YAMAHA AX-1200

[Mr.sylaw]

Specs

Rated output (20Hz-20kHz) 185W + 185W (6Ω, distortion 0.003%)

Dynamic power 460W + 460W (2Ω) 360W + 360W (
4Ω)
290W + 290W (6Ω)

Input sensitivity / impedance Phono MC: 160μV / 220Ω
Phono MM: 2.5mV / 47kΩ
CD etc .: 150mV / 47kΩ
Main in: 1V / 47kΩ

Maximum allowable input (1kHz, distortion 0.01%) MC: 13.5mV
MM: 170mv

Frequency characteristic All inputs: 20Hz to 20kHz ± 0.5dB

Total harmonic distortion (20Hz-20kHz) 0.003% (MM → Rec out, 3V)

0.007% (CD etc. → SP out, 72.5W, 8Ω)
Damping factor 350 (20Hz-20kHz, 8Ω)

S / N ratio (IHF-A) Phono MC: 68dB (250μV)

Phono MM: 86dB (2.5mV)

CD etc .: 110dB (Pure Direct SW on)

Residual noise (IHF-A) 35 μV (Pure Direct SW on)
Tone control Bass: ± 10dB (20Hz)
Turnover frequency: 200Hz, 400Hz
Treble: ± 10dB (20kHz)

Turnover frequency: 2.5kHz, 5kHz
Subsonic filter 15Hz, -18dB / oct

Maximum correction amount for continuous loudness -40dB (1kHz, depending on the hearing correction curve)

Power supply AC100V 50 / 60Hz

power consumption 260W

External dimensions Width 473 x Height 171 x Depth 448 mm

weight 26kg



I recently purchased this unknown beast of an early 90s Class A amplifier. I first auditioned this solid state with a pair of a Focal Diablo utopias at a local store. needless to say i was blown away by the performance. it had a very airy presentation and the projection was almost atmospheric. The mids were crunchy and the lows were very controlled. For the first time i felt like i need to buy this right now. this is pretty rare for me (specially i never felt this way for a Yamaha)

After listening to this i immediately ran back and purchased this amplifier for 145,000 LKR (around 750$) . Although i my self don't own a pair of focals , i own few pair of diatone speakers. With this amplifiers my Diatones came back to life. Although i find the amplifier is particularly amazing with my Diatone Ds-800ZX. i always felt like it needed more than its rated energy to spit outits best, and this amplifier did just that.

Ultimately with my nw found love with this amplifier got me all curious as into why this device is not as popular as the lower end model "AX-900". Are there any folks who use the AX-1200 or has any experience to share with?

 

[Bratwurst7s]

I believe that the AX-1200 is the Japan market version of the AX-1070. Production about 1994. Great series of amps, I have an AX-1090 and used it for 20 years before replacing it with my current CX-1/MX-1 amps.

Being a series released only in Japan there are usually some small detail improvements over the models sold outside Japan. I'll have to look around and see if I can find a service manual for the 1200, but it should be very similar inside to the AX-1070.
HiFi Engine has the SM for the AX-1070: https://www.hifiengine.com/manual_library/yamaha/ax-1070.shtml

The AX-900 is simply more plentiful than the later "thousand" series. In my opinion your 1200 is a much better amp. The 1200 isn't less popular than the earlier amps so much as there were simply a lot less of them produced.

To the best of my knowledge it is not a class-a amp but rather class-ab. It will deliver an honest 145wpcRMS @ 8 ohm. The only weak point is the input selector switch, which gets oxidized. When that happened to mine it started dropping a channel. Spraying the switch with Deoxit cleaned it up for me. In a worst case situation the switch may have to be de-soldered from the board it's mounted to to get complete access to the contacts for cleaning.

Enjoy the amp, it's a keeper!
James

 

[Mr.sylaw]

I believe that the AX-1200 is the Japan market version of the AX-1070. Production about 1994. Great series of amps, I have an AX-1090 and used it for 20 years before replacing it with my current CX-1/MX-1 amps.

Being a series released only in Japan there are usually some small detail improvements over the models sold outside Japan. I'll have to look around and see if I can find a service manual for the 1200, but it should be very similar inside to the AX-1070.
HiFi Engine has the SM for the AX-1070: https://www.hifiengine.com/manual_library/yamaha/ax-1070.shtml

The AX-900 is simply more plentiful than the later "thousand" series. In my opinion your 1200 is a much better amp. The 1200 isn't less popular than the earlier amps so much as there were simply a lot less of them produced.

To the best of my knowledge it is not a class-a amp but rather class-ab. It will deliver an honest 145wpcRMS @ 8 ohm. The only weak point is the input selector switch, which gets oxidized. When that happened to mine it started dropping a channel. Spraying the switch with Deoxit cleaned it up for me. In a worst case situation the switch may have to be de-soldered from the board it's mounted to to get complete access to the contacts for cleaning.

Enjoy the amp, it's a keeper!
James

This is some great information James. very insightful and i didn't know that this was a JDM version of the AX-1070. That would be great if you can find a service manual for me . Also after some searching i found out that the ax-1070 and the ax-1090 are pretty much the same amplifier apart from the "Residual Noise (IHF-A Network)".. Since I'm from a country called "Sri Lanka" we get most JDM Hi-Fi products directly from vendors in japan. So i guess now i know how i got a domestic unit.

Also correct me if I'm wrong, I thought Yamaha used a class A design of their own to get better SQ out of these amplifiers. I came across this bit of information from "audio heritage" --- "The Yamaha original HCA circuit which compensates an ideal class A operation in the full load and all power range is adopted as a power amplifier. By using the logarithmic characteristics of the I C- V BE characteristics of the transistor as they are, a dual-conversion amplification (hyperbolic compaction amplifier) that can obtain linear rigidity characteristics without cutoff in the entire power region Application)"

Does it mean that these amplifiers have some sort of Qazi class A circuitry where in reality its just an class A biased class AB design ?

 

[Bratwurst7s]

To be honest I don't really understand that HCA circuit but believe it to be something like what you stated, A biased AB.

The 1090 is the 3rd version of the series. AX-1050 -> 1070 -> 1090. Each is a further development of what came before. All are very nice amps.

I have done a little looking but I think that the 1200 SM will probably take a good bit of time to find online. Another option is to look for an original copy on ebay, I have found quite a few service manuals that way and it's always better to have an original paper copy in my experience.

I work with a couple of guys from Sri Lanka. Good fellows.

Cheers,
James

 

[Mr.sylaw]

To be honest I don't really understand that HCA circuit but believe it to be something like what you stated, A biased AB.

The 1090 is the 3rd version of the series. AX-1050 -> 1070 -> 1090. Each is a further development of what came before. All are very nice amps.

I have done a little looking but I think that the 1200 SM will probably take a good bit of time to find online. Another option is to look for an original copy on ebay, I have found quite a few service manuals that way and it's always better to have an original paper copy in my experience.

I work with a couple of guys from Sri Lanka. Good fellows.

Cheers,
James

haha i suppose as Sri lankans we are pretty chill I will check it for sure james. Also do you think this series of amplifiers are on the bass light side? or do you think its because of my insufficient step down converter? does it even effect the sound ( specially the low frequency's?) im using a 500W step up converter to hit the 230V in my country. i Heard some people are using 1500W step up converters? the amplifier consumes about 260W

 

[Bratwurst7s]

I would think that ~double the max pull would be enough but I have never used an amp on a step-down converter and am not at all sure. I suppose that there is 1 way to find out.

I never thought of my 1090 as being light in the bass dept. Bass did tighten up some when I went from the 1090 to the MX-1, but it has more power and is a high current amp with dual transformers and just does a better job of controlling the dual woofers in my speakers.

Cheers,
James