New Stepped Attenuators from SW1X

Joe Cohen

Industry Expert
Jun 10, 2012
175
183
348
This is a review from another forum:

”Over the past 15 years I have owned a number of pre-amplifiers utilizing sold-state and tube typologies and have always been curious about the sound quality of these volume potentiometer and Khozmo attenuators used in these designs. I have read numerous articles on the degradation that these controllers have on the overall impact of destroying dynamics, scale and contributing to thin/flat sound.

I have experienced these attributes of poor sounding Alps volume controllers/digital attenuators with a scratchy like sound or a clicking/popping noises every time the volume is increased or decreased. It always led me to think, why would a builder use such an inferior product if a better sounding alternative would sound better for reasonable cost to upgrade and if the upgrade would highlight that builders’ designs? I’m sure cost weighs heavily on the designer and possibly the availability of quality part selections.


92BD0569-1155-4D19-B8B5-E23AC7B3B285.jpeg


I have searched many old threads on stepped attenuators and there was always a question if a reputable manufacturer was still producing them. I had been following my Dac designer/builder every month or so to see the progressions on his amp designs and discovered that he had built a reference level stepped attenuators and I knew from the moment I laid eyes on them that his device was going to replace my blue alps in my 2A3 DHT pre-amp.

Both Mono and Stereo models are offered in 5 versions:

1. Black Series, Black Fibre Boards, with Copper ground wire, non-magnetic 0.5W Carbon resistors in shunt, non-magnetic AB 2W resistors in series
2. Grey Series, Black Fibre/Brown Bakelite boards and Copper ground wire, non-magnetic 0.5W Carbon resistors in shunt, non-magnetic AN Copper 2W Tantalum resistors
3. Brown Series, with all Bakelite boards and fine Silver ground wire, non-magnetic 2W Carbon resistors in shunt and non-magnetic AN Copper 2W Niobium in series
4. Gold Series, no expense spared Series, with all Bakelite boards and fine Silver ground wire, non-magnetic 0.5W Copper Tantalum resistors in shunt, non-magnetic AN Copper Niobium resistors in series
5. Silver Series, no expense spared Series, with all Bakelite boards and fine Silver ground wire, non-magnetic 0.5W Silver Tantalum resistors in shunt, non-magnetic AN Silver Niobium resistors in series



E786EB01-9C9C-43DE-AD20-0207F3D304CA.jpeg



The moment of truth arrived on Christmas Eve and I was excited to get the Pre-Amp hooked up to hear it for the first time with a reference level stepped attenuator in place of the previous Alps. The sound was absolutely wonderful and with zero burn-in and based upon general internet opinions, it really starts to show its potential at 100 + hours of use. With just over 10 hours of use, more clarity is beginning to immerge.

I have really been evaluating these volume controllers in my pre and tube amp which also has a volume controller that I used while my pre was being upgraded… The first thing I noticed was the volume was more linear and more representative of loudness based upon the hands on a clock. My Alps at the 9 O-Clock position would yield my normal 70 Db listening level but 10-11 O-Clock position would run you out of the room…

So, what did I hear; musicality, unbelievable transparency, bold and articulate presentation, more holographic, effortless layering, lower floor noise, more refinement in sound stage width and depth with images being more tangible with real-life scale.

All of these characteristics are just amazing but the one thing that blew me away was the sense of being in the recorded space; You are not just hearing a three-dimensional rendering but instruments have body and dimensionality that swells and projects beautiful resonate sound toward the listener; this is a phenomenon that has to be experienced and heard to explain but breathtaking…

SW1X Brown Series 24 Way Stepped Attenuator Volume Control built by a renown engineer has been a revelation in my sound system and has brought me even more listening enjoyment. If you are using an inferior volume controller or even a so-called quality attenuator, I Highly Recommend that you contact Dr. Slawa to discuss your needs and be prepared to hear the very essence of natural and realistic sound.

https://sw1xad.co.uk/product/sw1x-stepped-attenuator-volume-control/


www.lotusgroupusa.com
 

Solypsa

Well-Known Member
Jun 7, 2017
1,086
719
220
Seattle
www.solypsa.com
Silver switch contacts/wipers?
 

Salectric

Well-Known Member
Jan 15, 2012
115
129
348
41
The different versions using quality resistors is impressive. I am a big fan of Audio Note silver tantalum resistors, and I use them in critical spots throughout my electronics.

But the review begs the question—how do these stepped attenuators compare to Dave Slagle’s AVC attenuator. I use the Slagle Elmaformer which has 43 steps and it sounds marvelous, with or without an active gain stage.
 

hbsry2001

Well-Known Member
Apr 9, 2018
21
20
70
This is a review from another forum:

”Over the past 15 years I have owned a number of pre-amplifiers utilizing sold-state and tube typologies and have always been curious about the sound quality of these volume potentiometer and Khozmo attenuators used in these designs. I have read numerous articles on the degradation that these controllers have on the overall impact of destroying dynamics, scale and contributing to thin/flat sound.

I have experienced these attributes of poor sounding Alps volume controllers/digital attenuators with a scratchy like sound or a clicking/popping noises every time the volume is increased or decreased. It always led me to think, why would a builder use such an inferior product if a better sounding alternative would sound better for reasonable cost to upgrade and if the upgrade would highlight that builders’ designs? I’m sure cost weighs heavily on the designer and possibly the availability of quality part selections.


View attachment 87231


I have searched many old threads on stepped attenuators and there was always a question if a reputable manufacturer was still producing them. I had been following my Dac designer/builder every month or so to see the progressions on his amp designs and discovered that he had built a reference level stepped attenuators and I knew from the moment I laid eyes on them that his device was going to replace my blue alps in my 2A3 DHT pre-amp.

Both Mono and Stereo models are offered in 5 versions:

1. Black Series, Black Fibre Boards, with Copper ground wire, non-magnetic 0.5W Carbon resistors in shunt, non-magnetic AB 2W resistors in series
2. Grey Series, Black Fibre/Brown Bakelite boards and Copper ground wire, non-magnetic 0.5W Carbon resistors in shunt, non-magnetic AN Copper 2W Tantalum resistors
3. Brown Series, with all Bakelite boards and fine Silver ground wire, non-magnetic 2W Carbon resistors in shunt and non-magnetic AN Copper 2W Niobium in series
4. Gold Series, no expense spared Series, with all Bakelite boards and fine Silver ground wire, non-magnetic 0.5W Copper Tantalum resistors in shunt, non-magnetic AN Copper Niobium resistors in series
5. Silver Series, no expense spared Series, with all Bakelite boards and fine Silver ground wire, non-magnetic 0.5W Silver Tantalum resistors in shunt, non-magnetic AN Silver Niobium resistors in series



View attachment 87232



The moment of truth arrived on Christmas Eve and I was excited to get the Pre-Amp hooked up to hear it for the first time with a reference level stepped attenuator in place of the previous Alps. The sound was absolutely wonderful and with zero burn-in and based upon general internet opinions, it really starts to show its potential at 100 + hours of use. With just over 10 hours of use, more clarity is beginning to immerge.

I have really been evaluating these volume controllers in my pre and tube amp which also has a volume controller that I used while my pre was being upgraded… The first thing I noticed was the volume was more linear and more representative of loudness based upon the hands on a clock. My Alps at the 9 O-Clock position would yield my normal 70 Db listening level but 10-11 O-Clock position would run you out of the room…

So, what did I hear; musicality, unbelievable transparency, bold and articulate presentation, more holographic, effortless layering, lower floor noise, more refinement in sound stage width and depth with images being more tangible with real-life scale.

All of these characteristics are just amazing but the one thing that blew me away was the sense of being in the recorded space; You are not just hearing a three-dimensional rendering but instruments have body and dimensionality that swells and projects beautiful resonate sound toward the listener; this is a phenomenon that has to be experienced and heard to explain but breathtaking…

SW1X Brown Series 24 Way Stepped Attenuator Volume Control built by a renown engineer has been a revelation in my sound system and has brought me even more listening enjoyment. If you are using an inferior volume controller or even a so-called quality attenuator, I Highly Recommend that you contact Dr. Slawa to discuss your needs and be prepared to hear the very essence of natural and realistic sound.

https://sw1xad.co.uk/product/sw1x-stepped-attenuator-volume-control/


www.lotusgroupusa.com
Ive not heard these but I replaced the ones in my hand built all P2P wired, no transistor crap, dual mono pre amp with the top of the line 48 step Khozmo a and the diffenernce was huge.
 

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