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Little Dot MK8SE / MK6 Super Mods (All verified mods are on first page)

Discussion in 'Headphone Amps (full-size)' started by redge78, Sep 26, 2015.
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  1. bloodhawk
    Oh yeah with the Crack, it made everything super clean. Like the background was super dark/blank, but after that it pretyy much pitch black. Made the amp cooler as well. The low end was more audible / had better texture as a result of that.
     
  2. gug42
    Here it is :)

    [​IMG]
     
  3. gug42
    And, well, a point I have learn : a real one watt is very loud for a headphone !

    So if you want a really good quality for money my advice would be :
    - lundhal LL2765 60 mA or 80 mA
    - Toroidy power transformers with the ability to use regulated heater (needs 7 V and x3 A)
    - hammond or toroidy self 10H
    - chemical + MKP capacitor
    - One 5998A tubes can power the two channel. But you can use other stuff :wink:
    - Input tubes depends what you want, there is multiple options
     
    Last edited: Feb 24, 2018
  4. baronbeehive
    Right!

    The CCS should rule out pretty much PSU artifacts in the audio signal, resulting in a cleaner signal. The balanced output of the LD is generally agreed to improve bass quality and detail over the SE output, and force balancing, which is what the CCS does, should further improve this because the LD balance depends very much on the tubes and can be in or out of perfect balance quite considerably.
     
  5. gug42
    The CCCS has one advantage : infinite equivalent resistance, BUT the CCS has one flaw : provide some disruption, some noise, by the principe of the ccs ... instability ...
    The most simple way to go : use one R by triode (not by tube but by triode), for sure less fun than a cccs ...
    And moreover, if you find that you have enough gain, no obligation to use a bypass cathode capacitor. Less distortion.

    A+
     
    Last edited: Feb 24, 2018
  6. SonicTrance
    This is exactly what the CCS doesn't do. The CCS provides balance and stability to the signal. Not sure where you got that info?

    You should look into building the "modern LTP"!
    https://www.head-fi.org/threads/modern-balanced-tube-amp-build.852879/

    No reason to use pricey Lundahl transformers in that amp :wink:
     
  7. baronbeehive
    I tried to find correct values, hope I haven't read wrong way round.

    upload_2018-2-25_17-29-29.png
     
  8. baronbeehive
    upload_2018-2-25_17-34-2.png

    That's very clear!

    The brown black black black brown resistors are 100R.

    OK. Could I connect to the cathode where the cathode resistor was, or better to connect direct to socket pin? I'm not sure of the board trace atm.
     
    Last edited: Feb 25, 2018
  9. SonicTrance
    The 270R is in series with a 220R for a total of 490R. I didn't have a 470R .6w 1%.
    That is called the sense resistor and is the resistor that sets the current. The formula is: Iccs = 1.16 / sense R. So, in my case its 1.16 / 490 = 2.37 mA. Thats the total current. Each triode will get half, about 1.2 mA.

    The gate stopper is 100R, not 2k like you wrote in the pic. Look at IRF830 datasheet to learn which pin is gate, drain and source.

    It doesn't matter if you connect the ccs where the cathode resistor was or directly at a cathode pin. It's the same thing. Just make sure to connect the ccs on the cathode side of the resistor holes and not the ground side. Use ohm meter to test.
     
  10. baronbeehive
    OK, thanks for that, don't know why I wrote 2K, I've got 100R in my notes!
     
    Last edited: Feb 25, 2018
  11. MrCurwen
    Yes I've built a bunch of different kinds of SE amps in my day. This is quite typical retro type SE amp; not bad to listen to, but not very good either if I'm being honest. Fun to build though, and very very informative if you go thru the trouble to find out what happens inside it.

    As drawn, the output section doesn't pass any kind of audio signal thru the OT. There's a mistake somewhere.

    Either it's meant to be a parafeed type amp, in which case it needs a plate load of some kind between KT66 anode and B+. Resistor, choke or a SS module of some kind.

    Or, it's meant to be ultrapath amp, in which case B+ needs to be inserted at the junction of the OT primary and C704 (the ultrapath cap). Then the OT primary can act as a plate load in the usual way for series feed OTs.

    It's probably the ultrapath one. The voltage markings are just made somewhat misleadingly. In that case the cathode caps are 100% completely unnecessary. Ultrapath trades cathode bypass caps for the ultrapath cap; it's a higher impedance node, so you can get by with a smaller capacitance, 30µF film cap in this case. Easier to use film caps than 100µF cathode bypass cap.

    Indeed. I suspect gug42 is talking about some other thing, not a CCS used as a tail. Or, he doesn't understand what goes on inside a balanced pair.

    If you are talking about your SE amp that's another thing. Separate cathode resistors in a balanced (or using the old terminology, push-pull) stage is just counterproductive.

    Ok I'm pretty sure you're talking about a SE amp here, right?


    I'm very happy there is excitement to try the CCS tail mod. It's not a fix-everything magick pill for the LD, but Sonic reported it as a noticeable improvement. Also it'll help ease some underlying worries about "THAT SS SOUND" that a lot of people might still have.
     
  12. baronbeehive
    I think so. I suspect that gug42's amp might exaggerate the transients somehow to get that alive sound that he has, especially in the treble frequencies,
     
    Last edited: Feb 25, 2018
  13. bloodhawk

    Yeah that is something i have been noticing post mods, that the amp sounds very close to an SS amp now. Would love to try out the CCS in the VI+ once Sonic posts some more info.
     
  14. baronbeehive
    What do you mean by SS sound? To me it means more exaggerated transients, hotter, splashy sound and not so rich or holographic as tube sound.

    Of course the best SS systems are not like this!
     
  15. bloodhawk
    I personally feel that SS amps sound very analytical and transparent. When we get Tube amps we get them for the musical/euphoric nature. And to me post mods the VI+ sounds very analytical. Which isnt really a bad thing, as it still sounds amazing. But it just seems to not have that warm tube sound anymore.

    Ill have access to a VI+ running similar tubes like mine, later this week and ill be able to do some accurate A/B comparisons then.
     
    Last edited: Feb 26, 2018
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