This has been posted many times and debated to death here. Is there a sound quality difference between amplifiers given that they are of good quality and at a reasonable price point? I was of the camp that believed that in a blind test no one could tell a difference so long as gains where set exactly equal and power range was within the amplifiers specified range (no clipping or under clipping).
So the Amplifier shootout by Matt Hall posted here gave me the idea to try and test this theory for myself as best I could in my garage with a blind listening test using my ears and my wife’s ears to be the judge, and by my modest means. My wife who is very much into music can recall any lyric to any song you can think of without stopping to think about it. She has become accustomed to good sounding systems thanks to me. I would consider her ears the best trained I have and also her hearing is better than mine. I’ve outfitting all of her vehicles over the years with some pretty nice sounding systems, including the full active system in her Toyota Sienna now.
The Test equipment consisted of some Kef C45 bookshelf speakers and a Parts Express Mean Well power supply to power the amplifiers at 14 volts. The benchmark amplifier I used to compare all my others in this test to is an Alpine 3548 2 channel 60 wpc Class AB amplifier made in Japan from the early 90’s, when Alpine made some top shelf awesome sounding stuff. I describe this amplifiers sound as dynamic, open, airy, and natural sounding, plus it’s the best one I have. Playing music through this amplifier makes the music come alive. I picked this amplifier up new back in the early nineties and it was one of the first amplifiers I owned.
The test consisted of swapping the speaker leads at the speakers to the amplifiers with quick connect banana plugs so I could swap amplifiers in less than 30 seconds. I did this by hooking up both amplifier’s to the power supply and using a banana plug for the remote turn on wire to only power one amplifier at a time so I didn’t overwhelm the power supply. So I just had to swap the speaker banana plugs to the speakers, remote turn on banana plug to power up one amp at a time, and swap the input RCA to the amplifier for the input source. I used my IPod gen 7, and played some lossless files consisting of Imagine Dragons songs with a phono to RCA adapter to feed directly into the amplifier. I used my Unik microphone and REW to set the gains on the amplifiers by matching their db output exactly to within 1/10 of each other so having one play louder than the other wouldn’t skew the result’s.
First test was against my Alpine MRP F240, which is a 4 channel 40 wpc amplifier. It served me well and I regarded it as a good sounding amplifier. This amplifier was recently swapped out for my Pioneer D8604 in my truck. The Alpine MRP F240 is a Chinese made Alpine and of class AB design. Let’s just say this one was the easiest to tell the difference. I was actually surprised that I could tell a difference at first. The 3548 by comparison sounded more open, had a wider stage, and more realistic sounding bass. Thinking it was because the MRP F240 has less power, I then bridged it for 100 wpc, and performed the test again and it didn’t seem to make a difference. Remember I set the gain to match the output of the 3548 so only dynamics should change.
Second test was against an NVX MVPA4, which is a Chinese made micro class D amplifier that many people buy for motorcycles or for tight spaces. This amplifier originally served as the main amp for the front stage in my wife’s Sienna because I had to hide it under the dash, and space was extremely tight. It is rated at 50 wpc, although Sonic Electronix's likes to claim it makes way more power, but I do not believe it makes much more power than 50 wpc, and this is based on my experience with it compared to more powerful amplifiers. There was a noticeable difference in sound quality when I swapped this amplifier for a Pioneer D9500F in my wife’s Toyota Sienna, and I’m not sure why I noticed that then but not now. Initially I did the test on this one first and had a harder time telling a difference. I had to run a few more tests for myself, and eventually I noticed that the songs seemed a little more hard edged in the upper frequencies and that the detail from the Alpine seemed to be a little better in the upper high end frequencies. I ran a couple of blind listening tests with my wife and she easily picked out the Alpine 3548 as the better sounding amplifier. Now I owe Sonic and NVX an apology because I kind of bashed this amplifier as sounding much worse than it actually does. It sounds better than the Alpine MRP F240 (class AB) and so did better in this test than I thought it would.
Third test was against my best class D I have, which is a pioneer PRSD4200 with ICE power design, for whatever that means. Holding this amplifier in my hands shows it’s made to a higher standard. The pots look and feel nice and the switches look and feel like they are of higher quality than typical for this class. When the amplifier turns on, it has a separate relay inside it that makes an audible click. This amplifier is kind of large and heavy too for a 75 wpc class D amplifier. Its specifications are some of the best I’ve seen for the price point and class D design. This amplifier was the one I swapped with that Alpine 3548 in my CX5 over three years ago, and I do not remember noticing a difference in SQ after the swap. The Pioneer is a 4 channel design rated for 75 wpc into 4 ohms and 150 wpc into 2 ohms, so this tells me it has a robust power supply. I did the first listening test and really could not tell a difference, but I also knew which one was playing so my thoughts were biased and I wanted it to win. When my wife did the test (not knowing which one was playing), she asked me to swap them back and forth one more time, but in the end she once again chose the Alpine 3548, stating that this test was the hardest for her to decipher. She said the crispness of the vocals was slightly better when listening to the Alpine 3548, but that this was the hardest for her to tell a difference. For me it’s not enough of a difference that I want to change my amplifiers for something better, but it’s an eye opening test that proves to me that there are small audible differences in sound between different amplifiers.
Lastly I ran a few pink noise tests and sweeps using my microphone and REW to see if I could measure any differences between all amplifiers. The pink noise testing revealed no real differences nor did the sweeps except for maybe the NVX in a small area. I then just played Imagine Dragons Believer (lossless ripped from a CD) and measured the song in Rew up to 100 averages. This revealed some slight differences of 1 db or less in the upper ranges and I also graphically it looked like there were softer edges to the peaks and valleys in the graph for the Alpine 3548 vs the others. I need to re-measure these though just to make sure that what I’m looking at is accurate.
So the Amplifier shootout by Matt Hall posted here gave me the idea to try and test this theory for myself as best I could in my garage with a blind listening test using my ears and my wife’s ears to be the judge, and by my modest means. My wife who is very much into music can recall any lyric to any song you can think of without stopping to think about it. She has become accustomed to good sounding systems thanks to me. I would consider her ears the best trained I have and also her hearing is better than mine. I’ve outfitting all of her vehicles over the years with some pretty nice sounding systems, including the full active system in her Toyota Sienna now.
The Test equipment consisted of some Kef C45 bookshelf speakers and a Parts Express Mean Well power supply to power the amplifiers at 14 volts. The benchmark amplifier I used to compare all my others in this test to is an Alpine 3548 2 channel 60 wpc Class AB amplifier made in Japan from the early 90’s, when Alpine made some top shelf awesome sounding stuff. I describe this amplifiers sound as dynamic, open, airy, and natural sounding, plus it’s the best one I have. Playing music through this amplifier makes the music come alive. I picked this amplifier up new back in the early nineties and it was one of the first amplifiers I owned.
The test consisted of swapping the speaker leads at the speakers to the amplifiers with quick connect banana plugs so I could swap amplifiers in less than 30 seconds. I did this by hooking up both amplifier’s to the power supply and using a banana plug for the remote turn on wire to only power one amplifier at a time so I didn’t overwhelm the power supply. So I just had to swap the speaker banana plugs to the speakers, remote turn on banana plug to power up one amp at a time, and swap the input RCA to the amplifier for the input source. I used my IPod gen 7, and played some lossless files consisting of Imagine Dragons songs with a phono to RCA adapter to feed directly into the amplifier. I used my Unik microphone and REW to set the gains on the amplifiers by matching their db output exactly to within 1/10 of each other so having one play louder than the other wouldn’t skew the result’s.
First test was against my Alpine MRP F240, which is a 4 channel 40 wpc amplifier. It served me well and I regarded it as a good sounding amplifier. This amplifier was recently swapped out for my Pioneer D8604 in my truck. The Alpine MRP F240 is a Chinese made Alpine and of class AB design. Let’s just say this one was the easiest to tell the difference. I was actually surprised that I could tell a difference at first. The 3548 by comparison sounded more open, had a wider stage, and more realistic sounding bass. Thinking it was because the MRP F240 has less power, I then bridged it for 100 wpc, and performed the test again and it didn’t seem to make a difference. Remember I set the gain to match the output of the 3548 so only dynamics should change.
Second test was against an NVX MVPA4, which is a Chinese made micro class D amplifier that many people buy for motorcycles or for tight spaces. This amplifier originally served as the main amp for the front stage in my wife’s Sienna because I had to hide it under the dash, and space was extremely tight. It is rated at 50 wpc, although Sonic Electronix's likes to claim it makes way more power, but I do not believe it makes much more power than 50 wpc, and this is based on my experience with it compared to more powerful amplifiers. There was a noticeable difference in sound quality when I swapped this amplifier for a Pioneer D9500F in my wife’s Toyota Sienna, and I’m not sure why I noticed that then but not now. Initially I did the test on this one first and had a harder time telling a difference. I had to run a few more tests for myself, and eventually I noticed that the songs seemed a little more hard edged in the upper frequencies and that the detail from the Alpine seemed to be a little better in the upper high end frequencies. I ran a couple of blind listening tests with my wife and she easily picked out the Alpine 3548 as the better sounding amplifier. Now I owe Sonic and NVX an apology because I kind of bashed this amplifier as sounding much worse than it actually does. It sounds better than the Alpine MRP F240 (class AB) and so did better in this test than I thought it would.
Third test was against my best class D I have, which is a pioneer PRSD4200 with ICE power design, for whatever that means. Holding this amplifier in my hands shows it’s made to a higher standard. The pots look and feel nice and the switches look and feel like they are of higher quality than typical for this class. When the amplifier turns on, it has a separate relay inside it that makes an audible click. This amplifier is kind of large and heavy too for a 75 wpc class D amplifier. Its specifications are some of the best I’ve seen for the price point and class D design. This amplifier was the one I swapped with that Alpine 3548 in my CX5 over three years ago, and I do not remember noticing a difference in SQ after the swap. The Pioneer is a 4 channel design rated for 75 wpc into 4 ohms and 150 wpc into 2 ohms, so this tells me it has a robust power supply. I did the first listening test and really could not tell a difference, but I also knew which one was playing so my thoughts were biased and I wanted it to win. When my wife did the test (not knowing which one was playing), she asked me to swap them back and forth one more time, but in the end she once again chose the Alpine 3548, stating that this test was the hardest for her to decipher. She said the crispness of the vocals was slightly better when listening to the Alpine 3548, but that this was the hardest for her to tell a difference. For me it’s not enough of a difference that I want to change my amplifiers for something better, but it’s an eye opening test that proves to me that there are small audible differences in sound between different amplifiers.
Lastly I ran a few pink noise tests and sweeps using my microphone and REW to see if I could measure any differences between all amplifiers. The pink noise testing revealed no real differences nor did the sweeps except for maybe the NVX in a small area. I then just played Imagine Dragons Believer (lossless ripped from a CD) and measured the song in Rew up to 100 averages. This revealed some slight differences of 1 db or less in the upper ranges and I also graphically it looked like there were softer edges to the peaks and valleys in the graph for the Alpine 3548 vs the others. I need to re-measure these though just to make sure that what I’m looking at is accurate.
