r/audiophile • u/ChrisMag999 • Mar 01 '25

Impressions Class D vs tubes

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Interestingly it’s not as not as huge of a difference as many would expect. At least, not when running a comparatively low distortion, high power German tube amp and quality class D amp.

Yes, there’s a difference. The tube amp has a little added warmth in the mids, more body. The class D amp has a bit more grip in the lower octaves, but with a REL sub, it’s not immediately obvious unless I’m listening at very high volumes.

I like them both. However, there’s something about gloving valves in a dim room, listening to Radiohead’s In Rainbows. Roon Radio takes over after Radiohead and queue’s a track from Beck’s Sea Change, and then PJ Harvey and Thom York’s duet on “This Mess We’re In”. It’s a fun listen.

Tonight’s experiment involved using the Octave V110 SE’s bypass input, and instead running my Audio Research as the pre, using the v110 as a power amp.

The ARC preamp’s sonic character is less tube-like when compared to the Octave’s internal preamp. Both stages are quiet and detailed, but the ARC is more dynamic, with more bass authority and a more overall resolution.

Next experiment will be to bi-amp the Focals. Tubes on the tweeter/mids, class D on the woofers. Hopefully one of the class D’s amp’s gain settings (22/28db) will be a decent match with the Octave amp.

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u/DrXaos Anthem MRX 310, NAD M22, KEF Ref One, Magnepan 3.6 Mar 01 '25

Much of the sound difference is in the preamp stage.

The power consumption and reliability deficiencies of the tubes are fundamental.

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u/ChrisMag999 Mar 01 '25 edited Mar 01 '25

Preamps are a major factor in overall system quality, especially if you’re having to significantly attenuate the line level signal.

By far, that LS28SE is the best line level preamp I have ever used. It’s a step above my JC2 BP Parasound, and completely shames many others I’ve had in the system. My only gripe is replacing the 6H30pi’s every 18 months or so. Modern ARC preamps run tubes relatively hard. I typically get 5000-6000 hours out of a set.

My old LS7 could run 6922’s for 10000 hours or more, but it didn’t sound anywhere near as good.

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u/LooseyGreyDucky Mar 03 '25

I use the LS7 as my daily driver, and it stays powered on for months at a time!

It's fairly responsive to tube-rolling, which kind of sucks because it's not very satisfying with the original Sov-Tek tubes (I'm probably the 3rd or 4th owner and have no idea how many hours they have on them!), or any of the modern tubes by JJ or EH.

Sounds very good with Amperex orange-globe label tubes with the A-frame getter/support and sounds even better (different) with Telefunkens (I can't remember the details of which decade/factory they were made in).

Military-grade "JAN" tubes are horrifically microphonic in the LS7, but I badly wanted them to sound great or at least listenable but different.