Something a little different this time - a review of three power amplifier choices by occasional guest contributor Clive, one of the moderators of the popular Linn Hifi and Music Enthusiasts Facebook group. Over to you Clive...
I'm fairly happy with my system, but, well, there's always room for improvements & I'd been
thinking maybe an amp or speakers upgrade.
My system at the time of writing comprises: -
Linn Klimax System Hub (Classic);
Linn Klimax Exaktbox with Organik DACs;
2 x Naim Olive 250s with Avondale HCR200 regulators & Witch Hat Phoenix amplifier boards;
Naim SL2s supplemented with a BK Electronics Double Gem sub;
English Electric 8 Switch & QNAP TS-251+ NAS drive;
Witch Hat Morgana interconnects & Spectre speaker cable;
Dedicated consumer unit with 5 x spurs in 6mm sq twin & earth & 6mm sq equipment leads
Maybe for those not in the know, I should explain the Linn System Hub & Exaktbox. The system hub
is a streamer only - it just controls the playlist from my NAS drive or streaming service (Qobuz or
Tidal) & other inputs (TV Box & Chromecast) and acts as a pre-amp with digital volume control. It has
no DAC and passes a digital stream of music and instructions to the Exaktbox. The Exaktbox is a digital crossover & 6 channel DAC (using the latest Linn Organik DACs). The advantage of having the crossover in the digital domain is that it can be far more accurate that an analogue crossover (I used to have a Naim SNAXO but this set up is far superior). The analogue outputs of the Exaktbox are fed to power amps - one for each speaker drive unit - so 2 x 250s in my case, SL2s being a 2 way speaker design.
In the past I've compared an Naim Olive 250 vs Naim Classic 250DR vs Linn Akurate 2200. I felt that the 250DR was more detailed but the Olive 250 more musical. Comparing Linn to Naim - Linn allowed all the separate elements of the music to be followed & analysed whereas Naim felt more like a band
performing. Both good - just a difference of presentation.
So I was interested a couple of months ago when I had the opportunity to compare, in passive
configuration, one of my modified 250s vs a new White Logo Naim 250 vs Linn Klimax Chakra Twin at a dealers showroom using a Linn Selekt Edition streamer with dual mono Organic DACs & Kudos 707s. When you consider the price differential Olive 250 with Avondale & Witch Hat boards ~ £1.7-2k vs New Naim 250 £5.7k vs Klimax Twin £9.4k you'd think it would be a fairly uneven contest... But was it?
First up was the New White Logo Naim 250 - bags of detail & pace but I found myself analysing the music rather than enjoying it. My feet stopped tapping! Switching to my modified Olive 250 & the foot tapping was immediately back. Sure it was a marginally less informative, but ultimately more enjoyable. Finally the Linn Klimax Twin. This was somewhere between the two. A bit more detailed than the Olive 250, more musical than the New White 250. But was it worth the £18.8k price tag for the upgrade (remember I need a pair of them)? I didn't think so - maybe a used pair but I would want to hear one in my home system.
So where did this leave me? Neil of Audiophile Musings & Speakerfilters has suggested to me a few
times that I should try Lejonklou Tundra 2.5 amps in place of my Naim 250s. For those of you who
haven't read Neil's previous posts about these amps - Fredrik Lejonklou used to work with Linn beforedeciding that he could build better amplifies for a much lower price. The Tundra Stereo was
first released in 2012 & is now in its ninth iteration in version 2.5 which sells for just under £3.25k.
Neil offered to lend me a spare Tundra he has to try in my system, which coincidently is for sale, so
no hidden agenda there (editor's note: it was a completely above board agenda, as it happens!). At the same time I've borrowed a Klimax Twin to try at home.
First thing was to put my system back to passive as I only had one Tundra & one Twin. It's a fairly
straight forward job with SL2s as they have external passive crossovers and put the Exaktbox into
pass through mode so the DACs are being used but not the digital crossover. I then played five of my
favourite test tracks to get a feel for how it sounded passive. The overall character remained
unchanged although a little of the precision of the timing & sound stage was missing but still very
Before putting the Tundra into my system, I'd been warned that:
a. They have less gain ~21dB compared to the Naim/Linn ~29dB so I would have to turn the
volume up +8
b. They take about 20 minutes to warm up - not after being switched on, but 20 minutes actually playing music to come fully on song, not that they are bad initially, they just get better with playing.
So when I first switched to the Tundra, I tuned the volume up & played the five tracks through
before going back to the beginning for a serious listen. The first thing that struck me was how similar
the sound was to that which I was used to. The Tundra has similar PRaT that Naim amps are famous
for. The Naim maybe had a smidge more authority on bass lines, the Tundra maybe a smidge more
transparency in the mid-range… But I would be hard pushed to choose one over the other - both are
Next up was the Klimax Twin. I was immediately taken by how much better it was than the Akurate
2200 I'd heard a few years ago. Previously I've found Linn amps great if you want to listen to all the
individual strands of the music, whereas Naim amps present the music as a whole performance.
While this is still true, the Twin is much more similar to the sound I am used to from my Naim amps
& more enjoyable for it. The Twin is a maybe smidge more detailed & informative but the Naim has
more swing & induces more foot tapping. Apart from the wallet bending price of a pair, I could
probably live with the Klimax Twin… if I hadn't heard my 250s or the Tundra.
I was able to have both the Tundra & the 250 in my system rack at the same time so it was only a
minute or so to swap from one to the other to do a tune dem. So having warmed the Tundra up again, in an effort to differentiate between it & the Naim, I played some tracks that I don't know on
one then the other. Now the differences became a bit more apparent. While the 250 still had a little
more weight & authority in the bass lines, where the Tundra really excels is in conveying the
emotion in the music. It's difficult to explain in words but I feel that I can really hear the musicians
putting their heart & soul into the performance, whether they are vocalists, guitarists or a
saxophonist you just get the feeling that they are giving it that bit extra. The listening experience is
just that bit more… well musical, more fluid although it still wasn't night & day differences.
A few days later I had a friend round who has no interest in hifi but enjoys music, particularly to
dance to rather than sitting down listening at home. First I played a couple of tracks she wouldn't
have heard previously using the 250 before switching over to the Tundra. Her initial reaction was
that the presentation of the two was quite different. The 250 was laid back & enjoyable whereas the
Tundra was more up front & in your face. She didn't like the way that the Tundra demanded her
attention, demanded to be listened to. Interesting. Then we played a number of tracks that she
knew from dancing switching back & forth between the two. Now her preference switched to the
Tundra, hearing the additional nuances it brought to the experience, describing it as more engaging
as though the musicians were performing just for her. By the end of the evening she said that both
were enjoyable but on balance although the Tundra is more demanding, she felt it is also (a bit)
So am I swapping my modded Olive 250s for Tundras? Hmmm! The 20 minute warm up is a bit of a
downer. Most mornings, I have a listening session that's, at most, ½hr while I have a cup of coffee
after I've done my morning workout & there would be that nagging doubt that the amps are not
performing at their best for the majority of that time. Additionally, I've been in discussions with John
Jackson (ex Naim & Witch Hat) about an further mod to my 250s to add another regulator to power the amplifier board to create a Phoenix Plus board if you like and elevate the performance further.
So the jury is still out.
At the end of the day, the Tundra is a very musical amp & should certainly be on your shortlist to
audition if you are in the market for amps at this sort of level. In my view it's considerably more
musical than the latest generation Naim 250 which, to me, is very hifi, which is great if that's what
you are looking for but for me, Naim have lost the PRaT that they were renowned for. I also
preferred the Tundra over the Klimax twin which, considering its ~⅓ of the price, makes the Tundra
something of a bargain. And if you have a standard Naim Olive 250, again the Tundra will be an
upgrade. At the end of the day, you could argue that my Naim 250's are no longer Naim amps - all
that remains of the original amps is the case, transformer & the sockets.
Thank you to Neil Hallworth for the loan of the Tundra, & Nigel Moore for the loan of the Klimax