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 Post subject: Re: How about this 6L6 amplifier
PostPosted: Jun Tue 04, 2019 12:11 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 20259
Location: Warner Robins, GA
The plate voltages should be fine so long as the sinewave out of each is equal in voltage and the output of the 6L6 tubes distorts before the previous stage.


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 Post subject: Re: How about this 6L6 amplifier
PostPosted: Jun Thu 06, 2019 4:42 am 
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Joined: Mar Sun 11, 2007 6:55 am
Posts: 11007
Location: Mission Viejo, southern California
A person on the diyaudio forum told me that he had tested 6SN7 tubes and found significant variations, with some very much unbalanced.

I got it playing nicely now, with 6L6GB tubes. I sounds great playing an FM jazz station. I can hear all of the instruments. I'll replace those with new production 6L6GC tubes tubes tomorrow.

Here is the schematic:
Image

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many of my radios http://s269.photobucket.com/user/FSteph ... t=3&page=1


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 Post subject: Re: How about this 6L6 amplifier
PostPosted: Jun Thu 06, 2019 8:49 pm 
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Here she is running:
Image

The bottom:
Image

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many of my radios http://s269.photobucket.com/user/FSteph ... t=3&page=1


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 Post subject: Re: How about this 6L6 amplifier
PostPosted: Aug Sun 18, 2019 7:34 pm 
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Joined: Jun Mon 04, 2018 3:35 am
Posts: 38
Excellent prototype & project, Steven. John Sparrow is a fine craftsman indeed. Your knowledge base is mind blowing to me quite frankly. As a Mechanical Engineering Technician that likes restorations & antique radios/juke boxes et cetera, you are a great find for precision prototyping & Art Deco manufacturing of antique radios as well as homebrew.

I admire your talent very much.

Robert

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Robert White
Ottawa, Ont. CANADA
fm453@ncf.ca


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 Post subject: Re: How about this 6L6 amplifier
PostPosted: Aug Sun 18, 2019 11:23 pm 
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Joined: Mar Sun 11, 2007 6:55 am
Posts: 11007
Location: Mission Viejo, southern California
Thank you! Many here are far more skilled in various areas. This forum has been extremely helpful.

Experimenting, I found it is FAR louder without negative feedback. I installed a switch and then a variable resistor to replace the 10,000 ohm fixed resistor in the negative feedback circuit.

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many of my radios http://s269.photobucket.com/user/FSteph ... t=3&page=1


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