Leslie's Review of the Audion Amp

First off, I would like to thank Leslie for contributing his review of his recently purchased Audion amp. The thoroughness and detail in the review is first class - YC

I would like to share with you my recent experience in changing my power amp from solid state to tube. You may like to post it on your website so that others who are in similar dilemma can have a hint. More importantly, I hope to see more people contributing so share their own experience. But for the very rich guys who can easily go for the Audio Note/Jadis types, perhaps they would like to skip this article. (he's just too modest - YC)

Please note that my comments are in the context of my music preference. If my preference has been different, the result might have been totally different. Also, you may want to make some editing/changes to this comments of mine in case there are certain things you think are not necessary or appropriate to include. Thanks.

My old system: CD player: Marantz CD63MkII KI-S
Pre-amp: Quicksilver LS (tube)
Power amp: Rotel RB971 power amp (solid state)
Speakers: Focus Audio FS68
Cables: Self-made Belden

Music preference (more than 90% of the time): Classical music (Western and Chinese), vocal (soprano, tenor, some slow jazz and oldies), solo instruments: violin, cello, guitar.

I have always wanted to change my power amp to tube, so that I can enjoy the wonderful sound of full tube system. But I was quite hesitant, mainly because of the trouble/maintenance and cost associated with tube power amp. But I knew that sooner or later, I would change. At the same time, I was on the look-out for something affordable/good value (I didn't want to spend too much). Among those affordable/good value system (e.g. Diva, Houston) that I have heard, I am most impressed (in terms of vocal sweetness/airy/emotion/musical aspects) with those at Soul of Music and Zenn Audio.

Then the other day I was at Audiolab (Adelphi) and casually (I was there with my friend who was looking for a pair of speakers), I slipped in one of my favourite soprano albums. Unprepared, I was immediately impressed and amazed. Based on my memory, it sounded warmer and more airy than my tube/ss combo and very similar to those full-tube systems I have heard. I checked the components - Audion Premier pre-amp (separate PS) and Audion Sterling power amp. I then learned that the power amp is a single-ended (SE) design with 12wpc of power. Price quoted was quite attractive. One concern was the power. My speaker has a sensitivity of 85db, though impedence is 8ohms; even the dealer was a bit sceptical.

So I decided to do some research on it. Audio Review website has some reviews of it and coincidentally, one of them is using this amp with a Focus Audio FS68 (without pre-amp). So I emailed him and his reply was very encouraging. Moreover, I recalled that Audio 88 was driving this speaker wonderfully with their 13wpc Houston Mini.

Additional information from magazines and some websites told me that SE tube amp is believed to be best sounding (I think this may be debatable), and they are cheaper to produce due to its simpler circuit and transformer. Because of this, it is also easier to make SE amps sound good. Now, I think this second point is important. That means theoretically, for a given price level, a SE amp would give better performance than others (e.g. push-pull). So for someone looking for tube amp with limited budget, a SE design is a good start.

So, after listening to many of my favourite CDs with the Audion and Rotel, I finally decided to buy the Audion. I believed that at this price level, I couldn't have bought better.

My comparison: I listened with many disc, mainly orchestral works, female vocal, male vocal, soprano, tenor, piano and violin.

1). Bass wise (double bass, drums, no rock or disco type of bass) - The Rotel sounded more controlled and tighter. (But I later placed three cheap metal cones under the Audion and it helped a little. Maybe I should get another set of DH cones.)

2). Female and male vocals - The Audion (as expected) is the absolute winner. Here, the Audion sounded fuller, thicker, and sweeter than the Rotel. There seemed to be more airy. This is especially obvious on tracks from albums of Jacintha and Sam Cooke (note these are recorded with tube equipments). Here, the Rotel tells you it's electronic.

3). Violin - Again the Audion won. The violin sounded smoother, more open, more real and less edgy than with the Rotel. Through the Rotel, some of my violin CDs sounded as though they are shrilling. With the Audion, I can listen to and enjoy all my violin CDs. This is a very important attribute.

4). Transparency - The Audion provides more transparency and details. With the Rotel, some of the vocal CDs sounded muffled. This is especially obvious in one of the soprano albums (also recorded with tubes). One piano CD contains some background noise which was easily revealed by the Audion. This, I believe, can be improved with a more capable (higher-priced) solid state power amp.

5). Power - The Audion did not lose out too much here, even with big orchestral works. The Audion handled complex passages equally well. With one of the tenor album, however, the Audion seemed to have some difficulty when I turned the volume up (much louder than normal listening level). But I am using a small room now (I guess most people in Singapore are), so this is not a big problem.

For above 1), 2) and 3), the texture of the instruments and vocals are indisputably better with the Audion.

My conclusion is, for people who listen to a lot of vocals, violin/strings, piano and very little of bass, a full-tube system will give a more satisfying result (at this price point). Please note that this is not really a comparison between Rotel and Audion. It was more a comparison between a budget solid state amp and a budget tube amp. I was thinking, how about a solid state power amp of similar price level (S$1,000+)? My guess is, with direct comparison, the tube one will still offer better sound for my kind of music. If I am listening to a lot of pop/rock, my conclusion might have been different.

But some people may say that my pre-amp+power is already in the range of S$3,000+, so with a little bit more, I can actually get a good (aka branded) integrated (e.g. Jadis Orchestra/Manley Stingray). But then I actually started off with only a CD player, power amps and speakers. I added the pre-amp later. Now, it's time for me to change my power amp (for the better). This is one advantage of separates. You can add/change one component at a time. My next target - CD player (tube?).

Finally, I would say that as far as I can recall, the tube systems at Soul of Music and Zenn Audio are still the most impressive in terms of emotion/musicality aspects. Perhaps, it's because at Soul of Music, they are using a tube CD player (Lector) and at Zenn Audio, his 300B pre-amp?

My current system:
CD player: Marantz CD63MkII KI-S
Pre-amp: Quicksilver LS (tube)
Power amp: Audion Sterling ETSE (stereo)
Speakers: Focus Audio FS68
Cables: Self-made Belden

I would like to add that the Audion amp runs at very high temperature. According to the manual, when in operation, the amp gives out heat equivalent to a 25w bulb (there are some tube amps which run hotter). I think this is partly because the whole unit is enclosed. Unlike most other tube power amps, the Audion has its transformers and all parts encased, such that heat cannot escape fast enough. But after using it for a week or so, I found it not a problem at all. When you touch the unit, it is hot, but not to the extend that you will get burn. But this design is another plus, as it is compact and looks neat and simple.

Furthermore, it comes with an Alps volume control at the front, so for those who uses only one source (e.g. CD player), they can use this amp without a pre-amp. From the internet, I know some people suggested changing this volume control to a step-resistor design which will give better sound. I think this amp gives another advantage to starters who just need a power amp with a CD player and speakers. They can then buy a (tube) pre-amp at later stage. Using it with other pre-amp is not a problem I believe, as the volume control can in effect adjust the input sensitivity to match any pre-amp.

You can contact Leslie here.

YC's 2 cents worth

Well, I've listened to the Audion as well, though I must admit that my listening time was far shorter than Leslie's, but I went along with 2 other people and sought their opinions as well :) But note - to be fair, and to satisfy a solid-state person like myself, I auditioned the monobloc version (twice the power) as the single version wasn't available for audition. The source was a Cairn CD player (theres that brand again) and the speakers were NSM monitors (not an easy load)

My test discs were female vocals as usual, so I expected the Audion to come back with a good showing. The discs were:

Natalie Merchant, Live on Broadway
Tori Amos, to venus and back
Mary Black, Speaking with the Angel

First, the positive. Mary Black was mighty fine and the vocals came across beautifully with no sign of strain though the acoustic bass was not as defined as I was used to. I can say this without qualification; this is very high-end sound in terms of female vocals, sounding more communicative and emotional than more expensive Sonic Frontiers and VTL amps that I've heard. This is also not at the expense of transparency. When not strained, the sound is extremely transparent.

Then we come to the negative - really, really, not enough power. You really have to use sensitive speakers and/or lower volume listening levels. I suppose this is why home trial is so important when you can get it.

Listening to Natalie Merchant at a moderate level with the band playing, apart from the fact that there was no much bass, there was a lot of distortion at the relatively louder portions of the passage. Having been used to a lot of 'clean' solid-state power from my McCormack and the Conrad Johnson downstairs, I did not like that distortion (of course it was the relatively warm and fuzzy tube sort of distortion, but it was distortion). Occasionally, complex passages became slightly muddled and confused.

Things did not improve with Tori Amos' album with the deep synthesised bass. As the amp struggled to reproduce low synth notes, it appeared that the midrange suffered as well. Glory of the 80s , which did not have any deep low synth notes but has complex percussion and layers of synths sounded disjointed and lacked coherence.

It almost seemed like I'm listening to a completely different amp; how could this be the amp that made Mary Black sound so wonderful. L,istening to quiet acoustic music, the amp definitely shined, it seemed to do a volte face everytime something challenging was thrown at it.

Please remember:

  • my music preferences are different.
  • I find bass quite important (so much so that I have a subwoofer) though I listen to 90% female vocals.
  • I've lived with solid state for a long time, so I might be biased towards the kind of 'clean' (but non-electronic - the electronic sound occurs mainly in the what hi-fi 5 star integrated amps [like my Quad77 I must admit]) sound of solid state.
  • Most importantly, I think the NSM minimonitors were a huge mismatch. But he apparently didn't have anything else around easier to drive (duh!) But still the potential for distortion, strain is still there - it'll occur at a later stage (i.e. at higher volume levels, bigger listening rooms), but when it does; this is what it'll sound like.

Also, Leslie hasn't mentioned the price; but I'll say that the price is very good and the nearest competition is the Anthem (i.e. Sonic Frontiers) Amp 1, Diva, or your self-built 300B amp. Frankly, the Amp 1 can't touch the Audion when the Audion is given a favourable environment - smallish HDB room, sensitive speakers. Leslie reminded me of an important point too - the low price is also because its relatively unknown. Anything that has a good review in Singapore seems to have its price jacked up. (except Sonic Frontiers for some reason :))

So Audiolab - get a better pair of speakers to demo the Audions! Do you want my Triangle Zephyrs? :)