I think for most implementations that’s true.
But that’s not a function of it being “Class A”, it’s a function of the choices designers who choose to go Class A tend to make.
i.e. While there is a correlation between Class A amps and those characteristics, it’s not causation.
As I said above a Class AB amp is Class A for in most cases the bulk of what you’re going to listen to. The difference is more about having decided to increase the complexity to save power, the designs just tend to be more complex.
When I design and build my own amps, since they’re one offs and I don’t care about packaging or cost for the most part I tend to design and build class A amps with 0 feedback, I think they tend to sound more natural and stage better.
Feedback isn’t bad perse, it’s necessary for a lot of circuits.
It reduces distortion, but it also can be used to reduce output impedance.
The last amp I built hits about -70dB- -80dB THD with 0 feedback, at listening levels with a Susvara, BUT it can only really do that because I use a very linear tube in the pre stage. I might be able to get close with a FET based input stage, but as soon as your using BJT’s or other “current amplifiers” your going to end up with at least some local feedback.
If you don’t put a capacitor or transformer on the output of your amp, both of which can be seen to be detrimental, you need some way to keep DC in check, and that’s usually accomplished with feedback (albeit only for very low frequencies).
I’ve built local feedback loops into some of my earlier amps, with pots to control just how much feedback there is in the circuit, and some can be a positive, I do think lots tends to take the life out of an amp, it doesn’t sound bad, but to me it just seems to sound flat. But I couldn’t explain the causality of that.
I’ll also note that 0 feedback is a bit of a misnoma, in reality most circuits have at least some hidden feedback even when it’s not explicitly added to a circuit.
I figured it out for you. You need to BUILD your own amp. That way the fact you put it together yourself will always improve the perceived sound, making it sweeter.
You need to start with the “speedball with crack” amplifier package.
Here’s my Crack build. This is a classic and a standard in the hobby headphone community, but kits are not everyone’s cup of tea. TBH, the sound quality is not too unlike the off-the-shelf DarkVoice 336. But, you learn a lot and risk death from electrocution, so it’s not all bad.
So when you try the different amps, you’re always using the Benchmark DAC 3 right?
The only variable in your preference then boils down to the amp itself? One of these days when I see a good deal on a Ifi Zen Can on ebay or marketplace I’ll get it and give it a try. Might need you to build me a capacitor bank though!
For me I really like an amplifier that has punch and can have power dynamic swings, so for me Slew rate is important. That would be one of my top things.
About to get the Valhalla 2 delivered tomorrow. Running the Clear OG, 660s and the HE1000 stealths. Going to be interesting to hear how the Hifimans pair with it. Took a punt despite views on “don’t use tubes with Planars”. I just thought the tubes would offset some brightness ( - not that it’s a huge issue). We’ll see!
I hope you enjoy it, it’s tough to go too wrong on it at the current price. It’s a real bargain, kinda tempted to get one again. But I need another amp like a hole in the head!
I think it pairs well with Clear OG and my HD 650, never had a 660s. Also sounds very good with ZMF dynamics. I guess you’ll find out on the HE1000, more of a
Tubes need some burn in time, but let us know what you think. What dac are you using with it?
I’ll keep you posted. Currently have a Mojo 2, audioengine D1 and also a Xduoo MT-602 hybrid amp. That little 602 really adds a little warmth and I prefer the combo than just the Mojo alone. I fear the Valhalla may not be a noticeable upgrade sound wise but we’ll see. Still a beautiful piece of design that I couldn’t resist at the price! The New Year’s resolution of not buying more hifi gear has gone to crap…(or Schitt. Sorry)
I found the Mojo2 as well as the 1 to have a slightly narrow soundstage. But great depth.
Didn’t care for the top end too much either. chord has their own thing going on which is pretty cool, but always came across to me as a touch thin and as I mentioned narrow.
Definitely good though. The latest Midgard I got was like a 1,2,3 ok it’s back in the box.
One thing that’s definitely dumb of me, is that when buying my Benchmark LA4 preamp , I didn’t just get the one with the premium headphone amp. The HPA4.
Super duh on me.
I mean I could sell my LA4 and take a hit and buy the HPA4. But who knows if that will do it for me as well. I have both the AHB4 ( typo AHB2) amp, the LA4 pre and the DAC3 ( without the headphone amp). They are all exquisite for speakers. IMHO of course. Especially the LA4 AHB2 combo or maybe just the LA4 is special. Just sound amazing with speakers. Not in the least thin or sterile or any of that. They were what I thought NAIM would give me, but failed miserably.
But as far as headphone amps. The DAC3 HGC didn’t quite do it for me. Don’t get me wrong it’s a great headphone amp. Way better than the Midgard. Geezus. No comparison. Better than the RME ADI as well.
Right now I’m having some fun making supercapacitors for the zen Can and I bought a good one last year as well. From this Ian Canada guy.
And also modding the two ipowerX SMPS with top of the line caps for the lowest ESR. Seems to make a bit of diff.
I would like to send the whole deal to someone to measure and see how much the supercapacitors make a difference in overall noise ( not that the zen can doesn’t measure well) , my homemade one and the bought one. But I don’t know who I’d send them to. Maybe Archimago would be up to it
I have a confession to make. Sometimes I do stuff that “shouldn’t work” and find that it actually works pretty well.
The Valhalla 2 does just fine with my Verum 1 planars, even though they are low-impedance (even by planar standards – 8 ohms). Works for me, that is. I keep the volume reasonable. My guess would be that the 4x-higher-impedance, somewhat less efficient HE1k Stealth would still be OK.
Let us know how it works for you. Inquiring minds want to know.
Regarding “shouldn’t work,” a lot of that is theoretical with headphones. In practice they often don’t generate enough bass to bloat, and the benefits of a given amp may be worth it when used with EQ.
