Stepped attenuators vs. Carbon pots - diyAudio
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Old 22nd April 2007, 11:24 PM   #1
Klimon is offline Klimon  Belgium
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Default Stepped attenuators vs. Carbon pots

I'ld like to inform after your experiences with volume pots and their impact on sonics, especially stepped atts vs carbon pots. There seem to be very mixed opinions about this topic, the classical story ascribing dramatically 'clearer' sound to higher cost of pot (from 1$ ratshack --> Alps --> stepped attenuator), the alternative story content with simple and cheap carbon pots (with preferance to some type)...

I myself haven't noticed any dramatic sonic signature even of the cheapest pots. I'll soon get my first taste of stepped attenuators (diy ladder type, built from scratch) but missing direct comparison I really don't expect an overwhelming performance of the ladders.

Please feel free

Simon
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Old 22nd April 2007, 11:54 PM   #2
cotdt is offline cotdt  United States
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It's very easy to find out. Simply build two identical amps, one with a stepper and one with a pot. Then A/B test them (blind or not, doesn't matter). Many people tell me that there is indeed a difference in sound quality, with the cheaper pots sounding livier and superior to the stepped attenuators.
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Old 23rd April 2007, 12:13 AM   #3
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I'm awaiting delivery of one of these http://cgi.ebay.co.uk/Stepped-100K-S...QQcmdZViewItem all the way from Hong kong. It is going in to a passive preamp and replacing an Alps Blue so I'll post my results when the time comes.
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Old 23rd April 2007, 12:24 AM   #4
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I think the key advantages of stepped attenuators over potentiometers as volume controls are:

* accurate tracking of stereo controls, giving better balance between channels, especially at low settings;

* avoiding possible noise due to poor contact between the wipers and tracks in worn or substandard pots.

Beyond this, there may be other advantages to be gained from using high quality resistors in attenuators, I don't know.
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Old 23rd April 2007, 05:18 AM   #5
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I'm really sensitive to balance, and ganged pots don't do that well at low levels. How can you have good imaging when the balance is off? Admittedly, the high end pots are darn good, for a price. If carbon pots are superior, then carbon resistors should be the resistor of choice for the rest of the circuit. Hmmm. I'll take a properly made step attenuator over pots any day of the week
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Old 23rd April 2007, 08:44 AM   #6
Klimon is offline Klimon  Belgium
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Quote:
Many people tell me that there is indeed a difference in sound quality, with the cheaper pots sounding livier and superior to the stepped attenuators.
Do you know if they were referring to series or ladder type attenuators?

Simon
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Old 23rd April 2007, 10:43 AM   #7
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I've tried Alps blue and black beauties and various other pots and prefer stepped attenuators with holco resistors. Best of all is a shunt attenuator between balanced legs.
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Old 23rd April 2007, 12:08 PM   #8
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Quote:
Originally posted by Eusebius
I've tried Alps blue and black beauties and various other pots and prefer stepped attenuators with holco resistors. Best of all is a shunt attenuator between balanced legs.
'
I would be VERY interested in your opinion of the ALPS 'blue' Vs the 'black'. I've never got round to trying the black and often wondered if it was worth the extra. It looks a little better made from the outside but it's what's inside that counts.

I've always liked the Alps blue. The matching and therefore imaging is superb except for the very lowest settings. It can be quite annoying late at night when I have to have louder than I need just to preserve the stereo image. I've spent many nights listening with my head tilted to compensate!!

I'm looking forward to using a stepped attenuator but I am a little concerned that 23 steps may not be enough. I can always modify it later.
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Old 23rd April 2007, 10:14 PM   #9
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I don't know that there's much difference between black and blue Alps. Of the ones I have the blue tracks better, funnily enough. you can improve the sound by putting good resistors across from signal to wiper and wiper to earth. I have 250k alps which I've reduced by using 68k resistors.

I've never had any problem with 12 steps myself - don't understand how you need to be more accurate, but then I'm a pretty flexible guy.
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Old 23rd April 2007, 10:30 PM   #10
phn is offline phn  Sweden
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I believe both Alps pots use plastic tracks and not carbon.

This is carbon: http://www.elfa.se/elfa-bin/setpage....03.htm&lang=en
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