ECP Torpedo III [indexed in first post]

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

  1. TheloniuSnoop

    TheloniuSnoop Friend

    Pyrate Contributor
    Joined:
    Oct 15, 2015
    Likes Received:
    588
    Trophy Points:
    93
    Location:
    Gold Canyon, AZ
    I finished mine a couple of days ago and have already been rolling some tubes. Mine has the Cinemags and stock cap's btw.

    My source is a Yggdrasil, and 'phones are HD800's.



    Here's my short take.



    The stock EH's sound OK, but are bit thin and harsh sounding.



    The RCA 6072/12AY7's I picked up on ebay are a noticeable step up. A much more fleshed out, full sound. Mid's are much sweeter without losing

    the detail.



    I also tried a pair of these that I had in my stash; platinum and cryo'ed. http://www.upscaleaudio.com/mullard-cv4003-12au7-vintage-new-old-stock/

    Even better yet than the 6072's above, but I paid less than 60 bucks for the RCA's, and to be honest, I'm not sure that the Mullards

    are enough better to justify the price difference, especially since the Torp III was designed around the 12AY7. The 4003's had plenty of gain though.



    I also had a pair of these on hand; also platinum and cryo'ed. http://www.upscaleaudio.com/mullard-cv4004-12ax7-british-new-old-stock/

    Tomb is correct that the 12AX7 is not the best choice. Even at their much higher price, these sound too aggressive, probably because of some

    distortion. As with the 4003's, plenty of gain.



    My main amp is an Eddie Current Balancing Act with PX4 output tubes. After reading the original Torp I thread, I wanted to build one just

    to hear it. Then along comes the Torp III with optional Cinemag OT's, so I couldn't resist ordering one. Besides, I haven't built anything for

    quite a while, and was Jones'ing pretty bad. [​IMG] Of course, I couldn't help but compare the two amps, and while the Torp III can't keep up

    with the BA's 'otherworldly soundstage', it holds its own quite well in all other aspects; detail, dynamics, bass, et al. At around $850 with the

    Cinemags, stock cap's, and a pair of vintage 6072's, it's a steal.



    A massive thanks to dsavitsk and tomb for bringing us this marvel and for their continued selfless assistance.



    Of course, FWIW and YMMV. [​IMG]
     
  2. fierce_freak

    fierce_freak Friend

    Pyrate
    Joined:
    Oct 22, 2015
    Likes Received:
    220
    Trophy Points:
    43
    Location:
    Western New York
    Love seeing impressions from others on this rolling in. Really, really good amp, favorite I've owned. Just need to hear some EC at some point, but I'm really satisfied.

    I'm interested in trying a 12au7, so I appreciate your thoughts on that!
     
  3. TheloniuSnoop

    TheloniuSnoop Friend

    Pyrate Contributor
    Joined:
    Oct 15, 2015
    Likes Received:
    588
    Trophy Points:
    93
    Location:
    Gold Canyon, AZ
  4. badf00d

    badf00d Friend

    Pyrate
    Joined:
    Sep 28, 2015
    Likes Received:
    55
    Trophy Points:
    28
    Location:
    Ohio
    Ok, I've had a lot more time to listen to my T3. This thing has been able to drive a lot more bass out of my HD800, unexpectedly closing the gap on my LCD-2 by adding more of the visceral sensation the LCD-2 has for me. My Gungnir Multibit is well burned in now and the combination is great. I bought some RCA 12AY7 tubes on eBay and will try them out when they arrive. I'll report back here with what I experience with that combination.

    Gungnir Multibit > Torpedo III > HD800/LCD-2 --- fantastic.
     
    Last edited: Nov 18, 2015
  5. jexby

    jexby Posole Prince

    Staff Member Pyrate Contributor
    Joined:
    Sep 28, 2015
    Likes Received:
    8,145
    Trophy Points:
    113
    Location:
    Exit stage left....
    Aww dammit! @MisterRogers are you going to loan me your Torpedo some day(s) to let me compare to BW (via Yggdrasil) ?!
    Inquiring minds want to know.
    :D
     
  6. MisterRogers

    MisterRogers Ethernet Nervosa

    Pyrate
    Joined:
    Sep 27, 2015
    Likes Received:
    2,063
    Trophy Points:
    93
    Location:
    Aurora, CO
    Home Page:
    Surely @jexby! better get it to you sooner than later while it's still stock. :)
     
  7. HitmanFluffy

    HitmanFluffy Hoping to see real genitals someday!

    Anti-SBAF PSYOPS Banned
    Joined:
    Sep 26, 2015
    Likes Received:
    1,532
    Trophy Points:
    93
    Location:
    Austin, Texas
    I ordered a pair each of NOS RCA 12AV7s and newer Sylvania black plate 12AT7s to roll, though I'm waiting for my sister to bring it back around Christmas time to build it.
     
  8. fierce_freak

    fierce_freak Friend

    Pyrate
    Joined:
    Oct 22, 2015
    Likes Received:
    220
    Trophy Points:
    43
    Location:
    Western New York
    Cool. I'm pretty happy with the GE 6072a 5-star tubes I have, but I'm definitely interested in trying some 12au7. Anyone have any suggestion on which might fit best in this amp? Way more variety for this tube than others I'm used to.

    -edit- think I'm going to try some rca 5963 first then maybe go for the mazda 12au7 if I'm still curious
     
    Last edited: Nov 19, 2015
  9. MisterRogers

    MisterRogers Ethernet Nervosa

    Pyrate
    Joined:
    Sep 27, 2015
    Likes Received:
    2,063
    Trophy Points:
    93
    Location:
    Aurora, CO
    Home Page:
    Belleson's installed, and the quick verdict is - I'm hearing an improvement. Upper, mid and low bass are tighter and better defined. Instrument separation seems better. I've been running a NOS pair of RCA 6072's. I'm building FlySweep's TIII right now. When done, I'll run both with stock tubes, with his still running the NJM2396. It'll give me a better chance of verifying my impressions.
     

    Attached Files:

  10. dsavitsk

    dsavitsk Friend

    Pyrate
    Joined:
    Oct 2, 2015
    Likes Received:
    1,616
    Trophy Points:
    93
    Home Page:
    The tail CCS provides something on the order of 50 to 60dB of isolation between the circuit and the PS which already provides ~60dB of PSRR. This decreases a bit above 10KHz. It's possible the Belleson makes a difference, though if it does, you can probably get a bigger improvement (as in orders of magnitude better isolation) for a lot less money (pennies instead of $70) by adding a cascode to the CCS itself.

    Also, check the dropout voltage.
     
  11. MisterRogers

    MisterRogers Ethernet Nervosa

    Pyrate
    Joined:
    Sep 27, 2015
    Likes Received:
    2,063
    Trophy Points:
    93
    Location:
    Aurora, CO
    Home Page:
    Thanks for chiming in! Yea, no doubt - the Bellesons a high spend for the gain.

    Thanks Doug - checking... (Drop out v)

    SPJ drop-out voltage = 0.6V at 1A, NJM2396 = 0.3V at 1A

    I'm at about ~6.2v at output.
     
    Last edited: Nov 22, 2015
  12. badf00d

    badf00d Friend

    Pyrate
    Joined:
    Sep 28, 2015
    Likes Received:
    55
    Trophy Points:
    28
    Location:
    Ohio
    Ok, for those of us that are green when it comes to DIY... can you explain this like I'm 5? :)
     
  13. dsavitsk

    dsavitsk Friend

    Pyrate
    Joined:
    Oct 2, 2015
    Likes Received:
    1,616
    Trophy Points:
    93
    Home Page:
    How to do it, or what it means? Doing it will require some surgery, but the circuit can be seen in Figure 7a at http://waltjung.org/PDFs/Sources_101_P1.pdf

    Basically, the CCS forms a voltage divider with the circuit. Depending upon the tube used, the circuit has an impedance looking into the cathode of around 5K to 20K Ohms. Since the CCS has an impedance of something on the order of 1M Ohms, most ripple is dropped on the CCS with only a small portion making it into the circuit (which, it might be noted, also has a huge amount of ripple rejection via CMRR) I would be very skeptical of this making much, if any difference, but audio is weird and we seem to be able to hear things that we should not be able to. So what do I know.
     
  14. peef

    peef Friend

    Pyrate
    Joined:
    Oct 5, 2015
    Likes Received:
    311
    Trophy Points:
    63
    Location:
    Montreal
    I'm not sure if it's relevant, but I was looking into cascoding a current source in a completely unrelated circuit (a current sink loading a folded cascode, with a parallel R to ground) and found that distortion increased as a function of the signal across the cascoded current source. In other words, the circuit simmed 2-3x higher distortion when it was dropping 7V instead of 10V (during transients), even if the devices are all correctly biased and saturated. It's especially bothersome since the distortion is level-dependant and independant of the CCS impedance.

    So, with the usual caveats of sims being sims and circuits being different, I guess I'd be cautious about cascoding the tail and wouldn't count on more than 6 or so volts across the entire cascode. BJTs seem to be a lot better than MOSFETs in that regard, but the JFET/IC could be perfectly fine. The J109 has a high Vgs and might be a good bet to avoid pinching off the lower device.
     
  15. fierce_freak

    fierce_freak Friend

    Pyrate
    Joined:
    Oct 22, 2015
    Likes Received:
    220
    Trophy Points:
    43
    Location:
    Western New York
    Got the case powdercoated. Take a look at the grill and where the tubes protrude from the top - trying to decide whether or not to keep the rings around the tubes. Thoughts?

    [​IMG]

    [​IMG]
     
  16. MisterRogers

    MisterRogers Ethernet Nervosa

    Pyrate
    Joined:
    Sep 27, 2015
    Likes Received:
    2,063
    Trophy Points:
    93
    Location:
    Aurora, CO
    Home Page:
    Nice. My vote would be to keep the rings; looks a bit more finished. Are you getting a better take on the caps?
     
  17. Hands

    Hands Overzealous Auto Flusher - Measurbator

    Staff Member Pyrate MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    12,285
    Trophy Points:
    113
    Location:
    Colorado
    Home Page:
    Keep the rings. Looks much better that way.
     
  18. OJneg

    OJneg The Most Insufferable

    Pyrate BWC
    Joined:
    Sep 25, 2015
    Likes Received:
    3,923
    Trophy Points:
    113
    Location:
    Grand Rapids, MI
    Very impressive matey
     
  19. kapanak

    kapanak Canucklehead - Friend

    Pyrate
    Joined:
    Sep 27, 2015
    Likes Received:
    259
    Trophy Points:
    63
    That looks awesome! Keep the rings :) Anyway, did you also change the volume pot?
     
  20. fierce_freak

    fierce_freak Friend

    Pyrate
    Joined:
    Oct 22, 2015
    Likes Received:
    220
    Trophy Points:
    43
    Location:
    Western New York
    Thanks guys. I'll keep th rings.

    I did change the volume pot to a TKD. I changed it at the same time as the caps, which was probably a bit stupid. Just impatient I guess.

    Between the caps and the pot (going from hazy audio memory now), the sound seems even slightly more transparent and fast and a certain clarity of tone. I'm glad they're in the amp and think it's been positive overall, but it's really hard without an A/B.
     

Share This Page