Trying to find the right attenuator

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doctorcilantro

Trying to find the right attenuator
« on: 16 Oct 2013, 08:07 am »
Hi all,

I'm a bit lost. I'm picking up a new DAC (Auralic Vega), and I really can't justify keeping this Zodiac Gold here even though it works nicely with my single-ended Decware EL34 amp.

I'm researching an attenuator to use with the Vega, and I would like to use its differential output. I was first looking at the Khozmo (http://www.akustyk.com/products_dale_shunt.html) and having him add supermalloy (80%Ni, 15%Fe, 5% Mo) transformers.

Input impedance of the Decware Rachel (straight amp no volume) is about 100K, and output impedance of Vega is 4.7ohm (XLR), and it does 4.4vrms on both RCA/XLR.

I'm out of league understanding if this would be excessive and if something like Slagle's autoformers do the same job with less.

A dual-mono XLR > RCA unit from Akustyk with all the extras he offers and silver wiring was about $800.


doctorcilantro

Re: Trying to find the right attenuator
« Reply #1 on: 16 Oct 2013, 10:09 am »
Sorry, I just found this thread with some good info:

http://www.audiocircle.com/index.php?topic=52560.0

John Chapman

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Re: Trying to find the right attenuator
« Reply #2 on: 23 Oct 2013, 03:27 pm »
Hello!

Sorry for the late reply - need to check in here more often......

It sounds like the DAC is your only source and that it has a digital level control. If that is indeed the case I'd for sure not introduce a resistor attenuator into the signal path - since that would take that nice super low output impedance of 4.7 ohms and crank it way up - loosing the drive to the amp and cables.

What I would do is get the DAC and run it direct. If you are running in the upper range of the volume control most the time then you are done - just enjoy some tunes! If you find that you are running quite far down in level from the top settings then give a call and we can talk about good ways to pad that down using an autoformer. This will bump you up into that upper level control range and make sure you are not throwing away information (bits) with the digital level control. You don't need anything elaborate feature wise - since the DAC will be your user interface so best to keep it really simple and clean signal path wise.

Thansk!

John