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Old 15th December 2009, 04:58 AM   #41
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Originally Posted by traw View Post

Ah ok... I thought maybe there was some rule of thumb could use to choose right ballpark of current, guess experiment away. Need to get scope.
May be there are guidelines. Let see other replies.
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Old 8th February 2010, 04:29 AM   #42
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Hello Panson,

about possible compensation optimization. Have you tried it?
Please take a look this Comparing LME49810, 49830 and 49811
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Old 8th February 2010, 10:51 AM   #43
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Will do. Thanks.
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Old 8th February 2010, 03:35 PM   #44
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Default Output inductor & Zobel network

Hi panson
A question about using your compact amplifiers inside active speakers. One amp to each element.

Is it really necessary to use those inductors and Zobel network when the connections between amplifier and speaker is only about 10 inch?
The answer is maybe the same for any other typical audio endstage?
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Last edited by Radioman62; 8th February 2010 at 03:39 PM.
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Old 8th February 2010, 05:22 PM   #45
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at very high frequencies the inductance of the Voice coil and the capacitance of the cable may not provide a nice benign load for the amplifier.
The Zobel guarantees an R+C load at VHF and this helps stabilise the amp.
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Old 9th February 2010, 01:15 AM   #46
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Originally Posted by Radioman62 View Post
Hi panson
A question about using your compact amplifiers inside active speakers. One amp to each element.

Is it really necessary to use those inductors and Zobel network when the connections between amplifier and speaker is only about 10 inch?
The answer is maybe the same for any other typical audio endstage?
Hi Radioman,

As AndrewT you need to take care of voice-coil inductance. However, cable effect is negligible for direct connection. I would recommend to have those parts to avoid problem in this part.
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Old 9th February 2010, 01:17 AM   #47
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Dear,

Always use the zobel and the output inductor/resistor.

I was stubborn and did it without (also active speaker project) but on some occasions I got oscillations in the far MHz. The Zobel solved this problem.

With kind regards,
Bas
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Old 23rd February 2010, 02:35 AM   #48
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Default New Compact 4981x ThermalTrak board being made

I revised the schematic to include Vbe multiplier, two-pole compensation and ThermalTrak diode current by-pass. We now have many things to try!!!

The new board is being made. Here is the new schematic.
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File Type: jpg Compact 4981x TT Sch rev2p1.JPG (266.1 KB, 1070 views)
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Old 23rd February 2010, 03:35 AM   #49
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Originally Posted by panson_hk View Post
I revised the schematic to include Vbe multiplier, two-pole compensation and ThermalTrak diode current by-pass. We now have many things to try!!!

The new board is being made. Here is the new schematic.
Dear Panson.

What is your reason to add the VBE transistor? My understanding was that the benefit of the Thermaltraks was that you don't need a VBE transistor anymore.

With kind regards,
Bas
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Old 23rd February 2010, 03:40 AM   #50
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Originally Posted by Sebastiaan View Post
Dear Panson.

What is your reason to add the VBE transistor? My understanding was that the benefit of the Thermaltraks was that you don't need a VBE transistor anymore.

With kind regards,
Bas
Hi Bas,

Good question! This is added for user to compare different bias schemes. I want users to have more fun with the new board. We can do simple bias with solely TT diodes, conventional Vbe without using TT diodes, Leach like Vbe with TT diodes, etc.

Cheers,
Panson
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