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

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

  1. JK47

    JK47 Guest

    Showed up at my doorstep today, and in perfect working order. Powered it up and dead silence in a good way, no hummm, or noise what so ever when turning the pot to max. My Aficionado had a tiny bit of noise, even with it's own power supply stowed as far a way as I could stretch the cable... What kind of sorcery is this?

    After 20 minutes of warm up time, I fired up the first test track on my bone stock HD600, Mötley Crüe's "Kick Start my Heart". Lord almighty, I was not expecting this thing to belt out Vince Neil's voice with such clarity at this price point. The SW51+ had my complete and undivided attention firmly in it's little grasp, and I've been listening almost non stop for the last 3hrs.

    Like most of the previous impressions have already said, this sucker sounds very SS, and not bloomy as in a stereotypical tube amp in this price range. I'm extremely impressed with the texture of the treble using the stock tubes, it doesn't sound rolled off, but exhibits no glare with the HD600, tons of nuance and microdetail. The mid range is also silly good with the HD600, and the low end isn't too shabby at all. The HD600 is rolled in the bass department anyway, so I tried my uni-cough, cough-corn LCD2, and the bass was solid, and linear, but lacked the mid and treble magic of the HD600. I also like the party trick this amp can do... by plugging my HD600 into the H output it changes into a HD650 sound wise, moar mid bass, lol.
    IMG_3115.jpg

    I briefly tried some NOS Phillips military toobz from the 80's, that I got for a song ($25 for a sleeve of 5). I've always found NOS military tubes from the 70's and 80's solid, reasonably priced, measure extremely well, with minimal noise, and generally lack microphonics (Philips military are usually green print when made in the 70's and blue in the 80's). They sounded a little fuller in the mid range, but will run them in at night over the next week before giving them another listen. The stock tubes are excellent in my opinion.
    IMG_3114.jpg


    To me this amp embodies the spirit of SBAF and the hobby community, high value, and BIG performance!!! Thanks to @Zampotech, @Hands, and @atomicbob, as well as the countless others for bringing this amp to fruition, developing, measuring, and just getting the word out.
     
    Last edited by a moderator: May 27, 2020
  2. YMO

    YMO Chief Fun Officer

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    I'm more worried about the dusty gaming consoles + the cable monster@JK47
     
  3. atomicbob

    atomicbob dScope Yoda

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    My part in this was whimsical at first. Acquired out of curiosity. Then measured. Then listened ... listened some more ... and listened still some more ... and you know where this is going. SW51+ is impressive. As mentioned before, this is a great gift from @Zampotech to our community.
     
  4. Zampotech

    Zampotech Friend

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    It's probably time to share the changes in the production process of a new batch.

    Now I have a "dead time". All that I could do from the stock I had already done. All the components that I ordered and paid for on the road.
    But I can share some photos.

    Amplifier housings, painted. The photo didn't get another box with the chassis

    [​IMG]

    New-style knobs arrived.

    [​IMG]

    This is what the amp looks like with the new knobs

    [​IMG]

    In addition, I can show two photos from the warehouse of the carrier from China.

    This is a 1/4 Jack

    [​IMG]

    These are tube connectors

    [​IMG]

    While the components are on the way, I'll take care of the new amplifier. It should be also transformer amplifier, valve tube with nutrition. A little later I will share the information on this amplifier.

    To @atomicbob I've reserved one of their new batch of amplifiers for you.

    Amps are still available and there is still a possibility to order.

    This batch will be the final and the remnants of this batch of amplifiers can probably be ordered by forum participants and forum guests.

    Addition:

    The previous batch was sent, except for 4 amps.
    1. In India. Waiting for delivery to open
    2. In USA. Waiting for an additional phono preamp
    3. In Japan. Waiting for a 100-volt transformer.
    4. In Hong Kong. My mistake, made on 110 volts. It will be fixed.

    I noticed that was sent to the US, Canada and Australia are delayed at the arrival airport. This is probably me either to a shortage of personnel at sorting points or the need for a two-week stay as a quarantine. (in my opinion, a completely useless event)

    To keep track of your amplifiers, please use the site gdeposylka.ru
    This site is very detailed and can even show the geographical location of your parcel.
     
    Last edited: Jun 7, 2020
  5. msommers

    msommers High on Epipens

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    @atomicbob If you have the opportunity, I would be curious how long it takes for the tube temps to be brought up to being temp-stablized as you've done previously. Of course this is really for my own amusement so feel free to sluff it off :)
     
  6. atomicbob

    atomicbob dScope Yoda

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    Tube warm up time technical measurements
     
  7. msommers

    msommers High on Epipens

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    Cheers Bob, that's really appreciated!
     
  8. TheIceman93

    TheIceman93 El pato-zorro

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    Has it been confirmed that there will soon be an upgraded successor to the SW51?
     
  9. Polygonhell

    Polygonhell Acquaintance

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    I just received mine and while I need to spend some more time with it for any real impressions, I'm willing to say even with just a few hours listening time it's a pretty special little amp, I don't think there is a Valve amplifier that competes with it favorably in the price range, if anyone is still on the fence about this, I'd encourage them to jump in.
    The Amp it reminds me most of is the Haggerman Tuba (which is almost 2x the cost), with the stock tubes it a very clean, very impactful little amp. I'll get around to an A/B with the Tuba when I get a chance.

    [​IMG]
     
    Last edited: Jun 12, 2020
  10. gixxerwimp

    gixxerwimp Professional tricycle rider

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  11. Polygonhell

    Polygonhell Acquaintance

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    I’ll just add it to the list of my recent technical fails.
    Thanks.
     
  12. HotRatSalad

    HotRatSalad Friend

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  13. Polygonhell

    Polygonhell Acquaintance

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    No that’s how it came, shipped with the tubes in the sockets, I just made sure they were inserted.
    Maybe Zampotech changed the sockets for this batch.
     
  14. HotRatSalad

    HotRatSalad Friend

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    Oh it's yours sorry. Yeah could be the angle of the pic. Now that I've looked they are about the same.
     
  15. gixxerwimp

    gixxerwimp Professional tricycle rider

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    @polygone's definitely look like they're sticking out.* Mine are flush with the chassis.
    Maybe there was a rolling change.

    *edit: Could just be the angle the photo was taken from though.
     
    Last edited: Jun 13, 2020
  16. HotRatSalad

    HotRatSalad Friend

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    Mine are pretty flushy
     

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  17. Zampotech

    Zampotech Friend

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    You have good eyesight and attention. Sockets are really 1.5 mm higher.
     
  18. Zampotech

    Zampotech Friend

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    Today I started measuring and testing the next amplifier, the successor to the SW51. Working name SW4

    The amplifier is also built on the concept of "Shortest Way". This is an ultralinear SET amp on a 6Z4 (clone of the American tube 6AC7) tube

    Here is a photo of the amp's embryo.

    [​IMG]

    While he's ugly.

    Here's his THD

    [​IMG]


    The total THD is approximately 0.04% at a 100 Ohm load. Only two harmonics dominate, the second and third. There are practically no other harmonics.
    I admit, I didn't expect to get such low distortion from a vintage tube developed in the 30s.
    It should be noted that the amplifier has not yet installed a transformer intended for it. The transformer for this amplifier will have transformer steel with improved magnetic characteristics.
    Of course, there is still a lot of research work with this amplifier, but I am happy with the preliminary results.
     
  19. HAL9000

    HAL9000 Almost "Made"

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    From Russia With Love
     
  20. HAL9000

    HAL9000 Almost "Made"

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    @Zampotech just got my SW51. It is a fantastic amp! Feeding it with my Bifrost 2 and listening with Focal Clears... a match made in heaven! Thank you for your labor(s) of love!

    What differences will we hear with SW4?
     

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