Balanced to Single-ended Buffer

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Ray P
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#1 Balanced to Single-ended Buffer

Post by Ray P »

Ray P wrote: Fri Jul 10, 2020 9:46 pm...most of my source components are equipped with balanced outputs (or could be very easily)... ...the amps I have working (or in progress) all have single ended inputs...

...I have a balanced passive attenuator so what I believe I actually need is a buffer stage that'll take the outputs from the balanced attenuator and convert them to single-ended to drive my single-ended amplifiers.
Following up on that post (on my 'Vintage Silicon' thread) I've started to cast around for possible circuits. So far there doesn't seem to be much turning up but for starters, here's what I've found so far.

The Broskie BCF (which I've used before on the output of a DAC and been impressed with) is probably the most obvious candidate;

Image

I also turned up this lampizator sketch from an article about using it on the output of a voltage out DAC (TPA Buffalo3)
Lampizator 6SN7 IV.jpg
I know I could use a 'hybrid' interconnects to make the connections, or I could wire the outputs of the source devices to be singled-ended, but I like the 'heft' that using a buffer mparts to the mix and as I already have balanced attenuators I may as well take the advantages that balanced connections offer where I can.

Any advice/comments/suggestions?
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Nick
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#2 Re: Balanced to Single-ended Buffer

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Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
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Ray P
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#3 Re: Balanced to Single-ended Buffer

Post by Ray P »

Thanks Nick - I'll take a look. I was looking at those Sowter transformers earlier - probably not rational but as two of my DSD decoders use output transformers (Lundahl LL1684) I find myself having an aversion to 'stringing' transformers one after the other. And, yes, I'm conscious of the irony that I have source components with output transformers whilst building amplifiers without them.

Something else I came across were some pages on the 'Nitro' DAC from 2012. The designer makes a bit of a song and dance about something she's labelled the 'DAB' in her DAC output stage design, which is basically a balanced to unbalanced (balun) solution in front of a single-ended buffer. She implies balun is commonly used by radio enthusiasts - I guess it won't be new to you?
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Nick
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#4 Re: Balanced to Single-ended Buffer

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I guess the action of that depends on the values of R's and C's used.
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Ray P
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#5 Re: Balanced to Single-ended Buffer

Post by Ray P »

Nick wrote: Sat Jul 11, 2020 1:47 pm I guess the action of that depends on the values of R's and C's used.
There's a calaculator for various scenarios on the webpage;

http://www.tubeclinic.com/A_RuSubMin_index2.html
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