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Old 29th April 2009, 03:54 AM   #1
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Default Comparing LME49810, 49830 and 49811

Now I have enough plug-in driver boards to do LME498xx comparison efficiently. Three driver boards will be prepared for working with two pairs of NJL3281D/1302D. I will see do we need driver stage for 49830 and 49811, and more.

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Old 29th April 2009, 08:30 PM   #2
Segran is offline Segran  Sweden
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Great stuff, Panson!

I'm really looking forward to your comparison of the 3 LME chips, w/wo drivers etc. Will you also compare 49830 w FET's`?

The amatueristic comparisons I did during the last 6 months tells me only what I think about my own amateuristic designs using LME 49810/49830. It will be really interesting to see your scientific approach and measurement results!

Good job!
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Old 29th April 2009, 10:04 PM   #3
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Quote:
Originally posted by Segran
Will you also compare 49830 w FET's`?
Hi Segran,

Yes, I have some IRF240/P9240. Hope they are not fake! Did you find any differences between 49830 and 49810?
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Old 30th April 2009, 03:53 PM   #4
Yoshy is offline Yoshy  Canada
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I must say I too would like to see the results !

Also if you could post the pin out, spacing of the connectors and voltage limits I might want to buy a "driver board" but design the front-end myself. I was also currently working on a "plugin" amp but this would speed things up.

Cheers !
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Old 30th April 2009, 09:36 PM   #5
Segran is offline Segran  Sweden
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Panson wrote
:
Quote:
Did you find any differences between 49830 and 49810?
I don't have the instruments needed to measure distortion low enough to tell the difference between 49830 and 49810.

Both amps turned out pretty good, THD+N below 0,002%. I found a "sonic" difference that I blame on a higher level of odd harmonics in the 49810+BJT amp that makes me prefer the 49830+IRFP amp. It kind of sounds "sweeter", most noticeable when playing music with brass instruments or piano or acoustic guitar. Even human voices sounds often better. The best way I can describe it is that the sound is less tiring to me ears (and the other people who have compared the two).

But again, that may all be due to shortcomings in my overall designs!
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Old 30th April 2009, 10:45 PM   #6
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Quote:
Originally posted by Yoshy

Also if you could post the pin out, spacing of the connectors and voltage limits
I use standard 2.54 mm pin headers (two 2 x 5 and one 2 x 10). The image shows you center point space. Is it okay? The board can actually be used for any voltage within LME498xx limit.
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File Type: jpg connector spacing.jpg (92.0 KB, 5706 views)
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Old 30th April 2009, 11:03 PM   #7
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Is the convention for polarized caps to use octagonal pads on the neg leg rather than square pads on the pos leg?
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Old 1st May 2009, 01:08 PM   #8
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Quote:
Originally posted by Yoshy
... the pin out ...
I can e-mail you the schematic for pin out.
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Old 1st May 2009, 01:13 PM   #9
Yoshy is offline Yoshy  Canada
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Quote:
Originally posted by panson_hk


I can e-mail you the schematic for pin out.

Yes, that would be nice, I'm still trying to decide if I get the ThermalTraks or regular BJTs (or MOSFETs). I'll wait on your conclusions but I'll be in for 6 boards
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Old 1st May 2009, 11:14 PM   #10
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LME49810 THD vs output level vs load

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LME49830 THD vs output level vs load
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R1 and R2 are 22 Ohm, Cc = 22 pF
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Load (100k, 1 k) applied at output to ground. Results show that LME49830 has better driving capability.

More to come ...
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