Hello there, I am new here and although I am an electronic hobbyist this is my first time on audio. I would like some advice please as i have lately purchased a ready built amp kit with 2 TF3886 which is capable of around 140 watts into 4 ohms. My speakers are 6 ohms.
1) Transformer rating for this amp. Which one is most suitable?
I have two transformers not toroid but scavenged from old HIFI systems, both are 28-0-28 vac one is 300va and the other is 150va
2) How large the heat sink should be? Mine is going to be fixed outside the cabinet and possibly not fan assisted. The data sheets got me a bit confused in choosing the right one.
3) The filter capacitors are Nover 10000 UF X 2. Does the amplifier need a
soft start?
4) Can someone guess what type of amp this is from the Pic below? (A, AB, C or D )
LM3886 Power Amplifier Board Kit DC SERVO 5534 Independent op amp DIY Amplifier | eBay
1) Transformer rating for this amp. Which one is most suitable?
I have two transformers not toroid but scavenged from old HIFI systems, both are 28-0-28 vac one is 300va and the other is 150va
2) How large the heat sink should be? Mine is going to be fixed outside the cabinet and possibly not fan assisted. The data sheets got me a bit confused in choosing the right one.
3) The filter capacitors are Nover 10000 UF X 2. Does the amplifier need a
soft start?
4) Can someone guess what type of amp this is from the Pic below? (A, AB, C or D )
LM3886 Power Amplifier Board Kit DC SERVO 5534 Independent op amp DIY Amplifier | eBay
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I have a website set up to answer those questions. I suggest reading my Taming the LM3886 Chip Amplifier pages.
Tom
Tom
Since its using LM3886 and doesn't appear to have external current source biassing (besides that, the power rating of 68W) then it'll be classAB. Class C I've never seen in audio circuits.
Choosing Transformer and setting up
Thanks all for your replies, I tried the 150va transformer and at full power the ac voltage sagged at 27 volts of which i think it will suffice. I am not running the Amp at full power anyway.
The output was with exceptional clarity and very strong.
I learnt that the LM3886 is a quasi class AB amplifier chip
I would like to add a 6.3mm headphone jack to my amp, can anybody show me how to set this up. I guess it is taken from the output via series resistors but need to know some values and a sketch if possible
Thanks all for your replies, I tried the 150va transformer and at full power the ac voltage sagged at 27 volts of which i think it will suffice. I am not running the Amp at full power anyway.
The output was with exceptional clarity and very strong.
I learnt that the LM3886 is a quasi class AB amplifier chip
I would like to add a 6.3mm headphone jack to my amp, can anybody show me how to set this up. I guess it is taken from the output via series resistors but need to know some values and a sketch if possible
Hey Fast Eddie I tell you its a real good value for money with that price. The audio quality is very good and clear and high notes are sharp. With the volume turned to maximum without any signal I could not hear any hum from the speakers. Base notes are also deep and full. It gave me 50 watts rms per channel into 6 ohms
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