Massdrop Cavalli Tube Hybrid Amp

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by purr1n, Aug 11, 2017.

  1. Biodegraded

    Biodegraded Friend

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  2. msommers

    msommers High on Epipens

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    Has anyone ever had an issue where the amp all the sudden clicks and the front light flashes red and white? @runeight any ideas? Is this protection?

    I powered it off and turned it back on again and placed normally. I did have the amp on for a few hours but still it doesn't get hot...
     
  3. dBel84

    dBel84 Friend

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    That is a protection indicator, not sure what might have triggered it.
     
  4. StageOne

    StageOne Friend

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    I've only had that happen once when swapping SE headphones. It clicked, flashed and rebooted. If it continues to happen, maybe try swapping the tubne.
     
  5. msommers

    msommers High on Epipens

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    I have an adapter in there using a 6C8G tube. Thinking the tube or adapter may be bunk but fortunately have another of each to test. Hopefully that's all it is. None of the items look shorted or anything and played fine for ~3 hours.
     
  6. Biodegraded

    Biodegraded Friend

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    6CG8 is likely the problem. MCTH's daddy is on record saying the heater current supply starts to max out around 400 mA (quoted by @busterbrown77 earlier in this thread), whereas the 6CG8 wants 450 (see eg here).

    Stick with 6DJ8/ECC88 or 7DJ8, and equivalents (c. 360 mA heater current draw).
     
  7. msommers

    msommers High on Epipens

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    Good to know and I found the quote on Massdrop. Bummer. I mean I guess I'll try it again and see but it would be annoying if it goes into protection after such a short period and I keep risking it catching on fire LOL.

    Regarding the 7DJ8 found on Massdrop as well:
     
  8. Biodegraded

    Biodegraded Friend

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    Ha, I didn't know about a possible effect on cathode current. 6DJ8 and equivalents it is then.
     
  9. dBel84

    dBel84 Friend

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    yeah, I would not use anything but 6922 / 6DJ8 tubes in this amp . If the wrong tubes don't cause an immediate kill , the stress on the circuit from overloading long term will kill or compromise the performance at some point.
     
  10. SmashBruh

    SmashBruh New

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    Maybe he stated differently elsewhere, however I believe you may have misread what tube type he said he was rolling. The 6C8Gs only have a heater current draw of 300 mA.
    http://tubedata.milbert.com/sheets/121/6/6C8G.pdf
    http://tubedata.milbert.com/sheets/127/6/6C8G.pdf

    So that should be fine in there shouldn't it?

    That said...
    Any update on whether it was that particular tube or adaptor?? I'm using a Tung-Sol 6C8G in mine and I'd really hate to have to stop... :(
    It just sounds so good in there...
     
  11. msommers

    msommers High on Epipens

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    I stopped using it after I read posts here, so I put in my old Amperex 6922, went and had dinner and an hour or so later found the whole thing shut off off, including my LPS and amp. Checked the fuse in the LPS and was fine. Put in the old EH stock tube and everything powered up again. I double-checked the DC connector that goes into the amp and have had to reterminate that damn thing so many times. I've taped the shit out of it now so hopefully that holds everything in place properly!

    For fun I decided to put the 6C8G back in and sure enough it works fine. I only listened for 30-45 minutes but the sense of space and openess I get with that tube is pretty dramatic vs. either 6922 I have. Maybe that Amperex tube is fucked, I'm a little gun-shy to put it back in.

    The amp is beyond warranty now anyways so I'm not really concerned about that. Plus I've been using an LPS which I'm sure will void the warranty anyways. Maybe I can open it up and tinker with things a bit, never have seen what's actually inside of it.

    Also good catch on the tube spec sheet! Admittedly I also read 6C8G, but actually it is 6CG8 for the 450 mA...Thanks.
     
  12. Biodegraded

    Biodegraded Friend

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    Ok now I'm confused. @msommers , is the tube in question 6CG8 or 6C8G? If you're suspicious of that Amperex 6922, contact the vendor to discuss a refund - you're likely still in the warranty period ;). And yeah, the little screw connectors on those DC plugs aren't the most secure with that heavy cable.

    @SmashBruh , you're right, I did misread and quoted 6CG8 specs. Wondering if the 6C8G might like a bit higher plate voltage than the amp supplies, though; input from @runeight or @dBel84 required, I think.
     
  13. Phantaminum

    Phantaminum Friend

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    The tube is not a 6CG8 it is a 6C8G. The documentation is correct for both tubes but the tube that @msommers is using is a 6C8G tube which has a heater rating of either 300 or 350 (I’m on the go and can’t remember). It falls in line with the specs for the 6922.
     
  14. msommers

    msommers High on Epipens

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    Going to run the amp for a few hours with the stock tube to ensure everything is normal, then introduce the spacer, and then the adapter and tube combo. I have two tubes and two adapters so hopefully if anything is fucked it'll show itself. Everything appears of good quality so hopefully nothing crazy is going on.

    Queue the MCTH modding thread lulz
     
  15. Guidostrunk

    Guidostrunk New

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    Figured I'd chime in on this thread. I've had this amp for a year now , and wanted to post some of my journey with it. I'm on headfi under the same username. I've known @Phantaminum for a while now over on headfi.

    I've been using my MCTH with an Acopian A28MT300($50 used and shipped) since January of this year, with the walwart since may. I have been rolling all kinds of other variants other than the required 6922 with no issues. The Tung-sol 6C8G is 300ma and works fine in the amp. However, some have had issues with hum specifically using the 6C8G. I have not had that issue. No hum with any tube.
    Tubes variants rolled so far:
    12at7/ecc81
    12au7/ecc82
    396a/5670
    6C8G

    Of course all with the proper adapters.
    Right now my 2 favorite tubes are the Telefunken ecc801s, and GEC B329. For me these 2 tubes represent the best of both worlds in sound. The Tele has an open, detailed , airy 3d soundstage. Great bass that extends deep, and a great sense of realism. The GEC is on the opposite end of the spectrum. Very liquid rich flow, very detailed and the most holographic sounding tube I've ever heard. One day I think I like the Tele better, the next day I like the GEC better, so fk it I'm keeping both. Lol.

    I'm using this amp with a Modi Multibit, and a pair of 58x. I have to say it's pretty impressive that you can get this type of SQ on budget gear these days. I've owned far more expensive gear in the past. Always trying to "upgrade". Left the hobby for about 8 months due to some personal family related issues, and came back on a limited budget I set for myself.
    Honestly, I don't remember having this much enjoyment from any previous rig I've put together. I would definitely put the MCTH up against anything below $800 , especially with the mods. I just saw one sell for $100 shipped on headfi. This amp is an unbelievable steal of a bargain! Even at its msrp. I've had the Lyr, Valhalla, BHC, Woo Wa6,MJ1,MJ2 , and wouldn't even consider the MJ2 or Liquid Platinum when you can have the MCTH for peanuts. The icing on the cake is single tubes. The LPS was an amazing addition as well. Really showed the capabilities of this amp. I have no plans on moving on from it. I wish more people would have done some of the mods we have before dumping their cth. The tubes and LPS really take it to a whole new level.

    I know my warranty is void but I really don't care. I plan on picking up a second one and storing it in my closet in case something should fail. Lol. So far , with one year on the desk. It works flawlessly, and I'm loving it.

    Cheers!
     
    Last edited: May 12, 2019
  16. Guidostrunk

    Guidostrunk New

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    I saw that @CEE TEE liked my post so I wanted to respond.

    I can't thank you enough for giving back to the community bro! There's a lot of people that never gave this amp a chance. It's a true hidden gem! I judge everything by my ears.
    I'm on such a tight budget with tuition costs for my kids I thought I'd never experience SQ levels of my previous gear. You've only opened my eyes! I can't thank you enough for upping the game in this industry! You're the epitome of the future! I sincerely mean that man! Thank you! I will always seek your products or anything you touch first!

    Cheers!
     
  17. Guidostrunk

    Guidostrunk New

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    I absolutely have to give a shout out to @atomicbob for all his time and effort with his LPS thread. He's the reason I have my Acopian!
     
  18. CEE TEE

    CEE TEE MOT: NITSCH

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    Yes, shout-out to AtomicBob for his validation and testing with different power supplies.

    And: to the community for help developing this amp and in the choices made along the way.

    Finally, a shout-out to you Guidostrunk...for taking the time to come back and share your experience!

    Keep us going. :)
     
  19. gixxerwimp

    gixxerwimp Professional tricycle rider

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    I love my MCTH with Clears, but a Laconic Night Blues Mini is available and I'm wondering if it's different enough to make it worth having both. Also have HD650M. I don't listen to much acoustic or classical, which is where the NBM may shine better from what I've managed to find here. Source is Modi Multibit FW v2. Any thoughts?
     
  20. purr1n

    purr1n Desire for betterer is endless.

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    Worried NBM and MM might be too mushy and laid back for Clears and HD650M.

    HD600, HD650K, Elex might be better suited for NBM.
     

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