Explain tube amp "solid-state power supply"

Discussion in 'Amp Central Station' started by Neener, Sep 21, 2020.

  1. Neener

    Neener Tele-Holic

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    Total amp noob question, but I'm looking at a Univox 1221 Tube head. From what I've read it runs on 7 tubes and a "solid-state power supply"

    How does that compare to say the power supply of a Fender Blues Deluxe?
     
  2. sonicsmitty

    sonicsmitty Tele-Holic

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    Diode rectifier instead of a tube. Blues Deluxe is solid state rectifier too. You won't get that tube sag like you would with a tube rectifier, but there's nothing wrong with that. It's just personal preference.
     
  3. Neener

    Neener Tele-Holic

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    Ok right on. I love my Blues Deville, deluxe and junior :)
     
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  4. DavidP

    DavidP Friend of Leo's

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    ...what sonicsmitty said!
     
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  5. soundchaser59

    soundchaser59 Tele-Afflicted

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    Besides, I think a lot more of the tonal character comes from the preamp, so that's where you really want tubes vs solid state. The power section is just amplfying, so some people think the power should be completely clean and transparent, which solid state will more likely be. Some describe it as harsh or sterile, but I think that's just another way of saying it's too honest, more likely to reporduce exactly what you put in. Tube power is a bit more forgiving.
     
  6. Neener

    Neener Tele-Holic

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    I was looking up cheap vintage tube amps and the Univox came up. Seems like a cool little unit.

    I’m assuming tube rectifiers are way more expensive. Hence why the univox was so cheap

    Mojo = $$$
     
    Last edited: Sep 21, 2020
  7. dogmeat

    dogmeat Tele-Afflicted

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    price of the parts is about 20-25 bucks between tube & ss rectifier... basically the price of the tube. a set of diodes cost about the same as a socket for the tube .. the rest is a wash
     
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  8. 39martind18

    39martind18 Tele-Afflicted

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    My 70 DR is set up with a solid state rectifier that allows me to run 6L6s (the ss rectifier supplies slightly higher voltage to the 6L6s. The sound, especially in the lows, is considerably tighter, and overall headroom is increased. YMMV
     
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  9. scooteraz

    scooteraz Friend of Leo's

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    Rectifiers for guitar amps come in two general types. The older style of rectifiers are tube types. A tube, besides providing rectification, has additional capacitance, inductance and resistance. This causes the associated power supplies to have different characteristics, most notably voltage sag during high demand. This voltage sag causes a bit of distortion that many (most?) find pleasing.

    The other rectifier uses silicon diodes to perform the same work. Diodes have so significantly lower parasitic capacitance, inductance as to be effectively zero. The resistance in forward bias (when the current is flowing) is also much less. This makes the voltage from the power supply more stable. This means when there are transient power demands, there is less induced distortion. Those amps are seen as being brighter with less breakup.

    Of course, no rule is hard and fast, so don’t worry so much about the circuit details and listen to how it sounds when you play, and use what you find pleasing. IIRC, all of the blues Deluxe have silicon diode rectification.
     
  10. aging_rocker

    aging_rocker Tele-Afflicted

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    Marshall switched to SS rectification decades ago.

    I don't think anyone minds too much...
     
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  11. dogmeat

    dogmeat Tele-Afflicted

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    so did Fender, started in the '60s. about half their tube amps have SS rectifiers
     
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  12. Euphonica

    Euphonica Tele-Meister

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    I have an Eden bass head that has a preamp tube but everything else is solid state. I thought that’s what he meant? I’ve also got old tube amps that have solid state rectifiers but tubes for everything else.
     
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