Spectral DMC 12, 20 or 30 preamp?

The *difference* between the DMC 12 and the DMC 20 *is* the split passive RIAA *and* a change in the board layout and materials... iirc the 20 used a foamed polypropylene pcb material. The gain stages were otherwise identical.

Neither of them used any ribbon connectors.

As I mentioned I have no idea what is in the DMC 30, and no idea what if anything they have done to these models in any newer versions.

All of them are very clean, and low distortion designs. Imho, far better than a majority of solid state preamps.

Robertd made a comment in which he somehow misinterpreted what I wrote earlier. "...According to Bear, I shouldn't really expect much change." I'm not sure what he was thinking about, but I don't think that's what I was talking about.

Anyhow, if I had to own a commercial solid state preamp, Spectral's would be on my list.They are clearly a step or two up from the average stuff being sold.

Bear, it is both pretty funny and amazing how using the exact same parts but in a different layout on a board can get you very different results, isn't it ? Since i work with RF for a living, which can be EXREMELY layout sensitive due to impedance changes and circuit stability, i found this out a LONG time ago. I don't think that most audio designers / engineers pay attention to such things. In my opinion this could be the difference between a good product and a TRULY great one. Sean
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While we are on this subject, I'd like to raise the question again of whether anyone has directly compared the dmc20 vs. the dmc30S or dmc30sl. I haven't done so, and would like to hear the opinions of others.

Thanks. (It's still on topic.)

Yeah Sean, layout does matter as soon as you care about a bandwidth beyond a few hundred kHz. That is one of the things that set Spectral's design off from some others. In fact there is/was a PS Audio preamp that more or less borrowed the same circuit (really, really close) but did not sound worth a damn, imho. Although it may have been one of the better PS Audio units. The layout just was not up to the same standards...side by side the PS looked like a clusterknot compared to the Spectral.

Take a look at the Halcro amp, they had to pay attention to RF layout as well... (not for raw bandwidth, but to keep wide bandwidth so that the feedback would work to drop the distortion 2 orders of magnitude lower than usual).

_-_-bear

Bear,
Out of curiousity, do your comments on split RIAA and pcb's relate to the dmc 20 series I or series II? I thought the series II, at least, was a Keith Johnson design and not Demian Martin's.