First of all, special thanks to Todd at TTVJ Audio for the opportunity to participate in this loaner program.
Introduction:
The Sangaku is the first Apex Hifi product I have had the opportunity to audition. It is one of, if not the first headphone amps to utilize the new Korg Nutube, which is a miniaturized vacuum tube based on previous Vacuum Fluorescent Display. It uses much less power and generates less heat than traditional tubes. But what is especially unique about the Nutube is that it is technically a directly heated triode. So, the Sangaku is unique in that it is a DHT hybrid headphone amp. Yet it retains the smaller footprint of traditional solid state headphone amps.
For comparison, I have owned a few comparable amps in price and performance over the past few years. Namely the DIY Torpedo III amp, the Trafomatic Head 2, and the Eddie Current Super 7.
Setup:
Chord Mojo as DAC using a generic 3.5mm to RCA cable from Amazon. Focal Elear and modded Sennheiser HD-650 as headphones. Mostly used the Elear though. Macbook Pro using Vox player and PC using JRiver MC 22.
Build:
Build quality seems pretty standard all black Apex style. Nothing fancy. The relay switched inputs and gain with LEDs are a nice touch. Unfortunately, the Nutube is inherently microphonic by nature of being a DHT which never really gets “hot”. Switching inputs or plugging in a headphone results in an audible “Ping!”
Sound:
The sound of the amp is difficult to describe without sounding paradoxical. The midrange is clean and clear, yet has a sweet slight warmth. Treble is extended and more present than a lot of amps, and in combination with the midrange creates a certain lucidity to the imaging that is slightly reminiscent of (though not the same as) top SET DHT amps. The greatest strength though IMO, is it has an excellent sense of rhythmic drive. This is most apparent with small ensemble Jazz with a lot of rhythmic stuff going on.
One thing that must be taken into account when reading this review, is that I find this amp to be very transparent to source. So much so, that I almost was going to give it a lukewarm review, but discovered my nitpicks were with my source. I recently applied a tweak to my Mojo of adding a large RFI ferrite suppression choke to my USB which made a noticeable improvement to the DAC, and the improvement was readily audible through the Sangaku. The clear and open midrange and treble does not do any favors to digital hash present in the source. Having previously owned the Schiit Yggdrasil and Gungnir Multibit, I can imagine they would pair well with the Sangaku. The amp seems thoroughly resolving enough to take advantage of what the Yggdrasil has to offer.
Therefore, I’m hesitant to try to nail down the sound description in too much detail. Simply because it lets the source shine through. However, it’s not a “wire with gain” so to speak. It does apply it’s own tube harmonics in a tasteful way. And maybe not the tightest bass I’ve ever heard. I deliberately haven’t commented on the bass, because I think it’s just carrying over some of the Mojo, but maybe a touch looser. Again, I think the Gungnir Multibit might be a better match. I thought the Torpedo III had better bass, but I had the Gungnir when I had the Torpedo III.
My only regret with this review, is that I don’t currently have more equipment to try with it. I would love to try the HD800 with it, having owned it twice. I also have no balanced headphone cables at the moment to try with it. I don’t think the amp is fully balanced, but it may have a differential output. I’m not sure though, I’d have to ask the designer.
I do think this amp can really keep up with some of the best out there, but source matters. It brings it’s own unique and addicting flavor to the mix, without spoiling the original sound. If I had to sum it up I’d say airy yet rhythmic. Not the absolute tightest across the frequency spectrum, but still clean and clear. Looseness probably isn’t the best descriptor, but rather it’s the harmonic decay that gives it some nuance and detail to trailing edges of music. This also helps to convey rhythmic information.
Value:
This is a tough one for me, and an area I am personally really nitpicky. On sound alone, it competes well against similarly priced amps, despite stiff competition. But when you compare it to the previous Peak/Volcano combo at the same price, it’s clear this amp is more cost effective to manufacture. The copious use of op amps and simple case work, psychologically make it harder to swallow at the price point. I’m guessing that they really just don’t want to have to build a ton of them to keep up with the demand of a lower price, so they are intentionally lower volume, perhaps. It probably has to have a certain margin for it to even be worth Pete Millett taking his time to design. That kind of stuff is time consuming, especially when it’s not your day job.
This doesn’t mean it’s a poor value by any means, it just means there is probably a healthy margin. But probably less so than a lot of big name manufacturers. If anything, this is a testament to Pete Millett’s design chops, that he can take generally pedestrian parts, and make a stellar sounding amp out of it. I really don’t have any problems with the choice of power op amps in the output stage. There is nothing inherently wrong with them, just less flexibility in integrating into a design. But they are implemented well in the Sangaku.
Introduction:
The Sangaku is the first Apex Hifi product I have had the opportunity to audition. It is one of, if not the first headphone amps to utilize the new Korg Nutube, which is a miniaturized vacuum tube based on previous Vacuum Fluorescent Display. It uses much less power and generates less heat than traditional tubes. But what is especially unique about the Nutube is that it is technically a directly heated triode. So, the Sangaku is unique in that it is a DHT hybrid headphone amp. Yet it retains the smaller footprint of traditional solid state headphone amps.
For comparison, I have owned a few comparable amps in price and performance over the past few years. Namely the DIY Torpedo III amp, the Trafomatic Head 2, and the Eddie Current Super 7.
Setup:
Chord Mojo as DAC using a generic 3.5mm to RCA cable from Amazon. Focal Elear and modded Sennheiser HD-650 as headphones. Mostly used the Elear though. Macbook Pro using Vox player and PC using JRiver MC 22.
Build:
Build quality seems pretty standard all black Apex style. Nothing fancy. The relay switched inputs and gain with LEDs are a nice touch. Unfortunately, the Nutube is inherently microphonic by nature of being a DHT which never really gets “hot”. Switching inputs or plugging in a headphone results in an audible “Ping!”
Sound:
The sound of the amp is difficult to describe without sounding paradoxical. The midrange is clean and clear, yet has a sweet slight warmth. Treble is extended and more present than a lot of amps, and in combination with the midrange creates a certain lucidity to the imaging that is slightly reminiscent of (though not the same as) top SET DHT amps. The greatest strength though IMO, is it has an excellent sense of rhythmic drive. This is most apparent with small ensemble Jazz with a lot of rhythmic stuff going on.
One thing that must be taken into account when reading this review, is that I find this amp to be very transparent to source. So much so, that I almost was going to give it a lukewarm review, but discovered my nitpicks were with my source. I recently applied a tweak to my Mojo of adding a large RFI ferrite suppression choke to my USB which made a noticeable improvement to the DAC, and the improvement was readily audible through the Sangaku. The clear and open midrange and treble does not do any favors to digital hash present in the source. Having previously owned the Schiit Yggdrasil and Gungnir Multibit, I can imagine they would pair well with the Sangaku. The amp seems thoroughly resolving enough to take advantage of what the Yggdrasil has to offer.
Therefore, I’m hesitant to try to nail down the sound description in too much detail. Simply because it lets the source shine through. However, it’s not a “wire with gain” so to speak. It does apply it’s own tube harmonics in a tasteful way. And maybe not the tightest bass I’ve ever heard. I deliberately haven’t commented on the bass, because I think it’s just carrying over some of the Mojo, but maybe a touch looser. Again, I think the Gungnir Multibit might be a better match. I thought the Torpedo III had better bass, but I had the Gungnir when I had the Torpedo III.
My only regret with this review, is that I don’t currently have more equipment to try with it. I would love to try the HD800 with it, having owned it twice. I also have no balanced headphone cables at the moment to try with it. I don’t think the amp is fully balanced, but it may have a differential output. I’m not sure though, I’d have to ask the designer.
I do think this amp can really keep up with some of the best out there, but source matters. It brings it’s own unique and addicting flavor to the mix, without spoiling the original sound. If I had to sum it up I’d say airy yet rhythmic. Not the absolute tightest across the frequency spectrum, but still clean and clear. Looseness probably isn’t the best descriptor, but rather it’s the harmonic decay that gives it some nuance and detail to trailing edges of music. This also helps to convey rhythmic information.
Value:
This is a tough one for me, and an area I am personally really nitpicky. On sound alone, it competes well against similarly priced amps, despite stiff competition. But when you compare it to the previous Peak/Volcano combo at the same price, it’s clear this amp is more cost effective to manufacture. The copious use of op amps and simple case work, psychologically make it harder to swallow at the price point. I’m guessing that they really just don’t want to have to build a ton of them to keep up with the demand of a lower price, so they are intentionally lower volume, perhaps. It probably has to have a certain margin for it to even be worth Pete Millett taking his time to design. That kind of stuff is time consuming, especially when it’s not your day job.
This doesn’t mean it’s a poor value by any means, it just means there is probably a healthy margin. But probably less so than a lot of big name manufacturers. If anything, this is a testament to Pete Millett’s design chops, that he can take generally pedestrian parts, and make a stellar sounding amp out of it. I really don’t have any problems with the choice of power op amps in the output stage. There is nothing inherently wrong with them, just less flexibility in integrating into a design. But they are implemented well in the Sangaku.