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45 amp build direct coupled
45 amp build direct coupled
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Old 14th May 2018, 05:43 AM   #131
mbrennwa is offline mbrennwa  Switzerland
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Quote:
Originally Posted by Soundhappy View Post
Find this directly coupled " Lafon " 45 amplifier
in my old paper " L'Audiophile" collection
Nice! Can you scan the full article? Yes, I do understand some french if I really have to
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Old 14th May 2018, 05:51 AM   #132
soulmerchant is offline soulmerchant  Switzerland
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Hi Soundhappy

Push-Pull 45 is a nice idea. These days though, 45‘s are getting more expensive to source. Pity that.

The Cascaded 6sn7 brings almost too much gain for the little 45 tube. Indeed, it would be a lot for 2a3 as well. Also, output impedance is really still high on the 45 grid. Last part that I don‘t like with these designs is that the whole thing works like a house of cards - it assumes all valves/tubes are in like-new condition running like in the specs sheet.

Also, that variable 2.5K Ohm 50 watt cathode resistor... Pretty big. And no cathode by-pass cap from point G to ground? I have a hunch that bass response might suffer. Did you ever hear this amplifier?

Ian
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Old 14th May 2018, 08:12 AM   #133
mbrennwa is offline mbrennwa  Switzerland
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That pretty much summarises my thoughts when I looked at the schematic. It would still be interesting to read the text. There are sometimes some nice ideas hidden in those circuit descriptions that are not obvious just from looking at the schematic alone.
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Old 23rd May 2018, 03:25 PM   #134
Soundhappy is offline Soundhappy  France
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45 amp build direct coupled
45 amp " Lafon " amplifier schematic was inculded into article
"Aspects of electronics " but not precise informations, bandwith frequence response , constructions details etc.
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Old 23rd May 2018, 04:52 PM   #135
nicoch58 is offline nicoch58  Europe
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tnx
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Old 15th June 2018, 12:30 PM   #136
mbrennwa is offline mbrennwa  Switzerland
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Default Parts!

Partssss.... Muuaaahahahaaaaaa!!!
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