New amp sounds too controlled ... what to fix

[Coolin]

Just bought a new AV amp from Yamaha but the sound is too controlled, its killing the expressive musical quality of the music.
Now i got it for the surround channels and figured i will just use my own amps for the fronts if the sound is not what i expected.
But the other channels should be expressive as well.

Now for the price i got it i dont really want to send it back and get something else. I'm hoping i can revive some of its qualities by reducing the feedback on the outputs. This is how it sounds to me. I have experiance buiding a few gainclones and willing to dive into the interior of my NEW amp but i'm hoping i can get some pointers here as what could be the cause of the too clean sound. Its has plenty of detail but lacks the free flowing quality i much seek.

Now please be gentle as this is just a hobby for me..
If i decrease the feedback then i will have more gain and this will need to be compensated by lowering the incomming signal right?
First i'll need to find out what exactly is powering the amp

the specs say the amp has a damping factor of 120. Its also still breaking in but i doubt very much it will improve to the point i want.

I will post pictures later today.

Thanks, Collin

 

[PMA]

Put a resistor in series with speaker cable.

 

[Coolin]

Theres already quite alot of R in the X-over coils and its not enough...


Oh and i also lost some low end going to Yamaha compared to an old cheap sony amp.
Unfortunately my chipamp is stored at the moment as I am moving soon.

 

[homemodder]

If you have just bought it, let it run in for a week or two, the sound changes and maybe youll like it.

 

[Coolin]

Yes i will but i dont think thats enough..

 

[h_a]

Put a resistor in series with speaker cable.

May I ask why reducing the damping factor could help?

Don't forget to use a high-power resistor.

Have fun, Hannes

EDIT: @original topic: I don't think reducing negative feedback is a good idea. First, it increases gain, so the usable way of your volume control is reduced. 2nd distortion will go up and you don't know by how much. If you go too far with this, it might become a distortion generator.

 

[Coolin]

Reducing the damping factor will diminish the control of the amp on the woofer thus letting it move more in its own will (driver / box / environment interactions)

I Have used a very high gain on my chip-amp and it sounded much better than low gain. Yes the volume becomes an issue that’s why you need to reduce the incoming signal. Not sure about the best way to do this though … That’s one of my questions.

May I ask why reducing the damping factor could help?

Don't forget to use a high-power resistor.

Have fun, Hannes

EDIT: @original topic: I don't think reducing negative feedback is a good idea. First, it increases gain, so the usable way of your volume control is reduced. 2nd distortion will go up and you don't know by how much. If you go too far with this, it might become a distortion generator.

 

[lineup]

Use one Tube Power amplifier, instead.
You will soon run out of control plenty enough & get those sounds.

My reasoning is
that you can sell your Natural Sound Yamaha on eBay,
in ORIGINAL Un-destroyed status.
And get one amplifier that suits your 'Sounds' better.

Tube amplifierd are know to often have very low damping factors.
Problem might be that there are more advanced modern valve power amps,
that may even have better damp factors
So look for very old tubes amplifiers, please.
Before year of 1950 is a good bet
So called Vintage -- they do not always come very cheap, man.

Also a few of Nelson Pass' amplifiers are known to very well out of control.

For example F1, F2, F3, F4, F5 line should not have too high damping factor level.
They ar built for to adjust themselves to the speaker impedance
www.firstwatt.com


Lineup
Lineup Audio Lab - where we take pride in making power amps
with damp factor close to 0.1 ... or lower!!!!

 

[Coolin]

Yes, tube amps, I know, lots of $, F1,F2 amps not an option.

thanks for your views but I’m not getting much advice in the direction I’m asking for….

HOW to change the sound on this model to suit my tastes. I know it can be done as I have done something similar before but not on a brand new who know how it looks like on the inside AV amp..

When the pictures are posted I hope I get some helpful answers.

 

[wg_ski]

Oh and i also lost some low end going to Yamaha compared to an old cheap sony amp.
Unfortunately my chipamp is stored at the moment as I am moving soon.

The Sony amp may not have been flat to begin with. Was the loudness function on? The cheap amp may have also had some other built-in bass boost to help compenate little bitty speakers. When it's gone you will miss it.

If the new amp has pre-out/main-in, get a parametric equalizer. Then you can adjust it the way you like it. You're only going to be able to change the response near resonance, and somewhat at the crossover frequency, by adding series R with the speaker. An EQ can do more.

 

[Bonsai]

quote
"Just bought a new AV amp from Yamaha but the sound is too controlled, its killing the expressive musical quality of the music."
unquote

Try a glass of Aussie red about 20 minutes before your listening session.

Works wonders mate.

 

[h_a]

Reducing the damping factor will diminish the control of the amp on the woofer thus letting it move more in its own will

Not exactly like that, I refer to D. Self. The passive crossover really cooks damping factor down. As does the usual Zobel.

Try a glass of Aussie red about 20 minutes before your listening session.

Now that's some real advice.

A lot of amp shortcomings can be fixed that way. Unfortunately it's not permanent.

Have fun, Hannes

 

[Coolin]

PROBLEM SOLVED !! Back EMF

Hey guys it actually IS the damping factor.

Now I've got very lightweight cones so this could be the reason its so audible but using the resistor really works !
But dont use it in series ! It improved the low end but not much more than that. Use it Parallel. My reasoning is it gives the back emf (motion from the cone without applied signal) from the drivers a chance damp in the resistor as the amps resistance is too high to be of any good.

Now while it is a good solution sound wise i still dont like it..

What can be done to the amp itself to lessen the damping factor??
There are indeed ams with adjustable damping factors, that would be nice but not practical for this amp..

Picture of the output stage coming next . Looks pretty standard to me but i know very little

Can someone point me to information ?

Thanks, Collin

 

[PMA]

The best solution is another amplifier, or ...

 

[AndrewT]

a damping factor of 120 sounds quite normal.
What impedance is that into?
How does it vary with frequency?

Adding half an ohm in series with the speaker cable will reduce the damping factor to lower than just about any SS amp on the market.
But it will also alter the Q of the speaker and may sound a bit boomy after adding the resistor.

Have you read the ESP site yet?

 

[Coolin]

output stage

The sound is now close to the sony amp. Still a little more compressed though

 

[Coolin]

Originally posted by AndrewT
a damping factor of 120 sounds quite normal.
What impedance is that into?
How does it vary with frequency?

I saw a curve for a different model Yamaha someone measured and it was lower in the bass area but still somewhere around 50 or so.
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Adding half an ohm in series with the speaker cable will reduce the damping factor to lower than just about any SS amp on the market.
But it will also alter the Q of the speaker and may sound a bit boomy after adding the resistor.

It was actually 6,8 Ohm ! in series. Ive gor 15 ohm in Parralel now.
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Have you read the ESP site yet?

A long time ago, going to check it again...
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[Coolin]

Adding half an ohm in series with the speaker cable will reduce the damping factor to lower than just about any SS amp on the market.
But it will also alter the Q of the speaker and may sound a bit boomy after adding the resistor.

[/B]

Yes the sony amp sounded boomy with a different bass driver..

This experience i speak of are with pro drivers, light weight and heavy motors, low Qes.
I guess every extra Hz you can get out a driver with a high Fs has a big impact. Still, it worked for the midrange driver as well, also very light cone.

!!!!! So could this be the heavenly match between tube amps and high eff. drivers !!!!!

Gr, Collin

 

[Conrad Hoffman]

Coolin, you said it improved when you put 15 ohms in parallel. That actually increases the damping seen by the speakers, though not by much. My guess is the amp is now supplying more current (you have to drive both the resistor and the speakers) and maybe the amp isn't very good at low power levels- it just likes working a bit harder, or it doesn't like the cables, the speakers or something. As long as the combined value isn't too low, I'd just leave the resistor in parallel.

 

[Lumba Ogir]

Hi,
I strongly suspect the notorious Japanese commercial amplifier philosophy of huge open-loop gain an GNF resulting in an extremely clean, lifeless sound without any kind of warmth, spirit and dimension. The musical qualities can thereby be rated as negligible.