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Dave Slagle Monoblock Transformer Volume Control Build

Discussion in 'DIY' started by SET12, Feb 7, 2016.

  1. SET12

    SET12 Super Member

    Messages:
    1,841
    Location:
    Appleton,WI
    I recently built these after hearing Redboys TVC's a while back.

    SD531533.JPG
    The sound is outstanding, better than any passive volume control I have ever heard by a wide margine.

    On the site http://www.intactaudio.com/atten.html top of the page you'll see the basic kit for $350 which I purchased.

    [​IMG]

    I found a couple of Black ABS boxes on Digikey, knobs I already had. Switches are gold over silver contacts and were $75/pair. RCA jacks were from Parts Express and are of very good quality. The footers are from Maple Shade and are solid brass with black powder coated paint these were $160 for the six footers http://shop.mapleshadestore.com/Brass-Surefeet-With-Black-Finish-set-of-3-/productinfo/SFSET-BL/ They give a lot of mass and make the boxes feel like battleships.

    SD531567.JPG SD531563.JPG SD531558.JPG

    I wired the TVC's with CAT5 wire 24AWG and have no complaints with the CAT5 sound quality.

    SD531547.JPG

    They are very easy to demonstrate their sound quality as I did here http://www.audiokarma.org/forums/in...e-slagles-transformer-volume-controls.701044/

    All I can say is I'll never listen to anything with conventional pot volumes or for that matter resistor step attenators and they are damaging to the sound.

    So one can use these TVC's as they are called with any preamplifier or integrated amplifier. If you do it will be like hearing the full potential of your amplification like you have never heard before.

    I am currently using these with a $500 Marantz PM5005 2ch Integrated Amplifier and its as though the Marantz should cost thousands not hundreds of dollars as it is able to do things that no $500 amplifier has done for me before.

    SET12
     

     

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  2. seti

    seti MonkeyButtonPusher

    Messages:
    115
    Location:
    Arcansas
    I agree 100%. The slagle autoformers are the shiznit!

    Here is what I did with mine and a 1920's phillips radio battery box.
    [​IMG]
     
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  3. sqlsavior

    sqlsavior AK Subscriber Subscriber

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  4. enginedr

    enginedr Well-Known Member

    Messages:
    913
    Location:
    nyc
    TVC is on my upgrade list . I would like to convert my CI audio passive controller to TVC
     
  5. SET12

    SET12 Super Member

    Messages:
    1,841
    Location:
    Appleton,WI
    Great work guy's, I can't thank Redboy enough for allowing me to hear them, it didn't take much to convert me! I heard the improvements immediately!

    Have any of you guy's just tried the TVC with a preamp or integrated amplifier like I have?

    Just insert the TVC into a tape loop with the TVC volume down and the Integrated amps volume all the way up and your in business.

    The same can be doe with a preamp, then you have the line stage gain if need be. The TVC turns the amplifier or preamp into a whole different animal.

    I can't get over the sheer musicalness. :)

    I'll never be without one.

    SET12
     
  6. jdg123

    jdg123 Active Member

    Messages:
    245
    Location:
    Traverse City, Michigan
    I too have but in many hours and many, many dollars into investigating the best way to control volume. The Slagle method shines on as the best! I wish I would have found it first! But then I wouldn't know for sure :)

    For me, a simple box that fits in with the rest of my equipment rack. I used $1 switches and military surplus wiring. The Mahogany is from an old table leaf, the top is scrap Ash. I put all my pennies into the device!

    Below the AVC is a Nelson Pass B1 buffered volume control. It's good, but I use it in the basement now...
     

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  7. danbisawsum

    danbisawsum Active Member

    Messages:
    145
    Location:
    Nottingham, PA (chip country)
    Has anyone here compared them to an LDR design, light the lightstar? If so, what's the impression?
     
  8. mkane

    mkane AK Subscriber Subscriber

    Messages:
    6,326
    Location:
    103 miles N. of S.F.
  9. HypnoToad

    HypnoToad Ms Puss Puss Subscriber

    Messages:
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    Melbourne, Australia
    +1
     
  10. mkane

    mkane AK Subscriber Subscriber

    Messages:
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    Location:
    103 miles N. of S.F.
    I'm afraid if I bought the main pieces I wouldn't be able to finish the project.
     
  11. SET12

    SET12 Super Member

    Messages:
    1,841
    Location:
    Appleton,WI
    Sure you can! They are Ultra Easy, I didn't even need a powered drill. I used a hand reamer I have two, one is about a 1/2 in. tapering down to about 1/8 in. and the other is a micro going from maybe 1/16 in to about 1/4 in. The micro is great for circuit boards when I want small holes in traces. Mine are both made by Hall made in Sheffield England. But there certainly are many manufactures. I like the handle gripe better than the T-handles I commonly see. I've had mine for many years. Also you don't need to expensive of a soldering iron. I have a Hakko soldering station (for variable temperature) and a Hakko #454 25 watt soldering iron. The tips are reasonable and they are directly interchangeable. One gets what they pay for. These are worth every penny. The iron is all you need.

    Hand Reamer.jpg Hakko #454.JPG

    My boxes are ABS with non magnetic brass inserts and screws. The box size is a little over 4.5 in wide from the front 2.5 in tall and 6 in long. I used brass footers. Get some decent jacks from Parts Express and some Belden 24 or 22 gauge copper door bell wire or some CAT5 wire like I did and your all set. I put mine together while I was watching a classic SciFi. I also worked with a MM plastic ruler to very carefully mark to within 1 mm where to use my reamers. I enjoyed the putzing with the project immensely. I did one writing down measurements then I did the other. Nothing to it.

    You don't have to be like me. But IMO the TVC's deserve something nice as they do sound great.

    I know jdg123 personally and he is a craftsman whose skills I admire greatly.

    I'd also like to add he is using the TVC's with these gorgeous sounding 1.6 watt BOS45 Monoblock amplifiers. One of the finest amplifiers I have ever had the pleasure of hearing. And these aren't little as they are almost 3ft x 3ft next to each other.

    BOS 45 2.jpg


    I have actually heard one, in fact jdg123 built it and while it was musically pleasant I found the bass to be a bit on the loose side IMO. I might add it is IMO not competitive with the Dave Slagle TVC. The Slagle is way more dynamic and better in to many areas to mention. I think if you hear it it will be very obvious, its nothing subtle :)
     

     

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  12. mkane

    mkane AK Subscriber Subscriber

    Messages:
    6,326
    Location:
    103 miles N. of S.F.
    SET12, thanks for the reply. I have the tool's to do the job. What I don't have is the knowledge to Purchase the right parts and wire it up the right way.
     
  13. SET12

    SET12 Super Member

    Messages:
    1,841
    Location:
    Appleton,WI
    You have plenty of help here! Piece of cake ;-)
     
  14. mkane

    mkane AK Subscriber Subscriber

    Messages:
    6,326
    Location:
    103 miles N. of S.F.
    So I need one pair of TVC's, 6 female RCA jack's, 2 switches of a 'certain' kind and 2 enclosures along with some footers.
     
  15. SET12

    SET12 Super Member

    Messages:
    1,841
    Location:
    Appleton,WI
    That's correct!
    Switches are a DPDT (double pole double throw) it will have 6 solder posts on it. The center pair are the out. I use the double poles for + and - so hots and grounds are both switched. You need a switch with at least silver contacts. These are high quality gold flash over silver which is what I'm using. http://www.alliedelec.com/te-connec...OEcB4NAgoKdDceQCCb_LNyusxoCQKbw_wcB#tab=specs

    They are $11.22 each,

    Footers can be your choice I would prefer brass as its non magnetic. In theory rubber is fine as well. I like brass for mass.

    SET
     
  16. SET12

    SET12 Super Member

    Messages:
    1,841
    Location:
    Appleton,WI
    NEW HIGH END LISTENING SESSION WITH THE TVC's

    SD531573.JPG SD531576.JPG SD531574.JPG

    I got together with the founder Carl (roozer) of my local audio club NEWAS http://www.newaudiosociety.com/cgi-bin/yabb2/YaBB.pl and NEWASer member Greg (squidboyw).

    We listened in two rooms one was maybe 10ft x 12ft room that he made work. It had a SS Odyssey Power amplifier with a $2000 Cambridge Audio CDP that had a very nice digital volume control. Even in that small room the TVC expanded on the space in the recording and the slam factor was better as well as a higher level of detail was heard without any harshness whatsoever. Greg also concurred.

    The Second room was in Carl's basement which for a home in Wisconsin was one of the Largest I have ever been in, it was just huge. Maybe 80 or 90ft long. It was split into two rooms and we were in the smaller of the two, side walls, wall to wall might of been at least 40ft. He was set up over to one side of the room, I myself always prefer symmetrical set up for even reflective recorded room ambiance, but the floor area that the equipment was setup on, he had said, had some kind of acoustic treatment that absorbed acoustic reflections. I guess the previous people living there were musicians. Anyway that area had a way of enhancing the listening experience which offset any other setup prospects for him.

    In the photo's you'll see the Krell Amplifiers, the Main power amp between the speakers and the line stage in back on the right side of the equipment stands both are running in Balance Mode. The Krell amplifiers more than a decade ago retailed $14,000 for the power amplifier and $7000 for the line stage that I was told and it does have a reference phono board installed. The turntable is about a $10,000 VPI with its speed control to the left of it. The CDP is a McCormick probably in the 4-$5000 range running in single-ended mode. Last but not least are the speaker cables. Dominus by Purist Audio Design they are $10,000, yeah $10,000/pair and they are liquid filled to quell mechanical vibration.

    Speakers were Talon's about a $4000 mini monitor that could reach down into the low 30's for bass but being out into the room it was unlikely that they would reach that far down.

    Also on hand were a brand new set of $11,000 Merlin's that we listened to briefly, and wow they were real Hi Rez, Carl the owner of these thought they needed to be worked with in set up to tame some of the Rez down a bit I could hear where poor recordings were not going to fair well with them. But still they are a buckle your seat belt kind of speaker. In the past at audio shows I have always heard them with tube gear and never with SS.

    So we listened to the Talons I'll have to get the name of the recording that we used for comparison. But the recording threw out the largest sound stage that I have ever heard. I would estimate it was at least some 40 feet wide. Speakers were maybe 9-10 apart so lateral imaging extended some 15ft or more to the left and right of each speaker. And now that I think of it, it was likely more! And this was with the TVC's installed!!!!!

    We had installed the TVC between the CDP and the Krell line stage. We turned the TVC all the way down then turned the Krell all the way up controlling the level with the TVC. I'd say we never were more than mid level on the TVC. We did some A-B-A comparisons. I really noticed that the lateral definition was much better with the TVC and the stage size of course was also wider and deeper.Everything was more compressed without the TVC. Still with the Krells volume was still a very large presentation with a lot of space, but the TVC for me drew me into the recording everywhere and its as though there was more air separating the performers making it easier to focus on them individually.

    Carl wanted to try the TVC direct to the power amp but I was out of time.

    As I was packing up Carl noticed that his small sub was turned off, he normally adds a little of it under 40hz. This really surprised him as normally its very easy for him to pick up on that his sub is off. But in this case with the TVC it was never missed. We figure it must of been the TVC's transit enhancement that might have come across as extension of the bass.

    In the end we all thought there were improvements in many areas with no negatives really to be heard. Its hard to be picky when so much good is happening.

    All in all it was a great time and much was learned.

    I want to especially thank Carl for a great lunch and fine beer on hand.
    As well as Greg for his listening opinion as well.
     
    Last edited: Feb 14, 2016

     

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  17. mkane

    mkane AK Subscriber Subscriber

    Messages:
    6,326
    Location:
    103 miles N. of S.F.
    SET12, limited here concerning DIY. If you would be so kind could you put together a cut sheet for me? I'll gladly send you a nice bottle of wine, real nice wine from my region or some of our favorite chocolates.:angel:
     
  18. rooze

    rooze New Member

    Messages:
    2
    Hey Dan,

    Thanks for visiting and bringing along the TVC's. I was particularly interested in hearing what these things can do as I'm in the market for a new preamp, though I'm leaning towards something to add a little tube bloom to the system.

    On the first listening session, in the smaller room, I could clearly hear a positive contribution from the TVC, though from my listening vantage point it was less profound than that heard on the basement system.
    I think the well executed digital volume control in the Cambridge 851c player/pre perhaps minimized the effect of the TVC. Still, I felt I could hear a slightly improved resolving of detail and a more effortless and organic presentation.

    On the larger basement system the presence of the TVC was more impactful.

    Let me start out by saying that I made a mistake in replacing my Talon Khites with the new Merlins the evening before our listening session. Each time I've introduced new speakers into this space they've always worked well at or around the Cardas recommended setup of a third into the room with the chair at the two thirds position.
    With the Merlins, they really didn't seem to like being so far out into the room. The sound when I started out at 92 inches from the front wall to the front of the speaker, was extremely lean and forward. Being a pigheaded sod I was reluctant to push them back toward the front wall so spent late into Friday evening and the early hours of Saturday morning messing with toe-in and distance apart. A couple hours before you arrived I experimented with pushing them back towards the front wall and then the sound began to warm up somewhat. But I basically ran out of time so we got to spin only a couple of tracks before I replaced them with the Khites.

    After you left Squidboy and I played a few tunes and the Khites didn't sound right. I then found the left side speaker negative spade hanging out of the Cardas binding post clamp. I also hadn't dialed in the toe-in properly so that needed further adjustments. All of this took place unfortunately after you had left. So the talons actually sound far less dark and lifeless than the speakers you heard!

    That said, I think the comparison with and without the TVC was still meaningful. It was clear to me that with the krell volume control wound fully open and the TVC in circuit, a very positive contribution was being made. I wasn't sure about enhancements to the soundstage width, as you had noted, but I think perhaps the issue may have been the fact that I'd forgotten to switch in the sub after we'd done the recabling, and perhaps the loose connection on the left speaker. But I clearly heard a more dynamic sound and a more organic presentation with the TVC controlling volume. I heard greater overall clarity with improved instrument separation. The Manu Katche track I played is sans vocal, so I wasn't able to focus on center image placement and solidity, but I could sense that all of the instruments across the width of the stage were more solidly formed and better focused.
    I can't explain why I didn't detect the subwoofer missing on that track. Katche is a percussionist and the bass drum on that track goes deep and moves some air. I've replayed that track today without the subwoofer and it's absence was very obvious. So perhaps there's something being contributed to lower frequency solidity and maybe even extension, or perhaps the added dynamic of the TVC simply filled-in for the absent sub. Further experimentation would have answered these questions but unfortunately we ran out of time.
    One small correction to your post- the Purist Audio Dominus cables were actually the balanced ICs running pre to power, my speaker cables are Tara Labs Master.

    Thanks again for a fun and enlightening day and for showing us your quality workmanship, both in the TVC units and the crossover you brought along.

    Cheers

    Rooze
     
  19. rooze

    rooze New Member

    Messages:
    2
    SET

    The recording we used for the basement TVC evaluation was by a local band called "Green Tea", the disc was "Beautiful Fault" and the track "Rights of Man".

    The Jazz track I played at the end was Manu Katche, form his Neighborhood CD.

    (I have the Merlins back in the system, pushed back 12" from the front line of thenTalons, and they're a whole different animal. I know it's an old audiophile cliche but these really do respond to minute changes in position).
     
  20. SET12

    SET12 Super Member

    Messages:
    1,841
    Location:
    Appleton,WI
    Thank you for the offer but you really don't have to. I have so many receipts piled up I don't know where to begin to look through them. So why don't we take this one step at a time.

    1st step Order the basic $350 TVC's, at the top of his sites page here http://www.intactaudio.com/atten.html if you order them they should only take a couple of days as he is really fast at getting them to you, at least mine were.

    Then we will talk about the Boxes, jacks and switches and footers.

    You won't regret it, IMO as nice as the CI seems, the TVC is vastly superior.

    I thought I posted this in this thread, but I have had it in my home, and I'm sorry to say it was not up to my standards. It was pleasant to listen to but the bass was so loose I couldn't live with it. It was a real nice idea but not enough performance. My CDP's ALPs volume control was much better. But in a head to head with the TVC, it isn't even a contest seriously.

    SET12
     

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