averydonovan
Headphoneus Supremus
Pre-Intro
This is my first ever full-length review of any sort, so it may be a bit rough at first. Your suggestions are most definitely welcome on how to improve this review and you might consider this review a work in progress since it will be revised over time. This review is a copy of that posted at my web site at http://www.donovansmith.us/node/view/93 with this note added and the HTML replaced with vbCode, so some stuff in this review may be a bit different from the style normally posted here on Head-Fi since it is designed for a more general audience.
Introduction
Singlepower Audio Inc. is a Denver-based manufacturer of hand-built tube headphone amplifiers and pre-amplifiers. Their concept is to build their amps as a platform where the tubes are the star of the show, so the circuit topologies used are relatively simple and the power supply is one of the biggest differences between models. Their top-end models use power supplies that would put to shame the power supplies in most power amplifiers. All the production models as of this review are single-ended triode designs with no output transformers.
Equipment Used in Review
The Amplifier
I bought one of their entry-level models, the PPX3 headphone amplifier, and got it in late April. The PPX3 uses an unregulated power supply and 6CG7 tubes, while others models further up the line use fully-regulated power supplies and 6SN7 tubes. It is encased in a very nice looking small gloss-black aluminum chassis with the power transformer, which is housed in a gloss-black metal box, and the 3 6CG7 tubes on the top of the chassis. The case is very well built and does not creak or groan at all. There are four rubber feet on the bottom. I have noticed no issues with tube microphonics, even with the amp being on my computer table which means there are constant taps from my keyboard to deal with. The front panel has the power switch on the left, volume control in the center, power indicator light to the right, and on the far right is the headphone jack. The tubes are arranged in a diagonal from roughly the center front to the right rear, with the gain tube in the front-most position and the two output tubes right behind it. It is designed to work with headphones of nearly any impedance, from 32 ohm Grado Labs headphones to 300 ohm Sennheiser models. As of this writing the retail cost for this amplifier is $465.
The Sound
The stock tubes that come with the PPX3 are new production tubes made by Electro Harmonix and I have heard that Ei Elite tubes, also new production, are offered. Using different tubes in the PPX3 will dramatically affect how it sounds yet there are some underlying characteristics of the sound that are the same regardless of the tubes used. The soundstage is somewhat immediate, bringing you closer to the stage rather than sitting many rows back, but is in not claustrophobic or closed-in sounding. The bass is quite prominent yet not excessive and extension in both the bass and the treble regions is good. Even at low volume levels the sound is all there, I don't feel the need to turn up the amp just to hear all of the music. The overall sound can best be described as fun. It is quite engaging and enjoyable to listen to.
My favorite thing about this amplifier is that I find it very difficult to analyze its sound, it just draws me into the music. Nearly every time I try to use a song to test various aspects of the sound I kept getting drawn into the music. I don't know if I can call this an audiophile headphone amplifier, it just doesn't seem fitting to call it that when it really is a music-lovers headphone amplifier. The PPX3 definitely adds its own coloration to the sound but at the same time it steps out of the way and lets you enjoy the music.
Tube Rolling
Tube amplifiers seem to attract people who like to customize their equipment's sound through tube rolling. The PPX3 uses relatively inexpensive, easy to find, and durable 6CG7 and 6FQ7 tubes. Electro Harmonix of Russia and Ei of Yugoslavia both make 6FQ7 tubes today, and there is a large number of older tubes out there. 6CG7s have a shield in between the plates inside the tube, while 6FQ7s do not. Sometimes the designations are mixed by manufacturers, but I will designate them based on their shield or lack thereof to try to mitigate confusion.
RCA cleartop 6FQ7s seem to be among the most popular of the 6CG7 and 6FQ7 types. They have their getter at the side of the tube, making their tops clear and giving them their name. I have a set of Brazilian-made cleartops and I like them in either the output positions or the driver position, but find that transients get rolled off a bit if used in all 3 positions. I am liking them most as output tubes.
PPX3s up to and including the one I got came with Electro Harmonix 6FQ7s. I can't say they are bad tubes, but they just don't live up to either Ei current production tubes or the older tubes I have heard. A rather flat sound with slightly recessed vocals. The Ei tubes that are supposed to be coming with PPX3s currently are very good sounding, with a smooth yet lively sound with great bass and treble extension. The bass is especially notable, sounding very tight and well-controlled. If you hear the PPX3 with the Ei tubes you may not desire another set of tubes.
I have tried a few different older tubes in the driver position. The highly regarded RCA black-plate 6CG7s have a lively, fast sound and are fun with faster-paced music. A Sylvania black-plate 6CG7 I tried is very smooth, very relaxing sounding and is good way to tame brighter headphones. My current favorite is a GE gray plate 6CG7, which has a smooth presentation overall, yet has excellent transient response and great treble and bass extension. Everything on this tube is well balanced, the midrange fits perfectly in with the bass and treble. A GE gray plate on the driver position and RCA cleartops on the outputs will provide a sound that will surely put a smile on your face for rock and electronic music.
Comparisons to Other Amps
My headphone amplifier collection prior to getting my PPX3 has been modest portable models, my first one being a self-built model that was a buffered opamp design, the most recent and one I still have is a PIMETA amplifier. To say that the PPX3 is far superior to either of those amps is an understatement. And it should be, those two both combined would be less than half the cost of the PPX3 and are designed more for portable use than home use. I imagine I'm not the only one who has upgraded from a PIMETA or similar headphone amplifier to a PPX3, so a comparison should help give a feel for just how big of a leap this is.
My PIMETA uses OPA627 opamps biased into class A operation and the BUF634 output buffers were in full bandwidth mode. It provides good sound for something that costs well under $200 to build. The PPX3 provides much more body to the sound, vocals are more fleshed out and the bass is far more impactful and full-sounding. The soundstage is a bit wider and the sound is actually a little faster. Compared to the PPX3, the PIMETA sounds a bit analytical and the PPX3 far more musical. The PIMETA can be a good little amplifier but once you hear the PPX3 next to it you will not want to go back.
I no longer have my first amp around to do a comparison, but from memory it was more musical than my PIMETA but less detailed and refined sounding. It used a single 9V battery and did an admirable job for what it was. The design and topology is most similar to a MINT except my amp had a global loop configuration rather than the multi-loop design of the MINT. The PPX3 would smash that amp in every category, but compared to my PIMETA that amp had a more similar character to the PPX3. I imagine if you have owned both a MINT and a PIMETA (or maybe META42) and missed the musicality of the MINT in your PIMETA and are looking for an upgrade, then you will welcome the PPX3 as being able to be more refined than either the MINT or PIMETA, by a pretty long shot, while being more enjoyable than either amp to listen to.
Music
Bruderschaft “Forever (Darkness Pulls Me Under Remix)”: An electronic track written by DJ Rexx Arkana with vocals done by Ronan Harris of industrial act VNV Nation. The synthesized keyboard sounds come through with all their texture and the song has a somewhat atmospheric sound to it. Ronan Harris's vocals are definitely the star here, his singing just comes through with so much realism. It sounds almost like he is standing in front of me. The percussive beats in the track are there yet don't take over the song.
Steve Perry “You Better Wait”: The former Journey lead-singer takes his amazing vocal talent to new heights in his solo act, especially on the album For the Love of Strange Medicine from which this track is taken. Steve Perry's voice comes through with full force and just takes over the music, as it should. Lincoln Brewster's guitar work sounds smooth and detailed. Drums figure in a little more prominently in this song and they have excellent impact.
T.O.Y. “Fairytale”: Off of White Lights, the second album from the renamed industrial turn electro-pop act Evil's Toy. It has a very bouncy, fast beat and it definitely comes on full force, propelling the music forward. You can hear that it is a generic drum-machine produced sound but it is rendered with full impact and a nice “thump” that makes this track a lot of fun to listen to. Vocals still figure in prominently in this track but the beat seems to override them a bit. If tubes are stereotyped as slow sounding, this track really helps break that stereotype.
Fiction 8 “Stasis”: An instrumental track off of their album Chaotica. The violin used on this track sounds sweet and emotional, it is what helps make this one of the most unique electronic songs out there. The percussion sounds in the track are not very prominent and have a nice impact yet don't overpower the violin. This song also has some electronic keyboard sounds added to help with a somewhat atmospheric sound in this song and they are put in their appropriate place. The soundstage in this track is very nice, not so wide as to be laid back but wide enough for the song to envelop you.
Conclusion
If you want a headphone amplifier which will allow you to enjoy your music, the Singlepower PPX3 is for you. When you're tried of listening to your equipment and want to just relax and listen to the music, which is what being an audio enthusiast or audiophile is really supposed to be about, you'll find the PPX3 a great way to help you accomplish that. It sounds better than a headphone amplifier in this price should and combined with excellent build quality and the awesome customer service of Singlepower, I couldn't rate the PPX3 at anything but 10 out of 10.
Value Rating: 10/10
Links
Singlepower Audio, Inc.
This is my first ever full-length review of any sort, so it may be a bit rough at first. Your suggestions are most definitely welcome on how to improve this review and you might consider this review a work in progress since it will be revised over time. This review is a copy of that posted at my web site at http://www.donovansmith.us/node/view/93 with this note added and the HTML replaced with vbCode, so some stuff in this review may be a bit different from the style normally posted here on Head-Fi since it is designed for a more general audience.
Introduction
Singlepower Audio Inc. is a Denver-based manufacturer of hand-built tube headphone amplifiers and pre-amplifiers. Their concept is to build their amps as a platform where the tubes are the star of the show, so the circuit topologies used are relatively simple and the power supply is one of the biggest differences between models. Their top-end models use power supplies that would put to shame the power supplies in most power amplifiers. All the production models as of this review are single-ended triode designs with no output transformers.
Equipment Used in Review
- Source: Terratec EWX 24/96 sound card, Sony D-14 vintage compact CD player
- Interconnects: Self-built RCA-to-RCA
- Headphones: Sennheiser HD600 with Oehlbach replacement cable, AKG K 271 Studio
- Music: Mostly industrial, electronic, and rock
- Tubes: GE gray-plate 6CG7 (driver), RCA cleartop 6FQ7s (outputs) (picture shows different tube configuration)
The Amplifier
I bought one of their entry-level models, the PPX3 headphone amplifier, and got it in late April. The PPX3 uses an unregulated power supply and 6CG7 tubes, while others models further up the line use fully-regulated power supplies and 6SN7 tubes. It is encased in a very nice looking small gloss-black aluminum chassis with the power transformer, which is housed in a gloss-black metal box, and the 3 6CG7 tubes on the top of the chassis. The case is very well built and does not creak or groan at all. There are four rubber feet on the bottom. I have noticed no issues with tube microphonics, even with the amp being on my computer table which means there are constant taps from my keyboard to deal with. The front panel has the power switch on the left, volume control in the center, power indicator light to the right, and on the far right is the headphone jack. The tubes are arranged in a diagonal from roughly the center front to the right rear, with the gain tube in the front-most position and the two output tubes right behind it. It is designed to work with headphones of nearly any impedance, from 32 ohm Grado Labs headphones to 300 ohm Sennheiser models. As of this writing the retail cost for this amplifier is $465.
The Sound
The stock tubes that come with the PPX3 are new production tubes made by Electro Harmonix and I have heard that Ei Elite tubes, also new production, are offered. Using different tubes in the PPX3 will dramatically affect how it sounds yet there are some underlying characteristics of the sound that are the same regardless of the tubes used. The soundstage is somewhat immediate, bringing you closer to the stage rather than sitting many rows back, but is in not claustrophobic or closed-in sounding. The bass is quite prominent yet not excessive and extension in both the bass and the treble regions is good. Even at low volume levels the sound is all there, I don't feel the need to turn up the amp just to hear all of the music. The overall sound can best be described as fun. It is quite engaging and enjoyable to listen to.
My favorite thing about this amplifier is that I find it very difficult to analyze its sound, it just draws me into the music. Nearly every time I try to use a song to test various aspects of the sound I kept getting drawn into the music. I don't know if I can call this an audiophile headphone amplifier, it just doesn't seem fitting to call it that when it really is a music-lovers headphone amplifier. The PPX3 definitely adds its own coloration to the sound but at the same time it steps out of the way and lets you enjoy the music.
Tube Rolling
Tube amplifiers seem to attract people who like to customize their equipment's sound through tube rolling. The PPX3 uses relatively inexpensive, easy to find, and durable 6CG7 and 6FQ7 tubes. Electro Harmonix of Russia and Ei of Yugoslavia both make 6FQ7 tubes today, and there is a large number of older tubes out there. 6CG7s have a shield in between the plates inside the tube, while 6FQ7s do not. Sometimes the designations are mixed by manufacturers, but I will designate them based on their shield or lack thereof to try to mitigate confusion.
RCA cleartop 6FQ7s seem to be among the most popular of the 6CG7 and 6FQ7 types. They have their getter at the side of the tube, making their tops clear and giving them their name. I have a set of Brazilian-made cleartops and I like them in either the output positions or the driver position, but find that transients get rolled off a bit if used in all 3 positions. I am liking them most as output tubes.
PPX3s up to and including the one I got came with Electro Harmonix 6FQ7s. I can't say they are bad tubes, but they just don't live up to either Ei current production tubes or the older tubes I have heard. A rather flat sound with slightly recessed vocals. The Ei tubes that are supposed to be coming with PPX3s currently are very good sounding, with a smooth yet lively sound with great bass and treble extension. The bass is especially notable, sounding very tight and well-controlled. If you hear the PPX3 with the Ei tubes you may not desire another set of tubes.
I have tried a few different older tubes in the driver position. The highly regarded RCA black-plate 6CG7s have a lively, fast sound and are fun with faster-paced music. A Sylvania black-plate 6CG7 I tried is very smooth, very relaxing sounding and is good way to tame brighter headphones. My current favorite is a GE gray plate 6CG7, which has a smooth presentation overall, yet has excellent transient response and great treble and bass extension. Everything on this tube is well balanced, the midrange fits perfectly in with the bass and treble. A GE gray plate on the driver position and RCA cleartops on the outputs will provide a sound that will surely put a smile on your face for rock and electronic music.
Comparisons to Other Amps
My headphone amplifier collection prior to getting my PPX3 has been modest portable models, my first one being a self-built model that was a buffered opamp design, the most recent and one I still have is a PIMETA amplifier. To say that the PPX3 is far superior to either of those amps is an understatement. And it should be, those two both combined would be less than half the cost of the PPX3 and are designed more for portable use than home use. I imagine I'm not the only one who has upgraded from a PIMETA or similar headphone amplifier to a PPX3, so a comparison should help give a feel for just how big of a leap this is.
My PIMETA uses OPA627 opamps biased into class A operation and the BUF634 output buffers were in full bandwidth mode. It provides good sound for something that costs well under $200 to build. The PPX3 provides much more body to the sound, vocals are more fleshed out and the bass is far more impactful and full-sounding. The soundstage is a bit wider and the sound is actually a little faster. Compared to the PPX3, the PIMETA sounds a bit analytical and the PPX3 far more musical. The PIMETA can be a good little amplifier but once you hear the PPX3 next to it you will not want to go back.
I no longer have my first amp around to do a comparison, but from memory it was more musical than my PIMETA but less detailed and refined sounding. It used a single 9V battery and did an admirable job for what it was. The design and topology is most similar to a MINT except my amp had a global loop configuration rather than the multi-loop design of the MINT. The PPX3 would smash that amp in every category, but compared to my PIMETA that amp had a more similar character to the PPX3. I imagine if you have owned both a MINT and a PIMETA (or maybe META42) and missed the musicality of the MINT in your PIMETA and are looking for an upgrade, then you will welcome the PPX3 as being able to be more refined than either the MINT or PIMETA, by a pretty long shot, while being more enjoyable than either amp to listen to.
Music
Bruderschaft “Forever (Darkness Pulls Me Under Remix)”: An electronic track written by DJ Rexx Arkana with vocals done by Ronan Harris of industrial act VNV Nation. The synthesized keyboard sounds come through with all their texture and the song has a somewhat atmospheric sound to it. Ronan Harris's vocals are definitely the star here, his singing just comes through with so much realism. It sounds almost like he is standing in front of me. The percussive beats in the track are there yet don't take over the song.
Steve Perry “You Better Wait”: The former Journey lead-singer takes his amazing vocal talent to new heights in his solo act, especially on the album For the Love of Strange Medicine from which this track is taken. Steve Perry's voice comes through with full force and just takes over the music, as it should. Lincoln Brewster's guitar work sounds smooth and detailed. Drums figure in a little more prominently in this song and they have excellent impact.
T.O.Y. “Fairytale”: Off of White Lights, the second album from the renamed industrial turn electro-pop act Evil's Toy. It has a very bouncy, fast beat and it definitely comes on full force, propelling the music forward. You can hear that it is a generic drum-machine produced sound but it is rendered with full impact and a nice “thump” that makes this track a lot of fun to listen to. Vocals still figure in prominently in this track but the beat seems to override them a bit. If tubes are stereotyped as slow sounding, this track really helps break that stereotype.
Fiction 8 “Stasis”: An instrumental track off of their album Chaotica. The violin used on this track sounds sweet and emotional, it is what helps make this one of the most unique electronic songs out there. The percussion sounds in the track are not very prominent and have a nice impact yet don't overpower the violin. This song also has some electronic keyboard sounds added to help with a somewhat atmospheric sound in this song and they are put in their appropriate place. The soundstage in this track is very nice, not so wide as to be laid back but wide enough for the song to envelop you.
Conclusion
If you want a headphone amplifier which will allow you to enjoy your music, the Singlepower PPX3 is for you. When you're tried of listening to your equipment and want to just relax and listen to the music, which is what being an audio enthusiast or audiophile is really supposed to be about, you'll find the PPX3 a great way to help you accomplish that. It sounds better than a headphone amplifier in this price should and combined with excellent build quality and the awesome customer service of Singlepower, I couldn't rate the PPX3 at anything but 10 out of 10.
Value Rating: 10/10
Links
Singlepower Audio, Inc.
