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Pioneer A-400

Stereo Integrated Amplifier (1990-91)

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Pioneer A-400


Power output: 50 watts per channel into 8Ω (stereo)

Frequency response: 5Hz to 100kHz

Total harmonic distortion: 0.03%

Input sensitivity: 0.2mV (MC), 2.5mV (MM), 150mV (line)

Signal to noise ratio: 69dB (MC), 87dB (MM), 108dB (line)

Output: 150mV (line)

Dimensions: 420 x 352 x 126mm

Weight: 8kg

Year: 1991

Price: GBP £240 (1991)



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Reviewed Nov 24th, 2016 by Vecino

I have had the A-400 for some 25 years. It is fantastic. Just one problem: nowadays it seems to be very difficult to tune it to a very low output. If I want an undistorted sound, I have to turn it up to (too) loud.

Reviewed Apr 04th, 2016 by dubstepic

I heard a lot about this amp. And when I seen it for sale cheap I bought it. Amazing detailed sound. Great soundstage and punchy bass. Some say it is bright. I heard brighter for example my Yamaha CA-510. Only bad thing I miss bass/treble corrections.

Reviewed Feb 05th, 2016 by Hallscool

Extremely good sound.
Works very well with digital or analog sources.
Great amp!

Reviewed Feb 28th, 2015 by VISHALFERNANDES

excellent amplifier. totally flat response.

Reviewed Oct 08th, 2014 by Simon Spiers

What you put into the input comes out of the output!
Phono stage is a bit coarse, used models will need the volume put replacing or at least cleaning.
Capable amp with great load tolerance lots of mods out there supposedly improving performance.
Used mine for 15 years now, still going strong.
A real good amplifier.

Reviewed Apr 10th, 2014 by Lawrence13

I have one from 1992, upgraded with the Tom Evans mod plus DNM slit foil capacitors when I stopped using it for a valve amp in 1999 ish for a valve amp I forgot all about it. Anyhow 2012 I go for the Lavardin IS and several weeks ago I upgraded to the IS ref and as the only valve I had left was lent out to a friend I dug out the trusty old Pioneer A-400 and was astounded just how good it still sounded, not as clean an open as the Lavardin but blimey it drove my twin Lowther horns a treat.

Now some say Lowther and horns due to their efficiency don't really go together with budget transistor amps but boy oh boy the pioneer sounded great fun with all music popping along , but no sign of harshness.
The Pioneer sounded so good that I was dreading getting my new £3,200.00 quids worth of Lavardin IS ref as I could be very disappointed.
Okay the Lavardin turned up last Friday and yes it does sound cleaner, more detailed than the Pioneer but the Lavardin is 35/45 watts per channel and the Pioneer sounded at fifty watts per channel far more powerful!!

So I would have no hesitation in sticking the Pioneer back in again as in some ways its preferable to the Lavardin.

Shhh...don't tell anyone I said that.

Reviewed Mar 30th, 2014 by fredy

Sorry for my bad English.
For me the best amp I've ever heard in its class and beating many of twice the price.
Unbeatable price-quality ratio.

Reviewed Jan 30th, 2012 by JaS

A good budget amp in it's day (around £250 in 1991), the A400 worked especially well with CD. The MM/MC phono stage was less impressive. The improved A-400X (£300) had numerous tweaks which left it smoother sounding but lost some of the punch and excitement of the original model.



re: A-400

Had one for 3 years in early 2000s. It is a good amp, but that's it. It is not in the same league as something really gem like Audiolab 8000A or Arcam Delta290 Alpha9, not even a Marantz PM80.
It's just a good amp for what it worth.
Considering the age, be prepared to do some service job.

Hi-Fi That Rocked The World

In May 2006, Hi-Fi Choice's reviewers sat round an email client program and between them came up with the 50 most important hi-fi components ever sold in the UK. The results were published in an award-winning supplement Hi-Fi that Rocked the World. If you missed it, here's the top ten:

1. Linn Sondek LP12 turntable
2. NAD 3020 integrated amplifier
3. Quad ESL-57 electrostatic loudspeaker
4. Rega Planar 3 turntable
5. Pioneer A400 integrated amplifier
6. B&W Nautilus 801 loudspeaker
7. BBC/Rogers LS3/5a loudspeaker
8. Marantz CD-63 MkII KI Signature CD player
9. Garrard 301 turntable
10. Wharfedale Diamond loudspeaker

re: Hi-Fi That Rocked The World

what about Nakamichi and thorens and MOST,,, "MCINTOSH TUBE AMP",, M400 I THINK, HAS FREqUENCY RESPONSE UP TO 40kHZ THATS 40,000 HZ.. DBL WHAT HUMANS CAN HEAR..???JUST A THOUGHT and speaks go to Klipshe.

re: Hi-Fi That Rocked The World

Pandovski has identified the exceptional accolade bestowed on the A400 which was, and still is a truly remarkable amplifier.

I have been a hi-fi enthusiast for nearly fifty years and whilst I admit that my hearing may not be equal to a 21 year old's, it is well experienced and still capable of detecting and appreciating the delicate nuances captured by high-end equipment that less capable amplifiers do not and in many cases cannot reproduce. Moreover, I have learned to know good sound quality when I hear it and believe me, the A400 is capable of producing both surprisingly good sound quality and expressing those very nuances that give so much life and character to music.

If you are seeking a really laid-back, easy-going listen, then I would say look somewhere else, the A400 certainly can provide an engaging well controlled listen, but it masters on so much more that you won't appreciate!

If you have a relatively small budget, (and here I am talking about no more than £150 for a mint condition unit) but hanker after an amplifier that provides a level of ability way beyond what one would have any right to expect for such a meagre sum, don't hesitate to go for a well looked after A400, in my opinion (and that of many others) an unbeatable buy!

Given a little time to warm-up, from the first note you will be impressed. There is something about the sound quality that commands attention. It is certainly not aggressive, but perhaps more attention seeking, simply because of the level of detail retrieval in every note, complimented by the clear definition of individual instruments no matter what the complexity of the music. One simply finds oneself engaged and attentive to what you are hearing, its just too good to let it pass you by!

The A400's presentation is clear and open with very good treble and bass extension, the mid-range, quite exceptional bearing in mind we are here referring to a so called "budget" amplifier costing around £245.00 when new. Of course ultimately your speakers will determine what you hear and be the limiting factor, but have no doubt about the fact that whether you have a small pair of bookshelf units, or like me, a £900.00 pair of vintage heavyweight floor-standing speakers, the A400 will bring them to life. Take what you save on buying an A400, and spend it on the best speakers you can afford, the A400 will utilise every ounce of their abilities and produce beautiful music!

Pioneer A400

Thank you


TQ bro

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