A List of Low Noise Amplifiers

[ZolaIII]

For folks on the budget intending to use unbalanced inputs old (school) Yamaha A-S700 as amplifier only if you can find old stock of new ones. It's a good work horse and should be 500~600 $/€. Even similar and lower A-S, R-N models with be death silent if you use network - digital inputs (but you probably won't limit to it).

 

[staticV3]

Below rated 8 ohm power

I think what they mean is that the noise is >100dB below the rated 8Ω Power, but yeah, sure is vague and poorly written.

 

[tktran303]

In practical use, be careful of wiring if you are hearing noise. The cheapest quickest way is to use balanced cabling.

Balanced wiring can make a difference from “that’s a little annoying but it’s not too bad; I will put up with it, I don’t think I will buy another amp” to

“OMG it’s dead quiet why didn’t I do this before?! There’s nothing wrong with my amp it was the wiring and this noisy environment”


This is why professional or commercial audio (audio for a job, or an installation always runs balanced lines. No one has time to be mucking around trying to track down the course of hum/buzz/hiss.

 

[ZolaIII]

In practical use, be careful of wiring if you are hearing noise. The cheapest quickest way is to use balanced cabling.

Balanced wiring can make a difference from “that’s a little annoying but it’s not too bad; I will put up with it, I don’t think I will buy another amp” to

“OMG it’s dead quiet why didn’t I do this before?! There’s nothing wrong with my amp it was the wiring and this noisy environment”


This is why professional or commercial audio (audio for a job, or an installation always runs balanced lines. No one has time to be mucking around trying to track down the course of hum/buzz/hiss.

Cheapest easiest way with integrated amplifier is to use digital inputs (network, WiFi, Toslink, HDMI... depending what it supports). But this isn't ideal when you have need for more I/O and primary analog one's. Other way is to get one unbalanced with very good implemented inputs. For example mentioned A-S 700 has 110 dB rated RCA inputs. Anyway you won't get tweater hiss from A-B close amp, you may get buzz from wafer which is much less annoying. Hiss you get from typical by any means not great implemented class D one's which have increased THD with frequency. Again with good implemented one's this is taken care of. Going balanced is actually costliest solution as then you need to go all the way balanced I/O (from DAC, preamp, or DSP to speakers/amplifier and sub's). Sometimes balanced is the only way for long cable installations or if you simply want to be sure there won't be any ground loops but it will cost you as stated before.

 

[Elgrosso]

Awesomw @Tuocsteem, exactly what I needed.

Just a note on the Gjallarhon, they are very quiet indeed, but both mines had transformer hum, hard to un-hear once heard.
Now I’m on the fence for the rekkr. It’s a never ending quest between hum/hiss/noise etc!

 

[rp86]

3e audio's TPA3255 with PFFB modules are claimed to have 18uV A weighted residual noise: https://www.3e-audio.com/amplifier-kits/tpa32xx-with-pffb/

I'll have one plugged into a compression driver within a month or two so will be testing out the noise performance.

 

[mdsimon2]

I've been struggling with finding a desktop, near-field amplifier that has a low enough noise floor that I can't hear constant hissing from my speakers. In the chance that anyone else has the same problem, here's a collection of amplifiers that are probably quiet enough to be inaudible and some related notes.

The results of my experience with 86dB sensitivity speakers on a desk are as follows: 347uV is incredibly distracting, can hear it clear across the room. 70uV is quiet but still always noticeable. 16uV is approaching inaudible at the listening position- I can clearly hear it with my ear against the tweeter but can only follow the hiss ~1.5 feet before I lose it. I have never had an amplifier that is truly inaudible in a quiet room but it stands to reason that <4uV would be approaching "can't be heard without tool assistance" levels of performance. Therefore my arbitrary determination for this list is that <50uV is worth mentioning and <20 uV is good.

If there are any additional amplifiers that fit these noise requirements please do let me know. I probably won't continually update this post but I might make a spreadsheet if there is enough new info.


Benchmark AHB2 (Power Amp)- 7.1 uVrms A-wtd

• Has low gain mode (9.2 dB Low Gain, 17.0 dB Mid Gain, 23 dB High Gain)
• No volume control
• Not compact

Hypex Nilai500DIY (Amplifier Module)- 27 uVrms un-wtd (High gain), 15 uVrms un-wtd (Mid gain), 9 uVrms un-wtd (Low gain)

• Has low gain mode (Low Gain 11.86 dB, Mid Gain 21.75 dB, High Gain 27.88dB)

Hypex NC500 OEM (Amplifier Module)- 10 uVrms un-wtd (Unbuffered)

• Without buffer has low gain of 12.4 dB. Buffer implementation depends on assembler, some have switchable gain.

Hypex NCx500 OEM (Amplifier Module)- 20 uVrms un-wtd (Buffered), 7 uVrms un-wtd (Unbuffered)

• Without buffer has low gain of 11.5 dB, otherwise 26.8 dB with stock buffer.

Neurochrome Modulus-86 (DIY Power Amp)- 13.7 uVrms A-wtd, 17.2 uVrms un-wtd

• No finished units for sale. Requires significant assembly including acquiring a case and soldering components.
• Release spec was 33 uVrms A-wtd, 42 uVrms un-wtd and later changed to new spec. I'm not sure if there's any documentation of the improvements made or third party measurements of the new performance. Source
• Compact

Purifi 1ET400 (Amplifier Module)- 11.5 uVrms A-wtd (Unbuffered)

• Without buffer has low gain of 12.8 dB. Buffer implementation depends on assembler, some have switchable gain.
• Not compact

Purifi 1ET7040SA (Amplifier Module)- 14 uVrms A-wtd (Unbuffered)

• Without buffer has low gain of 13 dB. Buffer implementation depends on assembler, some have switchable gain.
• Not compact

Schiit Rekkr (Power Amp)- 4 uVrms A-wtd

• Manufacturer does NOT provide residual noise spec, the value is computed from SNR and output specs.
• Fixed low gain of 12 dB
• Extremely low output (3Wx2 at 4 Ohms)
• No volume control
• Compact

Schiit Gjallarhorn (Power Amp) - 12.6 uVrms un-wtd

• Manufacturer does NOT provide residual noise spec, the value is computed from SNR and output specs.
• No volume control
• Compact

Schiit Vidar 2 (Power Amp)- 20.0 uVrms un-wtd

• Manufacturer does NOT provide residual noise spec, the value is computed from SNR and output specs.
• No volume control
• Not compact

Soncoz SPG1 (Integrated Amp)- 9.8 uVrms A-wtd

• Manufacturer does NOT provide residual noise spec, the value is computed from SNR and output specs.
• Not compact

Topping LA90/Topping LA90D (Integrated Amp)- 3.4 uVrms A-wtd (high gain), 1.8 uVrms A-wtd (low gain)

• Has low gain mode (9.4 dB Low Gain, 19.4dB High Gain).
• Original LA90 is discontinued.
• Compact

Topping PA5, PA5 II, PA5 II Plus (Integrated Amplifiers)- 16 uVrms A-wtd

• Potentially serious reliability issues.
• Original PA5 is discontinued.
• Compact

Topping PA7, PA7 Plus (Integrated Amplifiers)- 17 uVrms A-wtd

• Compact

Topping RA3 (Integrated Amp)- 16 uVrms A-wtd

• No US-based reseller at time of posting, only direct from AliExpress.
• Not compact

Honorable Mentions:

Hypex NC2K OEM (Amplifier Module)- 20 uVrms un-wtd

• Has fixed low gain of 20 dB.

Hypex NC1200 OEM (Amplifier Module)- 28 uV un-wtd (buffered), 8 uV un-wtd (unbuffered)

• Without buffer has low gain of 11.6 dB.

Hypex NC52MP (Amplifier Module)- 35 uV un-wtd

• Not sure if you can buy this anywhere

Hypex NC122MP, NC250MP, NC252MP, NC500MP (Amplifier Modules)- 40 uV un-wtd

• NC502MP is slightly worse at 47 uV un-wtd.
• Not compact

ICEpower 1200AS1, ICEpower 1200AS2 (Amplifier Modules)- 25 uVrms A-wtd

• Not compact

ICEpower 2000AS1 HV, ICEpower 2000AS2 HV- 38 uVrms A-wtd

• Not compact

Neurochrome Modulus-286 (DIY Power Amp)- 28.5 uVrms un-wtd, 23.0 uVrms A-wtd (High gain). 22.0 uVrms un-wtd, 17.0 uVrms A-wtd (Low gain)

• Has sort of low gain mode (20 dB Low gain, 26 dB High gain) with resistor swap during assembly.
• Compact

Neurochrome Modulus-686 (DIY Power Amp)- 25.0 uVrms un-wtd, 20.0 uVrms A-wtd (High gain). 20.0 uVrms un-wtd, 16.0 uVrms A-wtd (Low gain)

• Has sort of low gain mode (20 dB Low gain, 26 dB High gain) with resistor swap during assembly.
• Not compact

Neurochrome LM3886 Done Right (DIY Power Amp)- 29 uVrms A-wtd, 38 uVrms un-wtd

• Compact

Schiit Aegir (Power Amp)- 31.8 uVrms A-wtd

• No volume control
• Not compact

Yamaha A-S2200, A-S3200 (Integrated Amplifiers)- 33 uVrms A-wtd

• Totally different price category and market. If you are considering one of these you most likely do not need this list.

Yamaha A-S301, A-S501, A-S701, A-S801 (Integrated Amplifiers/Stereo Receivers)- 40 uVrms A-wtd

• The only members of this list that function as Stereo Receivers. Some of the only modern devices with a bunch of varied inputs AND subwoofer out AND tone controls AND acceptable noise floor. Very safe bet if reliability is a concern.
• Most specs assume CD input with PURE DIRECT or CD DIRECT AMP mode and SNR loss with tone controls on is not documented. DAC performance is unknown.
• Not compact

Notes:
Most of this information is available elsewhere on this forum albeit scattered. I'm mainly compiling all of this for my own research and to keep the discussion alive. Credit to this thread for inspiration and particularly @staticV3 for listing a bunch of these already.

All of the info comes direct from manufacturers, whatever number is specified as maximum residual noise. Computed values assume SNR is relative to the highest stated total output.

There are many additional parameters that I find useful (multiple inputs, balanced architecture, amplifier class, idle power consumption etc.) but I'd rather not make this too encyclopedic. Purposely omitted are:

• Distortion and power specs as I don't think they are relevant for most of the entries on this list.
• Price as it is variable but suffice it to say only a handful of these devices are "affordable".
• SNR spec as it is in relation to total power. Generally any device with meaningful output needs >110 dB SNR w.r.t peak output to have a low noise floor. High output devices likely need >120 dB SNR. Add another 10 dB to these requirements if you want noise inaudibility. This is also all relative to speaker sensitivity and listening distance.

Compact vs. Not compact is roughly equivalent to "is it smaller than a textbook?". This has nothing to do with topological spaces. It is important to me that a desktop amplifier actually fits on a desk.

Some of the DIY Hypex and Purifi amps could theoretically be made compact as monoblocks or with separate power supplies but I went with common implementations e.g. VTV to determine that they are all not compact. All of the units listed as "Amplifier Module" either require significant assembly or are only available from assemblers such as VTV, Buckeye, Nord etc. Most are designed as pure power amps with no integrated volume control. Actual performance depends on implementation and, in general, noise levels will be higher than listed here but still acceptable.

I omitted from this list anything that would be classified as vintage or long discontinued. Devices which overwhelmingly failed to make it on the list were 1) Basically every TI, Infineon etc. chip amp (excluding LM-3886), including those that power most desktop amps that are popular on this forum. Some of the ICs are theoretically capable of good noise performance but good implementations are few and far between and 2) Basically every AVR, although I did not search too thoroughly.

Don't forget it is total system noise that you hear, not just amplifier noise. Your amplifier will multiply the noise from your DAC, so in general higher amplifier gain means higher system noise, although lower gain amplifiers often have lower residual noise as well. This is where an analog volume control can help as it lowers how much the noise from DAC is being amplified.

What DAC / amplifier combinations were using when you came to the conclusion on audibility of 347 vs 70 vs 16 uV? I should say that in general your amplifier numbers seem to agree with my experience and I shoot for low-100 uVs un-wtd of system noise and my main system is under 100 uV un-wtd (amplified DAC noise + amplifier noise).

Michael

 

[Joe Smith]

"Some of the ICs are theoretically capable of good noise performance but good implementations are few and far between..."

Really?

 

[Tuocsteem]

What DAC / amplifier combinations were using when you came to the conclusion on audibility of 347 vs 70 vs 16 uV? I should say that in general your amplifier numbers seem to agree with my experience and I shoot for low-100 uVs un-wtd of system noise and my main system is under 100 uV un-wtd (amplified DAC noise + amplifier noise).

That would be Crown XLS 1502, Topping PA3S, Topping PA5 II, respectively. All with Topping E30 DAC and PC as audio source, but with the DAC turned off to test just amplifier noise. In my experience it seems like shorting the amplifier inputs doesn't make a difference and neither does the volume pot position as long as it's below 3/4 of the way or so. None of these units seem to have any sort of auto-muting.

Don't forget it is total system noise that you hear, not just amplifier noise. Your amplifier will multiply the noise from your DAC, so in general higher amplifier gain means higher system noise, although lower gain amplifiers often have lower residual noise as well. This is where an analog volume control can help as it lowers how much the noise from DAC is being amplified.

For anyone that's trying to set up a quiet system for the first time, it's worth reiterating that 2uV Noise + 26dB gain = 39.9 uV Noise. A standard well performing DAC simply plugged into a power amp without attenuation blows past some of these noise thresholds. That's also why I'd consider any pure power amp, even if it's miniature, to be non-ideal for desktop use as you need a separate preamp/volume control in the signal chain.

I've heard that many preamplifiers attenuate their own output to control volume, sort of keeping constant SNR with varying volume levels. I wonder if most modern DACs with preamp functionality use the same design? The Topping E30 has a preamp mode but I don't have a quiet enough amplifier to test my DAC noise currently.

 

[Tuocsteem]

"Some of the ICs are theoretically capable of good noise performance but good implementations are few and far between..."

Really?

Per TI's own specs TPA3255 has 85 uVrms A-wtd noise, TPA3251 has 60 uVrms A-wtd. MA12070 has 45 uVrms A-wtd but most implementations are noisier. There are some advanced designs such as Neurochrome's LM3886-based amps or the 3e TPA3255 unit mentioned by @rp86 that somehow beat the manufacturer's noise spec. These do appear to be few and far between though, certainly none of them come up if you search for desktop amplifiers on Amazon.

 

[GXAlan]

For anyone that's trying to set up a quiet system for the first time, it's worth reiterating that 2uV Noise + 26dB gain = 39.9 uV Noise.

The flagship Accuphase preamp is 0.32 uV

https://www.accuphase.com/technical_information/c-3900_technical_information.pdf

Which gets you to 6.2 uV after 26 dB gain.

For measurements + reliability, if I won the lottery or found my myself in a financial position to get 2 ch audio gear instead of buying a car, it seems like the flagship Accuphase amps are truly clean!

 

[mdsimon2]

That would be Crown XLS 1502, Topping PA3S, Topping PA5 II, respectively. All with Topping E30 DAC and PC as audio source, but with the DAC turned off to test just amplifier noise. In my experience it seems like shorting the amplifier inputs doesn't make a difference and neither does the volume pot position as long as it's below 3/4 of the way or so. None of these units seem to have any sort of auto-muting.


For anyone that's trying to set up a quiet system for the first time, it's worth reiterating that 2uV Noise + 26dB gain = 39.9 uV Noise. A standard well performing DAC simply plugged into a power amp without attenuation blows past some of these noise thresholds. That's also why I'd consider any pure power amp, even if it's miniature, to be non-ideal for desktop use as you need a separate preamp/volume control in the signal chain.

I've heard that many preamplifiers attenuate their own output to control volume, sort of keeping constant SNR with varying volume levels. I wonder if most modern DACs with preamp functionality use the same design? The Topping E30 has a preamp mode but I don't have a quiet enough amplifier to test my DAC noise currently.

Good know, the Toppings obviously have rather low gain at 19 dB and the Crown is 30+ dB gain. The volume pots are an analog volume control and will effectively reduce the amount of noise going to the amplifier from the DAC. Of course the penalty to this is channel imbalance at lower volumes.

Almost all DACs use digital volume control in preamp mode. If they don’t they will in general advertise they are using an analog volume control. Some like the RME ADI-2 use a hybrid volume control that has fixed analog steps along with digital volume control.

Michael

 

[Roland68]

That would be Crown XLS 1502, Topping PA3S, Topping PA5 II, respectively. All with Topping E30 DAC and PC as audio source, but with the DAC turned off to test just amplifier noise. In my experience it seems like shorting the amplifier inputs doesn't make a difference and neither does the volume pot position as long as it's below 3/4 of the way or so. None of these units seem to have any sort of auto-muting.


For anyone that's trying to set up a quiet system for the first time, it's worth reiterating that 2uV Noise + 26dB gain = 39.9 uV Noise. A standard well performing DAC simply plugged into a power amp without attenuation blows past some of these noise thresholds. That's also why I'd consider any pure power amp, even if it's miniature, to be non-ideal for desktop use as you need a separate preamp/volume control in the signal chain.

I've heard that many preamplifiers attenuate their own output to control volume, sort of keeping constant SNR with varying volume levels. I wonder if most modern DACs with preamp functionality use the same design? The Topping E30 has a preamp mode but I don't have a quiet enough amplifier to test my DAC noise currently.

Most DACs use the DSP function in the DAC chip to digitally reduce the volume before D/A conversion.
It has nothing to do with conventional preamps.