Yamaha YST-A5 ?

legal eagle

legal eagle

Sound Hound
Got a Yamaha YST-A5 amp. It's a smallish amp, the size od a monoblock, but its actually a full amp, with some interesting features: it has inputs for a pair of speakers, and then there is a speakers INPUT. There is a rotary knob on its back that may be a gain knob, and than there is a cartridge "for use with normal speakers only". To put it mildly, this is not a "normal amp: I looked at the manual (http://www2.yamaha.co.jp/manual/pdf/av/english/zot/YST-A5.pdf
), and quite honestly - I don't understand what this amp is supposed to do that "normal" amps don"t.

I have not hooked it up or tested it yet. It'll take me a few days getting to it.

What can the brain pool here tell me about this amp? Will post pics later, once I get over a tech problem.
 
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Going from memory here having sold Yamaha when the YST gear came out:

The YST amps were designed to work with specific Yamaha YST speakers. They did not have a flat frequency response. They had a frequency response that was the inverse of the bass roll off of the YST speakers, extending their response. Not unlike what Kef did with their KUBE equipped speakers. This was an era when lifestyle audio and multiroom were all the rage and companies were trying to shrink speakers and make them domestically acceptable.

Yamaha realized that making a non linear response amp would limit their sales, so the frequency contour was in the special YST cartridge. Putting a "normal" cartridge in gave an amp with a linear response you could use with any speaker. Clever system let down by generally poor speakers IIRC.
 
Raynald said:
Going from memory here having sold Yamaha when the YST gear came out:

The YST amps were designed to work with specific Yamaha YST speakers. They did not have a flat frequency response. They had a frequency response that was the inverse of the bass roll off of the YST speakers, extending their response. Not unlike what Kef did with their KUBE equipped speakers. This was an era when lifestyle audio and multiroom were all the rage and companies were trying to shrink speakers and make them domestically acceptable.

Yamaha realized that making a non linear response amp would limit their sales, so the frequency contour was in the special YST cartridge. Putting a "normal" cartridge in gave an amp with a linear response you could use with any speaker. Clever system let down by generally poor speakers IIRC.
Click to expand...

Thanks :thmbsp:.

So if I got you right, the "normal speakers" cartridge I have in means the YST amp I have is basically a normal linear anp, with the versatility of plugging a Yamaha specific cartridge for specific Yamaha speakers?

BTW - that's a nice looking frame in your avatar - what is it?
 
You understand correctly, from what I remember.

The photo is my Look 595. The colour is a fairly rare special order White/Metallic Blue from 2007 that is quite stunning in person. I like it because it is so unusual every year I have people very familiar with the 595 ask me if it is a new version. Never looks dated. Absolute gas to ride.
 
YST = Yamaha Servo Technology

In YST mode, it is a negative-impedance output drive to create low amplitude signals in the YST speaker cabinet that in turn create high amplitude bass sound through the port / air woofer (Hemholtz resonator theory). I have one cheap surround YST speaker from the old days, and a surround amp to drive them, but I don't use them anymore. I have always wished I could test similar speakers side-by-side (YST vs normal) as Yamaha has some interesting YST mains in the old days. I use several YST subs now, but they are all active designs.
 
Been using that small wonder for a while now in the home office system. What a sweet little amp! Punchy and clear. I like it a lot. I guess not many of those show up in the market 'cause they just wanna keep them.
 
Sorry to bring up an old thread, can this amp be used in a normal stereo set up with normal components cdp and speakers?
 
If you have the Standard Cartridge for normal speakers it will do fine. If you have the Active Servo Processing cartridge for YST speakers the frequency response will be off.
 
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