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What makes an amp sound more direct ?

In our hifi journey we have probably all heard amps with different topologies and implementation. Most of these amps would have an implementation which is a combination of one of these:

1. Single Ended
2. Push-pull
3. Balanced
4. Differentially Balanced
5. Class A, A/B, D
6. High/Low Damping factor
7. Zero Negative Feedback (global & local)
8. Low/Medium/High Negative feedback
9. 2/3/4/multiple gain stages

There will be more such items that can be added to the list. My curiosity arises from the fact that some amplifiers (or even preamplifiers) sound much more direct than others. The ones that does this trick generally seems to do the "they are here" trick very well. While the components which sound relatively indirect cast a sound scape which gives the perspective of "we are there".

Just from my observation, single ended and zero feedback designs sound much more direct than balanced designs especially ones with high negative feedback. Is this a coincidence or is there a valid reason behind this ? 
pani

Showing 4 responses by pani

pani OP
1,220 posts
 
unsound, I am talking about directness of a system. If you have listened to some horn speakers you will relate to it. They may not sound forward but horn speaker have a way to convey the music in a very focussed way. That aspect also happens in the electronics side. 
pani OP
1,220 posts
 
jmcgrogan2, it is not exactly a soundstage phenomenon per se. Immediacy...yes. Direct sound is a bit self-explanatory already, the way the sound is directed to the listener. The listener actually feels a touchy-feely with the instruments in the room as if they are being played "for him". Even if the stage is behind the speaker, the way the notes are formed is like looking through a lens whose focus on the objects are spot-on. Sometimes it becomes difficult explain these phenomena even though it is ubiquitous.

Larryi, I had a couple of 300B SETs at home and also the famous Tenor Audio OTL 75 amp (its a push-pull). It was very clear that the Tenor did not have the directness of the SETs but it was clearly faster with wider bandwidth. Interestingly Naim amplifiers have a very direct sound though not in the same league SETs, still...
Similarly the Nelson Pass Firstwatt amps also sound more direct than most of the other typical SS amps including the Pass XA.8 amps.

Recently I heard some SS amps which were very well built, with very high damping factor. Even though they were tonally nice (not SS dry) they clearly sounded "indirect". 
pani OP
1,220 posts
 
apparently you've never heard a good OTL

That would be incorrect because most solid state amps are OTL. I also owned the Tenor 75 OTL.
pani OP
1,220 posts
 
Just to make this discussion more "direct", the fact that I posted it on amp/preamp forum indicates that I wanted to discuss this aspect from the amplification perspective. No, not all amps can be made to sound direct. Thats not my experience at all. When we talk about house sound of any brand, it comes mostly from a certain topology that they employ in the amplifier and that signature sound normally remains in the system. For example ARC and Wavac sound very very different though both of them are equally deep into valves. An ARC can never sound as direct as a Wavac or Audio Note. OTOH an ARC carves out a huge sound space well beyond the speaker boundaries as its house sound which a Wavac doesnt do. It is a design thing. It is clear that Wavac and Audio Note being 0 feedback SETs do the direct thing well. But I am sure there is more to it. For example an amplifier based on ultra-short signal path with only 1-2 stages of amplification would probably sound more direct than a 4 stage behemoth (in general). 
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