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Old 3rd May 2009, 01:15 PM   #1
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Default LME498xx in branded amplifiers

Has anyone seen any branded amplifier using LME498xx?
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Old 21st September 2010, 11:10 PM   #2
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Any luck finding the answer?
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Old 21st September 2010, 11:43 PM   #3
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Not sure about branded but LME498xx Driver and Power Boards Group Buy
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Old 22nd September 2010, 06:12 AM   #4
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I can retrieve the e-mail which is a review for a 498xx based amplifier shown in last CES.
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Old 28th September 2010, 02:34 AM   #5
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I can retrieve the e-mail which is a review for a 498xx based amplifier shown in last CES.
Any luck with this, Panson?
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Old 28th September 2010, 03:17 AM   #6
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Any luck with this, Panson?
Still don't know where it is. I remember it is a US brand.
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Old 28th September 2010, 09:45 PM   #7
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Still don't know where it is. I remember it is a US brand.
Dear Panson,

It almost happened in a commercial France (you can guess the brand) active loudspeaker where I design the amplifiers for... but on last moment we decided to go for the LM4702. Subjectively speaking, the LM4702 sounds more "magic" then the LME49810 on the Sanken STD03.

With kind regards,
Bas
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Old 28th September 2010, 11:00 PM   #8
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Originally Posted by Sebastiaan View Post
Dear Panson,

It almost happened in a commercial France (you can guess the brand) active loudspeaker where I design the amplifiers for... but on last moment we decided to go for the LM4702. Subjectively speaking, the LM4702 sounds more "magic" then the LME49810 on the Sanken STD03.

With kind regards,
Bas
Dear Bas,

Did you compare 4702 and 49811?

Cheers,
Panson
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Old 29th September 2010, 07:27 AM   #9
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Dear Bas,

Did you compare 4702 and 49811?

Cheers,
Panson
Dear Panson,

Yes we did. To be honest in my subjective opinion they sounded the same (despite the fact the LME49811 can deliver slightly more current). I like both 4702 and LME49811 more then the LME49810, but I have to say, all chips sound very good, this is nitpicking and also depends on personal taste. The reason we choose the LM4702 in first instance was more for economical reasons (two channels in one chip, and one heatsink).

However it turned out that I love the sound endless and it was an improvement over the LME49810 we used in the first prototype.

Just be sure you use the Y version of the STD03's with the highest hFE, to keep distortion of the LM4702 low.

It needed some tweaking though. The STD03 needs a pre bias of 2.5mA through it's tempo diode string. Standard the LME4702 gives to much voltage on it's Source and Sink pins. Trim it with just a resistor between source and sink works of course but wasn't totally satisfying for me. (sound-wise and stable current source)

I end up with using a red LED (vf 1.9) in series with a resistor between Source and Sink to set the current on 2.5mA. This works very well, constant, stable and sound significant better then using just a resistor. I will try to add some pictures later this week.

Last but not least, We set the idle bias on 12,5 mV over each Re (Re is 0.22R). Thermal tracking seems very good, and stabilize fast after full power operation.

With kind regards.
Bas

Last edited by Sebastiaan; 29th September 2010 at 07:39 AM.
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Old 3rd October 2010, 10:52 PM   #10
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Dear Bas,

I heard that 4702 is essentially a dual version of 49811 with some layout changes.

Is that a floor standing active speaker? How many ways? I am also trying active XOR, currently using dbx 234XL and my amps for two-way.

Cheers,
Panson

Last edited by panson_hk; 3rd October 2010 at 11:01 PM.
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