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Linn AV5125 5-channel Amplifier Review

amirm

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This is a review and detailed measurements of the Linn AV5125 5-channel amplifier. It was kindly sent to me by a member. It is out of production but originally cost US $2999. I only see one used one on ebay for $2100 which seems pretty expensive for an old amp. Then again Linn is a high-end audio company so maybe it holds its value?

EDIT: member feedback shows prices are really in US $600 range for used units.

Despite the high channel count, the AV5125 is quite light and small:

Linn AV5125 4-channel amplifier Audio Review.jpg

The back of the unit shows the unusual BFA (British Federation of Audio) speaker connectors:

Linn AV5125 4-channel amplifier Back Panel Inputs Outputs Audio Measurements.jpg

I had to rebuild my test harness to test it which I was none too happy about it. It basically a banana plug but hollow on the inside.

The trick to light weight is a switching power supply and a set of fans to cool the heatsinks:

Linn AV5125 4-channel amplifier Teardown Audio Review.jpg

A pair of integrated IC amps are used for each channel. The heatsink is beefy despite its reduced height. In use the fans never came on. I am suspecting some kind of rail switching is used to keep power consumption low.

Overall, it is a "cute" design if you have to ask me. :)

Amplifier Audio Measurements
As usual we start with a simple 1 kHz tone driving the amplifier to 5 watts with 4 ohm load:

Linn AV5125 4-channel amplifier Audio Measurements.png


SINAD which is a combined metric of noise and distortion is above average of 90+ amplifiers tested in all forms:

best multichannel amplifier review measurements 2020.png


Crosstalk is not very good:

Linn AV5125 4-channel amplifier Crosstalk Audio Measurements.png


Frequency response is also not flat which is surprising:

Linn AV5125 4-channel amplifier Frequency Response Audio Measurements.png


Dynamic range though is very good especially near full power:

Linn AV5125 4-channel amplifier SNR Audio Measurements.png


As noted though, when I ran the full power test momentarily, it started to scream quite loud. How loud you say? Well, my wife who was downstairs, listening to her podcast using headphones heard it and asked, "are you making that beeping sound?" So there, we also have wife stories in our tests!

Power test produced an unusual curve:

Linn AV5125 4-channel amplifier Power into 4 ohm Audio Measurements.png


As you see in the two reference amplifier tests in dashed lines, usually the graph points down due to noise contributions lowering as power goes up. Not here. The curve is flat which indicates constant distortion. That is not a bad thing per se as we see really good performance until we exceed 20 watts and then we get ordinary response.

Same repeats with 8 ohm load:

Linn AV5125 4-channel amplifier Power into 8 ohm Audio Measurements.png


Here, at low power we have very clean output.

Back to 4 ohm load, we can see how much more power we get if we relax distortion to 1% and also measuring momentary power:

Linn AV5125 4-channel amplifier Power into 4 ohm Max and Peak Power Audio Measurements.png


The news is not good as is typical in amplifiers with switching power supplies which run regulated. For good or bad, you get maximum power they have in all conditions. Typical class AB amplifier has unregulated power supply rails which due to a capacitor bank, can produce more power in short duration.

Conclusions
This is an unusual design from a high-end company which went after "home theater" market back in the day when they could (prior to HDMI video standard putting them all out of this business). The guts is not high-end but seems custom and well thought out. Performance is reasonable to good. I tend to like the originality, small size, light weight and proper engineering from this Scottish company.

If you can find one on the cheap (well under $1000), then it is worth looking at the Linn AV5125. I am going to recommend it more from emotional point of view, than logic. :)

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As always, questions, comments, recommendations, etc. are welcome.

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confucius_zero

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What the hell?
 

GXAlan

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This is a good example of how amplifiers can sound different. -1.5 dB is potentially audible especially as you begin to have more reactive loads where the dip occurs at lower frequencies.
 

Sal1950

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Overall, it is a "cute" design if you have to ask me.
Power amps aren't supposed to be "cute".
They should reflect a muscular, beefy, mean look.
Something that will scare a speaker into submission. LOL
 

VintageFlanker

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This is a good example of how amplifiers can sound different. -1.5 dB is potentially audible especially as you begin to have more reactive loads where the dip occurs at lower frequencies.
I second this. In that case, the drop starts from 5Khz, which should be audible. It isn't a matter about amps sounding different or not: We have the data to understand why they do so.
 

tkr

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I very much like that Linn does things their own way, i.e. embracing music streaming early on when the rest of the high end folks still sniffed at it. Their pricing has kept me from getting any gear from them so far. Their production is mainly inhouse near Glasgow so high wages add to the bill. And their depth of manufacturing is quite high, even running their own metwalworks for cases etc.

I took a tour of their site during a visit to Scotland and they do show most of their production and the R&D offices, anechoic chamber etc. as well. Recommended, if you happen to be in the area, but needs to be booked in advance on the website.
One of the other guests specifically inquired about the wood used for producing the LP12 turntable. He was convinced he could clearly hear differences between different types of wood. My wife had quite a hard time keeping a straight face when she heard that claim while our host of the day had only the slightest, barely noticeable smile quickly pass over his face.

Edit: some typos corrected
 
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bunkbail

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Did you forget to run THD tests with different frequency of test tones? Or do you only do that with 2-channel power amps? I really like that test.
 

DSJR

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In the UK, these aren't hugely expensive (I'm certain they're under a grand, which may be pricy for a twenty-ish year old amp). With the 'aktiv' cards fitted, I seem to remember they made a wonderful active power amp 'pack' for their Ninka speakers wired for active, with the fifth amp channel spare. Very long time and a few lifetimes ago now, but it was a nice enough sounding amp to be fair and looking at all the circuitry per channel in there, I'm amazed it sounded any good at all to be honest.

Quick look on ebay for completed sales and this is the dearer of four I immediately saw - £625 is rather better I think.

https://www.ebay.co.uk/itm/LINN-512...533553?hash=item594b301c71:g:D1oAAOSwfZpen18E
 
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Ajax

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My all time favourite piece of gear was a Linn Sondek LP12 turntable with an Ittok arm. I purchased it from Graham HiFi while working in London in 1983 as a very young engineer. It was the front end to a very small Naim Nait Amp and a pair of Linn Kann speakers. System cost me 6 months salary and was a very irresponsible purchase, however, It gave me many many years of listening pleasure until I stupidly traded the LP12 for a pair of crap speakers.

Like most I find their gear too expensive in recent times and it just doesn't make sense to purchase their products when compared with say second hand Benchmark DAC2s (or a Topping DAC) combined with D class amps. However, back in the day they were class leaders. RIP Ivor Tiefenbrun, you were one of the very best audio engineers of all time.
 

Linus

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I’m still using a Linn 5103 as a pre amp and DAC for the living room. I wonder how it would mesure...
 

Doubleroll

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I have one of these amps which is fitted with an upgraded power Supply Linn calls Dynamik. Doesn't seem By the pictures like the test unit is fitted but it made some improvement for sure. Also, these go for about USD $500-$600 used from what I see, $2100 is probably one of the newer Linn Akurate amps.

https://docs.linn.co.uk/wiki/index.php/Dynamik
 

Panelhead

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See one today on eBay for 599.00. Seems about right.
Only electronics from Linn ever owned was a Linto phono stage with a Brilliance power supply. Was not my cup of tea.
Seemed overrated. Sound was compressed, no dynamics.
 

Bamboszek

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THD vs frequency would be very interesting.
Output inductors seem to be ferrite cored. There is possibility that distortion would rise dramatically due to the saturation of magnetic core.
 

anmpr1

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I very much like that Linn does things their own way...
Sometimes Linn's way was every which way but up. I remember Ivor the Linn Guy telling dealers they needed to have 'single speaker' demos. His idea was that the SPL from the 'active' speaker would somehow cause the unswitched speaker in the room to interfere sonically with the speaker under demo. Thus, the only way to make a valid comparison was to only have one set of speakers in the listening room. You can imagine the pain this was for dealers who had to lug speakers in and out of the room. It made A/B impossible. Just another pseudo-scientific bit of high-end mumbo jumbo. LOL
 
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DSJR

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I was one of those dealers and can tell you subjectively, that with two and maybe three pairs in the same dem room (unused pairs well separated from the playing pair), you can just about get away with it, but more than this and all the speakers begin to sound the same unless way off in balance and I personally found it difficult to 'sell up' to a 'better model' despote the perceived differences being greater if heard in isolation (I know I know, but that's how I 'experienced it' at the time). To me, this was repeatable but obviously sighted subjective and nobody measured the output of the non-playing pairs of speakers. No problem with the small UK boxes we mostly sold, but obviously more difficult with heavy floor-standers - these latter dems took longer anyway so not really an issue with us then-young chaps moving stuff about.. I suspect common sense should prevail here to anyone looking in who still works in an audio store.

The 5103 AV preamp set for two channel stereo was a big step up from the Kairn (irrespective of the supply it was fitted with). Again subjective sighted, but the 5103 did seem to reproduce venue acoustic and 'reverb' better. Current ones can suffer and be difficult to repair (can't remember if it's eprom or power supply, but the early smps Linn used were not long lived but can be repaired if they've not totally blown).
 
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