Class A/AB amplifier recommendations

[DSJR]

I know an ask for a warm (sounding?) amp won't go down well here and arguably for good objective reasoning, but I'm going to turn it round just a little bit and suggest an amp without 'grain' at high frequencies (compare a modern Naim with say, a Luxman, Accuphase and maybe a McIntosh at any volume level and you may see what I'm getting at )

In the meantime, I doubt you'd go wrong with a Quad power amp, available cheaply enough used and the 606 series (especially from 606mk2 onwards), need apologise to nobody if you can get one at a fair used price. Low enough distortion and ample 4 ohm power, coupled with serviceability, if your dac has variable output, it's well worth considering.

 

[LD644]

If I'm played 20 samples between 2 amps and random volumes and can tell what amp it is wouldn't that be more significant and more difficult. Sure I can AB but these amps have digital knobs and might be off by a fraction of a Db. If I'm played 3 samples in a row on one amp at 3 different volumes then played a single sample on the second amp at a random volume I can't rely on fractions of a Db to tell. Then switch back to the original amp at more random volumes and told to pick one that should be nearly impossible to tell assuming no meaningful difference exists. Then obviously the test needs to be extended. Obviously if I Ab at similar volume levels I will be able to tell because they won't be the exact same volume. So let's take volume out of the equation entirely. I know at different volumes we perceive things slightly differently but maybe I can hear something at a higher volume but can't distinguish it at a lower volume. All that data should be collected.

 

[kemmler3D]

This might explain it. In a few months I will get a class D nc502mp based amp. I will ab them and maybe I will be wrong but I just want to be 1000% sure as this will be my only amp for a while. The b200 looks interesting and that will go on the list.

I have some NC500 based monoblocks and among class D amps the Hypex stuff have some of the least load dependence of anything on the market, so they're definitely "neutral", not warm or bright.

 

[Svend P]

If I'm played 20 samples between 2 amps and random volumes and can tell what amp it is wouldn't that be more significant and more difficult. Sure I can AB but these amps have digital knobs and might be off by a fraction of a Db. If I'm played 3 samples in a row on one amp at 3 different volumes then played a single sample on the second amp at a random volume I can't rely on fractions of a Db to tell. Then switch back to the original amp at more random volumes and told to pick one that should be nearly impossible to tell assuming no meaningful difference exists. Then obviously the test needs to be extended. Obviously if I Ab at similar volume levels I will be able to tell because they won't be the exact same volume. So let's take volume out of the equation entirely. I know at different volumes we perceive things slightly differently but maybe I can hear something at a higher volume but can't distinguish it at a lower volume. All that data should be collected.

All amplifiers sound the same. You are overthinking it.

 

[kemmler3D]

If I'm played 20 samples between 2 amps and random volumes and can tell what amp it is wouldn't that be more significant and more difficult. Sure I can AB but these amps have digital knobs and might be off by a fraction of a Db. If I'm played 3 samples in a row on one amp at 3 different volumes then played a single sample on the second amp at a random volume I can't rely on fractions of a Db to tell. Then switch back to the original amp at more random volumes and told to pick one that should be nearly impossible to tell assuming no meaningful difference exists. Then obviously the test needs to be extended. Obviously if I Ab at similar volume levels I will be able to tell because they won't be the exact same volume. So let's take volume out of the equation entirely. I know at different volumes we perceive things slightly differently but maybe I can hear something at a higher volume but can't distinguish it at a lower volume. All that data should be collected.

I think this is actually a reasonable way to get around level matching if you don't have the tools on hand to do it super precisely. You will need more trials but I don't see an inherent problem.

The more important thing is to do it blinded, i.e. you don't know which unit is on at any given time. When you expect to hear something, you tend to hear something whether or not it's there. So it's important to give the eyes and brain a rest so the ears can do their job without distractions.

To extend @Svend P 's point... many members here report hearing differences between amps, DACs, and so forth, that went away when they actually did a proper blind test. This is what you would expect from looking at test results and comparing those to known thresholds of audibility for distortion etc. The brain has a lot more effect on what we hear than is obvious.

Even when you can find an pair of amps with a real audible difference for music listening... (genuinely rare) the amount of difference will be like 1-2% of the subjective quality, not 10-20%. So along with others, my advice is find an amp that fits the power requirement and your budget and don't worry about it.

 

[Palmer]

I wouldn't worry about the class, except class-A just dumb and energy inefficient!

Class-A isn't the best, it was just first. And then for a long time it was standard because class A/B requires one more tube, transistor, or MOSFET.

Now that electronics are cheap there is no cost advantage. And no other advantage. In fact, as you go-up in power it becomes more cost-effective per-watt to use a more complex design, with class-D being the most economical way to get high power.

Not disagreeing necessarily, but having owned both Threshold S/500 and Mark Levinson No. 23.5 for a number of years - I must say the only dumb thing was letting them go.
Miss them both and paid less for both new - than used, plus refurbish would be today.

 

[LD644]

I think this is actually a reasonable way to get around level matching if you don't have the tools on hand to do it super precisely. You will need more trials but I don't see an inherent problem.

The more important thing is to do it blinded, i.e. you don't know which unit is on at any given time. When you expect to hear something, you tend to hear something whether or not it's there. So it's important to give the eyes and brain a rest so the ears can do their job without distractions.

To extend @Svend P 's point... many members here report hearing differences between amps, DACs, and so forth, that went away when they actually did a proper blind test. The brain has a lot more effect on what we hear than is obvious.

Even when you can find an pair of amps with a real audible difference for music listening... (genuinely rare) the amount of difference will be like 1-2% of the subjective quality, not 10-20%. So along with others, my advice is find an amp that fits the power requirement and your budget and don't worry about it.

Don't worry I have a friend that would rather me be wrong than right.

 

[Chrispy]

Yes they have a way to AB test the integrated amps. One brand noticeably sounded warmer. I don't know why or how or if it was some kind of room correction I wasn't aware of but there was a difference. I'd say I have decent hearing because I'm young "maybe dumb" but I've had a friend use random volumes and use Bluetooth then lossless and I could always tell if it was Bluetooth or not.Maybe they messed with the tone knob. I'll see if I can go back and test it. I'll have a friend mess with the volumes and at a random volume tell which amp is which. No need to level match because I will test at a random volume and a random amp and keep score. I think the brands in question were Marantz Yamaha and Denon.

Since when? How does a brand, let alone which brand, consistently make an amp roll off at higher frequencies (i.e. a general description of "warm" aside from perhaps a bass boost)? Is that desireable? Making sure all were level matched and not using dsp/eq would be a good start, tho, as well as blind testing and quick switching. Having owned and still own quite a variety of amps, don't understand this "warm" thing particularly. BT has gotten better over the years, but it is still less than ideal. So what amps could you actually distinguish with the 'random' volume thing?

 

[tineared]

I'm looking for a class A/AB power amplifier (No integrated) for my ls50 metas that's under 1000$ new or used, ideally under 800. Right now all I can think of is the Vidar 2. I'm looking for linear that's maybe slightly warm with rca and balanced inputs. It also needs enough power to power the Ls50 metas. I'm probably in the wrong area to post this but I can't figure out what to get. The only reason I'm not going class D is I'm looking for slightly warm and sometimes class D doesn't like the swing from 8 ohms to 3.5.

If you don't mind buying used, a Parasound Halo A 23 would likely make you grin. They can be had for around $700 on ebay. They are built to last.

https://www.ebay.com/itm/3265888218.../VTvHol11do6v7lsz4wi9EkoUQ==|tkp:BFBM2LfCiOBl

 

[Chrispy]

Since when? How does a brand, let alone which brand, consistently make an amp roll off at higher frequencies (i.e. a general description of "warm" aside from perhaps a bass boost)? Is that desireable? Making sure all were level matched and not using dsp/eq would be a good start, tho, as well as blind testing and quick switching. Having owned and still own quite a variety of amps, don't understand this "warm" thing particularly. BT has gotten better over the years, but it is still less than ideal. So what amps could you actually distinguish with the 'random' volume thing?

So you can't provide specific amps you deem "warm"?

 

[LD644]

So you can't provide specific amps you deem "warm"?

I mean if we go into the realm of headphones for a second the Schiit hel and the smsl sp200 both being fed from the same dac don't sound the same. The smsl in particular sounded linear and really wide with my Ananda's. The hel I'm not sure how I would describe it but definitely wasn't as wide. Maybe I would call it a darker sound. Both have low distortion. I don't own any AB testing equipment. Maybe I'm wrong but I'm pretty sure things sounded more detailed on the smsl. I'm not at home right now so I won't be able to do that test for a while.

 

[Chrispy]

I mean if we go into the realm of headphones for a second the Schiit hel and the smsl sp200 both being fed from the same dac don't sound the same. The smsl in particular sounded linear and really wide with my Ananda's. The hel I'm not sure how I would describe it but definitely wasn't as wide. Maybe I would call it a darker sound. Both have low distortion. I don't own any AB testing equipment. Maybe I'm wrong but I'm pretty sure things sounded more detailed on the smsl. I'm not at home right now so I won't be able to do that test for a while.

Sounding the same or not can be due to a variety of parameters....particularly level. DACs are not usually an issue at all. Try a good proper blinded level matched test....

 

[LD644]

So you can't provide specific amps you deem "warm"?

Also amps that 100% sound warm. Xduo ta-26 with rolled tubes. I like that on hd6xxs but some songs the S's have to much sibilance and it hurts my ears.

 

[Chrispy]

Also amps that 100% sound warm. Xduo ta-26 with rolled tubes. I like that on hd6xxs but some songs the S's have to much sibilance and it hurts my ears.

Wow one obscure amp....way to go with an opinion.

 

[LD644]

Wow one obscure amp....way to go with an opinion.

No way you think a tube amp sounds linear. The whole point of tubes is to add distortion. That's why I wrote it. I figured that we could agree a tube amp is going to be flavored.

 

[Old_School_Brad]

I'm looking for a class A/AB power amplifier (No integrated) for my ls50 metas that's under 1000$ new or used, ideally under 800. Right now all I can think of is the Vidar 2. I'm looking for linear that's maybe slightly warm with rca and balanced inputs. It also needs enough power to power the Ls50 metas. I'm probably in the wrong area to post this but I can't figure out what to get. The only reason I'm not going class D is I'm looking for slightly warm and sometimes class D doesn't like the swing from 8 ohms to 3.5.

There are many excellent Class A/B amplifiers available on the used market that align well with what you're looking for.

You’ve already mentioned the Schiit Vidar 2, which is a solid option.

@ZolaIII also made a strong suggestion, although his recommendation focused on integrated amplifiers.

Personally, I’m a fan of Yamaha amplifiers. When it comes to used Yamaha power amps, I can’t think of many that wouldn’t leave you satisfied. Just search the marketplaces for "Yamaha power amplifier" and choose one that’s been well cared for and looks nice to you.
The only downside is that most of these models don’t offer balanced inputs, which I understand is on your wishlist.

 

[Chrispy]

Also amps that 100% sound warm. Xduo ta-26 with rolled tubes. I like that on hd6xxs but some songs the S's have to much sibilance and it hurts my ears.

No way you think a tube amp sounds linear. The whole point of tubes is to add distortion. That's why I wrote it. I figured that we could agree a tube ampT

Soime tube amps are more linear than others but that's not the point. The whole point of tubes is to stick to an old technology that is not particularly good. Fuck tubes.

 

[BeeKay]

The whole point of this hobby or passion is to strive for high fidelity in music reproduction. Adding outdated technology that measurably cannot keep up with later, better, even more reliable technology is weird. To say it politely.

 

[dlaloum]

I have some 40 year old Quad 606 power amps - the family was updated to 707, then 909 then the more current "named" versions...

The core "current dumping" design has remained the same since Peter Walker first designed it, and refurbished ones are available especially if you are in the UK. (harder to find in the USA).

More than enough power for pretty much any domestic environment, and unconditional stability under any speaker load - means it will work OK regardless of the speaker impedance/phase.... yes it will drive a 1 ohm speaker (!!!)
They are current constrained by their power supplies, but I have never heard them run out of puff, even driving my 1.6 ohm Gallo's.
A lovely, slightly eclectic, vintage design, that holds its own even with current generation amps.

 

[LD644]

Soime tube amps are more linear than others but that's not the point. The whole point of tubes is to stick to an old technology that is not particularly good. Fuck tubes.

I find it more pleasant when I play my guitar on a tube amp. I like the way it sounds. Basically everything I listen to is guitar dominant. If it wasn't recorded on tubes and I'm to lazy to learn it myself why is listening to it on a tube amp wrong. I like it. Sounds old fashioned without a ton of high order harmonics.