Tube / SS amp that handles 4ohm loads well and delivers lively texture / palpability


For Triangle signature theta speakers. Real 90db(measured - most manufacturers would claim 94db) Minimum impedance 4.4ohm
amp or integrated. Low volume listening. I would drive an amp with a dac with included class A Ss preamp.

triangles have very sharp high frequencies (horn loaded tweeter) and need a very warm fullbodied amp with texture that manages to be still lively and fast and open.

that screams tube amp but in am concerned about bass performance an coherence as rock solid timing is my goal no.1 and full body my goal no.2 

I thought about el34 amps like lm211ia or class a amps like densen or valvet, class b like LFD.
Small and light gainclones would be nice as well if they can deliver the performance.


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Well Bass speed might not be the right term. But most of the systems have serious issues with bass lag. Especially tubed ones. Wobbly, undefined, out of rhythm bass.
But most of the systems have serious issues with bass lag. Especially tubed ones. Wobbly, undefined, out of rhythm bass.
I find that if one is careful about the match between the amp and speaker that this need not be the case at all.

In fact I've found that tube amps often deliver more natural bass than solid state.

Now my speakers are 16 ohms, as that better takes advantage of the capabilities of any tube amp which is how you want to approach it. My speakers also go down flat to 20Hz owing to dual 15" TAD woofers. Plenty of impact, extension (my tube amps are full power to 2Hz, so no measurable squarewave tilt at 20Hz), no 'wobble' (whatever that is) and  plenty of definition.

Many speakers today are 4 ohms in the bass and otherwise 8 ohms in the mids and highs. An example is the B&W 802. This is not a tube-friendly speaker and designs like this should be avoided if you want to get the performance out of your tube amps! If you use the 4 ohm tap, the output transformer is less efficient and may lose an octave off the bass response. Why do that when tube amplifier power is more expensive?? Instead (and this is true of any amp, tube, solid state or class D), don't make the amp work hard for a living. Its life should be easy like a walk in the park. Then it makes less distortion and will sound more like real music.

Ralph, your Atma-Sphere amps are known for, among other things, their superior reproduction of bass frequencies and instruments. In the technical details you provide for the amps, you cite their unusually wide bandwidth, possible only by not containing output transformers. One of the benefits of wide bandwidth, I understand, is less phase shift than is possible when employing bandwidth-limiting (i.e. all, to one degree or another) output transformers. Isn't the presence of those transformers in non-OTL tube power amps one cause of their often mediocre bass reproduction?

Transformer design and manufacture is a tricky business. One has to strike a balance between abilities at low frequencies (requiring a large transformer) vs. high frequencies (the smaller the better, all things being equal). Music Reference amps have unusually good bass because, amongst other factors, Roger Modjeski is an expert in their design, winding his own for some applications. Of course, no transformer is better than any transformer, but not without a penalty (amp-to-speaker impedance matching).