Tube devices, such as amplifiers, pre-amplifiers, and buffers, are prized for their unique sound signatures. Different equipment and tubes impart different qualities to the sound of the music that is being reproduced. It’s comparable to the use of analog tape vs. digital recording in that the old tech is often favored due to the pleasant qualities that it gives to sound. After doing some research over the past month, I decided to give tubes a try in one of my systems. I bought the Yaqin SD-CD 3 and have listened to music with it for the past week.
The Yaqin SD-CD 3 is a tube buffer processor that you put in-between a source (PC, CD player, etc.) and an amplifier. Its primary use case is to give the sound of tubes to a solid-state amplifier. It IS NOT a phono preamp that you would use to connect to the phono output of a turntable. You could put in in the path of a turntable after a phono preamp, though.
The device is simple in terms of connections and function. There is an on/off switch near the rear on the left side of the unit. It uses a standard power cable and has 1 RCA stereo input and 1 RCA stereo output. The device comes with two preinstalled 6H8C tubes and a power cable. I had to supply the RCA cables. In my case, I have mine installed between my PC and my Sony STR-DH190 solid-state amplifier at my desk.
For reference, here is my signal path: JRiver Media Center, Foobar2000, or Spotify in Windows 10 –> MPG X570 Gaming Edge WIFI motherboard –> Yaqin SD-CD 3 –> Sony STR-DH190 –> 2 x KEF Q100 bookshelf speakers
Setup is dead simple. All I had to do was plug in the power, route the PC audio to the input of the device, and route the output to the input of my amplifier. After turning it on, I can see the glow of the tubes and the Yaqin logo lights up with a blue light. Shortly after it turns on, you can feel the heat coming off of the tubes. You definitely don’t want to touch them while it’s on.
During my research of tube devices and reviews for this tube buffer, I found that most people preferred to buy other non-stock tubes that give better characteristics to the sound. There are two types of tubes that are available for purchase nowadays. There’s NOS (new old stock) and new tubes. NOS tubes made in England and the US and audiophile tubes made in Russia and China go for exorbitant sums of money. I bought 2 Electro-Harmonix 6SN7 EH tubes from VIVA TUBES at the same time I bought the Yaqin SD-CD 3 from Amazon. The stock 6H8C tubes appear to either be from Russia or China. The Electro-Harmonix tubes I bought to replace them are new tubes made in Russia and were reasonably priced.
I don’t have a setup to do A/B testing so I can only provide my impressions of what I think changed with the sound. Also, I haven’t done any deliberate burn-in process with the device. I only keep it turned on when I’m using my computer to watch videos or listen to music. I generally think burn-in as a concept is just one’s brain getting used to a sound, but I’ve read that burn-in with tubes is a real thing. Supposedly, the more you run sound through the tubes, the better the sound becomes. I’ve used the Electro-Harmonix tubes for longer than the stock tubes at this point. I’d say the difference between the two sets of tubes was subtle with the Electro-Harmonix tubes imparting slightly more “tube” character to the sound.
Well, how does it sound? I DO think my music sounds different with the device in the signal path. There are 4 things that I think have noticeably changed.
The first is the treble or high frequencies of the music. My speakers are KEF Q100 and are known to be a little bright in treble. The treble seems to be noticeably “tamed” or reduced now. I see that as a plus, but I could theoretically do the same thing with an equalizer like Equalizer APO.
The second is the bass of the music. Music has a “warmer” feel in that there is more bass. The bass doesn’t seem to be as “refined” or “punchy” though. Things seem a little too boomy on modern volume compressed music. Music with a thin sound like 80s new wave and pop definitely benefits from the bass boost and warmer sound.
The third is sound staging. The placement of your speakers is incredibly important for sound staging or being able to hear the stereo position of instruments, vocals, and effects in music. With my speakers already positioned optimally with a little bit of “toe-in” or angling towards my listening sweet spot, I was looking for alternative methods to increase stereo spatialization. With the SD-CD 3, it sounds like everything has been pushed back further in the sound stage, giving it more “depth”. I think this effect can result in increased realism in the stereo image.
The fourth is the noise floor. If I crank up the volume on my amp beyond my normal listening level with nothing playing, I can hear a lot of static noise. I think the noise is due in large part to how many cables I have lying next to each other in my small setup with my computer and the close proximity of two LCD screens. For instance, when I move windows on my screens with my mouse, I can hear noise that seems to correlate with the movement. I’m not sure if it because the device itself or some of my cables in my setup lack the proper shielding. At normal listening levels between 10 – 27 volume on the amp with music going, you cannot hear this noise.
In reviews, some people have reported hearing no change with this device in their signal path with some types of tubes. Overall, my impression is that this device DOES change the sound. Rather than simply sounding better or worse, I’d say it sounds it mostly just sounds different. In my situation, I think it’s a tradeoff of the “accuracy” of my solid-state amp for the “warmth” of the tubes. I think it’s a worthwhile and interesting tradeoff, but it probably isn’t for everyone.
I bought mine at the price of $180 on Amazon. If you’re looking to add the tube sound to your solid-state amplifier instead of buying an expensive tube amplifier, this is the route to go.