Transformer coupled vs Capacitor coupled?


Guys,

I’m sure their are different schools of thoughts on these typologies but are transformer coupled better in terms of sound quality in regard to pre-amps.

Thanks,
Wig
128x128wig
As with everything it's about implementation, good caps will sound better than bad trannies and vice versa. I've heard both types sound good my current preamp is capacitor coupled.
Transformer-based volume control in a pre-amp is probably the best sounding kind. Implementation is king though. Transformers on inputs/outputs bring system-wide benefits in terms of isolation from common-mode noise that capacitors cannot give.
wig
Transformer coupled vs Capacitor coupled?


So long as the stage before is good in design low output impedance and has more than enough current and all your doing is stopping any dc offset, then a good cap is far better than a good transformer that will always have coloration’s.

But then doing a dc servo instead and having it all dc coupled, is then better than both.

Cheers George
The problem with transformers is bandwidth. Usually in a preamp level situation their bandwidth can be fairly wide, but to prevent phase shift in the audio band the bandwidth of the preamplifier circuit has to be from 2Hz to 200KHz and even in smaller sizes this is tricky for a transformer to do. But its not tricky at all for a coupling capacitor as long as the timing constants have been taken care of around the capacitor.

As George has pointed out, it is also possible to direct-couple. The trick with direct-coupling is the servo circuit has to have good stability.  Many don't and so 'hunting' (oscillating around the correct value) can be a problem. Servo theory is a field of considerable girth bit if a servo is done properly there's no going back to coupling caps or transformers.