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What is the Single Ended Triode thing?

Discussion in 'audio' started by Coda II, Oct 18, 2021.

  1. Disarmamant

    Disarmamant Certified foo free

    PM’d you Steve.
  2. Steve 57

    Steve 57 pfm Member

    Don't forget the s6 is a ultra linear pentode amp, and, if its anything like my simply 845 amp I owned for a short time in the late 90s, it had pretty mediocre output transformers..
    True triodes are much more forgiving to varying loads, and the original types much better in that regard than most modern production valves in my view and experience.
  3. benjaminreed1

    benjaminreed1 Benjamin Reed

    I just sold a 845 SET tube amp. Guy comes round for a listen and glass of red. Put on Grant Green My Funny Valentine, jazz guitar kicks in. Jaws drop. Even the kids were quiet. Replace with solid state, and now need to buy another 845 tube amp! Different strengths but the emotional trigger is ridiculously powerful.
    Also acts as a heater in winter.
  4. Coda II

    Coda II getting there slowly

    In simple terms, did you find the step to not having valves for output difficult? What I mean is, did you find that you needed to do a good amount (as suggested in the snip above, though not sure) to ‘make up for’ using mosfets? (Which autocorrects to misfits!) Or are they perfectly capable in their own right?
    I suppose the question is: if you get all the benefits of SET without the triode then why aren’t more people doing it? Or are the steps needed elsewhere to onerous for a wider market?
  5. Caledon1297

    Caledon1297 pfm Member

    For an SET virgin (in fact, someone who has little experience of valves in general), any suggestions for SET integrated amps to try, to experience the 'magic' some find they offer?
  6. Old Shatterhand

    Old Shatterhand pfm Member

    That depends on the budget @Caledon1297 . If your budget is limited too much I wouldn't do it. Especially cheap stuff from China. Good SET amplifiers are expansive.

    Safe and trouble free is the stuff from Tzakirids (alternative Line Magnetic) but you don't get the quality (especially bass and high frequency) like stuff from companies with better parts.
    Caledon1297 likes this.
  7. Enrae8

    Enrae8 pfm Member

  8. G T Audio

    G T Audio Trade: Manufacturer and Distributor

    Looks like the later ones are running fixed bias, hence the increase in power.
  9. kneecap

    kneecap pfm Member

    Fortunately i don't live in a mansion and only listen at moderate volumes. And der klang ist gut. :)
  10. Old Shatterhand

    Old Shatterhand pfm Member

    Not fully, IIRC 2/3 automatic bias and 1/3 by hand.
  11. Steve 57

    Steve 57 pfm Member

    The reason people aren't doing it is because its a diy thing.
    Using a mosfet without gain, as a follower is quite big in the diy scene. Look up mofo on diy audio
    There are mixed results because with any low output design, suitable speakers are critical to get the very best from them.
    And most build it as just an output stage and use it with a high gain pre amp.. the quality of the pre used is also crucial
    Mine is an all in one amp, the driver stage is a nice output valve with a gain of 5 (mazda shortpath ac/p1) connected with a nice pair of nano tribute interstages.
    The output caps are important too
    I'm in East Yorkshire if anyone would like a listen. Or at the audio talk meets next month
    It's low distortion and it makes about 4 watts as it is. Different drivers would change the amp and the output.

    There is no grey or grain i hear with this design, I read somewhere that mosfets introduce that grey/grain when you use them for amplification, but in this design they are only adding current as a follower. .
    A friend built one for use with a separate pre and he said it was not as good as mine, but like all amplifiers it's easy to spoil a good design.
    Coda II likes this.
  12. russel

    russel ./_dazed_and_confused

    There are two reasons why people say X,Y or Z are not good for amplifiers, one is they have a commercial interest in selling another type of amplifier and the other is they don’t know what they are doing.
    Robert, Steve 57 and John Phillips like this.
  13. G T Audio

    G T Audio Trade: Manufacturer and Distributor

    There is of course a third reason: They do know what they are talking about!
    Steve 57 and Old Shatterhand like this.
  14. Cappuccino

    Cappuccino pfm Member

    Id love valves but for three reasons cost, dog n heat. I’m sure there are other reasons.
  15. russel

    russel ./_dazed_and_confused

    We will have to agree to differ.
  16. Coda II

    Coda II getting there slowly

    Something that hasn’t been mentioned thus far in this context is digital amplification.
    It may well be that no one has thought it worthy of serious discussion but it is not uncommon to see comments along the lines of some digital having a tube like clarity. In addition, and though they may have gone out of fashion to an extent, some of the early chip amps were relatively simple circuits.
    It may be that digital creates a whole new set of problems that then need solving, but is there anything in the current offerings to suggest that digital may leapfrog solid state and actually get closer to where SET is/was?
  17. G T Audio

    G T Audio Trade: Manufacturer and Distributor

    Coda II: You can use digital to process the sound, as in D to A or A to D conversion, but if you need amplification to drive a loudspeaker, you still need a conventional audio output stage. Now that could be a classic class A, or a Class AB, or a switching amp (Class D or Class T), which basically switches or pulses a conventional output stage using transistors or mosfets etc, or a combination of technologies, as in the Devialet designs...

    The reference to a "chip amp" means that the whole output stage is in a complete chip package and that all you need for the circuit to work is a power supply and a few components around the chip to make it function. Depending on the chip and the whole design, these can sound extremely good. These are analogue devices.
    Coda II likes this.
  18. Coda II

    Coda II getting there slowly

    So the chip in a chip amp still uses transistors, just in their miniaturised IC form?
  19. tuga

    tuga Legal Alien

    The two problems with SET amplification are the exponential rise in harmonic distortion as you turn up the volume and the high output-impedance which makes it very sensitivy to load (combined amp/speaker frequency response depends on the speaker impedance characteristics).
    I wouldn't be surprised if your Unison is already putting out 1% THD at 10W.
    As I see it, SETs should ideally be used band-passed in active configuration with high sensitivity speakers ≥100dB.
    But because the harmonic distortion is low-order it sounds nice to some people. Of course it will be accompanied by high levels of IMD and that is not as pleasent.
  20. tuga

    tuga Legal Alien

    What about the Lyngdorf "power DAC" technology? It doesn't seem to use analogue amplification of any kind:


    Lyngdorf Audio specifies the TDAI-3400’s power-amp section as able to output 200Wpc into 8 ohms or 400Wpc into 4 ohms by using extremely rapid-switching, low-Rds MOSFETs, and to provide a maximum current output of 40A. Although Equibit, Lyngdorf Audio’s version of the PWM switching technology, is proprietary, other companies make PWM amps -- less usual is how Equibit controls the output volume. Instead of attenuating the analog signal after it goes through D/A conversion and is sent to the power-amp stage, the signal is sent directly to the power amp while still in the digital domain; the volume control then adjusts the voltage output of the power supply, which regulates the amount of power sent to the loudspeakers. Lacking a traditional DAC or preamplification stage, the TDAI-3400 has much simpler circuitry and acts as a power-DAC, which makes it theoretically less susceptible to noise and distortion -- the digital signal is not converted to analog until just before it’s sent to the speakers.

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