[MikeC]

Andy wrote:

Or are are you saying because it can't reproduce frequencies over 10Khz AND it's "less susceptible to saturation and thus clipping" it must be a good thing?

I'm sure that Hugh (or Ginger/Tinker/any other EE's) will jump in here. I'm just a Mech Eng, so some of my terminology may be wrong, but the reason that a C core would be preferred over a toroid is their immunity to passing mains borne RF or other high frequency hash. This is as a direct result of their poor frequency response due to poorer inductive coupling than a toroid. A toroid has a better magnetic field containment due to the better inductive coupling and is also smaller for a given power rating. Overall, either is a compromise - potentially more HF hash with a toroid or more hum with a C-core. Which set of compromises you choose is up to you.

Mike

[AKSA]

Hi Dan,

The 56-4 would maybe suit the 55N+, though at 28Vac output it will generate a 40-42V rail, which is much higher than the 36V rail for which it is designed, and which might overstrain it, pushing the output devices to the limit and maybe costing a few sonics along the way (more power usually costs quality in audio).  You really need to use a 25-0-25Vac transformer, and for this you might consider either Avel Lindberg (who are using Chinese trafos these days) or a Plitron from Canada.  There are quite a few other manufacturers of toroids and EIs in the US and Canada, and anything of 160-200VA would suit.

Andy,

The big problem for audio amplifiers is the power supply - all too often they are full of hash, which the power caps can't fully remove and which therefore gets to the amplifier, costing audio resolution.

As Mike said in his post, you need a trafo which does not pass mains borne hum and hash;  we need to make a clean, hash free DC rail for the amps.  The toroid has a frequency response up to 200KHz;  the EI and C core checks out around 10KHz.  This is good for a clean rail.

Cheers,

Hugh

[gonefishin]

thanks...