The latest addition to the SIT family. The baby 2SK180 monoblocks joining the 2SK82-2SJ28 amp, the BAF2015 THF-51S monoblocks, and the 2SK82 Luminaria preamp (barely visible).
I still need to add LED pilot lights to the front panels and then they go into the stereo system. Still deciding on LED colour.
I still need to add LED pilot lights to the front panels and then they go into the stereo system. Still deciding on LED colour.
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I finally got my amps into my main music system for listening yesterday. I replaced the BAF2015 THF-51S monoblocks which were powering the low frequency drivers of my biamped speaker system with the 2SK180 monoblocks. I use a modified version of the Pass LX-mini active crossover with the crossover frequency of 800 Hz. My 2SJ28 VFET follower amp powers the high frequencies. The preamp is a fixed bias version of the 2SK82 VFET Luminaria.
The speakers consists of JBL 2225s in about 9 cubic ft. cabinets in an EBS alignment. In room, they produce strong response to below 30 Hz. The higher frequencies are mainly handled by JBL 2445 compression drivers with JBL 2397 horns. JBL 2405s take care of the very upper frequencies and each is crossed-over using a single capacitor at about 9 kHz.
When I first played music with the new amps in place, I did not notice much in the change from the THF-51S amps. No obvious differences in sound were heard. The THF-51S and 2SK180 amps are quite different; one is configured as common source while the other as source follower. One probably has 10 times the harmonic distortion and twice the power. However, in my system powering the low frequency speakers, the overall results are very similar.
I have since spent quite a few hours listening to this new setup, and I can say that the new amps are equal to the BAF2015 THF-51S amps in doing the low frequency amplification duties. I thought that I would be to detect differences in sound, but what differences there are, my memory is not capable of providing an accurate comparison. Usually, I find that after listening to a system for a while, a change to it, if it is significant, is immediately obvious.
When I put the BAF2015 THF-51S into my system, replacing a Sony VFET amp, the TAN-5550, the changes were immediately obvious. The sound improved quite a bit. The most obvious thing was in the lower frequencies; the bass notes acquired tone and body. The bass also had much more weight.
Now, replacing the BAF2015 THF-51s with the 2SK180 did not produce any great differences. However, nothing was lost. The tunefullness and weight of the low frequencies are still there, and the coherence of the overall sound of the whole system remains. This system fills the whole room with music, and I can enjoy the sound anywhere.
Next, I will put the BAF2015 THF-51S amps back into the low end move the new 2SK180 follower amps to perform the high frequency duties.
I did make a decision of which colour LED to use. The thing is, I had been using a lot of blue LEDs and I am running low. I have other colours and I'm at the point where I want to use what I've got instead of buying more stuff. So, I looked at my stash and found some RGB LEDs and thought, why not try something new; and I did. I used the red and blue sections of the LEDs together at equal current and the result is a pinkish hue. Always fun to try something different.
The speakers consists of JBL 2225s in about 9 cubic ft. cabinets in an EBS alignment. In room, they produce strong response to below 30 Hz. The higher frequencies are mainly handled by JBL 2445 compression drivers with JBL 2397 horns. JBL 2405s take care of the very upper frequencies and each is crossed-over using a single capacitor at about 9 kHz.
When I first played music with the new amps in place, I did not notice much in the change from the THF-51S amps. No obvious differences in sound were heard. The THF-51S and 2SK180 amps are quite different; one is configured as common source while the other as source follower. One probably has 10 times the harmonic distortion and twice the power. However, in my system powering the low frequency speakers, the overall results are very similar.
I have since spent quite a few hours listening to this new setup, and I can say that the new amps are equal to the BAF2015 THF-51S amps in doing the low frequency amplification duties. I thought that I would be to detect differences in sound, but what differences there are, my memory is not capable of providing an accurate comparison. Usually, I find that after listening to a system for a while, a change to it, if it is significant, is immediately obvious.
When I put the BAF2015 THF-51S into my system, replacing a Sony VFET amp, the TAN-5550, the changes were immediately obvious. The sound improved quite a bit. The most obvious thing was in the lower frequencies; the bass notes acquired tone and body. The bass also had much more weight.
Now, replacing the BAF2015 THF-51s with the 2SK180 did not produce any great differences. However, nothing was lost. The tunefullness and weight of the low frequencies are still there, and the coherence of the overall sound of the whole system remains. This system fills the whole room with music, and I can enjoy the sound anywhere.
Next, I will put the BAF2015 THF-51S amps back into the low end move the new 2SK180 follower amps to perform the high frequency duties.
I did make a decision of which colour LED to use. The thing is, I had been using a lot of blue LEDs and I am running low. I have other colours and I'm at the point where I want to use what I've got instead of buying more stuff. So, I looked at my stash and found some RGB LEDs and thought, why not try something new; and I did. I used the red and blue sections of the LEDs together at equal current and the result is a pinkish hue. Always fun to try something different.
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I find it much harder to perceive meaningful differences when amps are used in a narrow band. Perhaps your bass channel is also not overly sensitive to Df.
Thank you, peppennino.
Here is a comparison of the left channel speaker showing the frequency response of the latest setup (2SK180 source follower amp for bass, and 2SJ28 source follower amp for treble) compared to a previous setup (THF-51S common source amp for bass and 2SJ28 common source amp for treble).
Not much difference in the bass (800 Hz crossover). The top end shows roll-off with the 2SJ28 common source amp. I had thought that my JBL 2405s were just getting old, but they are fine with the 2SJ28 source follower amp.
I am now listening to the 2SK180s powering the bass and will switch later to the THF-51S and see if I can hear any appreciable differences.
Here is a comparison of the left channel speaker showing the frequency response of the latest setup (2SK180 source follower amp for bass, and 2SJ28 source follower amp for treble) compared to a previous setup (THF-51S common source amp for bass and 2SJ28 common source amp for treble).
Not much difference in the bass (800 Hz crossover). The top end shows roll-off with the 2SJ28 common source amp. I had thought that my JBL 2405s were just getting old, but they are fine with the 2SJ28 source follower amp.
I am now listening to the 2SK180s powering the bass and will switch later to the THF-51S and see if I can hear any appreciable differences.
Attachments
More amplifier musical chairs. After listening to the new 2SK180 amps for a couple of hours, I took them out and put the BAF 2015 THF-51S amps back in. Initially, when I put the 2SK180s into play, it was in the morning and the last time that I had heard the THF-51S was the night before. So my memory of the sound before the change was not very good. Today, I have the advantage of a very short time for switching amplifiers.
This time, I did notice a difference; the bass notes appeared to have more weight. It's probably not a huge difference, because I enjoyed the sound with the 2SK180 amps greatly. I hope it's not my imagination, but I don't think it is. But the bottom line is, I could live with either powering the low end.
Having tried the 2SK180s in the low frequency section, I wanted to see how they work in the higher frequency range. So, I pulled out my 2SJ28 source follower amp that was driving the upper frequencies (> 800 Hz). This 2SJ28 amp is very similar to Mr. Pass' latest VFET creation. It uses basically the same source follower output stage but has a 2SK82 voltage amplifier stage driving each follower (2SK82 -2SJ28 SE Amp). I replaced this amp in the system with the new 2SK180 monoblocks, fired the system up, and adjusted the low/high balance by ear (different gains).
I threw on an Ana Popovic album on and, holy smokes! Definitely some change, and I like it! Great dynamics on percussion. There was a saxophone line, I think tenor, and I noticed the rough, spitty, gravelly tone. So, with these things jumping out at me, I believe there are some real changes. Not that it was bad before, but there appears to be some changes that I like.
I'll listen to this setup for a couple of days and then switch back to the original setup and listen again to see if I can detect any changes. I want to make sure that this is not wishful thinking or my active imagination.
This time, I did notice a difference; the bass notes appeared to have more weight. It's probably not a huge difference, because I enjoyed the sound with the 2SK180 amps greatly. I hope it's not my imagination, but I don't think it is. But the bottom line is, I could live with either powering the low end.
Having tried the 2SK180s in the low frequency section, I wanted to see how they work in the higher frequency range. So, I pulled out my 2SJ28 source follower amp that was driving the upper frequencies (> 800 Hz). This 2SJ28 amp is very similar to Mr. Pass' latest VFET creation. It uses basically the same source follower output stage but has a 2SK82 voltage amplifier stage driving each follower (2SK82 -2SJ28 SE Amp). I replaced this amp in the system with the new 2SK180 monoblocks, fired the system up, and adjusted the low/high balance by ear (different gains).
I threw on an Ana Popovic album on and, holy smokes! Definitely some change, and I like it! Great dynamics on percussion. There was a saxophone line, I think tenor, and I noticed the rough, spitty, gravelly tone. So, with these things jumping out at me, I believe there are some real changes. Not that it was bad before, but there appears to be some changes that I like.
I'll listen to this setup for a couple of days and then switch back to the original setup and listen again to see if I can detect any changes. I want to make sure that this is not wishful thinking or my active imagination.
Thank you, peppennino and harrylime6.
I've listened to the latest setup (THF-51S on lows and 2SK180 on highs) for a few hours now and one thought is gradually emerging. The quality of the midrange seems to stand out. I'm not sure what it is about it, but I notice it.
I used to have single ended directly heated triode tube amps (45, 2A3, SV811, SV572, 01A) in my system. I've listened to music through Lowthers, Altec Voice of the Theatres, and Quad ESLs (the 57 model), so I have experienced some equipment noted for nice midrange reproduction. Now, it's, all SITs, except for my phono preamp.
The 2SK180 source follower in my system, though, does a nice job on the midrange. Not that the other SIT amps are bad, but the 2SK180 stands out. I'm sure having 15W powering high efficiency JBL 2445 compression drivers doesn't hurt.
I want to try other combinations, especially 2SK180 on bass and THF-51S on treble, but I'm going to listen to this current configuration for a while longer. It's just so nice.
I've listened to the latest setup (THF-51S on lows and 2SK180 on highs) for a few hours now and one thought is gradually emerging. The quality of the midrange seems to stand out. I'm not sure what it is about it, but I notice it.
I used to have single ended directly heated triode tube amps (45, 2A3, SV811, SV572, 01A) in my system. I've listened to music through Lowthers, Altec Voice of the Theatres, and Quad ESLs (the 57 model), so I have experienced some equipment noted for nice midrange reproduction. Now, it's, all SITs, except for my phono preamp.
The 2SK180 source follower in my system, though, does a nice job on the midrange. Not that the other SIT amps are bad, but the 2SK180 stands out. I'm sure having 15W powering high efficiency JBL 2445 compression drivers doesn't hurt.
I want to try other combinations, especially 2SK180 on bass and THF-51S on treble, but I'm going to listen to this current configuration for a while longer. It's just so nice.
I have been following your progression, this is the configuration I have been looking forward to. Thanks for sharing. I still have my SET 45 but has not been in rotation since I built the 2sk180 lil’amp.
Tony