ECP Torpedo III [indexed in first post]

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

  1. bazelio

    bazelio Friend

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    Went ahead and installed 5 uF Rike coupling caps this afternoon. Left them cooking for a few hours while running errands and have just now started to spend time listening to my "new" T3.

    First off, the installation of these is very similar to how you go about installing Mundorfs. Their size is very close as well. An easy fit in the T3, or at least, no more challenging than the Mundorfs. I'm sure folks will conceive of more than one way to go about it, but here's the lead bending scheme I employed:

    [​IMG]

    You can see that the bottom two caps will occupy the middle cap sites, and the top two caps will occupy the outer cap sites. I used teflon over the leads, and also covered the slightly exposed bends with double-thick electrical tape.

    Once installed, they look even more at home in the T3 than the Mundorfs IMO...

    [​IMG]

    I'll probably also follow MortenB's lead and insert some dynamat or silicon to fine tune their alignment and provide some damping, but for now... good enough for government work me thinks.

    How do they sound? Hmm, well... I'd like the local folks to give a listen and form an unbiased opinion. I think I've heard enough already to have my own opinion, so if anyone wants to know what it is ... send me a PM. :)
     
  2. MortenB

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    Cool stuff :cool: Unbiased opinion = make sure they don't read my impression of the caps ;)

    Actually, I installed mine in a different way than the ''Mundorf approach'' because I did not want the caps to be ''riding'' on the legs and I don't think the damping (the black stuff) is possible this way. I drilled some small holes in the PCB in the space between the caps and ran the legs down through these holes and soldered the legs on the bottom of the PCB. This way the caps can be mounted flush on the PCB with double sided adhesive for a strong and secure installation (and it looks nice because the caps sit perfectly straight / flush - see my picture earlier).

    I did the black silicone glue while I had the caps sitting on my work table and the legs bend in the right shape to fit into the new holes in the PCB. I wrapped each pair of caps in tape on 3 sides to hold the caps at exactly the right distance of each other and to cover the gap between the two caps. I then filled the gap with the black silicone glue for damping from the side not covered with tape (the bottom side with the legs, that I had facing up). After the black stuff had dried I pulled of the tape and then had a block with two caps. Finally I added the double sided adhesive to the bottom of the cap block and installed the two blocks in the amp. The installation done this way takes seconds.

    It might sound complicated, but it was easier than all the bending of the legs. I like the result, the damping seems to work because when knocking on a capacitor block it feels/sounds more mechanically damped. And I like that the cap blocks are flush with the PCB and well bonded for a secure installation.

    I think it will be too messy to work with the black glue inside the amp, it seems to be able to go everywhere and is tricky to get off again.

    Another way to apply damping to the caps is to add bitumen strips on the caps, that's what Rike Audio suggested me to do. This you can do easily with the caps installed by the ''Mundorf approach''. I just liked the other approach better.
     
    Last edited: Jul 3, 2016
  3. bazelio

    bazelio Friend

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    Yours looks really nice and tidy, Morten. I have a roll of this stuff in the garage, and will use it post-installation mainly on the underside to shim the caps up. It's good to about 200C and sticky on one side, so I won't adhere it to the PCB, only to the cap. I'm not really sold on gluing the caps to one another, though. Not because of the mess, but because it creates a mechanically coupled interface between two caps that didn't previously exist (albeit a weak one, since it's rubberized). So I think I prefer the gap, but maybe I'll change my mind later and insert strips. Adhering them to one another will certainly create a solid feel to the installation.
     
  4. MortenB

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    If you feel this can cause a problem, then implement the caps in a way, that works better. Choosing our own solutions is one of the beauties in DIY work :) I just hope you find a solution that's mechanically stable, so that the caps are not only held by their legs and the solder points. It's not safe.

    Electronics installed on a PCB must be a problem in general then, since the PCB creates a mechanical coupled interface between components, that didn't previously exist.

    Honestly: I don't get it, but hey, I'm Danish ;)
     
    Last edited: Jul 3, 2016
  5. bazelio

    bazelio Friend

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    Yeah, I don't suggest simply allowing them to flop around either. I've got an electrical tape "jig" that I used during soldering still in place for the time being.

    The coupled surface area is quite different on the interface between two sides of these large square caps vs anywhere else on the PCB. Maybe it won't be a problem, but as you say, there's more than one way of achieving one's aim.
     
  6. Jun

    Jun Friend

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    Measured with one end on the ground.

    Slight mismatch here. The resistance moves up and then stabilizes I think because of caps.

    edit: they measure 100k ohms... i went from ground to resistor and got those million ohm measurements disregard.

    R23 = 980K
    R24 = 992K
    R25 = 961K
    R26 = 972K

    Good here
    R19 = 21.5K
    R20 = 21.5K
    R21 = 21.5k
    R22 = 21.5k

    Waiting on those diagraphms for the voltage measurements.
     
    Last edited: Jul 3, 2016
  7. MortenB

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    Good, that you make sure the caps get installed safely. When looking at DIY work around the Internet there is lot's of unsafe installations of big components with high voltages on them. It always make me uncomfortable to see that.

    The mechanical problem point still make zero sense to me... Installing these square caps on a PCB should create mechanical problems then because of the coupled surface area between cap and PCB and between caps if more are installed next to each other. But that's how the caps are designed to be installed. Never mind, let's just leave it since it's not really the topic of the thread.
     
    Last edited: Jul 3, 2016
  8. dsavitsk

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    Double check. Those should all be 100K, not 1000K. If they are indeed incorrect, it would certainly lead to the amp not working properly.
     
  9. Jun

    Jun Friend

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    It really is that high. I traced the path and it seems to go through a transistor which is responsible for making the ohms close to a million.

    Maybe something didn't get grounded well.
     
  10. MortenB

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    Do you measure directly across the resistors Jun?
     
  11. Jun

    Jun Friend

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    Yes, The resistors all measure 100k ohms +- 1%
     
    Last edited: Jul 3, 2016
  12. MortenB

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    Great, that's what you should measure, directly across the resistors to check if they are 100K ohm. If you measure 100K ohm across all four plate load resistors then they are correct.

    You should not measure to ground. I believe that's where the misunderstanding happened.
     
    Last edited: Jul 3, 2016
  13. bazelio

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    They are, and the Amperex versions are seemingly like finding a needle in a haystack too. I have a few inquiries out to see if I can obtain a pair. Oh and by the way, the Amperex 12AZ7 and the GE 12AZ7 were two very different sounding tubes. For me both were enjoyable in their own way, but the Amperex clearly better.

    Incidentally, some of the local folks have already pinged me offline for the cap info, so one thing I'll say is that with these caps in place I believe our tube preferences would probably change to some degree. The nature of these caps makes me wonder if the Amperex 12AZ7A would retain its title, but the only way to find out is to try! The Valvo 6201 (blue label) is still fantastic.
     
  14. MortenB

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    Agreed... The Rike Caps has different tonality than the Mundorfs, so tube choice might change as I also mentioned in my impression of the Rike Audio caps on page 42.

    I still go back and forth between the Telefunken ECC801s and the Mullard M8162 CV4024 (see the excellent review by HitmanFluffy on page 27). I think my preference is still the M8162 CV4024, also with the Rike Audio caps.
     
    Last edited: Jul 3, 2016
  15. Riotvan

    Riotvan Snoofer in the Woofer

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    Interesting i will keep an eye out for the Amperex tubes. I reckon my Tubes are GE's since they were made in the US(according to the seller). Hard to say though i'm not that knowledgeable about tube construction.

    Unfortunately the Rike's are outside my budget, spent way too much the last couple of months, Yggdrasil, T3 and a new speaker amp+speakers. I'm pretty much drained lol. Anyways i will order the Mundorf's with AMRG resistors and call it a day.
     
  16. MortenB

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    Don't worry Riotvan. The Amtrans plate load resistors are such a good synergy with the Mundorf caps. Actually I feel the Amtrans + Mundorf combination is the real value for money upgrade on the T3. Wise choice :)
     
    Last edited: Jul 3, 2016
  17. bazelio

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    The GE 12AZ7A had, for me, a very relaxed and pleasing sound. Not the technical accuracy many would want, but for the price, and for a well-rounded, kick-your-feet-up and relax to the music crowd it would do well. I'd take it over the EH tubes myself.

    The Mundorfs and AMRG resistors will be a good day for you. We talked about value proposition the other night, and I would struggle to recommend Rike caps under that criteria alone. The AMRG resistor based amp was both a clear winner the other night and a great value proposition.
     
  18. Riotvan

    Riotvan Snoofer in the Woofer

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    Couldn't have decided without you guys doing the ground work! So thanks allot, this thread has really become a great resource for this amazing amp :)
    I suspect i have those GE tubes then, they are a clear step up, not even subtle at all when compared to the stock EH tubes.

    Can't wait to try out the Mundorf AMRG combo, i suspect it will be a good day indeed! I think this little amp with all the tweaks is such a great value, throw in some cheap 12AZ7's and i consider this endgame.
     
    Last edited: Jul 3, 2016
  19. bazelio

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    If you haven't already purchased the Mundorfs, I'll give you mine on the cheap. Their leads are obviously clipped according to how I installed them, but I'm sure they're serviceable. Worst case scenario, I suppose, just solder on longer jumper wires if needed.
     
  20. Riotvan

    Riotvan Snoofer in the Woofer

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    Thanks but i have already ordered and i suspect shipping from the US to EU will not make this worthwhile :(

    I was talking to @MortenB and even shipping from Denmark to Holland was €19,- so yeah that was also not worth it, but anyway thanks for the offer, i'm sure you can make someone happy on your side of the pond ;)
     

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