Short List of Amps I prefer over the Pass Labs XA25 or INT 25

Feedback is not the only way amps can give the gane?

It's "gain" as in "to add or receive." And feedback in linear amplifiers actually reduces gain. You can learn some of this with op amp text books.

Somehow class d amps use double feedback to get to the switching waveform to transform analog sound to digital one?

I'm not aware of double feedback loops, but I am aware of multiple types of feedback being used with different Class D designs.  As Ralph (atma) mentions, it's not digital, but the feedback controls the switching.

To be a truly digital amp the signal at least has to go through an analog to digital conversion, which doesn't really happen in Class D.  The control of the on/off switching is in the analog domain and that's where the feedback is used.

The latest Technics Class D amps may in fact be considered digital, as there is an analog to digital conversion at the input, as well as DSP applied for impedance compensation. These types of amps are quite rare. Many, including Ralph, argue that since the output is analog no audio amplifier can be digital.  I side with Technics though, it's sufficiently digital to be called a digital amplifier.

Speaking of femto-distortion (TM) what ever happened to Halcro?  Wasn't the exceedingly small amount of distortion and noise their trademark? Here one moment, gone the next.

Does anybody on this thread have experience with Spectral?

Very limited. Got to hear it once at Goodwin's High End in Waltham, MA driving Avalon acoustics with mostly or all ceramic drivers (long time ago).

Sharp as hell sounding, razor like transients. Not really compelled to listen to it.  The presentation (amp + speakers) was the most sterile but also compressed. The transients were sharp, but the music didn't seem to open up.

This was a 30 minute listening session decades ago. Please listen for yourself and take the limited experience I had into account.

chorus:

The Luxman 507 runs ~ $3,500 used, or less.

@atmasphere

I already know you are comfortable with having a civil discussion when it comes to nuanced technical topics.  My disclaimer (that I like tubes) was meant for those who read only the convenient parts.

Best,

E

I’m also, often, reminded how malleable our tastes are. I’ve been drinking this new tequila (Tres Amigos, organic, silver) which a very nice bartender recommended to me. At first I thought it tasted watery. My taste buds kept searching for the agave and earthy notes which are not there. Now that is gone and it tastes very smooth.

We are not automatons with precise, and unchanging hearing or tastes. We have all taken different paths to get to this forum and we’ll go on different paths when we leave. Lets relish the diversity, and be grateful for those willing to share their experience and education with us openly.

If sound does something to your brain that feels great then enjoyment is achieved.
Enough?

@chorus

Yes. :-) The only judge of what you should spend your money on is ultimately the buyer. Neither I nor an oscilloscope nor countless reviewers have any right to interfere in that process.

Still, this is a discussion forum, and when asked to think about what we like and why we like it the technical differences in gear is a lot of fun to discuss.

Just like beer. We can talk about the brewing process and the hops added, which is fascinating, but ultimately the reason you end up in detox is up to you.

Best,


E

You used to be a reasonably affable and knowledgeable bloke and now this?

@fsonicsmith

It is clear from your starting sentence you are confusing me with some one else.  I won't be controlled by your disappointment, nor am I obliged to answer all of your obviously malformed inferences.

Do you really not comprehend the difference between MP3's shortcomings (and all of digital's) for the totally separate and distinct concept that Ralph is discussing?

I've never made any such equation.  I mentioned that Ralph was using a concept known to me (please read the entire Wikipedia article here:

https://en.wikipedia.org/wiki/Sound_masking

)  and to ask him to clarify the leap he made which I could not follow. I did so in a respectful manner, and gave him the opportunity to come back and illustrate his point so I could get it.  Fortunately for me, he did:


@atmashpere

Essentially though the tubes have enough 2nd and 3rd harmonic distortion that those harmonics are able to mask the presence of the higher orders. So they **sound** to the human ear as if the higher orders are absent altogether. That is why they sound smoother.

Oh, my bad. I thought you were saying that the masking some how improved resolution. You are saying that masking reduces the perception of distortion. I was confused because earlier you mentioned that tubes have more detail, but the masking of distortion is unrelated to the perception of detail.

Thank you for the clarification.

Masking though, AFAIK has to do with closely spaced frequencies. Hard to mask higher order distortion, isn't it?

BTW, I like tubes a great deal. :) I'm not attacking them I just want to make sure I understand the arguments.

Best,


E

Hi Ralph,

You, @atmasphere ,  make this statement which seems contradictory right after talking about tubes and distortion:

The answer has something to do with the ear's masking principle; that is where a louder sound can mask the presence of a quieter sound.

Right, and this is the basis of MP3 compression, among other things. Why do you think the masking principle benefits tubes??

Best,

E

I’m on the "NeverPass" camp. It’s not ideological, it’s not personal (Nelson Pass is a fine gentleman), it’s not anything about the quality of the gear. I just really find the sound scratchy or weak. I assume, without investigation, that the euphonic distortion Pass adds and which his fans love and which Stereophile often measures, is exactly what I do not like. This is an IPA vs. Belgian White discussion though, there’s no right or wrong, but for my wallet, no, never would I buy, nor would I put a Belgian White in my mouth deliberately. I’m in the minority, and happy to let Pass fans love the products.

I also wonder based on some of Pass' writing about proper matching of amp output impedance to woofers if he isn't targetting a specific type of big-woofer speaker like Tannoy and Klipsch folded horns.  Neither of which I listen to.  Not a criticism, but a question of intended matching.

Amps I like a lot:

Luxman
Arcam
Ayre
D’Agostino

Amps I don’t like as much, but still more than Pass:

Parasound
ARC


Amps I’d like to hear more of to make a better view:

Vandersteen