2-channel power amp recommendations?

Commander Shepard

[H]ardness Supreme
Joined
Apr 12, 2016
Messages
4,114
I've been using a Crown Audio power amp to drive my KEF LS50 speakers, but 2 of these amps have died in the last 6 months. I'm thinking I should look for something other than pro audio gear.

I'd like to find something in the 200-250wpc range. Just a 2-channel, stereo power amp. No more D class. A/B seems to be the way to go. I checked Emotiva, but wasn't very unimpressed. Monoprice's Monolith 2-channel 200wpc stereo amp is a beast, but $1000??? WTF?

Any ideas from the [H] crowd? Thanks!
 
Joined
May 20, 2016
Messages
644
Why do you need 250W though? Aren't you using these nearfield? You don't even need 5W of power to hit reference levels at that distance lol.
 
  • Like
Reactions: N4CR
like this

Brian_B

2[H]4U
Joined
Mar 23, 2012
Messages
3,356
Seems like you may have better luck going with a receiver and getting 250W stereo if you don't want to go with Pro gear.
 
Joined
May 20, 2016
Messages
644
Yeah but most receivers don't do that much power in stereo except higher end ones. You'd have to get at least a Yamaha RX-A2080 or Onkyo TX-RZ1100, so > 1k that way.
 
Joined
May 20, 2016
Messages
644
Have you ever listened to LS50s? They need a lot of power to open up.
I use the Reference 1s, they have even lower sensitivity and I use them nearfield like you. I've never seen these things draw more than a few watts on my Wattmeter and that's turning these up to 100+db. You have non-existent power requirements nearfield.
 

Commander Shepard

[H]ardness Supreme
Joined
Apr 12, 2016
Messages
4,114
I use the Reference 1s, they have even lower sensitivity and I use them nearfield like you. I've never seen these things draw more than a few watts on my Wattmeter and that's turning these up to 100+db. You have non-existent power requirements nearfield.
You and I have vastly different listening experiences.
 

Zarathustra[H]

Official Forum Curmudgeon
Joined
Oct 29, 2000
Messages
29,476
My needs are much smaller, but I just picked up a a Parasound 275 v.2 for my desktop, and I am liking it very much.

IMG_20191022_210942.jpg


A lot in a small package. Deceptively heavy too for its size.

It's just for my little office setup so the 90w into 8Ω is fine.

I have one of their bigger models (The Parasound Halo A31) and it has been absolutely fantastic for my HT setup with it's 3 250w channels into 8Ω.

IMG_20191022_222318~2.jpg
 
Last edited:

Commander Shepard

[H]ardness Supreme
Joined
Apr 12, 2016
Messages
4,114
My needs are much smaller, but I just picked up a a Parasound 275 v.2 for my desktop, and I am liking it very much.

View attachment 194632

A lot in a small package. Deceptively heavy too for its size.

It's just for my little office setup so the 90w into 8Ω is fine.

I have one of their bigger models (The Parasound Halo A31) and it has been absolutely fantastic for my HT setup with it's 3 250w channels into 8Ω.

View attachment 194633
That Parasound is a nice amp. Here's what I put together. I love the sound it produces.

audio.jpg
 

Zarathustra[H]

Official Forum Curmudgeon
Joined
Oct 29, 2000
Messages
29,476
Have you ever listened to LS50s? They need a lot of power to open up.

Interesting. How does this work? Because on paper I think they are nominal 8ohm, with a very high SPL of 106db, right??

To me they look pretty easy to drive, unless there is something I'm missing.
 

Zarathustra[H]

Official Forum Curmudgeon
Joined
Oct 29, 2000
Messages
29,476
That Parasound is a nice amp. Here's what I put together. I love the sound it produces.

View attachment 194967
Looks nice. I had considered some of those monoblocks in the past and did some reading. They seem pretty nice.

A/B amps can put out a good deal of heat. Is stacking them like that OK per the manual?

What pre-amp is that? Looks interesting.
 

Commander Shepard

[H]ardness Supreme
Joined
Apr 12, 2016
Messages
4,114
Yeah, stacking is okay. I wouldn't have done it if I had them in an enclosed space like a cabinet, though.

The DAC is Gustard X20 Pro.
 

Zarathustra[H]

Official Forum Curmudgeon
Joined
Oct 29, 2000
Messages
29,476
I'm still tuning the new little Parasound, but I have to say I am impressed.

It must be underrated.

It is supposed to be 90W but it seems to be powering my mildly inefficient RBH 41-se's better than my previous Emotiva UPA2, which was rated at 125W into 8ohm.

Since I use my headphone amp as a pre-amp, I try to calibrate the volume level between my speakers and my headphones, so I never get a "surprise". IN order to accomplish this, I have to turn the gain way down on this thing.
 

Zarathustra[H]

Official Forum Curmudgeon
Joined
Oct 29, 2000
Messages
29,476
Yeah, stacking is okay. I wouldn't have done it if I had them in an enclosed space like a cabinet, though.

The DAC is Gustard X20 Pro.
Ah, so it is a DAC and pre-amp in one?

Still curious about those KEF's and what makes them so difficult to drive, considering they are high efficiency and 8ohm.
 
Last edited:

DoubleTap

2[H]4U
Joined
Dec 16, 2010
Messages
2,346
Ah, so it is a DAC and pre-amp in one?

Still curious about those KEF's and what makes them so difficult to drive, considering their are high efficiency and 8ohm.
The LS50s are one of the most reviewed and discussed speakers, I'm sure you could find some in depth info on them.

I absolutely love mine and I'm just using an AVR but they are so smooth and detailed and just a joy to listen to.

I probably will buy an amp for them when I get my tax return, just to get the most out of them...
 

atarione

[H]ard|Gawd
Joined
Mar 17, 2011
Messages
1,979
I mean.. it is kewl to drop $$$ on new gear if that is what you wanna do...

but for anyone finding this in future... you can sometimes find used gear for pennies on the dollar... blah blah blah there are pitfalls with vintage.. gear needing repairs, no warranty..etc etc..

still none the less.. and perhaps somewhat geographically advantaged by being here in SoCal (first near San Diego and currently n. of Los Angles in Ventura county )... without a huge output of effort on my part I have acquired so impressive gear for audiophile / pc audio enjoyment for quite small outlays of cash.

most impressively perhaps.. a vg+ Sony ES Stack: TA-N77ES, TA-E77ESD..etc components (tuner , tape and cd player and a "bonus" non es 100WPC N110 amp for $75

a Onkyo stack for free (given to me by someone that was going to dispose of it) big meter M-5030 / P3030 ..etc related onkyo components .. ~slightly cosmetically challenged but not bad at all and working quite well indeed.. nothing to complain about for free certainly.

a monster Pioneer receiver that would be worth big monies if it was 70s silver faced but was black 89/90' type stuff and is probably more frequently found ~$200ish 130WPC @8ohms.. I paid $40 for it.

for any reasonable pc desk usage all this gear will be much much more than sufficient... and honestly (don't ask me how I know) for pissing the neighbors off in conjunction with appropriate speakers will sound GREAT and get the cops at your house... =\

a couple pics and a video..

Sony ES stack:
tan77es_ns344_2.jpg

stock image of Pioneer VSX-D1S (because I'm lazy and it is currently not in use..still works great however)
vsx-d1s.jpg

and old *** video of myself demoing the Onkyo stack... from circa 2013 ... I really wish I was still that skinny =\



I mean whatever it is all y'alls time / money but used gear can be pretty amazing for small money ... and can make your neighbors HAAAAATE you...
 
Last edited:

B00nie

[H]ardness Supreme
Joined
Nov 1, 2012
Messages
8,172
Interesting. How does this work? Because on paper I think they are nominal 8ohm, with a very high SPL of 106db, right??

To me they look pretty easy to drive, unless there is something I'm missing.
LS50 is relatively low sensitivity, 85db/1watt. They're small speakers and all small speakers require a powerful amplifier due to being inefficient. If you want to get 100db peaks from a LS50 you need a minimum of 50 watts of pure power per channel. A 5 watt single stage tube amp is not going to cut it.
 

B00nie

[H]ardness Supreme
Joined
Nov 1, 2012
Messages
8,172
The LS50s are one of the most reviewed and discussed speakers, I'm sure you could find some in depth info on them.

I absolutely love mine and I'm just using an AVR but they are so smooth and detailed and just a joy to listen to.

I probably will buy an amp for them when I get my tax return, just to get the most out of them...
My brother-in-law has LS50s and he's driving them with a Musical Fidelity integrated amp. I have to say I wasn't overly impressed with them. They were not bad by any means, just lack dynamic power and extension and can't approach the imaging of my electrostatics or horn speakers.
People are raving about the active versions of LS50 though. Those I haven't heard personally.
 

Zarathustra[H]

Official Forum Curmudgeon
Joined
Oct 29, 2000
Messages
29,476
LS50 is relatively low sensitivity, 85db/1watt. They're small speakers and all small speakers require a powerful amplifier due to being inefficient. If you want to get 100db peaks from a LS50 you need a minimum of 50 watts of pure power per channel. A 5 watt single stage tube amp is not going to cut it.
Heh. I must have Google'd the wrong speakers. The specs I saw said 96db
 

DoubleTap

2[H]4U
Joined
Dec 16, 2010
Messages
2,346
My brother-in-law has LS50s and he's driving them with a Musical Fidelity integrated amp. I have to say I wasn't overly impressed with them. They were not bad by any means, just lack dynamic power and extension and can't approach the imaging of my electrostatics or horn speakers.
People are raving about the active versions of LS50 though. Those I haven't heard personally.
My brother-in-law has LS50s and he's driving them with a Musical Fidelity integrated amp. I have to say I wasn't overly impressed with them. They were not bad by any means, just lack dynamic power and extension and can't approach the imaging of my electrostatics or horn speakers.
People are raving about the active versions of LS50 though. Those I haven't heard personally.
I'm sure there are better speakers, but few that would sit easily on a computer desk.

I think people are also going to have a different experience when they use them nearfield vs a more traditional setup.
 

Commander Shepard

[H]ardness Supreme
Joined
Apr 12, 2016
Messages
4,114
My brother-in-law has LS50s and he's driving them with a Musical Fidelity integrated amp. I have to say I wasn't overly impressed with them. They were not bad by any means, just lack dynamic power and extension and can't approach the imaging of my electrostatics or horn speakers.
People are raving about the active versions of LS50 though. Those I haven't heard personally.
If your horn speakers look like these, they better sound a helluva lot better than the LS50. ;)

df3538fd6e84b59e55db567bbc3933e6.jpg
 

Nenu

[H]ardened
Joined
Apr 28, 2007
Messages
19,130
Interesting. How does this work? Because on paper I think they are nominal 8ohm, with a very high SPL of 106db, right??

To me they look pretty easy to drive, unless there is something I'm missing.
They are 85dB.
They need over 100x the power to produce the same SPL :)
A strong amp is a must to get the best from them, I understand his need.

https://uk.kef.com/products/ls50
"Sensitivity 85dB (2.83V/1m)"


I use an Emotiva XPA-2 (300W RMS minimum) to drive 91dB TL speakers from 2.7m away.
Great for transients and clarity.
It gives more slam and depth at low volume, fat wire (6mm Van Damme bi-wired) helps too.
Bi-wiring cleaned the treble up but not the bass. I tried it on the off chance and was surprised at the difference though ribbon tweeters expose an incredible amount of detail. Moving back to single wire leaves a slight fuzzy trace to the treble.
Before the Emotiva I used an Onkyo 875 AV amp which was put to shame for bass depth, strength, detail and imaging.

OP, if you are in the market for a power amp again, keep an eye out for a second hand XPA-2.
The very first model was specced at 250W/ch but under test blew past that.
Gen 2 and 3 blow past 300W/ch.
 

Zarathustra[H]

Official Forum Curmudgeon
Joined
Oct 29, 2000
Messages
29,476
They are 85dB.
They need over 100x the power to produce the same SPL :)
A strong amp is a must to get the best from them, I understand his need.

https://uk.kef.com/products/ls50
"Sensitivity 85dB (2.83V/1m)"


I use an Emotiva XPA-2 (300W RMS minimum) to drive 91dB TL speakers from 2.7m away.
Great for transients and clarity.
It gives more slam and depth at low volume, fat wire (6mm Van Damme bi-wired) helps too.
Bi-wiring cleaned the treble up but not the bass. I tried it on the off chance and was surprised at the difference though ribbon tweeters expose an incredible amount of detail. Moving back to single wire leaves a slight fuzzy trace to the treble.
Before the Emotiva I used an Onkyo 875 AV amp which was put to shame for bass depth, strength, detail and imaging.

OP, if you are in the market for a power amp again, keep an eye out for a second hand XPA-2.
The very first model was specced at 250W/ch but under test blew past that.
Gen 2 and 3 blow past 300W/ch.


You guys must listen a fair bit louder (or farther away) than I do.

My Desktop setup uses a pair of 8 ohm RBH 41se bookshelves about 2 ft away. They are rated at 86db.

My little Parasound NewClassic 275 v.2 is rated at 2x 90W into 8ohm, and it is more than enough power for my needs.

It probably doesn't hurt that it has a high pass switch on it though, which can be set to off, 20hz or 40hz, so the amp doesn't have to waste power on low frequencies the speakers can't reproduce. Since my RBH bookshelves start to drop off below 60hz (but really produce sound down to 35 or so) I set the switch to 40hz. I also have a sealed 400w 12" powered SVS SB12-NSD sub under my desk, which helps.
 

DoubleTap

2[H]4U
Joined
Dec 16, 2010
Messages
2,346
I also have a 12" sub under the desk and the LS50s have an 80Hz HPF and the rear ports are stuffed.

The stands have them just above ear level in a 40" equilateral triangle to my head.

The detail and clarity are astonishing to me and while we all know the sky is the limit when it comes to audio, I feel like anything much beyond my current (speaker) setup is going to be be so fraught with diminishing returns and an unfavorable cost:benefit ratio that I consider this system to be essentially complete.
 

Nenu

[H]ardened
Joined
Apr 28, 2007
Messages
19,130
You guys must listen a fair bit louder (or farther away) than I do.

My Desktop setup uses a pair of 8 ohm RBH 41se bookshelves about 2 ft away. They are rated at 86db.

My little Parasound NewClassic 275 v.2 is rated at 2x 90W into 8ohm, and it is more than enough power for my needs.

It probably doesn't hurt that it has a high pass switch on it though, which can be set to off, 20hz or 40hz, so the amp doesn't have to waste power on low frequencies the speakers can't reproduce. Since my RBH bookshelves start to drop off below 60hz (but really produce sound down to 35 or so) I set the switch to 40hz. I also have a sealed 400w 12" powered SVS SB12-NSD sub under my desk, which helps.
High level amplification reduces transient compression, deep bass has more authority/impact/feel without an EQ.
My speakers respond below 22Hz.

I dont play that loud, enough to satisfy me with an incredible amount of micro detail and strong bass impact.
Probably around 90 to 95dB at most, often less.
Movies are phenomenal!

Very deep bass extension is provided by a BK Monolith subwoofer down to 15Hz.
I love it!

My speakers
http://iplacoustics.co.uk/S5tl Kevlar 2.htm
Sub
https://www.bkelec.com/HiFi/Sub_Woofers/monolith-df.htm
Both in Walnut :)
 
Last edited:
Top