FX Audio 6j1 tube preamp - a $31 wonder

Discussion in 'New Gear - Values' started by Poultrygeist, Dec 9, 2018.

  1. Poultrygeist

    Poultrygeist Lunatic Member

    I've been spellbound by the tiny FX for several weeks now. If you follow the TPA3116 thread you know I'm not the only one who has fallen for this pint sized beauty. There's so much buzz in the other thread after pairing it with the class d Volt+D I thought it deserved a thread of it's own. The Chinese tubes are ok but surpassed by a variety of vintage 5654, 6AK5, EF95 and WE 403B substitutes. The volume control is a delight with nice detent and the feel of an expensive pot. It comes with a DC 12v1a wall wart and I'll address that later. Wonderfully detailed and accurate in it's presentation it would be right at home with high end gear.

    [​IMG]
     
    Last edited: Dec 10, 2018
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  2. Poultrygeist

    Poultrygeist Lunatic Member

    Here it is driving the Volt+D which powers a pair of Frugal Horn Mk3 with planar tweeters. Y cables from the FX send it's signal to the plate amp powered OB woofers.

    P1010036.jpg
     
    Last edited: Dec 11, 2018
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  3. Poultrygeist

    Poultrygeist Lunatic Member

    Close up of the FX. LED's at the base of it's tubes give a nice red glow. I've seen another example with blue LED's.

    P1010035.jpg
     
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  4. HiFiJeff

    HiFiJeff Super Member

    Messages:
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    Thanks for starting this thread. I have enjoyed this combo quite a bit this weekend. What true hi fidelity sound for the price of my Olive Garden meal today. I mean seriously. We shouldn't be getting this kind of audio for these prices. But I am sure glad that we are! I am not complaining in the least bit. I look forward to hearing more from you on matching it with the Pyramid power supply. It makes that much of a difference???
     
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  5. Poultrygeist

    Poultrygeist Lunatic Member

    You might ask what I have to judge the FX by? Well I've enjoyed this Bottlehead Foreplay III for a number of years and always thought it hung the moon. It's fully tricked out and chocked full of Auricaps with NOS RCA clear tops.

    A comparable Bottlehead preamp today costs $500 not counting boutique caps which can easily run a few hundred. And I almost forgot that's the kit price and you have to build it yourself.

    While the Bottlehead sounds great I prefer the $31 FX and it's not even close. With it's three inputs and two outputs the convenience of the Bottlehead is off set by adding an input switch box and Y cables to the single input/output FX.

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  6. Poultrygeist

    Poultrygeist Lunatic Member

    Some years ago when I was playing around with Tripath amps I discovered this article regarding the TCC TC-754 which was referred to as the t-amp preamp. I happened to have a cheaper but identical version of the TCC and upgraded it's power supply as recommended in this article. The improvement in this preamp was night and day which proved to me that a good power supply can make a world of difference.

    https://www.tnt-audio.com/ampli/t-preamp_e.html
     
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  7. Poultrygeist

    Poultrygeist Lunatic Member

    This is what I used to replace the wall wart on the TCC preamp and it totally transformed the sound. I've seen them on sale for less than $30. More expensive ones with higher amps may be even better.

    [​IMG]
     
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  8. Poultrygeist

    Poultrygeist Lunatic Member

    As good as the FX sounded with it's tiny wall wart I was skeptical there was any room for further improvement using a better power supply. Wrong!

    P1010056.jpg
     
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  9. Poultrygeist

    Poultrygeist Lunatic Member

  10. Poultrygeist

    Poultrygeist Lunatic Member

    The Pyramid regulated PSU has expanded the sound stage and the music has far greater depth. It's like more meat was added to the bone.

    P1010062.jpg
     
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  11. Poultrygeist

    Poultrygeist Lunatic Member

    All you need for a connection is to run wires from the + and - terminals of the regulated psu to the + and - screw downs on this adaptor which plugs into the FX. These adaptors are common on the net and are probably 2.1mm x 5.5mm but I can't say for sure.

    [​IMG]
     
    Last edited: Dec 10, 2018
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  12. Poultrygeist

    Poultrygeist Lunatic Member

  13. HiFiJeff

    HiFiJeff Super Member

    Messages:
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  14. HiFiJeff

    HiFiJeff Super Member

    Messages:
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    Location:
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    Is there a better power supply that we can be using for the Volt?
     
  15. HiFiJeff

    HiFiJeff Super Member

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  16. Poultrygeist

    Poultrygeist Lunatic Member

    Those higher amp Pyramids would be excellent choices as would this Astron:

    https://www.dxengineering.com/parts/asr-sl-11r

    The Volt+ and +D amps use capacitance multipliers which allows them to sound great even with an inexpensive power brick.
     
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  17. KlipschFan61

    KlipschFan61 Smooth Jazzer

    Messages:
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    I was wondering is there was an alternative to the noisy power supply. I'll got a nice 12 volt PS I used to use to power a high-power CB. I'll have to dig it out and try it.

    I like this little guy. Works nice in front of one of my Crowns.
     
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  18. Poultrygeist

    Poultrygeist Lunatic Member

    Excellent. Many folks use Astrons like the one I linked to power CB radios.
     
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  19. Poultrygeist

    Poultrygeist Lunatic Member

    Wall wart power supplies are so common these days and we don't realize how much noise they can introduce. With the Pyramid I can hear the "rests" which is so important in music. Rests are the absence of sound between notes. A cheap wall wart can mask those all important rests with noise but you may not realize this is happening as the music can still sound very good. Not until you add a good linear regulated psu will you know what you've been missing.
     
  20. HiFiJeff

    HiFiJeff Super Member

    Messages:
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    Location:
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    So with everything you have in your system What are you running off of these upgraded power supplies? Is if just the FX tube pre? Or do you run the Volt+D and the Topping D30 dac off of them as well?
     

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