TDA1552Q overdrive & other questions

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P { margin-bottom: 0.08in; } Hi, i have three questions on a 12 Volt 22 Watt amplifier (based on TDA1552Q).

  1. Does this chip have an inbuilt protection against overdrive...when the input goes above a certain level can I rely on it to cut out without circuit or speaker damage?
  2. Can anybody recommend a switching power supply...I've heard that HP Printers do a suitable one?
  3. I'm considering adding a simple, very basic tone-control circuit. Where would I find information?
First post on the forum, for any help, much obliged
 
Great chip - capable of really excellent sound.

No, no protection against overdriving the input - if you feed too great a signal in, it will clip. Heavily overdrive it and you could fry your tweeters. There won't be any circuit damage, it protects against that.

I'm using a close relative, TDA8566 with a Meanwell SMPSU (100W, 18V) - I am using a pair of LM350T regulators after that, reducing the supply to 15.5V (I turned up the voltage on the SMPSU to guarantee there's enough headroom).

The sound quality in my experience is limited by the quality of the supply. If you feed the chip direct from a SMPSU you'll get reasonable sound but not high-end. To get the best you need great HF filtering of the supply plus a very low impedance down to bass frequencies. I've achieved this in mine by adding plenty of paralleled caps to the output of my linear regs.

No experience of tone controls so will leave that aspect to others.
 
On clipping...this amp actually clips at a lower volume just for one particular mp3 player...for other inputs I can turn input volume up much higher without a problem.
The supply problem...I'm currently using an old computer PSU...it's too bulky...considering a "Leicke" switching unit but it doesn't need to produce best-quality hifi.
 
I'm using a close relative, TDA8566 with a Meanwell SMPSU (100W, 18V)
P { margin-bottom: 0.08in; } I've been advised to go for a „Meanwell“ S-60-15 - 60W 15V 4A and adjust the voltage down to 14,5.
Thing is, I may have to add capacitance to the output to deal with ripple on the line. As you're somewhat familiar with this product, I thought you might be able to advise me on what value or even within what sort of range of capacitance we're talking about. I'm a little out of my depth here. Obliged.
 
P { margin-bottom: 0.08in; } To anybody with similar issues.. I found a suitable switching power supply for my needs... its a „Meanwell“ S-60-15 - 60W 15V 4A.....S-60-15 - 60W 15V 4A Enclosed Switching Power Supply
P { margin-bottom: 0.08in; }
Doesn't need extra capacitors, filtering or anything else, works perfectly!
On mp3 clipping...I had volume on mp3 player turned to high...didn't realise.
In conclusion, please, somebody....a circuit for simple, passive bass/treble tone control
 
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P { margin-bottom: 0.08in; } With an attenuation of -20dB., I'm reconsidering fitting a passive tone control circuit. I need an expert oppinion....with an amp of 2 x 20 watts, how diminishing is a -20dB loss...are we talking 50% volume loss or...?
Obliged
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I've been advised to go for a „Meanwell“ S-60-15 - 60W 15V 4A and adjust the voltage down to 14,5.

Why adjust the voltage down I wonder?

Thing is, I may have to add capacitance to the output to deal with ripple on the line.


The ripple from a SMPSU is high frequency (quite unlike from a linear supply where its at double the mains frequency) so simply adding capacitance to the output probably won't help you. That's because at HF you need very low ESR and ESL (parasitic resistance and inductance) to reduce the ripple.

I use a lot of capacitance not to deal with PSU ripple, rather to deal with the signal-generated ripple which comes from the amp itself. Having lower audio band noise on the supply definitely helps the SQ.

Incidentally this post is tardy because for some reason the email notification's not working reliably.
 
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