2. amps-preamps
  3. 139682-6504

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
atmasphere's avatar
atmasphere
11,625 posts
 
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.
zuio's avatar
zuio OP
96 posts
 
Okay, SS it is.
geek101
284 posts
 
@atmasphere what are your speakers the specs you posted sound great?.
bdp24's avatar
bdp24
9,487 posts
 

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).

atmasphere's avatar
atmasphere
11,625 posts
 
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...

More to discover