times more that other “I output DAC” I know. And I/U stage have to be designed to work on that high output current level.
At "Legato or IVY III" thread IngemarR did post simulation of Legato with some very nice results, I will try to ask him about possibility or running his simulation again with double current from Buffalo. Maybe he will find this subject interesting, and we could see how this works, at list on simulations.

As for higher output level at Legato this is of cause the case, output level is higher. If this is interesting for You I can check the real situation with the scope, this actually is interesting.

As for lowering Legato output level, there is very nice "Legato Tweekers" thread if I remember correctly, where this is explained by "the Legato maker" himself... so this could be "the best source" if You wish to do this.
As for me I "like" the higher than standard output levels, but I mod my PowerAmp, I feed directly from Legato, to be able to work with this. And for me this is another advantage of this setup.


Best Regards
Rosendorfer
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Old 15th November 2010, 03:00 PM   #24
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Quote:
Originally Posted by jgazal View Post
I am not an engineer. In fact, I am a layman, but a very curious layman,
Jose
Hi Jose

... are You sure about calling Yourself "layman"... this just doesn't relay seems to fit Your knowledge...
I'm sure You will have a lot of fun while get the Buffalo....

Best Regards
Rosendorfer
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Old 15th November 2010, 06:15 PM   #25
back is offline back  Greece
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Originally Posted by jgazal View Post
Is this helpful in anyway?
off course it is.
that`s all i wanted.
thanks.
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Old 15th November 2010, 11:16 PM   #26
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Quote:
Originally Posted by Rosendorfer View Post
Hi Anand
Or even "Dzień Dobry"

Well this is really good question how Legato is reflecting double current from Buffalo side. In theory this would be 2x16ma about 30-32ma and this is definitely few times more that other “I output DAC” I know. And I/U stage have to be designed to work on that high output current level.
At "Legato or IVY III" thread IngemarR did post simulation of Legato with some very nice results, I will try to ask him about possibility or running his simulation again with double current from Buffalo. Maybe he will find this subject interesting, and we could see how this works, at list on simulations.

As for higher output level at Legato this is of cause the case, output level is higher. If this is interesting for You I can check the real situation with the scope, this actually is interesting.

As for lowering Legato output level, there is very nice "Legato Tweekers" thread if I remember correctly, where this is explained by "the Legato maker" himself... so this could be "the best source" if You wish to do this.
As for me I "like" the higher than standard output levels, but I mod my PowerAmp, I feed directly from Legato, to be able to work with this. And for me this is another advantage of this setup.


Best Regards
Rosendorfer
Legato copes quite well with the higher current, but you will want to reduce the I/V resistor.

I am sorry I have not had to time to read the whole thread yet. It looks like you are doing well. If you need any specific questions still answered let me know.

Good work!

Cheers!
Russ
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Old 16th November 2010, 03:46 PM   #27
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i did a simulation with a Legato driven by two ESS9018, ie the current into the Legato is 32mAp-p AC at 0 dBFS. Fequency is 20 kHz.

My sim of the Legoto with one ESS9018 is here
http://www.diyaudio.com/forums/twisted-pear/166975-legato-ivy-iii-outputs-buffalo-ii-11.html#post2309745


Do note that I did not change the IV resistor as per Russ recommendation. Thus, output voltage is 3.2Vrms.



/IR
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Old 16th November 2010, 03:49 PM   #28
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Russ,
what resistor value changes do you recommend for running the Legato from dual BuffaloII:s?


/IR

Quote:
Originally Posted by Russ White View Post
Legato copes quite well with the higher current, but you will want to reduce the I/V resistor.

Cheers!
Russ
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Old 16th November 2010, 05:00 PM   #29
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Hi IngemarR

Thanks for Your post ..!!
Your simulations are very interesting...
Please correct me if I'm wrong but it seems that for
lets call this: normal stereo mode with 16ma input current at Legato the simulations results are absolutely much better.

The 3-rd harmonics, 60Khz with normal stereo mode we get -125,6dB and at Dual mode with 32ma input current at Legato there is -109,5dB this is like 16,1 dB difference.

And THD at normal stereo mode 60kHz Up is 0,0000772% and with Dual mode 0,0003369%.

So it looks that we get signal level up, but we do loose pretty much on distortion..having higher signal level.

Best Regards
Rosendorfer
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Old 16th November 2010, 05:20 PM   #30
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If you reduce the I/V resistor by half you will get much better performance.

The reason for the increase in THD is the much larger voltage swing at the output.

You could also increase the static current by reducing the 330R CCS resistors. But that may not be necessary or desirable.
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