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Old 9th December 2011, 01:44 AM   #421
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You guys made a pretty good product at a great price. But I'm trying to go with discrete outputs. I was looking for a different passive way to do things but a simple RC filter is the simple solution if only the balanced outputs of the Legato are used with discrete opamps that show "intolerance" to DC Bias. Maybe just using the "+" and the gnd of Legato outputs could be an alternative. There will still be DC to block but maybe less "complicated" for opamp inputs.
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Old 9th December 2011, 01:48 AM   #422
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Default Crazy...

If you want discrete, and you want to take advantage of the best possible performance the Legato has to offer, the answer is simple: Use the balanced outputs! Less components in the signal path, and common mode noise cancellation to the inputs of the next stage.
Try a balanced amp with it, or preamp if you prefer...
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Old 9th December 2011, 06:52 AM   #423
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Originally Posted by Russ White View Post
That is a completely silly thing to say for someone looking for help. I am having a hard time following you. If you claim to understand as much as you seem think you do why exactly are you asking for help?

The ES9018 does not work like other current output DACs, The critical factor is bias modulation at the output. The voltage at the outputs needs to stay as constant as possible. Thus the importance of extremely low input impedance.

To answer your earlier questions. I have no interest in that DAC, so you are on your own. Give it a go. If you do you should be able to simply adjust the gain of the BAL/SE stage. Simple enough if you understand the schematic.

If you don't like the idea of the Legato then do us all a favor and by all means don't try to use it.
I understand now the Legato was designed specifically for ES9018; I am not familiar with its operation / specifications, but the short explanation from you re bias modulation at the output (and some reading through limited information on ES chips) has meant a fair bit, explained why it sounds the way it sounds, and why it will always sound different to properly implemented 1704s, so thank you.

I am not going to comment your remark that my wish to obtain some specifications on your product / wish to use your product with 1704's in dual differential configuration is completely silly. Ill leave it at that.

I asked for help because I could not find any proper specs of your Legato 3 that are equivalents of OP input bias current and input offset voltage two main factors in obtaining the best from 1704s.

I also respect your statement that you dont have interest in 1704s the only reason why I am writing all this and asking for help is because I dont have interest in ES chips; I heard few players and DACs with these chips and was left with mixed feeling dynamic but without character / low level resolution / micro-resolution >but I can see why many here could love its sound it is just not for me

Boky
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Old 9th December 2011, 11:23 AM   #424
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Quote:
Originally Posted by crazyfrog View Post
You guys made a pretty good product at a great price. But I'm trying to go with discrete outputs. I was looking for a different passive way to do things but a simple RC filter is the simple solution if only the balanced outputs of the Legato are used with discrete opamps that show "intolerance" to DC Bias. Maybe just using the "+" and the gnd of Legato outputs could be an alternative. There will still be DC to block but maybe less "complicated" for opamp inputs.
You could try the fully discrete Ventus for Bal-SE conversion.
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Old 9th December 2011, 11:29 AM   #425
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Originally Posted by barrows View Post
If you want discrete, and you want to take advantage of the best possible performance the Legato has to offer, the answer is simple: Use the balanced outputs! Less components in the signal path, and common mode noise cancellation to the inputs of the next stage.
Try a balanced amp with it, or preamp if you prefer...
Yes, balanced to balanced is the best but that means a line driver or something similar in my case. Using the Ventus as a discrete balanced to SE stage would be a less complicated option. Thanks anyway.
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Old 9th December 2011, 12:20 PM   #426
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Hi Boky,

The part I was saying was silly was that there would be any possibility that we were not interested in "Low level resolution".

As for the TI DAC you wish to use. I am just saying I don't have any time to spare to research it. It probably would work fine. Your just going to have to try it for yourself.

I can't say I agree with your assessment of the ES9018 in the least. So it's hard for me grasp exactly what you might be looking for in a DAC. Plus the statement you made seems to be painting with far too broad a brush. You said nothing about the way the DACs you heard were implemented.

As for Legato 3.1 I think if you ask most people who have heard it you would find strikingly different opinions from the picture you paint. It excels at reproducing "low level details" in every way.

In short - I was not commenting on your DAC choice at all. I simply did not design the output stage for the DAC you are using - though it should work fine for the DSD1794 and similar by only doubling the output swing I have never used the particular chip you are using.

Cheers!
Russ
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Last edited by Russ White; 9th December 2011 at 09:50 PM.
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Old 9th December 2011, 02:02 PM   #427
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Default Hot Legato

Hi Russ,

I just fired up a Legato 1.0.3 i had to replace an old IVY board and it is working ok but the transistors get very hot, is this normal ?

I have it connected to my lab PSU at +-15V ( 330 ma per channel ),
injected a sine wave on input and i do get a nice clean amplified wave at output .

The Temperature of the transistors is arround 65-75C according to my laser thermometer....too hot to touch for long....
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Old 9th December 2011, 02:09 PM   #428
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Originally Posted by BrianDonegan View Post
You could try the fully discrete Ventus for Bal-SE conversion.
Interesting option indeed. An alternative to expensive AC coupling capacitors. I will read the Ventus thread. Thanks.
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Old 9th December 2011, 02:10 PM   #429
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Quote:
I just fired up a Legato 1.0.3 i had to replace an old IVY board and it is working ok but the transistors get very hot, is this normal ?
Yes, it's normal.
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Old 9th December 2011, 02:15 PM   #430
CeeVee is offline CeeVee  Portugal
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Thanks Brian
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