Balanced to SE to Balanced Again?


Hi all,

Would it make sense to connect a DAC’s balanced output to a balanced-to-unbalanced (1:1 conversion) transformer, then route that to a SE preamp input, then run the preamp output to another unbalanced-to-balanced (1:1 conversion) transformer, then route that ’balanced’ connection to the balanced input of a power amplifier?

I have a true differential balanced DAC, SE preamp, and true differential balanced power amp, and was wondering if I could still use all of these components with transformers between them... or if I need to spend more money upgrading to a fully balanced preamp.

Would this series of conversions destroy any point in running differential balanced connections in the first place, regarding sound characteristics such as detail retrieval, or microdynamics, soundstage/instrument placement/imaging? Would there be issues with things like phase?

Thanks!
acsystems
Using two outboard transformers will affect sonics in some manner. These extra devices will not provide the transparency of a direct cable run. It would also entail using extra cables and consideration of impedance values.

I have used a Jensen transformer successfully, but there was a slight change in sonics. A low impedance cable must be used at the input to a transformer.

If your DAC has a preamp section you could go balanced directly to the amp.


There may be an advantage at the output of the preamp if you have to run longer interconnect cables (for example I run 30 feet at home between the preamp and amps).  This will allow for short speaker cable runs and you may well hear more resolution.

But if the DAC is near the preamp, I would explore an alternative. Ask the DAC manufacturer if the unit is OK with pin 3 shorted to ground. If its not, then you can run an interconnection that goes from XLR in to RCA out, and just leave pin 3 unconnected. This will be a single-ended connection of course, but if the DAC isn't happy with pin 3 grounded, then its outputs are really single-ended anyway.
Now if the DAC is OK with pin3 grounded, then you just go ahead and connect it to pin 1 at the XLR end of the very same cable. Again, this makes the connection single-ended, but it will prevent a buzz that would otherwise occur.

In any event this will really work best if the connection between the preamp and DAC is fairly short.
If the DAC has its own volume control and is near the amps, then lowrider57 is making a good suggestion. The only issue here is whether the DAC is using a digital control; if so then the volume control in the preamp may be better, especially at lower volume settings.