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MiniDSP Flex as balanced headphone amp?

Daltong

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Basically what it says on the tin can.
I am not very satisfied with Qudelix (it is really annoyingly glitchy) and am looking for a beefier, more stable replacement with TOSLINK (because interfacing via USB with linux has a lot of unpleasant hairs like pulseaudio clicks which I only mostly sorta defeated)

Flex seems to fit the bill https://www.audiosciencereview.com/forum/index.php?threads/minidsp-flex-review-audio-dsp.30804/

questions:
1) is there anything I should mind when trying to use this as balanced headphone amp (other than finding necessary cable adapters)? Like it would seem 4v RMS is 4v RMS?

2) is there any practical relevance of output impedance, particularly for driving low impedance headphones like Aeon RT Closed ?

3) should I be at all concerned about its IMD or like, "it's okay enough" ?
 

DVDdoug

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is there any practical relevance of output impedance, particularly for driving low impedance headphones like Aeon RT Closed ?
I scaned the review and I didn't see anything about impedance..

Usually, line outputs are meant to drive an input of 10K-100K Ohms. Often they work at 1K, but headphones is "pushing it".

It's OK to use a headphone-output as a line-output (into a line input)... The voltage levels are similar and there's no issue driving a higher impedance.
 

NTK

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2) is there any practical relevance of output impedance, particularly for driving low impedance headphones like Aeon RT Closed ?
Yes, it is a problem in your case. The MiniDSP Flex has an output impedance of 200 ohms. The impedance of the Aeon RT Closed is 13 ohm.

From the voltage divider formula, the max voltage you'll get to the Aeon RT Closed will be: 4 * 13/(200+13) = 0.24 V.
 
OP
Daltong

Daltong

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Yes, it is a problem in your case. The MiniDSP Flex has an output impedance of 200 ohms. The impedance of the Aeon RT Closed is 13 ohm.

From the voltage divider formula, the max voltage you'll get to the Aeon RT Closed will be: 4 * 13/(200+13) = 0.24 V.
Thanks!
That indeed does sound like a problem (ouchie)

Hm, maybe I should wait for digital <-> digital version of Flex using it effectively as standalone equalizer and feed it into a more vanilla DAC+AMP (pricey but such is life)
 

TimW

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Thanks!
That indeed does sound like a problem (ouchie)

Hm, maybe I should wait for digital <-> digital version of Flex using it effectively as standalone equalizer and feed it into a more vanilla DAC+AMP (pricey but such is life)
Or just get a standalone headphone amp to use with the flex.
 

Snoopy

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OP
Daltong

Daltong

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The XLR out is not really balanced. I'm running the Aeon 2 Noire with a Singxer SA-1 (balanced) and I use roon for headroom management and DSP. And I'm at 2-3pm on the volume knob in high-gain if I want really loud.
Wait, you mean XLR outputs on the EX 5 ? hm. That means I need to somewhat reconsider my plans. Maybe use Flex-with-balanced-outputs as a preamp? That should work, right?
 

Snoopy

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Wait, you mean XLR outputs on the EX 5 ? hm. That means I need to somewhat reconsider my plans. Maybe use Flex-with-balanced-outputs as a preamp? That should work, right?

From the Review:

"Note that the XLR style headphone out is for convenience and does not produce more power."
 
OP
Daltong

Daltong

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Maybe I should go "optical to Flex digi-digi" -> "optical to a decentish DAC with balanced out like E50" -> "Topping A90"?
 
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Daltong

Daltong

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Or is concern about Flex's IMD shenanigans overrated and it is good enough to connect to a say A90 directly?
 

TheBatsEar

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Hm, maybe I should wait for digital <-> digital version
I don't think that is a good strategy as long as microcontrollers are unobtainium for MiniDSP.

I would look for another headphone amp that is available right now.

Or is concern about Flex's IMD shenanigans overrated and it is good enough to connect to a say A90 directly?
I personally think its not a problem for me, but i don't listen with headphones at all.
 
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