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.


128x128zuio

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).

what are your speakers the specs you posted sound great?.
@geek101
Classic Audio Loudspeakers model T-3.3
Isn't the presence of those transformers in non-OTL tube power amps one cause of their often mediocre bass reproduction?
@bdp24

I think you answered your question in the paragraph following the quote above. Roger is not the only one that has good bass response using an output transformer! Some other examples are:H/K Citation 2VaicVTL Siegfried-and this is a teeny tiny list, but made to show the range of amps that are out there; the 1st is a vintage amp, the 2nd SET and the 3rd a very large P-P amp.

I don't think I would say that transformer-coupled amps often have mediocre bass reproduction, with the possible exception of ARC and a few SETs (although I've heard some of the ARCs to be quite good). Dynaco did quite well for themselves back in the old days (and the way to improve them is through the power supplies)- as did Fisher and a host of others. I think the idea of 'tight bass' has been around too long and should be recognized for what it is: a coloration.

Careful transformer design is the key, but as you point out, it can get even better if there is no transformer at all...