ZD from first run

Discussion in 'Eddie Current' started by Streamline, May 23, 2018.

  1. Streamline

    Streamline Rando

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    Hello everyone,

    I'm serious about bringing that ZD #3 listed on HF right now back from Japan.

    I am motivated by both owning a piece with some history, EC's reputation for quality sound, and of course the price, even after shipping. I'm confident the schematic in the listing describes the entirety of the mods. I emailed Craig and he was kind enough to confrim my thoughts about the mods, and also how easy it would be to bypass/remove them. I will almost certainly restore it eventually, though who knows, maybe the "seriously boosted bass" (Craig's words) and rolled off trreble will synergize well with the HD800

    Unless there are reasons like "Stupid idea! Old estoric amps are a pain! Don't do it!" I'm inclined to buy the amp. Once those old custom caps go, how viable is the amp? I want to get at least a few more years out of it, and hopefully a lot more than that. Complicating matters is that EC is taking orders on the last run of ZD for this year. If the recent ZDS is more serviceable (because of parts availability) it would swing me to a new one, as I do tend to keep gear for a very long time. ZD #3 just looks like fun though...

    Thanks in advance!
    Kim
     
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  2. purr1n

    purr1n Finding his inner redneck

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    The 50uF output cap is paper in oil and should be fine for a long time. You might be better off replacing the 50uf+47uF output cap combo with a single 75uF cap used in the ZDS (PM me for details). Replacing the 470uF with 1uF is an odd choice, but if you like the sound that way, don't bother changing it as the 1uF will be higher quality. The ZDS keeps the 470uF electrolytic (or slightly differently value, maybe 560uF), but parallels a small higher quality cap with it.

    If there are cap replacement priorities (from age), it would be the electrolytics, namely the 280uF cathode bypass on the power tube. I believe the power supply caps should all be film type with no electrolytics. If you get hum, put a big electrolytic (substitute the film) on the first C in the power circuit after the rectifiers.
     
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  3. Mr.Sneis

    Mr.Sneis Friend

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    Film caps last forever, there's a small number of electrolytics and that's all you should need to change but even those are probably fine for a long while longer. The impedence knob just change out to look like a stock zdse, they are cheap and readily available.

    Makes no sense why that amp didn't get snapped up quickly.

    The footers are from the moth days!
     
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  4. Thenewerguy009

    Thenewerguy009 Friend

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    The shipment from Japan probably scared a lot of people away.
     
  5. Streamline

    Streamline Rando

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    Just a quick update: so the deal closed and the amp will be on its way to me soon. :) The input above was really helpful, thank you! I'm sure I'll be bugging Purr1n about the details he mentioned eventually, but for now I just want the amp to get here safely.
     
  6. Streamline

    Streamline Rando

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    The amp came in today -- took about 5 days, no issues with customs at all. First thing I did was to open it up to make sure nothing broke; the rattling as I flipped it over wasn't confidence inspiring. Sure enough, the modded output capacitor added in parallel with the 50uF stock had broken clean off. More surprising, instead of 47uF as in the schematic, it's actually 220uF. The original ZD had just the 50uF (I found some pics that seems to indicate that this was the case)? I'm tempted to just remove the other still-intact 220uF, and experience the treble as EC initially tuned it. Thoughts?
     
  7. Thenewerguy009

    Thenewerguy009 Friend

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    What's your other gear you will be hearing the amp with?
     
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  8. Streamline

    Streamline Rando

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    Tidal/MBP->Modi Multibit->ZD->HD800/SDR

    Instead of ZD I've been using a Vali 2 with vintage bugle boy tube and the treble isn't bother me at all. I also have a Benchmark DAC1 Pre and Mjolnir 1 and the combination of Benchmark DAC 1->Mjolnir 1->HD800 is way beyond the spike controlling capabilities of the SDR mod.
     
  9. Mr.Sneis

    Mr.Sneis Friend

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    While you're there you can/should swap the solen caps near the hp out for something like audyn, audyn plus, obligatto, or mundorf Evo oil for little money.

    Find a way to adhere or secure them to the chassis as those caps will bend at the leads and crack or break the joints.
     
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  10. Streamline

    Streamline Rando

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    I'm actually using the photos in your for sale posting as a reference. :) Your build looks a lot cleaner. I'll definitely swap those caps like you suggest, eventually.

    So this ZD #3 that I now own was your first ZD, is that right? And then you bought and sold another one?

    Thanks!
     
  11. Mr.Sneis

    Mr.Sneis Friend

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    Sad as it sounds I've owned too many to remember! Working on it should be pretty easy, point to point has pros and cons compared to circuit board.

    People get hung up on stupid stuff like age of electrolytics (which are cheap as nuts) but the old zana at half the cost of a zds... Have a look at the internals and do the math! You can also bring it up to close to zds spec for little money as well. The wiring is indeed way cleaner with the modern EC amps however. Someone with a lot of time and patience can replicate with Uber wiring job if they so desired.
     
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  12. Streamline

    Streamline Rando

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    I jumpered the cap back in, thought the treble could be more extended, so I removed them both, restoring the output section to stock.

    The requisite photo-or-it-didnt-happen ... very hygge :)
    [​IMG]
    [​IMG]
     

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