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Chip Amps Amplifiers based on integrated circuits

Is this a good LM3886 Kit?
Is this a good LM3886 Kit?
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Old 5th November 2017, 11:21 AM   #131
Mayday is offline Mayday  Sweden
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Is this a good LM3886 Kit?
A 0-24Vac + 0-24Vac 500VA from toroidy and a total of 6 10000uF capacitors, of those 4 are on a board with rectifier diodes. Don't recall the model, they are TO-220 type diodes.
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Old 5th November 2017, 02:54 PM   #132
dotneck335 is offline dotneck335  United States
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Quote:
Originally Posted by Mayday View Post
A 0-24Vac + 0-24Vac 500VA from toroidy and a total of 6 10000uF capacitors, of those 4 are on a board with rectifier diodes. Don't recall the model, they are TO-220 type diodes.
That's a LOT of capacitance! I like it!! I used two of these instead:
380LX333M050A082 Cornell Dubilier - CDE | Mouser
as it was a little bit less $$ and smaller than 3 x 10,000uF. Have you considered a regulated supply like this?:
High current dual rail regulator kit for power amplifier or bench power supply ! | eBay

Last edited by dotneck335; 5th November 2017 at 03:07 PM.
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Old 5th November 2017, 03:27 PM   #133
Mayday is offline Mayday  Sweden
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Is this a good LM3886 Kit?
Quote:
Originally Posted by dotneck335 View Post
That's a LOT of capacitance! I like it!! I used two of these instead:
380LX333M050A082 Cornell Dubilier - CDE | Mouser
as it was a little bit less $$ and smaller than 3 x 10,000uF. Have you considered a regulated supply like this?:
High current dual rail regulator kit for power amplifier or bench power supply ! | eBay
No, I have the other stuff mentioned.
I've not considered getting a different supply for this amp.
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Old 6th November 2017, 01:06 PM   #134
Mayday is offline Mayday  Sweden
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Is this a good LM3886 Kit?
The heatsink arrived today.
Some pics attached The 3mm thick alu-sheet looks very big lol
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File Type: jpg IMG_20171106_135048.jpg (338.4 KB, 457 views)
File Type: jpg IMG_20171106_135109.jpg (338.4 KB, 448 views)
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Old 12th November 2017, 06:30 PM   #135
SpirosD is offline SpirosD
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I`m watching how it goes. Well done ! I`m interested in as I have one kit on order.
I have an older LM3886 dc servo implementation which also has NE5534 as an input buffer or gain or something (I don`t know).
I have listened to this older one and I was very pleased. But I will do the new one too.

My questions:
As NE5534 is not unity gain stable and needs at least 3x gain then is this kit implementing such a gain? Maybe if I calculate well it is on 5x ?

Is the 523 Ohm an input NE5534 resistor and if so should be matching the value of the gain setting resistors? I mean in the older one there are three resistors, RR1A, RR3A and RR4A where RR1A should be 1K based on the values of the other two, you can see the attached schematic of the old one. I don`t recall where I had read about it neither the calculation formula but back then I was looking at it I was convinced it must be 1K or there will be a DC offset. Am I right on this? Am I missing something?

Is the supplied regulator for the uPC1237 a 7824 and not a 7812 one or the stuffing drawing is false?

What is the lead spacing required for the 4.7uF input capacitors? Can you measure?

Is the 10R supposed to be 10R or 10K? (as there is no schematic)
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File Type: jpg LM3886- DC-servo.jpg (77.1 KB, 408 views)
File Type: jpg opinp.jpg (29.6 KB, 400 views)
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Old 5th December 2017, 06:56 PM   #136
SpirosD is offline SpirosD
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Is there any progress on the build?
My kit arrived today, have not looked at it though. I`m a slow builder, the previous one is not finished yet...
But I would like to hear how it goes.
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Old 2nd January 2018, 10:49 PM   #137
r_kalar_2 is offline r_kalar_2  Bangladesh
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Quote:
Originally Posted by Mayday View Post
The heatsink arrived today.
Some pics attached The 3mm thick alu-sheet looks very big lol
Any update? I am thinking to get this kit. Please share your experience.
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Old 4th January 2018, 08:18 AM   #138
Mayday is offline Mayday  Sweden
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Is this a good LM3886 Kit?
No,
Everything is ready to be mounted in a case, but I have not gotten around to it.
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Old 4th January 2018, 12:50 PM   #139
r_kalar_2 is offline r_kalar_2  Bangladesh
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I will eagerly wait for your update. On the surface, the kit looks very nice. If it's as good sounding as it looks, it's worth the money I think.
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Old 4th January 2018, 01:26 PM   #140
dotneck335 is offline dotneck335  United States
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Quote:
Originally Posted by SpirosD View Post
As NE5534 is not unity gain stable and needs at least 3x gain then is this kit implementing such a gain?
NE5534 datasheet says:
"The op amps are internally compensated for gain equal to, or higher than, three. The frequency response can be optimized with an external compensation
capacitor for various applications (unity gain amplifier, capacitive load, slew rate, low overshoot, etc.)."
It says that they are internally compensated for gains > 3; so use of an external capacitor in the compensation circuit is required for unity gain operation. NOT that they are unstable at unity gain.
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