Shunt or Series Stepped Attenuator.

EarWorm · 3889

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Offline EarWorm

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on: June 27, 2015, 12:32:54 PM
I'm leaning towards a stepped attenuator for my crack build but I am not clear if an input impedance issue will be a problem for a Shunt attenuator with the Crack.  So I'm not sure if a Series or Shunt will be better.

Thanks. 

Sony 8FC-69WA AM/FM Digimatic Flip Clock Radio Circa 1971. 
1962 RCA Victor 4 Volt Superheterodyne AM Radio With ear Jack & plastic ivory ear piece.   What?


Offline Paul Birkeland

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Reply #1 on: June 27, 2015, 09:46:05 PM
You'd have to discuss further what specific designs your looking at and what source components you may be using to drive your Crack.

Most stepped attenuators that you see online are ladder attenuators.   

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline EarWorm

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Reply #2 on: June 28, 2015, 06:18:43 AM
My source is a W4S DAC2.   I'm working a slow build toward my crack by upgrading parts over time as I buy the items when they finally appear on sale.  Right now I have a large credit with a vendor and I'd like to obtain the new Khozmos Shunt Attenuator with that credit but I am confused about things I've read about input impedance and shunt attenuators.  Will something like that really matter? 

Eventually I'll design a chassis for all the upgraded components, and I'm not sure of the layout yet but I want to show some things up top the chassis for looks and the Khozmos shunt Attenuator is one of them.  Don't know yet how I would do that but it's too nice looking to hide. But if it won't work as a shunt then I'll do something else. 
I just don't have the experience with the impedance question.   

Sony 8FC-69WA AM/FM Digimatic Flip Clock Radio Circa 1971. 
1962 RCA Victor 4 Volt Superheterodyne AM Radio With ear Jack & plastic ivory ear piece.   What?


Offline JamieMcC

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Reply #3 on: June 28, 2015, 08:45:59 AM
Some pics on headfi of a Khozmo attenuator squeezed into a stock Crack enclosure

https://www.head-fi.org/t/476650/crack-bottlehead-otl/6630

Shoot for the moon if you miss you will still be amongst the stars!


Offline Paul Birkeland

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Reply #4 on: June 28, 2015, 08:56:19 AM
I'd like to obtain the new Khozmos Shunt Attenuator with that credit but I am confused about things I've read about input impedance and shunt attenuators.  Will something like that really matter? 
There isn't really enough data on these to even worry about impedance.  Just go with the 100K specified part.  The input impedance will vary, but your source shouldn't be very stressed driving it.


Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline EarWorm

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Reply #5 on: June 28, 2015, 09:46:37 AM
Thanks Paul.  I just needed to make sure it wouldn't be a gross mistake since I could find no data about impedance. 


Sony 8FC-69WA AM/FM Digimatic Flip Clock Radio Circa 1971. 
1962 RCA Victor 4 Volt Superheterodyne AM Radio With ear Jack & plastic ivory ear piece.   What?


Offline EarWorm

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Reply #6 on: June 28, 2015, 09:55:08 AM
Some pics on headfi of a Khozmo attenuator squeezed into a stock Crack enclosure

https://www.head-fi.org/t/476650/crack-bottlehead-otl/6630

Jamie, I saw that post when I was scouring the Internet for any info on the
Khozmos.   I think I forfeited the Crack chassis when I purchased these for the power supply.  :)

Warning! Capacitor Porn and choke porn ahead.

Sony 8FC-69WA AM/FM Digimatic Flip Clock Radio Circa 1971. 
1962 RCA Victor 4 Volt Superheterodyne AM Radio With ear Jack & plastic ivory ear piece.   What?


Offline JamieMcC

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Reply #7 on: June 28, 2015, 10:14:12 PM
lol that's going to be a fun build.

Shoot for the moon if you miss you will still be amongst the stars!


Offline mcandmar

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Reply #8 on: June 29, 2015, 03:43:24 AM
Now that is some cap porn, they are lovely :)

M.McCandless


Offline EarWorm

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Reply #9 on: June 29, 2015, 10:02:05 AM
Grabbed two of these for the output caps a few months back when HiFi collective had them at an excellent price.   MCap EVO Aluminum Oil.     Porn is porn.   :)
« Last Edit: June 29, 2015, 10:03:42 AM by EarWorm »

Sony 8FC-69WA AM/FM Digimatic Flip Clock Radio Circa 1971. 
1962 RCA Victor 4 Volt Superheterodyne AM Radio With ear Jack & plastic ivory ear piece.   What?