Hi, i am RishiGuru and from India. This is my first post on ecoustics. I am a newbie and new in the world of audio & audiophiles. Recently I bought this Yamaha DSP-A2070 [British Model] amplifier from a person at INR 8K [$160]. My dream of meeting an audiophile also came true.
I am so happy to have my first true audiophile grade amp. I am overjoyed right now. Kindly bear with me. And also with my English.
Well at last it seems that I started my surround-career with the Yamaha DSP-A2070. This is a "BEAST MASTER" of an amplifier and Yamaha's only second surround sound amplifier released in the year 1993 with a list price of $2000.
It has Dolby Pro Logic and all kinds of Yamaha Sound Field Processing (DSP) options. The DSP settings are incredibly complex and you can spend half of your life in those settings. It will take me some time, but anyway back in 1993 with such a sophisticated amplifier, Yamaha was ahead of its time & competition. The sound fields are calculated digitally.
The disadvantage seems that the front & rear surround channels seems to be weak compared to the main stereo & center channels, in other words the four surround speakers cannot keep up with the left, right & center speakers.
Still, there is something magical in the sound of the DSP-A2070 especially in true stereo mode that spells in my ears that it is staying with me for a long time. I am going to keep this Yamaha beast around. Sometimes I will also need to check whether I am going the right direction with my main setup.
If I want, I can also connect new or guest speakers to it, just to see what would happen. It is just fun to play around with A2070. It has got so many options. I can also use it as a pre amplifier.There is simply something magical to its sound that just makes me sit up and pay attention. It has immense power and drive; really making you part of the music.
Sure, it had mind boggling BASS & SLAM, this comes like a big tidal wave and simply washes you out. Tight, precise and solid with exact timing.
The detailing of mids & highs is also spot on and man it could really rock. The detailing and high frequency smoothness and extension, even in the context of a music setup(stereo mode), I am sure it can slay many well known amplifiers from Marantz, NAD & Bryston. I really like my DSP-A2070.
As rightly pointed out by its previous owner who happens to be an audiophile, this Yamaha DSP-A2070 simply refuses to die. He said once he ran this amp at full volume at his sisters marriage for the whole evening. He got the new Krell 300i by then and so wanted to test his 15 year old Yamaha A2070 to its limit. The center speaker blew. Nothing happened to the amp.
It is so incredibly heavy at 21 kgs, you need real muscle to put it in a rack. The internal electronic & mechanical components used are of very high quality & Yamaha seems not to have cut any corners with their top of the range "Signature Amplifier" of 1993.
You have no idea how big the EI power transformer is, it seems to be a 800VA plus & is simply gigantic. I very closely looked at this transformer, Japanese audiophile companies have this incredible love of EI transformers over toroidal ones, but is seems they have somehow perfected the black art of creating EI transformer which produces no hum.
Now comes the the humongous "tower power capacitors". What else than from the world's best. You have a pair of [B]Nichicon Great Supply Type-I Audiophile Grade, 22000uF, 71WV capacitors[/B] for the main stereo and center speakers. This caps are 4 inches tall and 1.5 inch in diameter and very heavy. This is the reason why Yamaha uses clamps to hold this caps to the chassis. And there is another pair of Nichicon Great Supply Type-I Audiophile Grade, 8200uF, 40WV capacitors for the four effect speakers.
So you end up with an almighty power supply consisting of a giant transformer & 60,400uF of pure HiFi grade Nichicon power. Now I know from where all this titanic power comes from. Mind you the above transformer & caps takes care of the power amp module only and are dedicated to power output. There is a separate smaller power supply unit with separate power caps that takes care of the DSP & other modules.
This power supply also allows Yamaha engineers to add an additional bass feature namely "Bass Extension". While the bass knob allows you to add +/- 10db (50 Hz) the bass extention adds another +7db (70 Hz). So now you can get +17db over the reference, which is a tremendous achievement from the bass boosting point of view. All of this due to its "King Kong" power supply.
The power amplifier module of this A2070 is discrete as it uses a pair of Toshiba 2SA1302/2SC3281 power transistors in push pull mode for each of its right, left & center channels. Each of these pairs has a rated 150 watts of peak dissipation and can easily pump out 100 watts of continuous power. So 300 watts & six power transistors here.
The four effect speaker channels uses a pair of Sanken 2SA1726/2SC4512 power transistors in push pull mode for each of the four surround channels. Each of these pairs has a rated 50 watts of peak dissipation and can easily pump out 35 watts of continuous power. So 54 watts & eight power transistors here. Fourteen power transistors in total.
All the electronic & mechanical components used in this amp are of "GRADE-A" variety, and are simply built to last for generations. The A2070 is supeflous with ultra high quality Nichicons and very high quality Panasonic (Matsushita) capacitors. Even after 15 years of abuse they seem new. Not a single leak from a single cap. Just speak of quality. Same goes for transistors, IC's, diodes, resistors, control pots, PCB's, wires & even the nuts used to mount the power transistor to gigantic heat sinks are of aero space grade.
And the heatsinks, man they are like the gates of a dam, so big & huge. Today I dismantled the DSP, pre amplifier module & the protection function circuit of this amp. Seems pretty sophisticated. I will analyze and provide the details later.
Now let me give you an example of the real strength of this amp: 1)Total Minimum Continuous Power(RMS): 100 + 100 + 100 + 26 +26 + 26 +26 = 404 watts @ 6 ohms @ 0.015% THD 2)Signal to Noise ratio : 96db + 3)THD: 0.005% 4)Dynamic Headroom : 2.0db @ 6 ohms
Remember that 2.0db headroom is when the DSP-A2070 is under full load from the seven speakers. When in stereo mode, only two speakers are active, so dynamic headroom will be over 3.0db.
3.0db dynamic headroom means that while A2070 is perfectly capable to deliver 100 watts X 2 = 200 watts of continuous power through the main stereo speakers, it can easily handle 200 watts X 2 = 400 watts of transient peaks in power output. This is an Incredible achievement. Very few amps have this type of monstrous capability. This amp can simply achieve two times its rated power output with out a hint of strain.
Yamaha's current top of the line stereo amp($2000) AS2000 have a dynamic headroom of only 0.67db @ 8 ohms. Marantz PM7004 & SR6003 have no such rating!!!;)