Changing Turntable to Balanced Output

Have you measured frequency response and phase accuracy ( across the full frequency range ) in these situations ??

Sure! I've been unable to measure any loss of bandwidth even with 100 foot cables. To be clear though that means only up to 100KHz. Most transformer systems that operate at line level will only be going about that high- our preamps go higher since they have a direct-coupled output and no need for a line transformer. Phase accuracy in a passive or zero feedback system is entirely dependent on bandwidth. 100KHz bandwidth means there won't be any phase shift below 10KHz.

You might want to consider than in almost any classical recording there is a good 100 feet of cable before the mic signal hits in the inputs of the recording system. Put another way, the bandwidth/phase issue was 'fixed' by balanced line operation back in the 1950s.

Do you really believe this. My understanding is that any low signal level cable over 3 metres no matter how whoopdido is going to have high frequency roll off. And what about phase shifts and internal reflections within the cable itself.

I find it hard to believe there is no degradation.

@dover 

No- I don't 'believe' it- I know it. I've run similar lengths for microphone signals myself- with no rolloff. Its helpful to keep in mind that a properly set up balanced line system is also low impedance (600 Ohms is typical) and the low impedance aspect allows you to run longer connections.

I’m not really sure this true balanced outs because the transformers feed both sidle ended and XLRs. I am relatively new to this.

@audiosaurusrex Transformers allow you to run single-ended or balanced simply by grounding one side for single-ended, or balanced by letting the transformer winding 'float' (not be referenced to ground in any way) and simply being connected to pins 2 and 3 of the XLR connection.

So to run it single ended you would use a switch or install a jumper to the XLR connection, thus connecting pin 3 to pin 1.

@rauliruegas The old Decca cartridges from the 1960s and 70s had only three pins and thus have to be treated as single-ended sources. They are the only exception to 'all cartridges are balanced' I've ever seen- even ceramic cartridges can be treated as a balanced source. The newer Decca cartridges have 4 pins and are thus balanced.

@audiosaurusrex I don't see anything there that has anything to do with the phono section.

balanced shmalanced..........unless all your components are differentially balanced, you will not get the improved performance.

This statement is false. The Ampex 351 tube tape electronics were used to record a great deal of classical and jazz recordings done by RCA and the like. Its internal circuitry is entirely single-ended except for the push pull output it has driving its output transformer to drive a 600 Ohm balanced line. The input used an input transformer as well. This allowed the tape machine to have microphones a good 150 feet from the machine with no degradation of the mic signal. This was long before an exotic cable industry existed. You might say that the balanced line system itself was the exotic cable industry prior to Robert Fulton creating his first ’Fulton cable’ back in the late 1970s.

Similarly if an input transformer is used with a LOMC cartridge (and the transformer is properly loaded to prevent ringing) then the tonearm interconnect will have far less effect on the sound of the system.

Its arguable that this is the one place you really want to get it right!

The advantage of running a cartridge balanced is of course to minimize any artifact from the cable- meaning an inexpensive cable can sound just as good as one costing 2 or 3 orders of magnitude more!

Now it is a fact that if the phono circuitry is fully differential that there is additional benefit (for example in our phono sections only two stages of gain are required to work with a LOMC cartridge run straight in- you get theoretically 6dB less noise per stage of gain). But balanced lines can be executed with single-ended gear if good transformers are used. Users of SUTs take note! All transformers including SUTs can be used to receive the cartridge signal in the balanced domain.