Hi panson,
On compact size board rev 2.1 there no zobel and no output coil, but i see in one of your building that thay are présent direct on speaker binding post. So they seems to be necessary, have you value for these? What about your work on adding diode to improve thermal compensation?
Marc
Marc
On compact size board rev 2.1 there no zobel and no output coil, but i see in one of your building that thay are présent direct on speaker binding post. So they seems to be necessary, have you value for these? What about your work on adding diode to improve thermal compensation?
Marc
Marc
Hi Panson,
I just started considering building an amp based on LME49811 and ThermalTrack transistors and I saw that you have that already built for me
However, there is one thing that I've noticed. Have you considered the difference between temperature coefficient of the junction voltage in MUR120 (the diode part) which is 1.7mV/C and NJL3281 which is 2.1mV/C ? I am not sure if that matters in the real life application, however Bob Cordell in his Designing Audio Power Ams, pg. 305 and after that thinks that it matters.
His suggestion is introducing compensator added to the bias transistor that involves (in one suggested setup) 4 resistors and 1 low-power transistor.
Igor
Hi,
Merry Christmas ! I am still alive, but "lazy". I am spending most time on loudspeaker lately due to my full-time job. Amplifier is still my main interest. But my boss is acoustic now. I will update my kits.
I enjoy doing speaker stuffs. I learn more about audio systems and good for amplifier side.
Cheers,
Panson
Merry Christmas ! I am still alive, but "lazy". I am spending most time on loudspeaker lately due to my full-time job. Amplifier is still my main interest. But my boss is acoustic now. I will update my kits.
I enjoy doing speaker stuffs. I learn more about audio systems and good for amplifier side.
Cheers,
Panson
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Hi, are you still around?
I'm looking for a higher power version of your lovely amp.
Hi, are you still around?
I'm looking for a higher power version of your lovely amp.
Hi,
Thanks for your message.
I am still around and focusing on loudspeaker driver design. Knowledge gained for this area would help me to better under amplifier and speaker interaction.
The driver chips are no longer supplied by TI. It is time to think something else.
Yeah. The discontinuance of the LME49810, 811, and 830 is a real bummer. They were really nice chips. I was about to design a high-power amp around those when TI dropped them.
I ended up with six LM3886es in a balanced composite topology instead: Modulus-686: 380W (4Ω); 220W (8Ω) Balanced Composite Power Amp with extremely low THD
Tom
I ended up with six LM3886es in a balanced composite topology instead: Modulus-686: 380W (4Ω); 220W (8Ω) Balanced Composite Power Amp with extremely low THD
Tom
I got 24 of the last LME49810 but thought at the time thermal trak transistors were discontinued (just the complement of the NJL4281 I had already was). Now no boards are available. I guess I'll have to become a board designer. Like tom and telstar I'd like at least two pairs of TO247 or TO-3P transistors.
Hi Panson
Just finished to of the compact size boards, they sound good -thanks for your work!!
However, I have a problem with the quiescent current. Between test point one and test point two only 8 mV are measured and above the 180 ohm resistor only 1.08 volts. The trimming pot is completely turned out (open). Do you recommend the change of certain values? The boards run at 2 x 44 volts.
Just finished to of the compact size boards, they sound good -thanks for your work!!
However, I have a problem with the quiescent current. Between test point one and test point two only 8 mV are measured and above the 180 ohm resistor only 1.08 volts. The trimming pot is completely turned out (open). Do you recommend the change of certain values? The boards run at 2 x 44 volts.
SPICE model
Hi,
I am able to source some chips from taobao and build amps around them. I run into trouble with a CFP design with +/- 54 volts. The 49810 chip is hot to touch and the sound coming out from the amp is only bearable. Something is definitely wrong with the design. The chips are genuine, as I have built good sounding amps with the batch. I want to spice the thing before going any further. There used to be TINA-Ti models around but the link is now dead. Is there anyone with the SPICE file for either 49810 or 49811? Thank you.
KK
Hi,
I am able to source some chips from taobao and build amps around them. I run into trouble with a CFP design with +/- 54 volts. The 49810 chip is hot to touch and the sound coming out from the amp is only bearable. Something is definitely wrong with the design. The chips are genuine, as I have built good sounding amps with the batch. I want to spice the thing before going any further. There used to be TINA-Ti models around but the link is now dead. Is there anyone with the SPICE file for either 49810 or 49811? Thank you.
KK
Hi Panson,
There is a heat sink behind the 49810 chip. A while back I did a single pair version of this on +30v/-30v with no issues. This time I want more power to drive a 10" bass unit in a 2-way setup, so I go for the parallel. I have 8mv running between the outputs. The drivers and the outputs are stone cold. But the circuit is not stable. The voltage dropped from 108 rail to rail to 99 -101 rail to rail when the amp is connected. Somewhere there is a big drain of current. I want to sim the circuit so that I have voltage figures to check against the real thing. In the mean time, I will probe some more.
KK
There is a heat sink behind the 49810 chip. A while back I did a single pair version of this on +30v/-30v with no issues. This time I want more power to drive a 10" bass unit in a 2-way setup, so I go for the parallel. I have 8mv running between the outputs. The drivers and the outputs are stone cold. But the circuit is not stable. The voltage dropped from 108 rail to rail to 99 -101 rail to rail when the amp is connected. Somewhere there is a big drain of current. I want to sim the circuit so that I have voltage figures to check against the real thing. In the mean time, I will probe some more.
KK
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