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Old 7th February 2018, 07:07 PM   #101
AlexanderTD is offline AlexanderTD  Ukraine
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Is Mercury working well with Sympatico? Any optimal gain setting or other last minute tweaks recommended?
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Old 7th February 2018, 07:11 PM   #102
Russ White is offline Russ White  United States
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It works perfectly with Sympatico (I use this in my main system) - I have mine set for 2Vrms output. You could go a little higher depending on the gain of the Sympatico and desired/practical output power. I would stick with 2Vrms to start - you can easily change later.
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Old 13th February 2018, 10:47 AM   #103
Dimdim is offline Dimdim  Greece
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I have been using Mercury with my ES9028-based DAC for a couple of days now and I must say that I'm impressed! Great job guys!

But I do have a question.. I am getting exactly 3V RMS out of the Mercury's SE outputs with the 9028 resistors installed. That is a bit on the high side, right?

I wonder if it has to do with my "mystery ES9028", sourced from Ebay, featuring no thermal pad and a chip_ID not matching either the 9028 or 9038.

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Old 13th February 2018, 12:31 PM   #104
Russ White is offline Russ White  United States
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Very glad you like it

Yes - it's intentionally high - because of the +/-14% chip to chip variation. This way you have headroom to adjust. Also it will depend on the AVCC supply.
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Last edited by Russ White; 13th February 2018 at 12:33 PM.
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Old 13th February 2018, 12:52 PM   #105
Dimdim is offline Dimdim  Greece
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I see. So what would be a suitable set of resistors for a more "sensible" (IMHO) output level? Let's say ~2.5V RMS or even a bit less.
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Old 13th February 2018, 12:56 PM   #106
Russ White is offline Russ White  United States
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Quote:
Originally Posted by Dimdim View Post
I see. So what would be a suitable set of resistors for a more "sensible" (IMHO) output level? Let's say ~2.5V RMS or even a bit less.
It is really simple - just do the math - apply any ratio you wish based on your current output level. You know the current R value and the current voltage output. Solve for desired Vout. Keep in mind the nominal impedance of each channel is ~200R(+/-14%)
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Old 13th February 2018, 01:24 PM   #107
Dimdim is offline Dimdim  Greece
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Fair enough.

Have you observed any undesirable side effects of lowering the output levels, like for example a subjective loss of dynamics?
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Old 13th February 2018, 02:12 PM   #108
Russ White is offline Russ White  United States
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Nothing to worry over - just choose the right output level for the rest of your chain. It's all about the gain of your next stage and other practical factors. For some applications ~2VRMs is ideal - for some 4 for some even 1. There is no "right" answer for everyone but 2-4VRMs is common.
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Old 13th February 2018, 05:36 PM   #109
barrows is offline barrows
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Default DimDim...

i think Russ' estimates for Vout on the Mercury might be a little off. For me I used 120R for gain setting resistors, as Russ suggested that ought to get me close to 4 V RMS out, and I have a bit over 6 VRMS out (measured). (Mercury with 9038 Buff PRO). Not a huge difference though...
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Old 13th February 2018, 05:40 PM   #110
Russ White is offline Russ White  United States
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My calculations are based on 50R output Z (for the 9038) keep in mind 14% lower output Z accross 120R would be about 6Vrms - where as 14% higher output Z would be just over 4Vrms. The goal was to get you at least 4Vrms with the understanding you will have to tweak that to get an exact target output swing.
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