Friday, February 4, 2011

27-71A Single Ended Amplifier
















































 27-71A Single Ended Amplifier

10 comments:

  1. Hi , i'm very interested in this project of this tube amp
    how can i contact you?
    Thanks in advance

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  2. hi Miguel, give me a couple of days to find and publish the schematic. thanks.

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  3. Miguel, the amplifier was really very very good sounding, unfortunately there was not enough gain when used with the 12A OT line stage, it needs a more conventional preamplifier.

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  4. Any sugestion from the preamps on this site?

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  5. The cap coupled is 2uf... any type or brand in special? film, pio, teflon?

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    Replies
    1. you can use a vintage pio or a good new film, 2uF was the available value but 1uF should be ok also.

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    2. The main transformer is 205 - 0 - 205v and how many mA? in same way the choke is 10H/__ mA...

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  6. rating of the transformers and choke was unfortunately unknown, anyway you need 20mA for the 71a and another 5mA for the 27, so around 50mA for both channels. power transformer should have around 380-410v center tapped and a minimum of 30-40mA (will double with ct) and the choke should ba around 10h 50mA. then you need to adjust b+ (1st cap, bleeder res, etc etc) so to go near 220v on the 71a plate.

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  7. What level I need at input?
    As an alternative solution may and step up transformer at input like the Lundahl LL7903 able to make in arranged 1:4 up to 8volts with an standard DAC output?

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