"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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    When I get a new tube to try out that looks promising, I try to find inexpensive small lots of tubes. Bought around two dozen EF184/6EJ7 tubes this way. There were tubes made in the US, Japan, E/W Germany , Holland and England in these lots.. Rolled through them and came to the same conclusion: The Mullard tubes sounded the best - the same listening impressions as yours.
    The Mullard Blackburn tubes I have are rebranded Zenith and Admiral, but by looking carefully on the lower side of the glass you can see the unmistakable Mullard markings. In all likelihood a Zenith or Admiral branded tube that says Gt Britain on it is made by Mullard..
    Enjoying the sound of the SW51+ - I find it very relaxing and natural sounding and no listener fatigue.
     
  2. mdr30

    mdr30 Acquaintance

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    Don't underestimste Soviet military valves, many of them are of very high quality. Running Telefunken now and previously GEC to good effect. But can't say they are better than Zampotec's originals. Going to swap them back now for a comparison after six months. Great fun!
     
  3. mokobigbro

    mokobigbro Acquaintance

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    I just got my SW51. (Arrived last week but I was on vacation).

    This amp is so engaging and impactful, yet it felt linear at the same time. I tried it with monitoring type headphones - AKG K371 and Neumann NDH20 and also Slate VSX.

    I feel that there is a burn in period around 20-30 minute.

    I notice there is a difference of sound for L and H (is this just a gain difference or impedance difference?). I prefer L for now.
     
  4. gixxerwimp

    gixxerwimp Professional tricycle rider

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    I would say it's most likely the interaction of the output impedance with the impedance of the headphones.

    I prefer Low Zout for lower impedance headphones (Clears) and High Zout for higher Z phones (Senn HD800/650).
     
    Last edited: Nov 30, 2020
  5. Mordy

    Mordy Acquaintance

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    What is the designation of the GEC tubes?
     
  6. Mordy

    Mordy Acquaintance

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    Another question: All the tubes I tried so far are drawing 0.3A. There is a tube I would like to try but it draws 0.45A. Is it safe to use in the SW51+ or does it overtax the transformer?
     
  7. mdr30

    mdr30 Acquaintance

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    Well, that's a British brand (not to be confused with American GE) with some highly desired and expensive tube models. They were also marketed under the Marconi brand - with telephone and electronics dating back the 19th century.

    I got the Marconis for a fair price, will check the details tonight after work.
     
  8. Zampotech

    Zampotech Friend

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    I strongly do not recommend using tubes with an incandescent current of 0.45 A. This will overload the transformer and stabilizer.
     
  9. Mordy

    Mordy Acquaintance

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    Thanks - Z749?
     
  10. mdr30

    mdr30 Acquaintance

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    Yes, that's it.

    If you're lucky you'll find a pair for a decent price. This is not the most wanted tube type on the market.
     
  11. Mordy

    Mordy Acquaintance

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    Thanks. One of the great things about the SW51 is that the tubes are very inexpensive.
     
  12. atomicbob

    atomicbob dScope Yoda

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    SW51+ Multi-tube measurements are posted:
    Shortest Way 51+ multi-tube technical measurements
     
  13. Skyline

    Skyline Double-blindly done with this hobby

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    [​IMG]

    Happy to join the club!

    Comparing to the Liquid Platinum, which I've been using since it launched, what...2 years ago now? I'm old and can't remember.

    It's not head and shoulders better than the LP, but it certainly has its advantages and I prefer it, overall. All impressions so far are via the Bifrost 2 and HD600.

    Notably:

    • It's punchier than the LP. Especially at low volumes. The LP needs to be cranked up a little to achieve something similar and the SW51+ seems to come by this characteristic more naturally and with more ease. It's a very "confident" sounding amp.
    • Bass is better defined (punchier, again) and easier to follow in complex musical passages.
    • Really, it's not just the bass. The headstage isn't bigger (as far as my limited hearing can tell), but instruments are well defined and easier to pinpoint which gives the feeling of more space.
    • It adds some soul to the HD600. I don't know the technical reasons for this, but the 600 now manages to sound warmer and less fatiguing without sacrificing the speed and clarity that causes me to prefer it over the 650. I've never modded my 650s, but what I'm hearing is what I imagined all of those mods were trying to achieve...650 sound with a little more speed and transparency. I could be way off on this one in regards to the 650 mods, but the bottom line is that the 600s are perfectly matched for this setup.
    Like I said, it doesn't put the LP to shame. I'd say the amps are pretty comparable in terms of technical capabilities and the final decision between them will come down to sonic preferences and synergy. I'll take the SW51+, but I'm happy to keep the LP and use it regularly in my secondary setup with my 650s for a change of pace.

    And, considering I paid slightly more than half the price for the SW51+ than I did for the LP ($400 v $750), that's impressive. Thanks so much, @Zampotech for all your hard work and generosity to the community. I imagine that high demand has taken a toll and turned into a much larger project than you anticipated, but we're all grateful.

    Random Side Notes

    • Ordered in July and received in December. Completely worth the wait. Shipping took 38 days for those waiting on theirs.
    • Amp arrived with 1 tube fallen out of the socket and bouncing around slightly. Thankfully, the tube seems to be unharmed. It was surrounded by tons of foam, so that seems to have saved it.
    • The glow from the LED under the tubes is a pretty deep red when the lights are off. From all of the daylight pics that have been posted I was expecting something more pink tinted. I like it. Has there been an LED change at some point, or have the pictures just been a little misleading?
    • The quality of everything is very impressive to me. Very heavy, solid-feeling amp. All of the connectors are nice and tight and feel solid. Especially the power cord outlet...this is super loose on my Bifrost 2 where moving the DAC slightly causes the power cord to come loose.
     
  14. Mordy

    Mordy Acquaintance

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    I have owned the SW51+ for two months by now and I concur with your impressions - great bass, non-fatiguing and very natural sounding. I have another couple of tube amplifiers and in comparison the advantage of the SW51+ is that it is completely silent - no hum at all at any volume level.
    In addition to listening with headphones I also use the SW51 as a preamp.. According to Zampotech it can be used as a preamp by connecting via the low Z headphone jack.
    All in all I am very pleased with my purchase. and the price/performance ratio is amazing.
     
  15. Prydz

    Prydz Friend

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    I'm tempted to try this. Has anyone heard both SW51+ and Whammy?
     
  16. JK47

    JK47 Guest

    Yes, no contest. I even tried Whammy with multiple different opamps.
     
  17. Pancakes

    Pancakes Friend

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    I'm waiting on my SW51 to arrive so I haven't heard it. The WHAMMY however I find very underwhelming. I've tried 7 different op amps and it just doesn't do it for me.
     
  18. Zampotech

    Zampotech Friend

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    I was silent for a long time, as I was on a business trip.
    Now I am back and will solve the accumulated problems and tasks.
    The first thing I want to tell the community is that all the amps except for India have been shipped.

    How it happened. In the photo, a table for ready-made amplifiers. The last 15 amps of the third batch.

    [​IMG]

    [​IMG]

    [​IMG]

    Two amps are stored in storage. One that should go to India when the delivery opens and another one whose owner took the prepayment from PayPal. The reason for this is unknown to me, but I hope everything is fine with the person.

    I've already ordered the main base components for the fourth batch. There are 1.5 times more components than necessary, so I still accept orders for amplifiers

    I didn't spend the income I received from selling the third batch of amplifiers on women and alcohol (which I sincerely regret), but used it to buy professional machine tools for the production of cases.

    In General life goes on [​IMG]


    [​IMG]
     
  19. YMO

    YMO Chief Fun Officer

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    @Ice-man just get your amp direct at this point.
     
  20. Pancakes

    Pancakes Friend

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    Hilarious lol.
     

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