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In Reply to: RE: Thank you Lew posted by Cousin Billy on December 22, 2015 at 14:39:36
Balanced cabling was developed to combat issues related to transmissions over very long runs of cable (hundreds of feet to hundreds of miles).
The short runs of cable in your system may not show any measurable noise reduction from using a balanced run of cable.
The effort to utilize balanced lines may require vastly more components than otherwise necessary (even transformers in some cases), it may cause other impedance issues, as well as inducing more self noise in the actual circuit itself.
For example, if you take the signal off your phono cartridge and send it into the grid of a half of a 12AX7 with a CCS loading the plate, you will get more gain and less tube noise than running a differential long tailed pair. In my experience, this additional noise is more audible than noise picked up by the 3 feet of cable coming from your tonearm (unless you run it right on top of a power transformer).
There's no free lunch in circuit design.
Did you know that the input stage of both our amps and preamps is a differential cascode with CCS? The top portion of the circuit is arranged as a CCS.
In the preamp, what this does is give us low enough noise and enough gain that even with passive EQ, only two stages of gain are needed for the phono section.
From what I have seen, the top portion of the circuit is not arranged as a CCS (I don't consider a cascode configuration to be related to a CCS since the load seen by the bottom triode is very low).
Such topology is reminiscent of Allen Wright's old circuit cookbook.
Still, you're going to get more self noise from the cascode differential pair than you would from a single cascode stage. This doesn't matter all that much in a linestage or power amp, but will start to bite you in a phono preamp.
-We've been using that topology since the mid 1980s.
Actually we've not been able to get SE implementations to be as quiet. Mind you, they come pretty close. The key to getting differential amplifiers to really work they way they are supposed to is through an effective CCS- and FWIW, most of the CCS circuits I've seen really don't perform all that well, leaving a lot of performance in the actual amplifier on the table.
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