Solen Polypropylene Caps

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by darkbluemurder, Sep 21, 2005.

  1. darkbluemurder

    darkbluemurder Member

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    Has anyone ever tried Solen polypropylene caps in a power section of a Fender tube amp, and if so, was there any noticeable difference to electrolytic caps?
    I am afraid the Solens will be too big to fit under the cap can.

    Any input would be very much appreciated.
     
  2. Wakarusa

    Wakarusa Member

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    The new high voltage high capacitance film caps are kinda cool. Not familiar with the Solen product, but I'm guessing they are similar to the new 'Electrofilm' line from CDE ('cept, of course, quadruple the price to get the 'Solen' name on the side ;)).

    The big advantages are low ESR and they don't dry out. ESR for a CDE 30uF@600WVDC is 8mohms. Most aluminum electrolytics have ESR values in the hundreds of mohms. The difference in size and mounting style makes 'em more appropriate for use in new designs -- I doubt the 'doesn't dry out' and the lower noise floor is worth hacking up your Fender to make 'em fit tho'.
     
  3. TheAmpNerd

    TheAmpNerd Member

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    Depends on where you put it.
    They distort differently then electrolytics.
    Meaning: some people can hear the difference when
    you have a film cap instead of an electrolytic.

    The only way you'll know is if you try them out.
     
  4. Wakarusa

    Wakarusa Member

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    <rant>
    You have got to be kidding me. A power supply filter cap? Distorting differently? That people can hear? I wanna see controlled double blind proof.

    Real physics - like reliability, effects of low ESR, ripple rejection, and the effect on noise floor - I'll buy, but this is just too much. :rolleyes:
    </rant>
     
  5. TheAmpNerd

    TheAmpNerd Member

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    Yep try it and see.

    Can you tell the difference between brands
    of Electrolytics?

    Some group called the NY Mafia (an audiophile group)
    describes their results and recomendations.

    Everything you mentioned should all contribute to
    slightly different distortion artifacts.

    AND

    If you haven't already done so, build an amp with all
    fast caps and let me know what you hear.

    I believe that O'Connor has some mention of
    it in one of his TUT books. Where I couldn't tell you.

    There are some other sources that describe it
    also. I just don't have time to go digging though
    my library to find the sources. They are there.

    You should be able to tell right away. Stuck a
    big old film cap in your preamp supply, not burried
    between electrolytics. Try a 2uf - 10uf film 400 - 600V
    instead of the 16uf - 20uf in a Fender pre amp stage.

    Then crank the sh*t outta the amp and have
    a listen when you play....It will sound different,
    if you have any ears left.
     
  6. markdurham

    markdurham Member

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    Like the man said, they are too big to fit into a Fender doghouse. Here is a photo of an 18watt amp I built using Solen caps in the power supply. The whole amp had to be built around them.
    markd
    [​IMG]
     
  7. loverocker

    loverocker Member

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    Hey Mark - are those Solens secured to the chassis with ties or something? :eek:

    I've got a KOC amp with Solens, and they do dictate a lot about how the amp is laid out. Would like to try them in one of my own builds one day.
     
  8. TheAmpNerd

    TheAmpNerd Member

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    There is a lot of stress in that amp Mark.

    Now for the important stuff:

    How does it sound?

    Did you have the chassis made locally?
     
  9. markdurham

    markdurham Member

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    Yeah, there is some silicon adhesive underneath. All the caps set on the chassis.
    mark
     
  10. markdurham

    markdurham Member

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    I like the way it sounds. It is built into a standard GDS 18watt chassis with Heybour 18watt trannies. Basically an 18watt with two preamp channels, an EF86 channel and a TMB channel with a 12DW7. I favor the EF86 channel.
    I threw a lot of "stuff" against the wall with this amp. The layout is a bit extreme, IMO, but it was fun fooling around with. It has cathode/ fixed bias switching. There is a lot of resistance(hey, a pun) to using fixed bias with EL84's, but my experience is it doesn't sound much different. Just a little stiffer. I have run several blind test on friends and they almost always prefer the fixed bias. Not what I expected.
    And a push/pull to single ended pot( this is a PPIMV that only works on one side). It's still loud even with only a single EL84 being driven.
    I would say the power supply caps do affect the tone somewhat. I have built several 18's with electrolytic caps and they are a bit grainier sounding. I'm not very good at describing these sorts of things, but even I hear a difference. Some people think it's better sounding, some don't. I'm just a tech and I like the idea of them outlasting me. Less maintenance that way. ha!
    mark

    .
     
  11. loverocker

    loverocker Member

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    Hey Mark, the idea I really like in your layout is the way the board sits around the valve sockets. I'd love to try that, but I expect it took a lot of drawing up and head-scratching?
     
  12. Nekle

    Nekle Member

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    Yes, that sideways board looks very nice. Lotta work though huh?It's nice to see the different ideas people have to make it all fit in.
    Very nice.
     
  13. Nekle

    Nekle Member

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    Are the Solen caps more expensive than the Mallorys?
     
  14. markdurham

    markdurham Member

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    Yeah it did, and it has some other drawbacks as well. I started with the premise that if shorter leads are better, what could be better than having the components directly on the tube sockets. But having the board directly over the sockets means it would have to be removed to work on something underneath. You can imagine how I came to find out what a hassle that could be.
    I have come to think that the way HiWatt did this is much better. As you know, they used a single row of turrets mounted alongside the tube sockets with the components wired between that and the socket pins. The components are still right on the sockets, but there is much more room to work. That's how I would do it next time.
    I WAS surprised just how easily and cleanly a Greenlee punch can cut through 1/8" G10.
    markd
     
  15. TheAmpNerd

    TheAmpNerd Member

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    Mark,

    What uf values did you choose for the solens?

    Did you use the same uF value as the electrolytics?

    Or

    If you used different uf values of film vice electrolytic,
    What were the values? Higher or lower? why?

    Just curious
     
  16. markdurham

    markdurham Member

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    33uF on the plates of the power tubes, 33uf on the screens, 22 uF on the PI and TMB preamp, and a 15uF just for the EF86.
    I think an EF86 needs a separate power supply node, ala Vox. You can affect the tone of an EF86(or any preamp) by playing with the values of the dropping resistor and filter cap of that power supply node.
    markd
     

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