After many years of exclusively using solid state gear, I decided to try modern tube amp. I had no intention to spend several thousand dollars on that new toy, so my only real choice was one of Chinese amplifiers, as many of them are available for under $1000. Speakers in my main system are 90dB efficient, so even though room is not that big, I thought that I need sufficient power. This requirement excluded almost all SET amplifiers (yes, I know there are some 30-40W amps with 845 or similar tube, but they were out of my decided price range). I did some search and decided to get one of Yaqin amplifiers. My final choice was MC-100B. I already have an almost perfect preamp (old Yamaha CX-1000), so my target was a power amplifier. Yaqin actually does not make any dedicated power amplifiers, but many of their so-called "integrated" are no more than power amplifier with volume control pot at the input. I decided to get the most powerful one - MC-100B. It is advertised as reaching 60W per channel, built as dual mono on a single chassis and does not have anything I DO NOT need like remote.
Yaqin does not have any official distributor in the US, so I ordered it amplifier from one of e-bay sellers (tabnaac) in Canada. He is dedicated to Yaqin brand and has almost perfect feedback history. There were zero problems with order, and in about a week
I got a very heavy box with Canadian shipping label. Again there were no problems with packaging, and soon shiny chromium plated amplifier was sitting on a stand which I bought for it. It is so heavy and produces large amount of heat, so I couldn't put it into my equipment rack. I new this in advance, and made arrangement to get a dedicated stand (VTI AGR404-01S), which arrived even before Yaqin was deliver to me.
I have only one set of speakers in my music room, and since I already have solid state amp powering them, I needed speaker switch. I spent a lot of time searching Internet for a something that can be used to connect one pair of speakers to two amplifiers, and didn't find that many options. Most speaker switches designed to connect several pairs of speakers to a single amplifier. Many of advanced one have a volume control etc. But this is not what I needed. My goal was to have a switch as transparent as possible and do not do anything I didn't need. I also found that many switches are designed to work with relatively low power amplifiers (under 100W), but my solid state rig delivers over 500W to 4 Ohm load. Finally I found device that was almost perfect - OSD ATM-7. This is remotely controlled (it actually comes with IR remote) switch that can connect seven pairs of speakers to two amplifiers (or seven amplifiers to two pairs of speakers). It prevents connecting the same speakers to two amplifiers at the same time
(it will likely result in amplifier failure). I jumped on opportunity to get one on sale, and got this switch. It is weird, but it is only available from a single on-line store, however it was not branded specifically for that store. It actually didn't have any label on it, which might attribute it to the manufacturer. So it is indeed "no-name" unit. But nevertheless, it works perfectly, exactly as advertised.
So after I connected everything together, I turned on Yaqin and let it run for an hour. After 30 minutes or so I checked bias of tubes (MC-100B has fixed bias, which needs to be adjusted once in a while). It was spot on at 52mA for each tube (recommended setting is between 50 and 60mA). To easily compare my SS amplifier with new Yaqin, I adjusted volume in both of them using pink noise source and sound level meter. Yaqin does not have balance control, so I adjusted volume in each channel of my solid state power amp (it has the separate volume pots for each channel) to match new tube amp, one channel at a time. I made both channels matching within 0.2 dB.
Now it was time to listen. I prepared several CDs, which I know very well, with different kind of music. From large classical orchestra, to chamber orchestra, to jazz, to classic rock. I went through all this disks (about 10 of them) for several days. I found that at moderate volume levels (when I only get under 20 Watts from amplifier) it was very hard to hear the difference between SS and tube amp. I also asked my wife’s (she is a trained musician) opinion, and she couldn't hear it too. But after some time and good concentration I was able to reliably identify Yaqin sound.
First was bass. In by SS amp the bass is very tight, and it is perfectly aligned with the rest of the sound. With Yaqin bass was a bit fatter. It seems that tube amp is not able to fully control speakers in the lower octave. On same type of music it is not pronounced at all. But where you have large drums recorded with low compression, and thus keep all dynamic and punch, here you go - tube amp simply couldn't match precision of SS amplifier.
Midrange was exactly the same with either SS amplifier or Yaqin. I tried hard, but never was able to identify any tube signature in it.
Now treble. What I found was that Yaqin had it a little muted. It was like light veil over tweeter. You can't hear it in any electronic sound, but on good acoustical recording it didn't produced that level of transparency, and sense of space around percussion instruments like bells and cymbals. This again was only heard on records with only little compression applied to them.
As a result of listening sessions, I can say that there is nothing mystical about tube amps. They (at least when we consider moderately priced gear) sound close to good SS amplifiers. They do have some deficiencies, but they are not very pronounced and might not be recognized, when record quality is not exceptional or speakers and room do not permit to resolve very fine details of the sound.
So after two weeks of listening it was time for a test bench. I searched hard trying to find any published measurements of Yaqin amplifiers, but got empty handed. Since there are no official distributors of Yaqin in any country I know of, there is no one to deliver a sample unit to any of usual testers (both on-line publications and print magazines). So I decided to run few tests with the goal to make them available to anyone, who consider Yaqin brand. And also as a starting point for tweaking this amplifier (which was the original goal behind purchasing it). In my next post I will provide details and results of measurements and results of my initial attempt to improve the sound of Yaqin MC-100B. Stay tuned…
Part 2: http://www.audiokarma.org/forums/showthread.php?t=430109
Part 3: http://www.audiokarma.org/forums/showthread.php?t=430113
Yaqin does not have any official distributor in the US, so I ordered it amplifier from one of e-bay sellers (tabnaac) in Canada. He is dedicated to Yaqin brand and has almost perfect feedback history. There were zero problems with order, and in about a week
I got a very heavy box with Canadian shipping label. Again there were no problems with packaging, and soon shiny chromium plated amplifier was sitting on a stand which I bought for it. It is so heavy and produces large amount of heat, so I couldn't put it into my equipment rack. I new this in advance, and made arrangement to get a dedicated stand (VTI AGR404-01S), which arrived even before Yaqin was deliver to me.
I have only one set of speakers in my music room, and since I already have solid state amp powering them, I needed speaker switch. I spent a lot of time searching Internet for a something that can be used to connect one pair of speakers to two amplifiers, and didn't find that many options. Most speaker switches designed to connect several pairs of speakers to a single amplifier. Many of advanced one have a volume control etc. But this is not what I needed. My goal was to have a switch as transparent as possible and do not do anything I didn't need. I also found that many switches are designed to work with relatively low power amplifiers (under 100W), but my solid state rig delivers over 500W to 4 Ohm load. Finally I found device that was almost perfect - OSD ATM-7. This is remotely controlled (it actually comes with IR remote) switch that can connect seven pairs of speakers to two amplifiers (or seven amplifiers to two pairs of speakers). It prevents connecting the same speakers to two amplifiers at the same time
(it will likely result in amplifier failure). I jumped on opportunity to get one on sale, and got this switch. It is weird, but it is only available from a single on-line store, however it was not branded specifically for that store. It actually didn't have any label on it, which might attribute it to the manufacturer. So it is indeed "no-name" unit. But nevertheless, it works perfectly, exactly as advertised.
So after I connected everything together, I turned on Yaqin and let it run for an hour. After 30 minutes or so I checked bias of tubes (MC-100B has fixed bias, which needs to be adjusted once in a while). It was spot on at 52mA for each tube (recommended setting is between 50 and 60mA). To easily compare my SS amplifier with new Yaqin, I adjusted volume in both of them using pink noise source and sound level meter. Yaqin does not have balance control, so I adjusted volume in each channel of my solid state power amp (it has the separate volume pots for each channel) to match new tube amp, one channel at a time. I made both channels matching within 0.2 dB.
Now it was time to listen. I prepared several CDs, which I know very well, with different kind of music. From large classical orchestra, to chamber orchestra, to jazz, to classic rock. I went through all this disks (about 10 of them) for several days. I found that at moderate volume levels (when I only get under 20 Watts from amplifier) it was very hard to hear the difference between SS and tube amp. I also asked my wife’s (she is a trained musician) opinion, and she couldn't hear it too. But after some time and good concentration I was able to reliably identify Yaqin sound.
First was bass. In by SS amp the bass is very tight, and it is perfectly aligned with the rest of the sound. With Yaqin bass was a bit fatter. It seems that tube amp is not able to fully control speakers in the lower octave. On same type of music it is not pronounced at all. But where you have large drums recorded with low compression, and thus keep all dynamic and punch, here you go - tube amp simply couldn't match precision of SS amplifier.
Midrange was exactly the same with either SS amplifier or Yaqin. I tried hard, but never was able to identify any tube signature in it.
Now treble. What I found was that Yaqin had it a little muted. It was like light veil over tweeter. You can't hear it in any electronic sound, but on good acoustical recording it didn't produced that level of transparency, and sense of space around percussion instruments like bells and cymbals. This again was only heard on records with only little compression applied to them.
As a result of listening sessions, I can say that there is nothing mystical about tube amps. They (at least when we consider moderately priced gear) sound close to good SS amplifiers. They do have some deficiencies, but they are not very pronounced and might not be recognized, when record quality is not exceptional or speakers and room do not permit to resolve very fine details of the sound.
So after two weeks of listening it was time for a test bench. I searched hard trying to find any published measurements of Yaqin amplifiers, but got empty handed. Since there are no official distributors of Yaqin in any country I know of, there is no one to deliver a sample unit to any of usual testers (both on-line publications and print magazines). So I decided to run few tests with the goal to make them available to anyone, who consider Yaqin brand. And also as a starting point for tweaking this amplifier (which was the original goal behind purchasing it). In my next post I will provide details and results of measurements and results of my initial attempt to improve the sound of Yaqin MC-100B. Stay tuned…
Part 2: http://www.audiokarma.org/forums/showthread.php?t=430109
Part 3: http://www.audiokarma.org/forums/showthread.php?t=430113
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