"Norwegian Wood"
Copyright 2007 Troels Gravesen

       

Review of MAE1, Single Ended Tetrode Amplifier Kit from Norway

This summer's holidays once more brought us to the Western parts of Southern Norway, to the mountains, the fjords, the highlands - and for the first two days also brought us loads of rain. The latter I really can't blame the Norwegians, because it's been raining cats and dogs for weeks in the whole of Northern Europe. But in Norway you find lots of small log cabins when weather doesn't make setting up your tent such an attractive option. The cabins may be constructed from huge logs of wood, the roof covered with grass and bushes. Two beds, a table and two chairs, a stove in the corner, that's all. No electricity, no telly, no radio, no hifi, no internet. And no sounds, but the faint sizzle from a distant stream carrying the water of melting snow from the mountains. If your cabin is in the right place you may get one more thing: Silence. Take a walk in the highlands and it will sharpen your hearing because there isn't much to listen to. A few birds and a faint "glock" of a bell hanging from a sheep's neck is all you hear. At home I live in a town, filled with noise and I have to close windows and doors to make complete silence.

Whether the silence of the hills and mountains helped sharpen the hearing of Bernt, Brynjar and Hans* of Norway, I don't know. Some twenty prototypes of the "Motron Audio Experience Single Ended Tetrode 1", MAE SET1, were built and the version tested here covers not the most expensive parts available, because as always, we apply to the law of diminishing returns and getting a commercial kit flying, compromises have to be made. However, you will find excellent components not often used in high-end gear but chosen for their good sonic performance. Even some special by-pass caps are used to balance the sound from the output trannies.
This amp should deliver some 6.5 wpc and if used alone, we're into high-efficiency speaker territory to find suitable partners that will deliver from such a set-up and this is what the second part of this story is about. Obviously the MAE1 can be used for bi-amping, relieving it from delivering the deepest bass.
For those interested in valves, we're finding Philips E83F and STC 5B/255M in this amp.

Good valve amps are like good wine. We do not have to be experts in any of these areas, but this doesn't prevent us from listening and tasting. When we have reached a certain level of technical perfection, it doesn't make much sense trying to rank the products any more. We may argue indefinitely about which brand of caps, coils, wires and resistors is the best or which amplifier circuit topology will deliver the best sonic value, but basically we're talking taste, and taste cannot be argued. It's a futile discussion. What we have to consider with this Norwegian MAE1 amp is it's limited output power and the fact that it's single ended, probably having relatively high output impedance. So, we need speakers with decent impedance and high sensitivity. From several weeks' experience I find that if we want to use this amp alone, we need something in the area above 94 dB/2.8 volts. BUT, this certainly depends on the impedance of the speaker; so don't despair if your speakers have lower sensitivity. But matching flea-powered amps to speakers is like finding the right wine for a given disc. Ingredients have to match to make a perfect dinner.

*Bernt has developed the MAE1, Brynjar delivers the components and sells the kit. Hans has built the version I'm testing. Thanks to you all for lending me the amp for so long. It was perfect timing for testing some HES speaker experiments.
For information, write Brynjar at
bryn@motron.no
Pics at Nowegian discussion site:
http://www.hifisentralen.no/forum/index.php/topic,12141.0/all.html (in Norwegian).

It takes an experienced builder to produce what's seen above. Very nice indeed. You may notice that a power input filter follows the kit. I wonder why the Hammond 125ESE output transformer used here is specified to having a frequency range of "only" 100-15.000 Hz, because the MAE1 can play bass, even deep bass given the right speakers. Some of you may remember Mezzoforte's "No Limits" LP. Try Joyride with the MAE1 plus the OB7 speakers and they'll shake your guts like you never thought possible from 6 watts.
To cut a long story short, I find the MAE1 having the following characteristics:
- Magnificent midrange with fine detail and resolution. Smooth like velvet.
- Treble performance is hard to comment, because I don't know what it could do better. Crisp, clear, extended.
- Bass is slow on low-efficiency speakers. Needs high-efficiency speakers to show good transient ability.
- Plays quite loud on a wide range of speakers. Drive it to clipping and it does so in an ear-friendly manner.
- Overall a slightly forgiving presentation; if your system sounds harsh with this amp, look elswhere.

I'd been surprised if this amp would kick my reference 20 wpc PSE mono-blocks off the ramp, and it doesn't. The 3-4 times amount of extra power display enhanced authority and low-end grip, but it comes at three times the price - not to forget.

The MAE1 is a charming amplifier and after some time you'd like to include it in your collection of amplifiers - like a vintage wine. But don't get me wrong here; I very much render this amplifier a high-end kit that given the right working conditions will deliver some of the best sound available. It faces fierce competition from all the Chinese valve amps flooding the market for the time being, but what you get here is a kit with schematics and competent people behind that can help should anything go wrong.
And by the way: It has 4, 8, 16 and even 32 ohms secondary tabs!


Speakers used in testing MAE1

The first pair of speakers tried with the MAE1 amp was the JA8008/TW034 delivering some 95 dB sensitivity from a TQWT cabinet. No problem in driving these speakers. Next I tried the Vifa C17-mk4 speakers. No problem in driving these speakers either, however not as good as the JA8008/TW034 speaker, which has smoother treble and better dynamics.


Eidsfjord, Norway, 2007