Fast amps, slow amps

ml

Member
What would you consider as fast amps, and which would you consider as slow amps? What determining factors or components of the amp would contribute to the amp sounding fast or slow?
 

tachyons

Active member
A fast-sounding amplifier is designed to accurately reproduce the rapid transients in music, characterized by a sharp "start" and a clean "stop." This quick response enables the amplifier to deliver a more dynamic and realistic sound by capturing subtle details and nuances that slower, less responsive amplifiers might miss. By precisely handling the timing and dynamics of each note, a fast-sounding amplifier ensures a faithful reproduction of the music's rhythm and pace. This capability is essential for conveying the groove and feel of a song, resulting in a more engaging and authentic listening experience.
 

tachyons

Active member
Subjectively, a fast amplifier, with its emphasis on tight control and quick response, can sometimes produce a sound that is perceived as leaner. This is because it may not linger on notes or emphasize the lower frequencies as much as a slower amplifier.

In contrast, a slow-sounding amplifier might not control the speaker as tightly, leading to a less defined bass response. This can contribute to a perception of heaviness or thickness, especially if the audio system is already biased towards a warmer tonality. While a fast amplifier excels in clarity and precision, a slow amplifier might offer a more robust and fuller sound, appealing to listeners who prefer a richer and more rounded audio experience.
 

blue_starfish

Active member
Fast amps to name some obvious ones. Mostly solid state: Goldmund, Naim, Spectral.

Read the rise time and slew rate where the manufacturer publishes them. Goldmund used to, then stopped. Their older amps claimed a <400ns rise time.
 

ml

Member
Nowadays lots of amplifiers do not publish slew rates or rise time. Slew rates are known for the various opamps components though, for people who may do DIY work, but amps don’t necessarily use opamps at all.

How tightly the amplifiers control the woofer or low frequencies are shown by their damping factors, which are related to their output impedances. High damping factor will lead to a leaner and tighter sound, with less overhang of the woofer movements. High damping factors are seen typically in solid state amps.
 

tachyons

Active member
Pace and rhythm are crucial elements in music, but I’ve come to appreciate that other aspects—such as timbre, texture, and structure—also significantly contribute to its overall musicality. Music playback involves a complex interplay of many factors, and individual tastes can vary and evolve over time as one gains experience with a broader range of equipment. Currently, I’m enjoying an R2R DAC that emphasizes the flow of the music over temporal aspects, allowing me to fully immerse myself in its presentation.
 

tachyons

Active member
A high-resolution audio system can also subjectively create the perception of a slower musical pace. By revealing previously masked subtle details and nuances, including micro-timing variations in performance, the system creates a sense of "space" or "breathing room" within the music. This leads to a sense that the music is unfolding more gradually.
 

ml

Member
A high-resolution audio system can also subjectively create the perception of a slower musical pace. By revealing previously masked subtle details and nuances, including micro-timing variations in performance, the system creates a sense of "space" or "breathing room" within the music. This leads to a sense that the music is unfolding more gradually.
This, I would personally consider the amp to not get the pace and rhythm right, and definitely not a fast amp. The ideal amp (if there is any) is one which can project the right PRAT (pace, rhythm and timing), at the same time displaying the subtle details etc of the music.

For me, audio or stereo has a lot to do with aural perception/illusion, and if what is projected is being perceived as such, then it is what it is being perceived as.
 
Last edited:

tachyons

Active member
My use of the term 'slow' to describe the heightened engagement that occurs when listeners are drawn into the details and experience an altered perception of time could be misleading. 😅
 

tachyons

Active member
What if I describe it by saying that you feel stuck in the present, experiencing the music's pace and tension for longer than usual. 😁
 

Audio

Administrator
Staff member
To me, every amplifier should be a fast amp, able to quickly respond to the input signal and produced an accurately amplified output to the speakers, without overshooting the intended amplitude at all times.

Nobody benefit from a slow amp.

Hence the input source is very important and will largely impact the overall listening experience.

(Audio)
 

tachyons

Active member
I’m currently exploring Laiv DACs paired with different amplifiers. Switching from the Chord amplifier to the Mola Mola immediately imparts a sense of relaxation and a laid-back character, making the music feel as though the tempo has slowed down. While the Mola Mola gives the impression of being a “slow” amplifier, it is far from sluggish in terms of transient response or control. Somehow, this presentation can be just as enjoyable as the more intense and fast-paced sound of the Chord.
1000009787.jpg
 

Audio

Administrator
Staff member
I’m currently exploring Laiv DACs paired with different amplifiers. Switching from the Chord amplifier to the Mola Mola immediately imparts a sense of relaxation and a laid-back character, making the music feel as though the tempo has slowed down. While the Mola Mola gives the impression of being a “slow” amplifier, it is far from sluggish in terms of transient response or control. Somehow, this presentation can be just as enjoyable as the more intense and fast-paced sound of the Chord.
View attachment 8862
I guess the defination of fast and slow amp differs here.

I was referring to fast amp vs slow amp on the technical prospective, the signal response.

I realised that you are referring to the tone of the amp, as with the warmth and musicality of the amp.

(Audio)
 

boxerfan88

Well-known member
What would you consider as fast amps, and which would you consider as slow amps? What determining factors or components of the amp would contribute to the amp sounding fast or slow?

My opinion on fast amplifier:
  • amplifier exhibits extremely high L/C/R load independence
  • rail-to-rail slew rate that supports the full amplifier bandwidth specification
  • high damping factor (low output impedance)
  • upper harmonics remain aligned with fundamentals across entire amplifier bandwidth (low group delay)
  • stable/same performance across full bandwidth from mW power level, all the way to rated power

How the amplifier interacts with the complex load imposed by a passive loudspeaker determines the “fast” or “slow” perception.

For this reason, I have shifted my preference toward active speaker systems, as they are designed and tuned as “one system”.

Consider this example: driving a Rolls Royce Flying Spur on a stone road vs. F1 supercar on the same stone road (speaker). Both are very expensive, both are well engineered. Yet we know which one will feel gentler on our butt (warm & musical), and which one make the butt feel each stone (pinpoint imaging/transparency). We also know which one is slow and which one is fast. 😜
 
Last edited:

tachyons

Active member
Unfortunately, my active speakers, Genelecs, are not particularly fast. However, I still appreciate their simplicity in setup for desktop applications, despite the performance gap compared to my other passive speakers. Another issue is that, like most DSP-based active speakers, Genelec performs an analog-to-digital conversion for analog inputs before converting the signal back to analog. This process is definitely not ideal for use with an external DAC.
 

tachyons

Active member
Recently, I conducted a comparison of DACs using active speakers. I observed that the distinctive characteristics of individual DAC types, such as the differences between R2R and Delta-Sigma architectures, were less pronounced compared to passive speaker setups. This attenuation of traits appears to result from the additional conversion processes involving the internal ADC (Analog-to-Digital Converter) and DAC within DSP-based active speakers.

From my experience, it’s important for others to consider the following:
If you are satisfied with the performance of the internal DAC and DSP of active speakers, opting for active speakers is a solid choice. They offer a streamlined setup with integrated processing that can deliver excellent sound quality without the need for additional components.

However, if you intend to enhance your audio system further by incorporating higher-quality external DACs, active speakers may present certain limitations. The internal conversion processes can constrain the potential improvements that external DACs might offer, making it challenging to fully realize the benefits of upgrading.

While I personally appreciate the convenience and performance of my current active speakers, I do not plan to upgrade to a higher-end model at this time.

Note: The observations and conclusions mentioned here specifically apply to active speakers that feature built-in DSP-based systems.

1000009265.jpg
 

boxerfan88

Well-known member
Thanks for sharing. Something for me to be aware of — the AD-DA reconversion in DSP speakers. If and when I do decide to shop for a dsp speaker upgrade, I need to factor this compromise into the buying decision.

For now, I have reached the “end game” setup that I am extremely happy with. One important aspect that differs from your setup, is that I am using old fashioned analog active speakers, therefore no AD-DA reconversion after the DAC. I certainly do get to hear the subtle difference between ESS chip-based DAC vs. Soekris R2R DAC.

I think the number of analog active speaker manufacturers are dwindling… right now I can think of ATC, PSI Audio, selected models in Neumann range.
 

tachyons

Active member
DSP is increasingly crucial for professional active speakers. There are many advantages to using DSP for precise acoustic optimization and room correction. Neumann’s newer models, such as the KH 80 and KH 150, are already starting to implement built-in DSP. But your choice of the older KH 310A, which lacks built-in DSP, is excellent. Without an additional ADC/DAC in the signal path, this remains the optimal way to handle analog input. As time goes by, these traditional active monitors are becoming rare.
 

boxerfan88

Well-known member
The DSP speaker trend is apparent and starting to make inroads into the HiFi world.

Yeah, I agree that DSP has many advantages. In my current setup, I took a different approach for DSPs -- instead of DSP at the speaker side -- my DSP chain is at the source side (before the DAC). This gives me more control over DSP processing chain (component sequence), fine control over time alignment of mains & subwoofer. On the downside, this constrains my DAC choices to the few multi-channel DACs choices (eg. Topping DM7, Okto dac8, etc..) because standard 2ch DAC won't be sufficient for my 2.1 setup.

With DSP at the source side, it also gives me lots of flexibility to experiment with different PC-based DSP components (IIR EQ or FIR EQ, crossover, various effects, time delays) without worrying about DSP hardware obsolescence if I were to use DSP at the speaker side. PC side also offers more computing juice for audio processing.

On the speaker side, I'm thankful I purchased the old fashioned analog active KH310A which are really good performers. I suppose in a few years time when Neumann release their DSP version of 420, it'll be a nice upgrade if I can snag the KH420 at clearance prices.

.
 
Last edited:
Top