Panson,
Are you gonna be selling them as a kit? or are you going to sell just the PC boards? I want to give it a shot.
Thanks,
Fred
Are you gonna be selling them as a kit? or are you going to sell just the PC boards? I want to give it a shot.
Thanks,
Fred
Hi Fred,
Yes, boards are available now. Kits will be ready soon. I am working on the web site's online purchase. If you would like to buy them now, please send me an e-mail.
Panson
Yes, boards are available now. Kits will be ready soon. I am working on the web site's online purchase. If you would like to buy them now, please send me an e-mail.
Panson
LME 49811 has a class A output stage, others a class AB one.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=132471&perpage=25&pagenumber=1
Audioman says 49811 sounds better.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=132471&perpage=25&pagenumber=1
Audioman says 49811 sounds better.
ClassA!
I seriously doubt it.
but he says it here
http://www.diyaudio.com/forums/showthread.php?postid=1707382#post1707382
I seriously doubt it.
but he says it here
http://www.diyaudio.com/forums/showthread.php?postid=1707382#post1707382
150W into 4r0 requires 34.7Vpk and 8.7Apk.
Into a reactive speaker load allow for transient current <=25Apk.
With 9mA available from the 811 you need an output triple or output double with a current gain >=2800 when delivering a total of 25Apk through the output device/s
A 2pair output stage with 12.5Apk passing each device you will need a triple.
A 3pair output stage (8.3Apk thro' each) may just work with a double if both driver and output have high gains at high currents.
Into a reactive speaker load allow for transient current <=25Apk.
With 9mA available from the 811 you need an output triple or output double with a current gain >=2800 when delivering a total of 25Apk through the output device/s
A 2pair output stage with 12.5Apk passing each device you will need a triple.
A 3pair output stage (8.3Apk thro' each) may just work with a double if both driver and output have high gains at high currents.
bobodioulasso said:
AndrewT said:
It seems possible (class A) to me since 49811 has a much lower output current. Its output stage or VAS indeed can remain in class A.
AndrewT said:
Ok, i get it better now.
Are you planning to make some kits?
If so, drop me an email. Note that I have a small budget on this, because i'll use it only for <200hz.
What is the purpose of the 2.2-20k resistor between the gates of the mosfets, from N to P gate not the gate resistors themselves? Often see 2.2k, other time 12k and one had suggested 10-20k.
Most times before the gate resistor, other times after.
The example in AN1850 does not show them at all.
Most times before the gate resistor, other times after.
The example in AN1850 does not show them at all.
Good question.
Looking at LME synoptic, it seems that some current have to flow from source to sink.
But i do not know ...
Looking at LME synoptic, it seems that some current have to flow from source to sink.
But i do not know ...
AndrewT said:
These chips do run a lot hotter than an operational amplifier -- with no load I measure 13 to 16mA on the Vcc and Vee rails respectively so they are biased hot. If you don't heat sink these chips the performance suffers.
jackinnj said:
I agree with you. Without proper heat sinking, THD increases substantially when load decreases.
THD vs output level vs load without proper heat sinking
THD vs output level vs load with proper heat sinking
panson_hk said:
Now, if you really want to see what they are capable, run the THD% analysis with a fundamental of 20kHz AND use only the
80kHz LPF on the AP Analyzer.
I´ve nsampled a few LME49810 too now to use w some huge heatsinks w three 2N3716 and three 2N3792, i plan on using BD139/140 as drivers.
Panson, can i borrow your ap to measure some thd and other stuff on my amp when built ?
Panson, can i borrow your ap to measure some thd and other stuff on my amp when built ?
