Best power amplifiers for low volume dynamics

B

Boomzilla

Audioholic Intern
Early in my audio career, I worked shift work at a local chemical plant. The evening before I began my night shifts, I'd normally stay up most of the night enjoying music in my listening room. My wife and new baby were asleep at the far end of the house, so I had to keep the volume very low to avoid disturbing them. I developed a taste for low-volume listening that I've kept ever since.

In the early days, I found that Klipsch speakers (including the Heresy, Cornwall, and La Scala) were good at low-volume dynamics, but I was never happy with their horn coloration. I eventually bought a pair of Dahlquist DQ-10s, and at the same time, an Adcom GFA-1 "power cube" amplifier. That combination produced very good low-volume dynamics.

But since then, I've owned a wider variety of speakers and amplifiers. What I've found is that most loudspeakers seem to have a "volume threshold" that must be exceeded before the speaker begins to sound dynamic. But recently, an audio amigo suggested to me that perhaps it isn't the speakers that have a volume threshold but the amplifiers.

I own a wide variety of amplifiers including:
  • A pair of Class-D (ICE module based) Emotiva PA-1 mono blocks
  • A Crown PSA-2 stereo A-B class "pro" amplifier
  • A Black Ice F22 tube integrated amp (EL-34 outputs)
  • A pair of Heathkit tube mono blocks (about 10 Watts each)
The only amps that will make my current speakers (Klipsch RP-600m) sound very dynamic at low volumes are the Heathkits.

So, finally to my question: What types or brands of amplifiers will sound the most dynamic at power outputs of one watt or less? I'm contemplating the purchase of some lower-sensitivity speakers (Emotiva T3+ models) and will want them to dance at very low volumes.

Thanks - Boomzilla
 
everettT

everettT

Audioholic Ninja
Early in my audio career, I worked shift work at a local chemical plant. The evening before I began my night shifts, I'd normally stay up most of the night enjoying music in my listening room. My wife and new baby were asleep at the far end of the house, so I had to keep the volume very low to avoid disturbing them. I developed a taste for low-volume listening that I've kept ever since.

In the early days, I found that Klipsch speakers (including the Heresy, Cornwall, and La Scala) were good at low-volume dynamics, but I was never happy with their horn coloration. I eventually bought a pair of Dahlquist DQ-10s, and at the same time, an Adcom GFA-1 "power cube" amplifier. That combination produced very good low-volume dynamics.

But since then, I've owned a wider variety of speakers and amplifiers. What I've found is that most loudspeakers seem to have a "volume threshold" that must be exceeded before the speaker begins to sound dynamic. But recently, an audio amigo suggested to me that perhaps it isn't the speakers that have a volume threshold but the amplifiers.

I own a wide variety of amplifiers including:
  • A pair of Class-D (ICE module based) Emotiva PA-1 mono blocks
  • A Crown PSA-2 stereo A-B class "pro" amplifier
  • A Black Ice F22 tube integrated amp (EL-34 outputs)
  • A pair of Heathkit tube mono blocks (about 10 Watts each)
The only amps that will make my current speakers (Klipsch RP-600m) sound very dynamic at low volumes are the Heathkits.

So, finally to my question: What types or brands of amplifiers will sound the most dynamic at power outputs of one watt or less? I'm contemplating the purchase of some lower-sensitivity speakers (Emotiva T3+ models) and will want them to dance at very low volumes.

Thanks - Boomzilla
What preamp are you using? The output of the preamp needs to closely match with the amplifier's gain structure. The new Purifi amps have 3 selectable gain structures to better match to preamps and conversely to the speakers.
 
B

Boomzilla

Audioholic Intern
Hi @everettT -

Thank you for the prompt response. I have options as to preamplifiers:
  • Emotiva Stealth DC-1 DAC with variable (digital) volume control directly to the power amps
  • Emotiva BasX P1 preamplifier
  • Either of the above routed through a Schiit Loki equalizer with the EQ outputs to the power amps
I'll soon also have the option of a fixed-volume output vacuum tube DAC (Black Ice Fx) playing through a passive volume pot into the power amps.

The pairing that sounded so dynamic with the Dahlquist speakers back in the day was a Van-Alstine modified Dynaco PAS (tube) preamplifier playing into the Adcom GFA-1.

Boomzilla
 
everettT

everettT

Audioholic Ninja
Hi @everettT -

Thank you for the prompt response. I have options as to preamplifiers:
  • Emotiva Stealth DC-1 DAC with variable (digital) volume control directly to the power amps
  • Emotiva BasX P1 preamplifier
  • Either of the above routed through a Schiit Loki equalizer with the EQ outputs to the power amps
I'll soon also have the option of a fixed-volume output vacuum tube DAC (Black Ice Fx) playing through a passive volume pot into the power amps.

The pairing that sounded so dynamic with the Dahlquist speakers back in the day was a Van-Alstine modified Dynaco PAS (tube) preamplifier playing into the Adcom GFA-1.

Boomzilla
I'll take a look and see if I can find some 3rd party measurements of the output stages. Which speakers are you going to be using primarily?
 
B

Boomzilla

Audioholic Intern
Hi again, @everettT -

At the moment, I'm using some (modified) Klipsch RP-600m bookshelf speakers and a Starke Sound S15 sealed sub. But I'm hoping to do away with the sub and end up with one of the three choices below (in order of current preference):
  • Emotiva T3+ towers
  • HECO Aurora 1000
  • Klipsch RP-8000f II
 
P

PENG

Audioholic Slumlord
Early in my audio career, I worked shift work at a local chemical plant. The evening before I began my night shifts, I'd normally stay up most of the night enjoying music in my listening room. My wife and new baby were asleep at the far end of the house, so I had to keep the volume very low to avoid disturbing them. I developed a taste for low-volume listening that I've kept ever since.

In the early days, I found that Klipsch speakers (including the Heresy, Cornwall, and La Scala) were good at low-volume dynamics, but I was never happy with their horn coloration. I eventually bought a pair of Dahlquist DQ-10s, and at the same time, an Adcom GFA-1 "power cube" amplifier. That combination produced very good low-volume dynamics.

But since then, I've owned a wider variety of speakers and amplifiers. What I've found is that most loudspeakers seem to have a "volume threshold" that must be exceeded before the speaker begins to sound dynamic. But recently, an audio amigo suggested to me that perhaps it isn't the speakers that have a volume threshold but the amplifiers.

I own a wide variety of amplifiers including:
  • A pair of Class-D (ICE module based) Emotiva PA-1 mono blocks
  • A Crown PSA-2 stereo A-B class "pro" amplifier
  • A Black Ice F22 tube integrated amp (EL-34 outputs)
  • A pair of Heathkit tube mono blocks (about 10 Watts each)
The only amps that will make my current speakers (Klipsch RP-600m) sound very dynamic at low volumes are the Heathkits.

So, finally to my question: What types or brands of amplifiers will sound the most dynamic at power outputs of one watt or less? I'm contemplating the purchase of some lower-sensitivity speakers (Emotiva T3+ models) and will want them to dance at very low volumes.

Thanks - Boomzilla
Well designed amplifiers should be linear from very low output to their rated output level. So I think the issue has to do with the well known Fletcher Munson effect. The Heathkit tube amp is likely bass biased, giving you the feeling of more dynamic at low output levels.

Fletcher Munson Curves Explained - F.I.R.S.T. Institute (first.edu)

It is of course a frequency response thing but it could be giving you the impression that at low volumes dynamic gets low too.

A simple and low cost solution is to use something (AVR, AVP, two channel receivers) that has Audyssey dynamic eq. Or use Dirac Live and customize a target curve to put various tilt/slope for the 20 to 200 Hz range.
 
B

Boomzilla

Audioholic Intern
Hi @PENG -

I agree that Fletcher-Munson curve could play a part. The Van-Alstine preamp I used with my old Dahlquists had been custom-equalized by Frank Van-Alstine to provide a slight bass boost specifically for the DQ-10a speakers.

I despise AVRs because of their wimpy power supplies & amps, and would prefer to avoid digital equalization as well. I do have the Schiit Loki analog equalizer, and alternately, my Emotiva preamp does have bass and treble contour controls. I'll work with those to see if the low volume dynamics seem better. Thanks for the suggestions!

Boomzilla
 
Replicant 7

Replicant 7

Audioholic Samurai
Well designed amplifiers should be linear from very low output to their rated output level. So I think the issue has to do with the well known Fletcher Munson effect. The Heathkit tube amp is likely bass biased, giving you the feeling of more dynamic at low output levels.

Fletcher Munson Curves Explained - F.I.R.S.T. Institute (first.edu)

It is of course a frequency response thing but it could be giving you the impression that at low volumes dynamic gets low too.

A simple and low cost solution is to use something (AVR, AVP, two channel receivers) that has Audyssey dynamic eq. Or use Dirac Live and customize a target curve to put various tilt/slope for the 20 to 200 Hz range.
@PENG, wouldn't say, a Class A amp be more inline and much better speakers do him better for low-level listening? Yeah I know you're gonna say, Class A/B amps will achieve the same thing at low levels. But isn't it true that Class A/B amps are only Class A for the first 10 to 25 watt's example, output before switching to Class B at higher output. And yes even 10 watts can get loud. I wouldn't mind setting up a two channel system for music only use with a very nice pair of bookshelves and a pure Class A amp and Pre-Amp.
Never mind PENG, come to think of it, that's a 10K idea alone before adding a source. Yeah OP could do with a nice integrated amp with a little better choice of speakers for what he's looking to achieve.
 
Last edited:
P

PENG

Audioholic Slumlord
But isn't it true that Class A/B amps are only Class A for the first 10 to 25 watt's example, output before switching to Class B at higher output.
Some people would say that but it isn't always true, in fact most popular and well regarded class AB amps do not switch to class B at all. I would stay away from those (probably only a few) that do switch to class B because they would likely have crossover distortions that could be audible even to non golden ears.

Class AB amps typically run in class A to very low output level or up to a few watts, though some would go much higher (e.g. some of the big Emo amps) or. Many class AB amps are biased to class AB practically full time, that is from almost 0 to rated output levels. My Bryston 4B SST supposedly goes up to about 20 W before switching to class AB, but if I remember right, the newer models such as the SST2, SST3 would switch over at much lower output level, may be less than 1 W. There is really no audible benefit as such well designed class AB amps have hardly any crossover distortions, i.e., the issue has been virtually fixed..

A quick and easy to read article for you:

What are the Different Types of Audio Amplifier Classes? | Audioholics

Class B
While all of the output devices in a Class A amplifier are conducting 100% of the time, Class B amplifiers utilize a push/pull arrangement in such a way that only half the output devices are conducting at any given time: one half covers the +180 degree portion of the waveform, while the other covers the -180 degree section. As a consequence, Class B amplifiers are substantially more efficient than their Class A counterparts, with a theoretical maximum of 78.5%. Given the relatively high efficiency, Class B was used in some professional sound reinforcement amplifiers as well as some home audio tube amps.

In spite of their obvious strength, the odds are good you won’t see too many pure Class B amplifiers floating around. The reason for this is known as crossover distortion.

Crossover Distortion

Crossover distortion affecting a simple sine wave; image courtesy of sound.westhost.com.

As seen in the image above, crossover distortion is a problem/delay in the handoff between the devices handling the positive and negative portions of the waveform. Needless to say, such distortion in sufficient amounts is audible, and while some Class B designs were better than others in this respect, Class B didn’t receive much love from audiophiles.

Class A/B
Class A/B, as one might deduce, combines the best of Class A and Class B in order to create an amplifier without the drawbacks of either. Thanks to this combination of strengths, Class A/B amplifiers largely dominate the consumer market. So how did they do it? The solution is actually fairly simple in concept: where Class B utilizes a push/pull arrangement with each half of the output stage conducting for 180 degrees, Class A/B amplifiers bump that up to ~181-200 degrees. By doing this, there is far less potential for a “gap” in the cycle to occur, and consequently, crossover distortion is pushed down to the point where it’s of no consequence.

And yes even 10 watts can get loud. I wouldn't mind setting up a two channel system for music only use with a very nice pair of bookshelves and a pure Class A amp and Pre-Amp.
Never mind PENG, come to think of it, that's a 10K idea alone before adding a source. Yeah OP could do with a nice integrated amp with a little better choice of speakers for what he's looking to achieve.
You don't need to spend 10K, if 10 to 25 W or so is enough for you, there are good class A amps that you can buy. If you need more, there's always the likes of Parasound A21, A21+, A23, A23+ that will give you a taste of class A for the first several watts. To me, there is no taste, they all taste the same but ymmv, thanks to Placebo.;)
 
B

Boomzilla

Audioholic Intern
Hi guys -

It's all fine information you're supplying, but not pertinent to the thread. At the volumes I listen to, NO amplifier will exceed two or three watts of output. Most of the time, I listen in the ½ watt output range. At those volumes, just about all amps are "Class A." As I said, I can get sufficient output from my 10 watt Heathkits to irritate my wife, and those tiny tykes sound more dynamic at those low volumes than ALL my other amplifiers.

Although you might think that I'd be more satisfied with "better" speakers, the (modified) Klipsch RP-600m speakers are both transparent and smooth while remaining dynamic at the volumes I listen at. So why am I contemplating replacing them? I'd like to do away with the complication of the subwoofer completely. Two of the three replacement contenders (the Emotiva T3+ and the Heco 1000) have -3dB points in the 20s AND sensitivities above 90dB / 1W / 1M.

Would those speakers be content with the flea-wattage of the Heathkits? I'm not so sure... Therefore, my request for specific makes and models of power amplifier that sound exceptionally dynamic at very low volumes. The two most dynamic low-volume amplifiers I've owned over the years are almost polar opposites in technology - the Class AB Adcom GFA-1 and the Heathkit tube amp.

So I'm despairing of finding any common amplifier characteristic that would indicate low volume dynamics. I'm hoping that this forum will have more experienced users with enough experience to tell me what their most dynamic amps have been. OH - I just thought of one other amplifier / speaker combination that was SUPER dynamic at low volumes - VTL Compact 100 tube mono blocks and Klipsch La Scala speakers. The VTLs were super unreliable, but when they worked, they sounded heavenly.

Boomzilla
 
P

PENG

Audioholic Slumlord
Hi @PENG -

I agree that Fletcher-Munson curve could play a part. The Van-Alstine preamp I used with my old Dahlquists had been custom-equalized by Frank Van-Alstine to provide a slight bass boost specifically for the DQ-10a speakers.

I despise AVRs because of their wimpy power supplies & amps, and would prefer to avoid digital equalization as well. I do have the Schiit Loki analog equalizer, and alternately, my Emotiva preamp does have bass and treble contour controls. I'll work with those to see if the low volume dynamics seem better. Thanks for the suggestions!

Boomzilla
I meant to suggest using an AVR or AVP as preamp/dac to drive a power amp of your choice. Audyssey's DEQ is really very well done base on both subjective reviews and measurements.

By the way, while AVRs do have wimpy power supplies/amps relatively speaking, if you are talking abut low level listening, they wouldn't be bad either. Measurements on ASR showed many AVRs perform as good or better than some integrated amps and power amps. It always depends..
 
B

Boomzilla

Audioholic Intern
Hi @PENG -

You're probably right. I'm thinking of AVRs of five or 10 years ago that were almost uniformly BAD. If I didn't have good stereo gear, I might consider an AVR, but no sense in replacing great equipment with only good.
 
O

OHMisback

Audioholic
It's all fine information you're supplying, but not pertinent to the thread. At the volumes I listen to, NO amplifier will exceed two or three watts of output. Most of the time, I listen in the ½ watt output range. At those volumes, just about all amps are "Class A." As I said, I can get sufficient output from my 10 watt Heathkits to irritate my wife, and those tiny tykes sound more dynamic at those low volumes than ALL my other amplifiers.
I think your can get what you need by paying attention to the type of valve used. I suspect you want to stay with valves first of all.
I like tone controls on some of my setup, depending on the source and the recording. If you're into Vinyl, or RtR that's one thing,
streaming, CDs and a loaded server is different too.

Low LOW volume listening usually take a different type of BIAS setting in the real world of valves. If you can't set the bias, I know you'll need tone contour at least
I'd go with KT66 or 6L6 valves for low level listening too. I know what would work with my gear, the issue is you need more preamp control not less IF you can't adjust
the bias HOT for lower level listening on your power amps. To be able to change the bias and the type of valve is the real reason you could take a lot of the tone control
off the table. I use C20s because they CAN color or NOT color the sound, but most of all it has a BASS contour, Bass tone controls, and loudness contours TOO.
Just for LOW level listening a C20 (rebuilt) and a MC240 or V12r because of the way the amp works are my choice, but I own a few.
V12r is A/B but variable tube NUMBER and type. 4, 8 or 12 valves. You can use 6V6,6L6,KT66,77,88,90,99, El34. You can flip 6 toggles to go single ended, too.

I'll be honest, The GAN amps are great. I have a 2 and 400 model. Pretty impressive to say the least. NO they are not valves but that is in how they are voiced and
it's my understanding some sound very good because of the tweaks and feedback. Peachtree sure is nice units. 32db of gain and tone control. It's an alternative.
Don't become to tube snobbish, you might miss some real nuggets in the SS world.

I tried a lot of the Schiit products, I always went back to Manley for my EQ. I had a D.W. Fearn VT-4 a buddy brought over. I'll stick with the 20 year old monster
I haven't used it in 5 years.

I often wonder how the Dahlquists would perform with GRs OB servos. I have a feeling that would be the cats meow at volume.
DQ-10s were wonderful speakers. I ran mine on Mac tube gear at the time. Maggies and 57s too, sure fun.

Room acoustics at 1/2 watt can be tighten to a lot closer proximity too.

Fruit for thought.
 
witchdoctor

witchdoctor

Audioholic
I see you own the Black Ice integrated amp. I would contact their tech support and ask for suggestion, they have extremely helpful when I sent them inquiries. I'll bet they give you some good ideas to try.
 
witchdoctor

witchdoctor

Audioholic
I would also recommend trying the DC Block from Audiolab with the amplifiers you already own before buying a new one. You can get with a 30 day money back from Amazon. If it doesn't work out just return it:
DC Block Overview
This combination of technologies ensures that the DC Block does more than solve the problem of transformer saturation caused by DC on the mains; it also helps to unlock the sonic potential of any audio component to which it is connected. The noise floor drops and the sound gains greater focus, with reduced grain, improved clarity, better-defined bass, and ‘airier’ treble.


 
Last edited:
B

Boomzilla

Audioholic Intern
Hi @OHMisback & @witchdoctor -

Yes, my Black Ice F22 integrated does allow custom bias, and I have communicated previously with the crew at Black Ice about how to do so. Although my F22 does not have tone controls, I have several options including using my Schiit Loki or else the DSP in my Roon software.

The factory tubes in my F22 are EL34s, and I do like their tone.

The power output on the F22 is from about 40 to 45 watts. As low a volume as I listen at, I'm confident that the F22 will be more than adequate for any speaker I choose.

As I've mentioned, my goal in choosing a tower speaker is the ability to dispose of subwoofers and their complexity in my system. Should I opt to use a solid state amp for better woofer control with the speakers I choose, I can always opt for a tube DAC and/or preamp. I've had good luck previously with upstream tubes and a solid state power amp. But some speakers I've used are far more articulate with a tube power amp. I'll have to see...
 
mtrycrafts

mtrycrafts

Seriously, I have no life.
... My wife and new baby were asleep at the far end of the house, so I had to keep the volume very low to avoid disturbing them. ...

Thanks - Boomzilla
When you lower the volume, all the signal values also get lowered and the ones that were still audible in normal listening once reduced enough to allow the high volume signals not to distract, those low levels and more become silent, dynamics suffer. Not an amp issue or speaker issue but human perception issue.
 
P

PENG

Audioholic Slumlord
Hi @PENG -

You're probably right. I'm thinking of AVRs of five or 10 years ago that were almost uniformly BAD. If I didn't have good stereo gear, I might consider an AVR, but no sense in replacing great equipment with only good.
Understood, I don't use AVR in my stereo setups either. Using AVR as prepro is just a viable option, and would mainly for those who trust specs, measurements, and the benefits of using RC. That being said, I may eventually go back to receiver/AVR, say when I am over 80 lol.... At that point I may think convenience is more important..
 
highfigh

highfigh

Audioholic Slumlord
Hi guys -

It's all fine information you're supplying, but not pertinent to the thread. At the volumes I listen to, NO amplifier will exceed two or three watts of output. Most of the time, I listen in the ½ watt output range. At those volumes, just about all amps are "Class A." As I said, I can get sufficient output from my 10 watt Heathkits to irritate my wife, and those tiny tykes sound more dynamic at those low volumes than ALL my other amplifiers.

Although you might think that I'd be more satisfied with "better" speakers, the (modified) Klipsch RP-600m speakers are both transparent and smooth while remaining dynamic at the volumes I listen at. So why am I contemplating replacing them? I'd like to do away with the complication of the subwoofer completely. Two of the three replacement contenders (the Emotiva T3+ and the Heco 1000) have -3dB points in the 20s AND sensitivities above 90dB / 1W / 1M.

Would those speakers be content with the flea-wattage of the Heathkits? I'm not so sure... Therefore, my request for specific makes and models of power amplifier that sound exceptionally dynamic at very low volumes. The two most dynamic low-volume amplifiers I've owned over the years are almost polar opposites in technology - the Class AB Adcom GFA-1 and the Heathkit tube amp.

So I'm despairing of finding any common amplifier characteristic that would indicate low volume dynamics. I'm hoping that this forum will have more experienced users with enough experience to tell me what their most dynamic amps have been. OH - I just thought of one other amplifier / speaker combination that was SUPER dynamic at low volumes - VTL Compact 100 tube mono blocks and Klipsch La Scala speakers. The VTLs were super unreliable, but when they worked, they sounded heavenly.

Boomzilla
The two things you're fighting are: the need for good sound & dynamics at low power, the average human's hearing acuity at low SPL and specifically, YOUR hearing ability since everyone hears differently to some degree.

That said, a good system can sound very dynamic and detailed at low levels, but after years and decades of being bombarded by sound & noise, it takes some concentration to realize what we're hearing.

Could the room where you listen be somewhat isolated from the space where your wife wants to be able to avoid the sound? If not, and you do need to accept the fact that low frequencies are very hard to stop, you may need to decrease the low end while they're sleeping.

This isn't 'a hill where you should choose to die', as the saying goes.
 

Latest posts

newsletter

  • RBHsound.com
  • BlueJeansCable.com
  • SVS Sound Subwoofers
  • Experience the Martin Logan Montis
Top