PSR-S970 is bi-amplified. What does it means this?

arvacon · February 24, 2018, 04:40:08 AM

I was reading this article and I have a query.
http://sandsoftwaresound.net/s770-s970-internal-arch/

I know that maybe I have understand this mistakenly, but I would like to know the difference and the reason of this.

The S970 is biamplified with two digital power amps (2*YDA164C).
The S770 has one digital amplifier (1*YDA164C).

As I see both have the same watts of speakers, and yamaha says in the bellow document, that this amplifier is a 20watt x 2channel, so one should be enough for both models.

http://download.yamaha.com/api/asset/file/?language=ja&site=jp.yamaha.com&asset_id=46325

Does the S970 use the second amplifier for something else or is it one amplifier for right and one for left channel?
What does this means in the real world usage?

panos · February 24, 2018, 04:49:55 AM

https://en.wikipedia.org/wiki/Amplifier
In human language I guess more "clear" sound maybe?

arvacon · February 24, 2018, 04:54:35 AM

Quote from: panos on February 24, 2018, 04:49:55 AM
In human language I guess more "clear" sound maybe?

Or maybe they were planning to use more powerful speakers for s970 and finally they changed their mind last minute.

panos · February 24, 2018, 05:01:35 AM

hahaha
I believe for the two models to have such difference in prices,the s970 got to have and support better sound.
Someone may use other speakers than those on board.
Look at how many members are using the s970 for playing live.
It is not just the color screen and some more styles.

arvacon · February 24, 2018, 05:10:47 AM

Quote from: panos on February 24, 2018, 05:01:35 AM
Someone may use other speakers than those on board.

Yes probably this has better sound, but these 2 amplifiers have nothing to do with the external speakers that you connect at audio out. The signal of the audio outputs is just preamplified and needs amplified speakers or external amplifier as PA systems to amplify the sound.
If in case the reason was the bigger build-in speakers, then that means that if someone modifies the instrument's speakers, he could use (in theory) 2x20watt speakers for every channel!

panos · February 24, 2018, 05:31:24 AM

...and pump up the volume and get the police out of his door!

You waitting for your new s770?
That's cool Arvacon!

arvacon · February 24, 2018, 05:43:06 AM

Haha, yep they will call 100 for sure!
I hope the s770 to be a huge upgrade compared to my poor e453.
I am waiting at anamena karvouna!

panos · February 24, 2018, 05:59:39 AM

Arvacon means he is too anxious for his new keyboard.
You got it at a great price and it worths every cent.

arvacon · February 27, 2018, 05:03:11 AM

Where is PJD friend to give us his lights here?

pjd · February 27, 2018, 05:51:54 PM

Hi --

PJD has been traveling on airplanes.

The key word is "bi-amplified." The digital amplifier is stereo. In the S970, one digital amp drives the two tweeters and the other digital amp drives the two woofers. In the S770, each channel of the digital amp drives a woofer/tweeter pair. (Picture attached.) A passive high-p[ass filter (HPF) suppresses low frequencies going to the tweeter.

The S970 does have a better sound system and should have all of the usual advantages of biamplification.

Hope this helps -- pj

P.S. The actual circuitry exceeds the specifications in the Owner's Manual.

[attachment deleted by admin]

arvacon · February 27, 2018, 06:17:37 PM

Thanks for your reply from the sky

This sounds like a big deal then, as theoretically bi-amplified system's sound quality can compared with the 2.1 speakers instead of just 2 speakers systems at desktop pc.
There must be difference in clarity I guess, but is the difference between the s970 and s770 sound systems so noticeable in person?

Does this difference means that when you turn the volume up at s770, that the sound will start to distorting?

Do they have any difference at the pre-amplifier of audio output too?
What do you mean exceeds the specifications?

Ps: Are you a pilot?

panos · February 27, 2018, 11:20:10 PM

hmmmm...

I didn't understand much but I understand that s970 have a better sound somehow,
and a Twitter account!!!

Thanks pjd

Toril S · February 27, 2018, 11:45:58 PM

I'll make a tweet on my S970

arvacon · February 28, 2018, 12:51:08 AM

Quote from: panos on February 27, 2018, 11:20:10 PM
hmmmm...
I didn't understand much but I understand that s970 have a better sound somehow,
and a Twitter account!!!

Thanks pjd

Hahahahaha, twitter account! lol

pjd · February 28, 2018, 01:23:52 AM

Quote from: arvacon on February 27, 2018, 06:17:37 PM
Do they have any difference at the pre-amplifier of audio output too?
What do you mean exceeds the specifications?
Ps: Are you a pilot?

Hi --

Not quite sure what you mean by "pre-amplifier of the audio output." The Yamaha YDA164C has an integrated DAC. It receives a serial digital audio stream from the tone generator integrated circuit (IC). It's all digital right up to the YDA164C.

WRT the specifications, I may have misled you (and me, too.

) After looking at the data sheet for the YDA164C, the amp is 20Wx2 "Maximum Instantaneous Output" and 15Wx2 "Maximum Continuous Output" into a 4 ohm load (i.e., a 4 ohm speaker). This is the old "peak vs. continuous" rating disparity. The spec in the Owner's Manual probably refers to "Maximum Continuous Output".

I don't know enough about the analog design to say if the S970 digital amps are further throttled back to 15W continuous for both tweeters and woofers, or if the design is 15W plus 15W per channel due to bi-amplification.

Whether the S970 actually sounds better than the S770 to the ear, I couldn't say because I haven't A/B tested them.

Hope this helps -- pj

P.S. Pilot? No. Just a grandparent whose grandson lives far away.

arvacon · February 28, 2018, 01:34:50 AM

Quote from: pjd on February 28, 2018, 01:23:52 AM
Not quite sure what you mean by "pre-amplifier of the audio output."

Let's say that we use a similar voice for both instruments. Will they perform the same if you connect them to a PA system via audio output or is there any difference at the sound that it comes from that output too? Is the audio out circuit similar to both keyboards?

pjd · February 28, 2018, 02:58:57 AM

Hi --

The S970 and S770 use exactly the same DAC and post-DAC circuitry. The DAC is the AK4396VF-E2. If the S770 and S970 are set to the same voice, I would expect the audio signal through the direct stereo outputs to be the same. [Purists would add: "Modulo the usual variation due to slight differences in component behavior, etc. etc." But, this is just being a snob.

]

Practically speaking, they're the same.

-- pj

arvacon · February 28, 2018, 03:04:41 AM

It feels nice to know our instruments from inside as outside too.
Thanks pjd for the great info, you have enlighten me totally.

arvacon · March 13, 2018, 03:25:42 AM

I was looking at the service manual tonight from curiosity and I found some more info about the difference of the 2 models about the speaker system.
There are some nice info of some folks of the German Yamaha forum, that worth to read.
Here is the link

Here are the interesting info that a member mentioned.

Quote
PSR-S770
YE178A00 SPEAKER 13.0cm 4ohms 20W WOOFER
YD681A00 SPEAKER 5.0cm 6ohm 10W TWEETER

PSR-S970
YE177A00 SPEAKER 13.0cm 4ohms 35W WOOFER
YE179A00 SPEAKER 2.5cm 4ohm 20W TWEETER

The S770 has as a tweeter only "normal" 5cm / 10W speakers and woofer speakers with 20 W load capacity,
the S970 , on the other hand, has so-called 2.5cm / 20W " dome tweeters" (and thus probably the "better" treble reproduction) as well as woofer speakers with 35 W load capacity.