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Old 29th August 2010, 09:45 PM   #111
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Hi Tyimo

Regarding load resistance just to to make this clear I've never told that 1KOhm is optimal for LL1517 and Buffalo. I did few measurements and they clearly showed that load resistance has really big influence on this how this combo works..mainly for THD but also other measurements. And please know that from my measurements 1KOhm in this setup could be too much and we should go for much lower value maybe about 300-200Ohm, as this trafo load values gives much better measurements for THD. But again based just on my sbjective listening tests I did find that load less than 600-700Ohm seems to kill bit of dynamics IN MY Setup, but this is just my subjective opinion. So I definitely recommend you to test also different load values..there is no proof that 1kOhm is optimal.

Dear Alex..

As for Input caps I definitely through them out... With Trafo caps at input are no use..there is no DC at trafo... And as for me no caps was definitely impovment..
All I can say is it is worth to try..

Dear Spartacus

Well You could be right that 195Ohm is for one phase... so between phase connection makes 390Ohm ...

And this could even explain me bit more why Russ "recommend/suggested" that for Buffalo he wouldn't use typical "current output"/"low imput impedance" trafos like for other current output dacs, as there is no chance to force Sabre to work in current output mode with any Trafo..but he "suggested" interstage trafo with 600:600Ohm...And 600Ohm could be probably "more optimal" for 390Ohm than 20Ohm from our LL1517.
But as I've mentioned few months back in this thread I'm not trafo/dac specialist and I really could use somebody with much greater knowledge in this subject...As there is lot of different ideas and probably with Sabre all this configurations are working but what is the best/optimal solution I really would like to know...

And I hope that Russ will correct me if anything I said He said is not what He said....


Regards
Rosendorfer
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Old 30th August 2010, 01:24 AM   #112
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Quote:
Originally Posted by Rosendorfer View Post
Hi Tyimo


And I hope that Russ will correct me if anything I said He said is not what He said....


Regards
Rosendorfer

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Old 30th August 2010, 06:33 AM   #113
Tyimo is offline Tyimo  Hungary
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Hi Rosendorfer!
Thanks for all the help!
I tried my LL1517 with another DAC and works super!
The ideal for this transformer: 10 R primary source impedance and 600 R Secondary load.
You should paralell the secondary windings to get 2:1 turn ratios. That would be good for you high voltage output DAC.

Greets:
Tyimo
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Old 31st August 2010, 01:18 PM   #114
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Hi Russ

Well that's nice to know..

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Rosendorfer
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Old 31st August 2010, 01:19 PM   #115
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Hi Timyo

Thanks I will thing about this....

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Rosendorfer
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Old 2nd September 2010, 12:24 PM   #116
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Thank you Rosendorfer!

That's good to know, I definitely have to try that
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Old 26th September 2010, 03:59 PM   #117
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Hi guys

Is there any proven circuit for connecting 600:600 transformers (I'm using UTC A-20's) to the Buf II? Just straight from the output to the primaries? And what about the secondaries - RC filter, or just a resistor?

Thanks,
Fedor
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Old 28th September 2010, 06:03 PM   #118
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Hi Fedor

This is the beauty of this situation, as far as I know there is no "provern" circuit ...
But on other hand it seems that with Buffalo moust of transformers "just" works..prety well.
As for and RC filter it seems that You are on Your own, just trust to Your ear...

It would be great to hear Your coments regarding this connection, as 600Ohm Trafos seems to be more siutable for Bufallo.
Do You have standard IVY or Legato to make any comparision..??

Regards
Rosendorfer
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Old 29th September 2010, 09:00 AM   #119
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Hi Rosendorfer, thank you for your answer.

Seems that I'll have to experiment with different circuits Buffalo II is 2-3 days away from me, so when it gets here, I think first I'll try straight out from dac to the primaries. And then will try some other circuits found in this thread.

I'll post the results, when I'll get this thing running.

As for the conversion board - alas, I don't have one, but maybe will get later.

Thanks,
Fedor
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Old 29th September 2010, 01:35 PM   #120
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Hi Fedor

I just get my second Buffalo, this time with Legato, parcel arrived hour ago......
Have fun with Yours ...

All the best

Rosendorfer
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