ECP Torpedo III [indexed in first post]

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by FlySweep, Nov 2, 2015.

  1. nephilim

    nephilim Acquaintance

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    Seems I got one of the last two kits but it will take a couple of weeks until I will have the time to build it. In the meantime I am wondering if I should directly jump to the Rike S-Cap (40x40x26mm). It seems the 5µF variant is gone, the next value is 4.7µF. Looking at the default 10µF this would be an even bigger change. Would it still be a recommended choice?
     
  2. MortenB

    MortenB Facebook Friend

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    If you're willing to spend the money (47 euro each / 39,17 euro each without tax), AND if you can find 4 of the now discontinued Rike S caps, then I don't think you will find better caps that fit the form factor of the T3. I checked every high end cap I could think of, and these are the only ones I could find that will fit. Most premium caps are too big. I find the Rike more transparent and with a slightly better tonal balance, than the Mundorfs (see my review earlier in the thread).

    Yes, the 10uF will be better = less phase shift in the bass (check Doughs simulation earlier in the thread). But look at the dimensions for the 10uF Rike S cap and as yourself how you will get them into the box? They are very big.
     
    Last edited: Sep 5, 2016
  3. nephilim

    nephilim Acquaintance

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    Just a heads-up - audiohobby is selling the Rike 4.7µF S-Caps on ebay, too. There is still one set (4 pieces) available. Got the other set last night (160EUR incl. shipping).
     
  4. TheloniuSnoop

    TheloniuSnoop Friend

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    I picked up the last kit today. I'm going to get a bit creative with my build. Stay tuned.
     
  5. Mr.Sneis

    Mr.Sneis Friend

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    What effect does the output ccs boards have on running the tubes? I don't remember the stock EH tubes sounding this good.
     
  6. dsavitsk

    dsavitsk Friend

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    None. Well, not much. By increasing the load on the transistors, their input impedance is slightly higher which translates to a higher load for the tubes. But the difference is pretty small as it is still in || with the tube's resistor load. So none.
     
  7. TheloniuSnoop

    TheloniuSnoop Friend

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    I looked into one of the Tentlabs chokes, which is what I did when I saw what they wanted to ship the little bugger.
    Around $35US just for that little thing? Seriously? Reminds me of the ads on TV; "And, we'll send you a second
    one absolutely free! Just pay separate shipping and handling". Which ends up being more than the item itself.

    :drunk:
     
  8. bazelio

    bazelio Friend

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    I believe Hi-fi Collective or one of those places has the chokes. I remember tossing it in my cart as part of a larger order that was far less than that to ship. Buying electronic parts ala carte online is never a good value, even when the retailer is Mouser.
     
  9. TheloniuSnoop

    TheloniuSnoop Friend

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    Thanks for the tip. Choke ordered.
     
  10. Mr.Sneis

    Mr.Sneis Friend

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    Bought some Sylvania 12AZ7A's for under $20 from our lame-o local tube store. They had a small box full of 12az7's of various makes, most did not match each other internally so I had to settle for the Sylvania's in the end.

    I am pleasantly surprised! I wrote off the AD2000's on the T3, but with these tubes they are a good fit somewhere in between the EH and Amperex PQ 7062. The EH tubes have gobs of detail at the expense of some brightness, 7062's are way more relaxed compared to either.
     
  11. TheloniuSnoop

    TheloniuSnoop Friend

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    I thought I'd chime in with a progress report. I have all the parts I need, except the choke. It seems that Royal Mail is still trying to
    find Arizona in the UK. o_O Hi Fi Collective sent it on Sept. 9th, but as near as they can surmise, it hasn't left the UK yet. :mad:
     
  12. HitmanFluffy

    HitmanFluffy Hoping to see real genitals someday!

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    Finally settled down in the States and gotten time to finish adding the output CCS boards to the amp. Thanks to @TomB for being a real gent with helping me stock up and address messups. Output CCS boards are pretty night and day SQ-wise, definitely worth every penny. Its so good that I'll feel slightly bad about relegating this amp to backup duty in a few months after dropping more on transformers than this entire kit for another build.
     
  13. fierce_freak

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    I'm getting low level 120hz hum in the right channel (louder with 12az7 vs the stock eh tubes), no change in volume with pot turn. Any ideas what to check first? Already ordered a replacement PT hoping to kill the physical traffo hum I get sometimes.
     
  14. dsavitsk

    dsavitsk Friend

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    Hum not related to volume is unusual. Any chance you have a ground loop somewhere? Or the amp sitting close to a monitor or something?
     
  15. fierce_freak

    fierce_freak Friend

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    I was thinking ground loop, but I haven't investigated any further. I've experienced the hum setup in different locations all with my amb gamma 3 dac. I think I'll try it out of another dac tomorrow just to rule out a loop with that.

    -edit- couldn't wait, just tried. Hum is gone using output from a battery powered source. Only other amp I have to try with my gamma 3 is my speaker amp, so I'll try that out this week. I hate chasing down ground loops.
     
    Last edited: Sep 25, 2016
  16. bazelio

    bazelio Friend

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    Or temporarily try one of these to see if it goes away. If you are sure it's 120 Hz then I wonder if a power rectifier filter cap might be bad. But this is easier to try.

    [​IMG]
     
  17. dsavitsk

    dsavitsk Friend

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    Is that USB DAC? I have definitely seen running a laptop from the wall lead to a loop, and battery power eliminating it.

    In the T3, we tie ground and earth directly together. They will be difficult to extricate, so you may want to undo the earth connection in the other box.
     
  18. fierce_freak

    fierce_freak Friend

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    AMB Gamma 3 is a desktop dac (AC power). It is connected via USB to various digital sources at different times (windows PC on ac, raspberry pi 2 on ac, sony zx2 pmp).
     
    Last edited: Sep 26, 2016
  19. JWahl

    JWahl Acquaintance

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    Just wanted to pop in and say, like others, I found the CCS upgrades to be quite significant. I was a little skeptical at first but was pleasantly surprised. Due to some financial obligations, I had to put it up for sale, sadly. The buyer asked me if I could perform the upgrades for him and I agreed, as I was curious of the changes. Needless to say, I'm kind of bummed now it has to go, but I need the money more at the moment. It was already a great value before, but it's really something special now.

    Like Doug mentioned earlier, the cap next to one of the output CCS boards is a little concerning for long term durability, and I expressed that to my buyer in the sake of transparency. TomB was thoughtful enough to add the heatsinks to the most recent output CCS boards, so that was a nice touch.

    After running for a few hours and taking the cover off, there was a slight smell of burning plastic, but nothing visually damaged and no smoke. It could just be a smell from the silicone sealant heating up as well. It doesn't seem like anyone else has experienced any function problems yet, but it could be concerning for long term reliability. That cap was quite warm to the touch, uncomfortably so but not burning. But not sure if it's exceeding it's 105C rating or not. I'm guessing if it was I might not be able to touch it at all. I advised my buyer it's probably not a good idea to leave it running overnight if you can help it.


    But seriously, this thing is a great value. Makes me hope that eventually, Doug will design an L-3 (L-2 with topology upgrades from T-3). If not, I have no problem re-purchasing a T3 again in the future. It definitely plays with the "big boys"
     
  20. TomB

    TomB MOT: Beezar

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    Keep in mind that by definition, 105 deg.C means 5 deg.C. above the boiling point of water. How many of us would touch our fingers to the sides of a boiling pot of water, much less immerse our fingers into the water? So, as hot as the capacitor might seem, I doubt seriously that it gets that hot. Plus, all the tests I did a while back indicate otherwise, too.

    I've owed you guys and Doug a permanent solution and JWahl describes it. Every set of Output CCS boards that I've sold and shipped since those initial tests have had a single, black heat sink glued onto each board with Arctic Silver epoxy. That would be my preferred solution, even though things tested OK just using thermal tape. The epoxy is much better and ultimately extremely stable. Those little holes in the board's ground plane form perfect glue "fingers" that give the heat sink glue joint industrial strength.

    I settled on the black heat sinks because 1) they're bigger and offer more heat transfer surface, and 2) the black anodizing provides at least a modicum of electrical insulation against shorting. Mr.Sneis's solution showed outstanding creativeness, but the silver heat sinks are both smaller and completely and totally conductive. Doug re-designed the boards a couple of times, simply due to the concern for shorting against the power transistors on the T3 heat sinks (mainly the mounting screws). In fact, those of you that have received the Output CCS boards with the heat sinks installed will notice that the black heat sink is even offset to the outside of the CCS board. This works for each board to keep the heat sink the furthest away from those power transistors as possible.

    So, anyway ... for those that are interested, please send me an e-mail ([email protected]) requesting the heat sinks. I will endeavor to check your request against the CCS and T3 Assembled/Kits sold, just so that I can keep track. I'll ship them to you with both thermal tape and an attempt to send you two "globs" of the Arctic Silver epoxy. Since it's two part and catalyzed by the actual mixing, not air, maybe it will work out better than my attempts to send the Dow Corning 748. Anyway, you can choose which to use - tape or epoxy. Although, I strongly recommend the epoxy.

    Also, I strongly advise you to line up all the parts before mixing the epoxy - it cures fast. Glue the heat sink to the right-side outside of the CCS board at top (looking at the front of the board). What you need to also do is slide the heat sink as far down toward the soldered tab of the large SMD transistor, but still keeping it flush with the board. It will overhang on the top, but that's OK.* Push the heat sink down too far, and it will pull up from being perfectly flush. I have been clamping them with office supply edge binder clips. Alternately, the tape is a cinch and easy to apply, but I don't think it gives any structural strength. Still, all the testing was done with tape, so it will work if you can't manage the epoxy.

    When I get a chance, I'll map this out with some photos and show you how it's done. It's all very straightforward and simple, but there are some little tweaks to make it optimal as described above.

    A single sink per Output CCS board should do it - if done properly. Start the e-mails coming. ;)


    * The ground plane goes all the way to the top of the board, so it doesn't matter that the sink is not on the transistor. In fact, it rejects more heat glued to the CCS board at top instead of onto the transistor.
     

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