Passive Volume Control for DACs/Sources

Discussion in 'Digital: DACs, USB converters, decrapifiers' started by Madaboutaudio, Dec 20, 2015.

  1. lehmanhill

    lehmanhill Almost "Made"

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    Dave Slagle is da bomb. Deep transformer knowledge.

    Years ago I did a back to back comparison of a better potentiometer, an LDR (light dependent resistor) attenuator, and a relay switched step attenuator. With those specific components, the relay stepped attenuator came out on top, but I have always wished I could have borrowed a TVC or autotransformer attenuator to compare. I may have to do that someday. Has anyone else compared a good stepped attenuator to magnetic attenuator?
     
  2. androxylo

    androxylo Acquaintance

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    I'm in 3rd day of non-stop relistening of all my favorite music through Slagleformer after ditching Sys. I am simply amazed that I was slowly upgrading my stereo for many years but for the past 2 years this little $50 pot was the real bottleneck straight in my face and I never knew that. You can have a perfect DAC and perfect Amp but until you ditch the pot (whatever it is, it could be inside your amp) you won't get progress past certain point.

    The real difference is larger than I first thought. Now I hear how the piano key springs back when the finger releases it and how the guitar string moves long after the finger lets it loose. And I'm only using just a $200 DAC, not a freaking multibit...
     
  3. RenEH

    RenEH Acquaintance

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    I don't want to hear that, I just bought two Schiit Sys haha. Well at least I can provide a comparison to a Marantz AVR and a bypassed volume pot of a THX 789 when it arrives.
     
  4. gixxerwimp

    gixxerwimp Professional tricycle rider

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  5. philipmorgan

    philipmorgan Member of the month

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    I checked it out a while back and it has different connectors and internal routing than the nanopatch, but for a lot of hifi uses it would be similar enough
     
  6. EagleWings

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    Picked up a slagle autoformer recently and it has been an eye opener. I have done attenuator comparisons in the past and in each case, the differences were on the subtler side. Chord's internal digital attenuation has been my least favourite, despite their claims. Wavelight's resistor ladder attenuator was better than the potentiometers, but the difference was small. The autoformer however seems to be a good step above potentiometers, in not just sounding more clear and transparent, but also sounding more natural. It removes a layer of homogenisation that there is now greater differences between recordings, but at the same time, it seems to have removed a layer of hash/grain, thus making the sound a tad less harsh. There is just more realism now.
     
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  7. Pharmaboy

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    I've become very interesting in transformer & autoformer-based volume controllers lately, particularly the few that have dual RCA outputs and remote control. Everything I read about units containing Slagle autoformers matches what you say here.

    BTW, the review below features the device I'm most interested in. Of course the price is nuts: many AVCs and TVCs are too expensive. But there's a lot of tech inside this thing that makes it way more interesting to me:

    https://positive-feedback.com/reviews/hardware-reviews/icon4/
     
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  8. AdvanTech

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    There aren't many other options for a commercial remote-controlled AVC. The Emia version is even pricer than the icOn. You'd save a lot of money DIY but add the request for Dave Slagle to do silver windings on that autoformer and cost shoots up even more.
     
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  9. EagleWings

    EagleWings Friend

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    Yea, what Advan said. There is a slightly more affordable option from icon4 called the Zen that doesn't have an optical encoded knob, but only a remote, that sells for about $2000.
     
  10. Pharmaboy

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    Exactly right. This is the one I want. But I'd much rather find it used than buy new. I have a HiFiShark listing set up for if/when one ever comes up F.S. (it'll be a long wait!).
     
  11. Clemmaster

    Clemmaster Friend

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    You can also look into the Vinnie Rossi LIO with Tube+AVC preamp stage. They go for not much more than the icon4 Zen and have a great headphone amp and power amp that can drive pretty much any headphone and sounds fantastic.
    I, too, found the AVC stage to be really great!
     
  12. lehmanhill

    lehmanhill Almost "Made"

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    Just to add to the list of silly expensive autoformer volume controls that I would like to buy used and cheap.

    https://www.townshendaudio.com/allegri/

    with no remote and single ended. Retail price is 2080 pounds w/o VAT.

    https://www.townshendaudio.com/allegri-reference-preamplifier/

    for remote control and balanced in and out. Retail price is 10,000 pounds w/o VAT.

    I have purchased the autoformers for a balanced set up from Dave Slagle. But making it work with a remote is going to take some time to figure out.
     
  13. Pharmaboy

    Pharmaboy Friend

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    These super expensive AVCs mentioned above are borderline-disturbing to me. Just as I don't understand why a high end preamp would sell for $10K-$15K, I don't understand how AVC passives, no matter how gorgeous their cases and switches, can get to $10K. And by "don't understand," I really mean "can't justify such a huge markup vs cost of parts and production."

    At least the icon4 AVCs (the cheapest being the Zen) involve novel chip-based solutions to the passive, lossless routing of line level signals. The fellow that runs the company is a true inventor, not simply a boutique passive maker. For the icon4 Zen, I can imagine that the sell price (~$2K) is actually a legit, normal markup (ie, approximately doubling) the cost of the parts in the box + factoring in the years-long development effort to perfect a complex non-mechanical signal routing design.

    Maybe I'm kidding myself there. But when it comes to passives that are >$5K and sometimes well over, I can't begin to kid myself. Those components become "audio jewelry," things to buy when you simply don't care about the money.
     
    Last edited: Jun 7, 2023
  14. Jh4db536

    Jh4db536 Friend

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    The Slagle/Emia AVC and ICON4ag ARE literally audio jewelry and more because they probably got a couple 1000' of pure solid core silver magnetics in them which sort of justifies their price.
     
  15. gsanger

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    I've thought for a while that it can't be that hard to wire up an Arduino and some relays to make Slagleformers remote controlled. Balanced would double everything, and I'm not sure what the maximum amount of relays an Arduino can control, but there's gotta be some other hobbyist microcontroller that could be wired up.

    What do you have in mind so far for your setup?
     
  16. EagleWings

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    @Pharmaboy , RKML0007 has a Townshend Allegri for sale. It is the basic, non-remote version, but has multiple inputs. I hear it is as good as the slagle former.

    @lehmanhill , Elma has a remote kit for their audio switches. Not sure which all models it is compatible with, but that might something worth exploring. They have 12, 24 and 47 step switches.
     
    Last edited: Jun 8, 2023
  17. Thad E Ginathom

    Thad E Ginathom Friend

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    I thought, "How much? for a volume knob?"

    But I am just a passive observer of hifi these years, and kept quiet. I'm glad you didn't.

    Having said that, I do own a passive (optionally active: plug it in!) pre-amp which was $1,000 new --- in 1995. Adjusted for inflation thirty years later?

    McCormack Line Drive TLC-1 preamplifier.

    It's in the museum cupboard. I have no current use for a preamp, it fitted into plans I had some years ago when I bought it used for a fraction of its original price. It has two outputs: buffered (requires power) and passive (completely, no power needed) and a fine array of inputs, tape in/out etc. All analogue, of course.

    I have no doubt that it is a fine piece of kit, but it is now in need of a restoration, the pot having become noisy, and the phono sockets badly tarnished. Otherwise, it looks completely clean inside.
     
  18. lehmanhill

    lehmanhill Almost "Made"

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    I sympathize with you and agree that sometimes these high prices are not justified. I certainly am not willing to pay $12k for the Townshend Allegri Reference. That said, winding an autoformer is not something that can be easily automated. Hand winding an autoformer with taps every 1.5 dB is something I don't want to even try myself. Dave Slagle sells a manual, stereo volume control autoformer with Elma switches for $1080 and I'm guessing there isn't much profit considering material cost. That makes a balanced autoformer $2160 before you get to a remote control, case, etc. If you want silver, the Elma silver autoformers are $2880 for a stereo pair or $5760 for balanced. So the icON pre and even the Emia balanced pre seem more reasonably priced than I initially thought. That said, it's still too much for me.
     
  19. Thad E Ginathom

    Thad E Ginathom Friend

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    Point taken!
     
  20. Brian D

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    A little off the overall topic but the autoformer talk here got me started researching them and I ordered a pair of the mono modules from Intact audio (Dave Slagle, great to deal with). I wanted to eliminate the preamp in my 2 channel setup, and since I have an amp that I assembled from a kit, I was pretty sure I could incorporate them in the same case. I finished it up friday night, and although I haven't had a chance to really let it rip, listening at low levels is really pretty amazing. The involvement with the music at low levels is much better, the details and dynamics that normally get squashed with a conventional attenuator are present to a much greater extent. I'm pretty jazzed, and feel like showing off a bit as well, as the addition of these are my first attempt at anything beyond kit assembly. The amp is a Zkit60 sold through Decware, I think it is very similar to a design that Van Alstine uses. Just wanted to add another reference point to the conversation here, I am a huge fan of the AVC now

    Amp Before:
    . IMG_0597.JPG

    Amp after:
    IMG_0701.JPG
     
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