[JimJ]

I've been coming up with a parts list for a 56 or 76 transformer-coupled pre, but I'm trying to decide what to do with the PSU. Looking to build a JE Labs design for a choke input supply:



How much of a benefit is there to going fully-dual mono, with two power transformers, etc? In order to get all the benefits, do I need to run two separate heater supplies as well (I was thinking about using regulated DC for the filaments)?

Following in that same vein, separate transformers for the heaters or just use a heater winding? Ah, so many choices...

Thanks in advance!

[Niteshade]

There is no reason to go dual mono with a preamp. The current used doesn't justify it. An external DC power supply for the filaments would be a good idea. It will be 12 volts, so you'll either want to use 12AU7's or place the 6.3v tubes in series, two per filament circuit.

[TheChairGuy]

I can't speak for technical reasons.....but of the preamps I've owned, the dual mono units were the best sounding of the lot.  The one dual mono unit with separate transformers is/was the best sounding of all.

They image better - giving you a slightly better perspective of the performance (particularly heard if you listen to un-amplified music)

John

[Niteshade]

I firmly believe that was due to a different audio circuit more than with the power supply. I honestly do not know why someone would make a dual power supply for something that has very low current consumption.

Which dual mono units did you own?

I can't speak for technical reasons.....but of the preamps I've owned, the dual mono units were the best sounding of the lot.  The one dual mono unit with separate transformers is/was the best sounding of all.

They image better - giving you a slightly better perspective of the performance (particularly heard if you listen to un-amplified music)

John