Toroidal vs. Non-toroidal Transformers

I have often wondered the same thing. Sooooooooo

Toroidal transformers are more efficient than the cheaper laminated E-I types for a similar power level. Other advantages compared to E-I types, include smaller size (about half), lower weight (about half), less mechanical hum (making them superior in audio amplifiers), lower exterior magnetic field (about one tenth), low off-load losses (making them more efficient in standby circuits), single-bolt mounting, and greater choice of shapes. The main disadvantages are higher cost and limited power capacity (see "Classification" above). Because of the lack of a residual gap in the magnetic path, toroidal transformers also tend to exhibit higher inrush current, compared to laminated E-I types.

Ferrite toroidal cores are used at higher frequencies, typically between a few tens of kilohertz to hundreds of megahertz, to reduce losses, physical size, and weight of a switched-mode power supply. A drawback of toroidal transformer construction is the higher labor cost of winding. This is because it is necessary to pass the entire length of a coil winding through the core aperture each time a single turn is added to the coil. As a consequence, toroidal transformers are uncommon above ratings of a few kVA. Small distribution transformers may achieve some of the benefits of a toroidal core by splitting it and forcing it open, then inserting a bobbin containing primary and secondary windings.

These responses are very informative. I, too, think exactly that: Denon players are a tad "screechy" in the highs. This term, "screechy," is an excellent way to describe it.

I have very sensitive ears, and I have posed this question because I already have the highly-regarded SA-15S2. I have had it for a week now. At first, I was very impressed with its performance--lush, dynamic, smooth. In the last couple of days, though, I am a bit puzzled by its sound. I cannot listen for more than 45 minutes or so, and I am trying to figure out why. It is bothering my ears some, and I am wondering if there is some type of problem in the highs. I am now taking a break from listening to it, as I am trying to rest my ears.

Also, the drawer opened once unexpectedly. I am 99% certain I did not hit the remote (or other button), and so I was puzzled by that, too. My previous unit, the SA8004, did not seem to bother my ears, and I do not remember the tray coming out unexpectedly.

I don't think it matters much as to the type of power transformer used. I am sure there are "cheap" and "better" forms of either type, but, how would you be able to tell. Both kinds will do the job effectively.

There is a bit more of a tendency for toroidal power transformers to hum or buzz (the transformer itself vibrating and creating noise, not noise injected into the output signal) if there is crap on the powerline, but that hardly happens.

If the only obvious difference that you can see between the two, in terms of build quality, is the choice of power transformer, I would call it a tie.

I have no experience with the Denon SACD player. I've heard various Marantz players and they sounded pretty nice for the money.

The DAC and analog output design will have much more impact on sound than will the type of transformer. You are looking at lower end processors and outputs that make use of cheaper op amps rather than discrete devices. Hence the screech. Save up for a good DAC instead. You won't regret it.

I am well aware of the ill effects of op-amp output stages. The problem is that so many players--even multi-thousand dollar units--have op-amp output stages or op-amps elsewhere in the design. Indeed, a discrete output stage will always sound better. Though, this HDAM thing in the Marantz units is pretty good. Some say its an op-amp, others say it is not. I have yet to figure out what, exactly, it is. In any case, is sounds better than whatever "OPA" three or four digit number (i.e. 627, 2132, 2134, and on and on) is offered by Burr Brown and the like.

A discrete output stage requires real design skills, and an op-amp is an inexpensive shortcut. This trend shows not the slightest sign of being reversed.