[LM3886] Best resistor value for mute ?

[carlosfm]

BTW, this amp ( 94V ) is driving a pair of speakers with a sensitivity of > 96dB and a bass that goes down to almost 2 Ohms!
This speakers really puch the chip! And still no problems

Really 'punch' the chip?
They are not easy to drive, but they play loud.
I bet you never listen to the amp at more that 1W, so why do you think your amp at that PSU voltage is reliable?
Try other speakers and the story will be very different.
I don't think you like those speakers, otherwise you would worry.

why is it that your chip survives xelb?

Answer is above.

 

[XELB]

My mistake! It's not "puch" it's -> they really pull out all the juice from the chip


Carlos, the 1200VA Trafo gets really hot!
And yes, they play really loud with just 1W. But as you imagine, we have tried the chip with others speakers.
I don't know what is worse to drive... 1 driver with 89dB sens. or 8 drivers with >96dB and a bass that goes down to 2 Ohms

If you don't believe, you are right now invited to listen to the amp at 94V!

 

[Greg Erskine]

I'm sorry XELB,

I meant no disrespect. I should have put a few smiles on the post.

I think its good to push things to the limits and see what happens and I was encouraging you to break the 100v barrier(well I thought I was). I also imagined you were the type of guy that also has wound up his computer to the max.

Again I'm sorry, it was all in jest.

Regards

 

[XELB]

Greg, no hard feelings


I just like the sound of the LM3886 under these circumstances. That's all.

I'am not advising to do this.... We burn a few chips till we got the "setup" stable.
Now runs perfect, even if we listen for 4 hours in very loud volume.


What I really advise is, connect the mute pin directly to the -Vcc
This seems radical but it works just fine

 

[carlosfm]

Carlos, the 1200VA Trafo gets really hot!
And yes, they play really loud with just 1W. But as you imagine, we have tried the chip with others speakers.
I don't know what is worse to drive... 1 driver with 89dB sens. or 8 drivers with >96dB and a bass that goes down to 2 Ohms

Sensitivity doesn't mean hard to drive, it just means how loud they play.
So, as you don't specify an impedance curve for those 89db speakers, assuming that they don't dip to 2 ohms as the other ones, they are easier to drive.
Also, you don't specify for the other speakers at what frequency they have that dip to 2 ohms. If it's in the bass, they are really hard to drive.
If you push the amp, at those PSU voltages and with those kind of speakers, SPiKe protection will trigger in.
In extreme circumstances you may kill the chip, but that seems to be no problem for you.
What you're not thinking about is that a burned chip can put high DC on your speakers and kill them.
But who am I to advice you, if you are happy and you don't care about that?

 

[XELB]

I know that sensitivity doesn't mean hard to drive!
I just said that they are sensitive but hard to drive.

If want get a decent sound with these speakers, you must use a Krell KAV300 or something better....
Audio Analogue Puccini SE doesn't "move" these speakers...
They need good capacitance and lots of current.

For example, the Jeff Rowland Concerto amp(LM chip based) lacks of deep bass when connected to these speakers but, it as a remarkable detail in the mid and treble range.


The LM3886@94V after getting hot, also as a very decent detail, especially in the mid range.
The bass range lacks of detail and deep bass, when compared with de KAV 300.
But this issue is due to the PSU… it was a fast implementation, so there's a lot to improve in this area.

We also are using just one 480uF cap(per rail) near the chip LOL

 

[XELB]

If you push the amp, at those PSU voltages and with those kind of speakers, SPiKe protection will trigger in.
In extreme circumstances you may kill the chip, but that seems to be no problem for you.
What you're not thinking about is that a burned chip can put high DC on your speakers and kill them.
But who am I to advice you, if you are happy and you don't care about that?

If the builder doesn't worry about them, why should I ?

At home, mine is at ~62V, and I will leave it this way!
But I prefer the sound of the chip under 94V

 

[carlosfm]

The LM3886@94V after getting hot, also as a very decent detail, especially in the mid range.
The bass range lacks of detail and deep bass, when compared with de KAV 300.
But this issue is due to the PSU… it was a fast implementation, so there's a lot to improve in this area.

We also are using just one 480uF cap(per rail) near the chip LOL

There surely are things to improve there, because those caps near the chip are small.
I've had a Krell KAV-300iL at home and the bass of my chipamp has dynamics on par with it, but tighter bass.
Everything else (mids, treble, detail, etc.) is much better on my amp than the Krell, in original form.
Modified, the Krell still was a little behind from what I'm used to hear on my main system.
Even using the Krell as a power amp, connected to my pre (huge difference), my amp was still better.
My PSU is ~+/-32 VDC.

I'm not so sure if you can conclude that using that extreme voltage sounds better, are the amps exactly equal?

 

[XELB]

As I told in my last post, I not comparing the sound of my amp(bridge @ +/- 31) with the single ended @ 94V.
I just said that I like the sound of the chip at 94V.
We compared the same LM3886 setup (the single ended) working at different voltages.
What we liked most was at 94V. That's all....


The KAV300 it's a nice amp.
It's not perfect in any range but its "good" in all.
I've tested other amps of the same price... but If I add to buy an amp, think that I would buy this one in second hand
I love "him" when "he" plays with the Rega pre-amp and Rega P3 turntable.... It smacks big budget setups, like the ones we found in the Audio Show. hehehehehe


The LM3886 setup needs a new PSU, that's for sure, and new LM PCB boards also.
That’s on the way...


Carlos, you have that "performance" with a small trafo of 280VA ?

What capacitance you have per rail ?

 

[carlosfm]

Carlos, you have that "performance" with a small trafo of 280VA ?

What capacitance you have per rail ?

What do you call a small trafo?
I use around 30,000uF per rail.
And I have similar results with a regulated PSU, with just 4,700uF before the regs.
What, do you really think performance is just a matter of PSU capacitance?

Let me tell you that the KAV-300iL integrated amp in standard form is not better than an old Pioneer A400, again, in standard form.
Surprized?
I don't care about brands and fancy looks, it must prove to sound good.
The KAV-300iL is not a good amp.
If you use it as a power amp, it's not bad, but it's very far from justifying it's price.
And IMO it's a huge waste of electricity.

 

[XELB]

I don't Know the A400, only from reviews but, I know that some old Pioneer amps play quite well ( some of the Reference Series )


Justifying it's price ? What better amp do you buy with less then 1500€ ?
Let's forget this question, we are here to "judge" buy the sound and not buy the price!
BTW, I have never used the KAV as an integraded.
For me, the ideal setup is, pre + power amp!


Performance is not only a question of PSU capacitance.
A good design combined with a good trafo and ideal capacitance for the setup( speakers included ) it's a big step forward to achive a top amplifier.


I said small trafo because if you use a 280VA and if you have a really hard speakers to drive, you will lack of current.... just my opinion!
That's why I asked how you have better performance.