Power supply filtering

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by ROKY, May 21, 2006.

  1. ROKY

    ROKY Member

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    I have a 1971 Traynor YSR-1(Custom Reverb) head(2 EL34, powered)
    It's a 4-input, w/ 2 seperate vol. preamp(like a Bassman/Marshall)

    The 2 filter cans are 40mfd/450v

    I can upgrade them to 50/500v, but should I not go any higher.

    What changes adverse, or otherwise, would I experience exceeding 50mfd ?
     
  2. Reeek

    Reeek Member

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    The answer will vary from person to person. I've heard as much as 40% more is ok.

    If I were you, I'd go with the 50/500.

    As for the wattage capacity, the higher the better. That part has no negative effects to my knowledge. Going lower is bad. YOu can't really have too much wattage capacity. When powered up, there is a bit of a surge and it is power up when filter caps usually blow if they are going to blow at all. Having lots of wattage capacity is good for the filter caps.
     
  3. hasserl

    hasserl Member

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    When working with an amp that uses a tube rectifier there are limits to the amount of capacitance that you should use. Exceeding the specified amount can and likely will result in premature wear and failure of the rectifier tube. The tech data sheets for the tubes lists this info.

    But your Traynor uses solid state rectification; hence no tube, and no limits to worry about. Effects of increasing the capacitance can be a tighter bass response, as the power supply does not sag when instant demands are placed on it, such as when you hit a power chord. But it can also sound sterile, as we tend to like a bit of sag. Sag in the power supply gives some compression, and lets notes and chords bloom as the power supply recovers. It can be a cool effect. How much sag is desirable is subjective, different people prefer different amounts, and that is often related to the type of amp and the type of music your playing. Classic rock styles tend to prefer more sag. More modern heavier styles tend to prefer less. That may be an over-simplification, but hopefully it helps you to understand the basics.

    Hope that helps,
    Hasse
     
  4. brad347

    brad347 Member

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    People talk about "various amounts of sag" but to me it's more intuitive to say that more filtering and SS rectifier, etc results in "punchier" sound.
     
  5. ROKY

    ROKY Member

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    Thanks for the responses, folks !

    I'm planning on upgrading the stock hammond OPT to a Marshall spec. and
    adding a filter choke, also.

    I'll start w/ the 50mfd/500v and see what happens, although I'm sure that
    should be sufficient,really ..

    I was just curious if overfiltering would be safe to do operationally-I'm sure I would not like the feel of too much filtering, for the results I want.

    The amp has a kind of splattery attack,and the tone is a bit blurry, but
    I attribute that just as much to the Hammond iron, and lack of a choke,
    as the power supply filtering-- it all works together,no ?

    The tubes are all Mullard, and the caps, the venerable Mustard type.
     
  6. donnyjaguar

    donnyjaguar Member

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    I'd leave the YSR1 as-is myself. Hammond transformers are part of the charm of old Traynor amplifiers. Also, if the 40uF/450V capactor tests okay I'd leave it alone.

    D-J
     
  7. AL30

    AL30 Member

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    I just got my '71 YSR-1 up and running. It does have a choke so maybe it's older than I thought.

    I used F&T 50-50/500V multi-caps in mine. No problems. I also added a bias control from JC Maillet's site http://www.lynx.bc.ca/~jc/tremoloCircuits.html

    I replaced ALL the electrolytics, gave a 3-prong cord, and did some basic clean up. No mods. I have been considering changing the tone stack but I haven't gotten around to it yet.

    I wouldn't recommend changing the transformer - yet. Traynors have BIG iron in them. I would try a cap job and a clean-up to see how it sounds before you start swapping big components in and out - that's a lot of $$$ up front for something you're not entirely sure of yet. You may like it as is - and if you don't at least you'll know that.

    Mine sounds BIG - lots of "oomph". Tight and focused attack. This may be in part to the 4 x 10" cabinet I'm using as well. It is anything but "splattery" - that makes me think you may have some maintenance to do inside. "Blurry"? - if we are thinking on the same lines I fixed my "blurry" sound by swapping the PI and V1 to a 12AT7. This focused the sound a bit more and gave some more definition. It also helped with the lack of headroom. It does have some touch response - cleans up when I back off my attack and breaks up nicely when I bite into the strings. It can be a bit sterile at lower volumes - not a problem past 3 on the volume - I have also been jumping the channels which added a touch of sparkle.

    I have used the amp in practice for the last few weeks and just took it for a test drive Saturday night. I asked the soundman about the amp and his answer was "I didn't have to adjust anything on the board". That's about as good a compliment as you're gonna get from a soundman.

    I suppose I should also add this - once the Traynor was ready to go I thought I would see how it sounded next to my Marshall. Good test base right? I fired up my 82 2210 (which does need some work), played it for a while then plugged in the Traynor... the Marshall is back on the shelf.

    AL
     
  8. Swarty

    Swarty Member

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    +1 AL30 :AOK. The blurry/splatty response sounds more like worn out power tubes than anything else. I think many Marshalls could be improved w/ the Traynor/Hammond iron (and this is coming from a guy who owns a bunch of Marshalls).
     
  9. ROKY

    ROKY Member

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    AL30- as far as the choke you might be looking at the reverb transformer.
    Mine is a '71(s/n 0100455) I had a 70 YBA-1 also and the filter chokes were
    gone, by this time.

    If you have a filter choke it would be between the OPT and PT, the smaller
    reverb tranny is near the back of the chassis.

    Re: the splattery/blurry descriptives: I knew, going in, that that wouldn't
    necessarily mean much to the next 'reader'.. so don't get hung up on
    that-- I was attempting to describe a lack of focus in the feel.

    It's not farty/saggy like an amp direly in need of a re-cap, just slightly
    not as forward as I want in the attack.

    I have run the amp thru a variety of cabs, and the basic issue is remains
    a softness(another vague word) to the initial attack, that, actually, I think
    might be also attributed to the volume pots(4 meg). I'm probably going to
    go to 1 megs(Marshall spec) vs the Fender-spec 4 megs, which can be a
    bit spongier feeling.

    The power tubes aren't worn, and I've also used Sylvania 6CA7s which
    we all know offer rounder bass and a more 6L6 response. Nice option, but
    the basic issue, I have is still there. I'm running older tubes, but not worn
    tubes(I do know the difference). I've also used a 12at7 in V3 and V1,and
    both, at the same time. It's not an issue of trying to tame the gain, some;
    I did explore that, also. Have also used other EL34s
    older Teslas, JJEL34Ls, winged Cs.

    Anyway, I realize that our amps may not sound exactly alike; also, that
    you might plug into mine and love it-- or, like it more than your YSR-1.

    This stuff, as usual, is always subjective(..of course, he says ..):)
     
  10. ROKY

    ROKY Member

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    Hey, Tim, there's an interesting article re: Traynors were the author asserted
    that had Jim Marshall incorporated Pete Traynor's power supply design ideas
    into the 60s Super Leads** they wouldn't have blown up so many and been
    so hard on tubes(although the Mullards were as rugged as could you ask)

    ------
    ** at least the ones that had 600+ volts on the plates..
    -------

    Re; the Hammond iron, I've read different OPINIONS
    The YBA-1s, as *Canadian Marshalls*, fall short, for some, due to the Hammond
    iron being perceived as too hi-fi/clean-sounding/not saturating in the right way.

    Obviously, others feel differently; no problem.

    I'm looking, right, now into a Marstran OPT- only $120- pretty well regarded,
    from what I can gather.

    That's less than the price of a set of strat pups, less than a set of PAF-type pups.

    Can't buy a decent guitar for that, most booteek peds cost that..etc.

    Anyway, I've had the amp for probably 4 years and wanna mess with it,some.
     
  11. AL30

    AL30 Member

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    Nope, it's definitely a choke. I *thought* it was a '70 or a '71. So, either it's a really early '70 or I need to re-check a few things. It's been a while.

    Did you try the 12AT7 in the PI slot?

    I also think mine has 500K volume pots - gotta check that too. Mine is certainly "focused" so maybe the choke and the pots are helping tighten things up a bit.

    Good luck with it.

    AL
     
  12. ROKY

    ROKY Member

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    Thanks !

    Yeah, as I'd mentioned, the 12AT7 in the PI didn't help.
    If you have a choke, I suspect it was added; of course I don't know what
    year you really, have, either.

    Traynor dropped the chokes, post-1970(went with a resistor,IIRC..)

    The pots are reputed to be a significant help re: "tightening", from what
    I've read(it makes sense to my limited understanding).

    If you happen to have a pic of your YSR, I'd like to see it,sometime.
     

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