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Ulfar4

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About Ulfar4

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  1. Ulfar4

    Egmont/Tubecad with CCS

    Thanks, so with feedback it should look like this. I also changed R3/C2 fo CCS. Or in this case it is better to run it without feedback?
  2. Ulfar4

    Egmont/Tubecad with CCS

    Hi, I know there are many schematics like this but this aims to be a very cheap amplifier for the estats and it should be better than the SRD boxes. The power supply for tube has +-300 V and there will be four windings on transformer for heaters. I know I can not trust the simulation so I think it will have a maximum output voltage around 500 V peak to peak with some luck, probably less. I took the CSS from SRX+, so credit goes to JimL. Output current is set to 6mA per one output. So 12mA per channel. I added small feedback to stabilize it with 470k resistors. My goal is to make a small cheap amplifier. Voltage output is rather small than other amps but I will not use it with something like SR-009 or simmilar. THD is approximately 0.4% at 460Vp-p. But I do not know how much are those models reliable, so it can be very different in the real world. Fr of course drops around 20kHz like all these amplifiers (Triology .....). Tubes I intend to use are: ECC83 6SN7 Thanks for any comments and sorry for my english if there is some mistakes.
  3. Ulfar4

    Technical Assistance/Advice Thread

    Thanks, it helped me alot.
  4. Ulfar4

    Technical Assistance/Advice Thread

    OK, so I have to put there resistor like this?
  5. Ulfar4

    Technical Assistance/Advice Thread

    I was trying to fix it. I put negative voltage on the feedback as you said. I cannot find bsp125 as to220, but i found irfbe20 which is up to 800V. I hope this time I have done it right. Only problem is that I cannot put css in there without ruining output. With those 50k resistors the simulation worked. Anyway, how much voltage swing is actualy needed for esl headphones? Something like stax sr207 for expample.
  6. Ulfar4

    Technical Assistance/Advice Thread

    I was assuming that the 600V supply will split to 300V per side. So I put in there 10m90s as css. Is my thoughts wrong then? I redraw the feedback little bit acording to hev70. If I am understanding correctly, the feedback is there for setting the offset? Yes, it will be easier. But for me, it's a lot more expensive than building something like that. Besides transistors I have all parts so it will be inexpensive. I will sure look at it, but I wanted to avoid tubes. But I believe that it can sound very well. This is only for fun so I could experiment with headphones.
  7. Ulfar4

    Technical Assistance/Advice Thread

    Hello everyone, I am going to build a DIY esl headphone but first I need some amplifier. I really do not want something fantastic, just to try out the headphones and then build something better. My inspiration was from John Broskie Tubecad schematic and head-fi forum. My question is will it play? And if not, what to change? Thanks for your help.
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