"Shortest Way" SW51 Amp Impressions (Simple SET Amp)

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by Hands, Jul 12, 2019.

  1. Mordy

    Mordy Acquaintance

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    I have the Beyerdynamic T1 Gen1, HD250 and HD650 and I concur - the HD650 sounds the best with SW51+.
     
  2. Prydz

    Prydz Friend

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    Possible to make a poll regarding which output people use?
    I still kinda prefer high-z althought low-z does clean the sound up.
     
  3. gixxerwimp

    gixxerwimp Professional tricycle rider

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    I use high-Z for high impedance Senns as it sounds more dynamic to me, low-Z for Focals to minimize the bass boost from the impedance curve.
     
  4. FlySweep

    FlySweep Friend

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    I don't use hi Z at all.. even with Senns. Presentation is too forward/aggressive for my taste. Low Z not as macrodynamic, but I find it better for my long term listening habits (evenings after work and kids have gone to bed).

    I have a Zenith-branded pair of 6EJ7's that haven't left the SW51+ in nearly a month. I'm not sure if they're Mullard or Siemens. Wonderfully clean, quiet, holographic, and dynamic. they go blow for blow with the Tele.. and I might even prefer them to the Tele. They're more neutral than the Tele and the midrange is so deep, open, and expansive. These are a "palette "cleanser" of sorts but they possess a sophisticated inner warmth that is quite addictive and keeps me listening. Will be hunting for a back up pair once I determine the build.
     
    Last edited: Feb 2, 2022
  5. mdr30

    mdr30 Acquaintance

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    Two different Telefunken EF184.

    [​IMG]

    [​IMG]

    The one to the left manufactured by Siemens, the right one by Telefunken: Raute, diamand, rhombus.

    [​IMG]

    [​IMG]

    Nice tubes, but presently I'm running Mazda 6F24.

    [​IMG]

    All three make the most of SW51 (as do others).

    I'm staying away from the variable mu types EF85, EF805S, EF183, 6BY7, 6EH7, W719, 6F19, 6F25, 6F26.

    Have some surplus tubes of different brands for cheap, check my profile.
     
  6. Zampotech

    Zampotech Friend

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    Dear friends

    I apologize for my silence and lack of responses by email
    The seasonal flu has clung to me. Or a fashionable disease :)
    There is a cast-iron weight in my head, my body is like after a week-long orgy of swingers, in which I was a double bed.
    I'll come to my senses, I'll answer everyone. Or if I don't answer, please repeat your questions.
     
  7. Grattle

    Grattle Friend

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    B0FA9DBE-98CB-446C-9DA8-B4E2C94AF17A.jpeg
     
  8. yotacowboy

    yotacowboy McRibs Kind of Guy

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    Surely there are funds in the SBAF war chest to send Zampo a care package. A couple or three "system synergy" tees wrapped around a couple bottles of Four Roses, perhaps?
     
  9. ColdsnapBry

    ColdsnapBry Almost "Made"

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    Ah, I love the high Z. High Z with even a lowly 6XX has about the macrodynamics of my Verite Open.
     
  10. Zampotech

    Zampotech Friend

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    A little news.
    I publish the appearance of the SW4 amplifier in a horizontal case. This is a rendering from the Solidworks program

    [​IMG]

    Image Description:
    -The two left identical caps hide the output transformers.
    -The big left lone hood hides the power transformer
    - To the right of the cap of the power transformer is a rectifier cenotron
    - The two right rear hoods hide the input permalloy transformers.
    - There are two 6Z4 (or 6AC7) tubes in front of the input transformer caps
    - The big wheel is the handle of the attenuator encoder.

    The attenuation value indicators and the toggle switch are not shown.

    Outputs - two combos (Jack+XLR)
    Input - 2RCA +2XLR

    Dimensions, width/depth/height 400/280/130 mm

    In the future, I will create a separate theme for this amplifier.
     
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  11. mdr30

    mdr30 Acquaintance

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    Always a surprise, do you get two voltages from the cenotron?

    Are the input transformers in circuit for the RCA only?
     
  12. Zampotech

    Zampotech Friend

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    I get only one voltage from the cenotron, for the anode of the tubes.

    Both RCA and XLR can be connected to the input transformer via the contacts of a special relay, depending on the required mode. Volume control is also carried out by a relay, in increments of 1 dB.
     
  13. Polygonhell

    Polygonhell Acquaintance

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    Is this a typo, isn't a 6Z4 a rectifier, or is there a pentode with that designation I'm missing?

    Looks interesting though, do you have any idea what the power output is going to be, I'm just interested in whether it will drive some of the more current hungry planar's.
     
  14. Merrick

    Merrick A lidless ear

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    Plans may have changed but Zampo has mentioned in the past that another amp, the SW9, is in the design stages specifically for planars.
     
  15. Zampotech

    Zampotech Friend

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    6Z4 is really a pentode. The cenotron will be a 6C5S (6X5GT) tube

    For planar headphones, there will be an amplifier of about the same appearance, but with a 6P9 (6AG7(W), 6AK7, 6L10) tube
     
  16. Polygonhell

    Polygonhell Acquaintance

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    Yes I see my error, there is a Russian Pentode 6Z4Pi where the Z is Cyrillic.
    In addition to the 6Z4 (Chinese designation) which is an EZ90 alternative.
     
  17. ZampotechNA

    ZampotechNA MOT: Zampotech NA Distributor

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    Hello again,

    We have received additional inquiries regarding expected pre-order dates and would like to provide an update. There was a severe shipping delay on the remaining transformer steel required for the manufacture of the transformers used in the SW51+ amplifiers. All transformer steel has been received and is undergoing final QC now and we expect that the remaining amplifiers will be completed in approximately 3 weeks.

    Pre-orders will still be made available once final shipment from Russia has been confirmed. We do not expect any changes to the pricing stated above.

    We apologize for the delay and thank everyone for their continued patience.
     
  18. Mordy

    Mordy Acquaintance

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    I have several pairs branded Zenith; some are made by Philips in Holland and some by Mullard. The way you describe the sound I would guess Mullard. Look carefully on the lower section of the glass and see if there are etched letters and numbers there beginning with a B (- could be difficult to see). If so, they were made in the Blackburn, Mullard factory.
    (If they were made by Siemens there may be scratched in symbols and numbers on the metal plate inside the tube).
     
  19. denny_dow

    denny_dow Acquaintance

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    hi all, I have my SW51+ for probably around a month now, been running it quite regularly, first with the original tubes and lately with the Telefunkens, driving HD650 and Fostex TR-X00 (my latest acquisition). I had a really strange experience with the stock tubes - I am treble sensitive, something I discovered pretty early in the game while driving Verum 1 off Liquid Spark. but here with the stock tubes I noticed that I started getting tired pretty quickly from... well.. base I suppose? it's hard to explain - it's like it was too slappy, straining my ears. it all went away with the Telefunkens (and I suspect the burn-in), and it seems just right with both headphones now, but I suspect that Mazda tubes will be a better combo with HD650 - have not tried the Mazdas yet. another interesting thing I noticed with the Telefunkens, specifically with the Fostex, is that if the track is subtle, they make it sound almost too subtle, intimate, but if the track is rocking, they carry that across beautifully - a side-effect of that is that I have to rotate the volume know here and there adding or reducing the volume.

    anyway, I am pretty happy with SW51+ so far, it's been really that 'one more track, just one more track... shit, it's 1 AM' sort of listening.

    today a switchbox arrived (SOLUPEAK thing, leaky unfortunately, but that is a separate story), and I was finally able to A/B the SW51+ against Feliks Echo. 1.5 hours in I have to say I don't hear that much of a difference. have Mullards PCC189 installed). it seems that SW51+ is a touch more dynamic, and the bas is a touch more defined, but other than that they both produce airy, spacious, engaging sound. by the way, could leaky switchbox mud the waters here and screw up the picture?

    or perhaps my ears are not that attuned yet - anything specific I should be listening to on OTL as opposed to SET?

    of course, I will give it more time, but for now I am leaning quite strongly in favour of letting the Echo go (was on the fence about keeping it alongside SW51+ for the sake of different sound and pre-out).

    yes, I am driving HD650 from High-Z output and Fostex from Low-Z.
     
  20. ColdsnapBry

    ColdsnapBry Almost "Made"

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    I don't have an A/B box, although maybe I should since I have so many amps I'm testing. But I have a SW51+ and a Feliks Echo MK1 here at the moment. I don't tend to do A/B, usually just sit in and listen to the music. I use the Verite Open / Aeolus and 650 to listen to music. Mostly on the Verite Open and 650 when I'm trying to listen to my chain.

    Roughly I percieve:

    Echo:
    More forward sound with everything - bass, mids highs
    Engaging mids
    Grainy in the highs and a bit peaky, really noticable with the 650
    Grain gest better and it gets smoother as you tube roll it
    Boomier in the mids, slightly more dynamic
    Actually pretty good instrument seperation and stage for an OTL

    SW51+
    More balanced presentation through the whole FR
    More stage depth, doesn't sound as engaging at first, but draws you into the music
    Excellent microdynamics that continues to draw you into the music
    Mids and highs are smooth
    Smaller stage than echo, but that stage depth is great

    Tough to call a winner here, but the SW51+ is on my desk and the Echo is not.
     
    Last edited: Feb 18, 2022

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