Class AB Power Amplifier Recommendations

[mdsimon2]

Have you looked at the AB options on audiophonics? Seems like a lot of amplification (esp. Soncoz and Tonewinner) for copmetitive pricing, but those brands are unknown to me.

Audiophonics

www.audiophonics.fr

I have not, thanks for the suggestion! In general I try to avoid buying Chinese brands if I can help but I will take a look.

Michael

 

[Miercoles2022]

To be the budget king you could play with some second hand Crestron 16x60 monsters. They are ATI built. With some DIYing you may get what you want for a fraction of your budget. https://www.diyaudio.com/community/...stron-16x60-amp-to-make-it-bridgeable.305988/

 

[pjug]

I think the Arcam PA240 specs all meet your requirements. Their noise spec is A weighted but well under 100uV (-114dB at 10W/8R). If you go open box at BestBuy it meets the price point as well.

 

[jhaider]

How much is an ATI AT4002? Can’t bridge but I think you’ll find the higher power and good headroom makes it fine to drive subs.

 

[mdsimon2]

I think the Arcam PA240 specs all meet your requirements. Their noise spec is A weighted but well under 100uV (-114dB at 10W/8R). If you go open box at BestBuy it meets the price point as well.

Wow, that looks about perfect. I like the selectable gain option as well. Obviously more power than I need but with the reasonable noise and gain I don’t mind.

Thank you! This was exactly what I was hoping to uncover.

Michael

 

[pjug]

Wow, that looks about perfect. I like the selectable gain option as well. Obviously more power than I need but with the reasonable noise and gain I don’t mind.

Thank you! This was exactly what I was hoping to uncover.

Michael

Too bed I can't find measurements anywhere though.

 

[Koeitje]

First let me say that I understand what I am asking for is not entirely rational.

I am looking for 5-6 stereo amplifiers for DIY speakers. My preference is to use identical amplifiers which is why I like the ability to bridge so I can get 400 W in to 8 ohm for subwoofer.

I currently have 5 Hypex NC252MP amplifiers which allows for a 3 way + subwoofer and have 3 four channel ICEpower 300A2 amplifiers which allows for a 4 way + subwoofer. Both of these were roughly $450 for 2 channels of amplification (although the ICEpower was DIY). I was hoping to get a set of Class AB amplifiers to fill similar needs.

It is disappointing to me that the old ATI 15xx series was bridgeable but only has RCA inputs. If the current 18xx series was bridgeable it would be great at a reasonable price.

Michael

Why do you want AB for that? Speakers can be run using FusionAmp a FA503 (500W/4ohm, 350W/8ohm). They also have passthrough which you can route into whatever amplifier you use for your subwoofer.

 

[Dave Bullet]

Cambridge audio do the 840w or 851w class AB power amp

Stereo is 200w/8ohm or 350w/4 ohm

Bridged is 500w / 800w respectively

Input sensitivity is 1.57v for either balanced or unbalanced inputs

 

[mdsimon2]

Cambridge audio do the 840w or 851w class AB power amp

Stereo is 200w/8ohm or 350w/4 ohm

Bridged is 500w / 800w respectively

Input sensitivity is 1.57v for either balanced or unbalanced inputs

Thanks! Both look interesting. 90 dB unweighted SNR at 1 W into 8 ohm is 89 uV residual noise. Manual shows 200 W into 8 ohm input sensitivity as 1.5 V + 1.5 V for balanced input which is 22.5 dB gain. Just about perfect.

Finding multiple on the used market may take some effort though.

Michael

 

[MAB]

I've been casually looking for a class AB power amplifier with the following specs without much luck.

100 W x 2 into 8 ohm
200 W x 2 into 4 ohm
400 W x 1 into 8 ohm (BTL)
< 100 uV residual noise, unweighted, 20-20K BW
19 dB < gain < 28 dB
balanced inputs
< $2000

Here is what I've considered so far:

1) Benchmark AHB2: Meets all specs but price is high
2) ATI 18XX series: Gain is on high end and doesn't seem to support bridging
3) Emotiva XPA series: Gain is on high end, noise is a bit high and doesn't seem to support bridging
4) Adcom GFA-565se: Noise is about double what I am looking for
5) Rotel RB-1552 Mk II: Doesn't seem to support bridging

Anyone have other suggestions?

Michael

Used Bryston 3B-ST.
I think it meets or exceeds your criteria. And has a 20 year warranty. And tends to not break.
Two exceptions:
I don't know if it exactly doubles power as load is halved. I think not, but this ability is rare, and costly.
The Pro versions have variable gain, the rest have 30.2dB gain on both XLR and RCA.

 

[mdsimon2]

Used Bryston 3B-ST.
I think it meets or exceeds your criteria. And has a 20 year warranty. And tends to not break.
Two exceptions:
I don't know if it exactly doubles power as load is halved. I think not, but this ability is rare, and costly.
The Pro versions have variable gain, the rest have 30.2dB gain on both XLR and RCA.

Thanks, looks solid! This -> https://www.stereophile.com/content/bryston-3b-st-power-amplifier-measurements says 23 dB for balanced input.

Michael

 

[MAB]

Thanks, looks solid! This -> https://www.stereophile.com/content/bryston-3b-st-power-amplifier-measurements says 23 dB for balanced input.

Michael

Oops! I typed it wrong, then doubled down on dyslexia...
Yes, they are incredibly solid.
And commonly available used.
I have 3B-ST, 4B-ST, and 7B-ST, plus a couple 2B-LP... I stack them for multi-amp active.
I have a couple 'Pro' versions with input sensitivity trim pots if I really need a different gain structure. But mostly don't need that. I used to use Bryston's 10b active crossovers, but DSP has replaced all of that.
I haven't heard any of the company's newer amps, I am stuck on the ST-series since I can't seem to break them and they keep on sounding great. I really like this company.

 

[AmadeusMozart]

Why do you want a class AB amplifier? You have special demands that cannot be met with other topologies?

Because digital amplifiers leak considerable amount of low frequency RF which affect the T-cell bloodcounts in your blood potentially leading to leukemia. Us, old HAM operators, know to stay out of RF fields. No guessing how I know.

 

[MAB]

To be honest... And I know it isn't balanced...

Niles SI-1230 Series 2

12-channel multi-room power amplifier

www.crutchfield.com

These amps are really quite good. 12-channels with multiple options for channel bridging. Back in the day, these had a reputation for being stable into all sorts of impedances, and was one of the few amplifiers in our store that was stable with Infinity Kappa.
I bought one used for under $100 dollars, used it for an active speaker, planned on replacing it with a stack of Bryston amps, but never got around to it because of the cost and the fact that the Niles was great.

 

[Rja4000]

Wow, that looks about perfect. I like the selectable gain option as well. Obviously more power than I need but with the reasonable noise and gain I don’t mind.

Thank you! This was exactly what I was hoping to uncover.

Michael

Those Arcam PA240 are class G, aren't they ?

 

[JSmith]

class G

Another pair of designs engineered with an eye towards improved efficiency, technically speaking neither Class G nor Class H amplifiers are officially recognized. Instead, they are variations upon the theme of Class A/B, utilizing voltage rail switching and rail modulation respectively. In either case, under low demand conditions, the system utilizes a lower rail voltage than a comparably rated Class A/B amplifier, significantly reducing power consumption; as high power conditions arise, the system dynamically increases rail voltage (i.e. switches to the high voltage rail) to handle high amplitude transients.

What are the Different Types of Audio Amplifier Classes?

We discuss the different audio amplifier classes, going over the real meanings behind Class A, B, A/B, G, H, and D and the pros and cons of each design. Which amplifier is best? Read on.

www.audioholics.com

Some detailed info;

Class-G Amplifiers

Class-G and Class-H amplifiers. There's not much information on the Net, so this article explains how they work, and provides comparative figures between Class-B, and Class-G

sound-au.com

Firstly, there is some dissent as to what constitutes Class-G compared to Class-H. I have explained the difference as I see it below, but there are many amps that claim to be Class-H that I consider to be Class-G. Because neither class is 'officially' recognised (as are Classes A, B C & D) it becomes a moot point. Ultimately, it doesn't matter all that much, so feel free to consider the two terms to be interchangeable.

JSmith

 

[tmtomh]

Thanks! Both look interesting. 90 dB unweighted SNR at 1 W into 8 ohm is 89 uV residual noise. Manual shows 200 W into 8 ohm input sensitivity as 1.5 V + 1.5 V for balanced input which is 22.5 dB gain. Just about perfect.

Finding multiple on the used market may take some effort though.

Michael

I don't think Bryston has ever made a bad amp. They're rock-solid and that 20-year warranty is fully transferable.

 

[Chrispy]

Curious, what sub is it?

 

[manisandher]

I've looked at Neurochrome in the past but again no bridging. I guess I could build mono amps with the 686 and be within 3 dB of my power requirements for 8 ohm x 1 channel which isn't too bad.

Hi Michael, I have 10x Neurochrome 286 monos here (shared between two active systems). They run cool, are almost inaudible at idle (through my horns), are rock solid, and sound superb. Can't recommend them highly enough.

I'm sure you'd be nothing but chuffed with a pair of 686s.

Mani.

 

[Koeitje]

Because digital amplifiers leak considerable amount of low frequency RF which affect the T-cell bloodcounts in your blood potentially leading to leukemia. Us, old HAM operators, know to stay out of RF fields. No guessing how I know.

Thank God class D isn't digital then!