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Audio power amps 30W rms?

F

Fred

Jan 1, 1970
0
I would like to take the easy way out and design in a power amp module. It
must have a 30W rms output into 8 ohms. Can anyone suggest a source for an
affordable amp module?

If not any alternative. I am analogue literate but time to market is an
issue and hence a module would be ideal. Alternatively a high and low side
driver with thermal protection.

This is for low to medium production so cost is of paramount importance.

Any help greatly appreciated.
 
J

John Fields

Jan 1, 1970
0
I would like to take the easy way out and design in a power amp module. It
must have a 30W rms output into 8 ohms. Can anyone suggest a source for an
affordable amp module?

If not any alternative. I am analogue literate but time to market is an
issue and hence a module would be ideal. Alternatively a high and low side
driver with thermal protection.

This is for low to medium production so cost is of paramount importance.

Any help greatly appreciated.

---
Go to

http://www.national.com/parametric/0,1850,811,00.html

and take your choice.
 
F

Frank Bemelman

Jan 1, 1970
0
Fred said:
I would like to take the easy way out and design in a power amp module. It
must have a 30W rms output into 8 ohms. Can anyone suggest a source for an
affordable amp module?

If not any alternative. I am analogue literate but time to market is an
issue and hence a module would be ideal. Alternatively a high and low side
driver with thermal protection.

This is for low to medium production so cost is of paramount importance.

LM1875, 5 pin TO220. Or LM4700. You have to add a few resistors
and caps to set gain etc, all very simple to do.
 
T

Tony Williams

Jan 1, 1970
0
I would like to take the easy way out and design in a power amp
module. It must have a 30W rms output into 8 ohms. Can anyone
suggest a source for an affordable amp module?

Look in the RS or Farnell cats at the Power Amp modules
from Prism Audio or ILP.

eg, Farnell 360-0195 is 40W, with built-on power supply
bridge rectifier and smoothing caps. It just needs a
centre tapped mains transformer. About £19 per in one-offs.

<http://www.farnell.com>
 
A

Active8

Jan 1, 1970
0
I would like to take the easy way out and design in a power amp module. It
must have a 30W rms output into 8 ohms. Can anyone suggest a source for an
affordable amp module?

If not any alternative. I am analogue literate but time to market is an
issue and hence a module would be ideal. Alternatively a high and low side
driver with thermal protection.

This is for low to medium production so cost is of paramount importance.

Any help greatly appreciated.
sci.electronics.equipment
sci.electronics.components
 
G

Georg Acher

Jan 1, 1970
0
|> I would like to take the easy way out and design in a power amp module. It
|> must have a 30W rms output into 8 ohms. Can anyone suggest a source for an
|> affordable amp module?

Not really a module, but easy to handle (no self oscillation, only a few
additional components), very robust (short-circuit/over-temperature) and a lot of
power (60W RMS@8Ohm):

TDA7294

http://www.st.com/stonline/books/pdf/docs/1057.pdf

I've build a few amps with it (some single, some bridged), no problems at all.
 
C

CFoley1064

Jan 1, 1970
0
I would like to take the easy way out and design in a power amp module. It
must have a 30W rms output into 8 ohms. Can anyone suggest a source for an
affordable amp module?

If not any alternative. I am analogue literate but time to market is an
issue and hence a module would be ideal. Alternatively a high and low side
driver with thermal protection.

This is for low to medium production so cost is of paramount importance.

Any help greatly appreciated.

You didn't include most of the specs people usually use in describing an audio
amplifier, so we're just guessing here.

If you want something relatively inexpensive, that provides good quality sound
with minimal additional components, you could do worse than the National
LM4701. It specs 30W into an 8 ohm load with less than 0.1% THD. The National
site says $1.17 USD in 1000 qty.

As with all of these audio amplifier ICs, layout and bypassing are important.
Consider getting some advice on the circuit layout if you haven't done it
before.

Good luck.
Chris
 
F

Fred

Jan 1, 1970
0
Tony Williams said:
Look in the RS or Farnell cats at the Power Amp modules
from Prism Audio or ILP.

eg, Farnell 360-0195 is 40W, with built-on power supply
bridge rectifier and smoothing caps. It just needs a
centre tapped mains transformer. About £19 per in one-offs.

<http://www.farnell.com>

Many thanks but this is getting very expensive for our budget cost. There
are a few very cheap single chip solutions which only require a few
associated components.
 
F

Fred

Jan 1, 1970
0
Frank Bemelman said:
LM1875, 5 pin TO220. Or LM4700. You have to add a few resistors
and caps to set gain etc, all very simple to do.
John, Frank

Thanks. I have looked at these and they look very promising.
 
F

Fred

Jan 1, 1970
0
CFoley1064 said:
You didn't include most of the specs people usually use in describing an audio
amplifier, so we're just guessing here.

If you want something relatively inexpensive, that provides good quality sound
with minimal additional components, you could do worse than the National
LM4701. It specs 30W into an 8 ohm load with less than 0.1% THD. The National
site says $1.17 USD in 1000 qty.

As with all of these audio amplifier ICs, layout and bypassing are important.
Consider getting some advice on the circuit layout if you haven't done it
before.

Good luck.
Chris

There seems a consensus here that the Nat Semi range is good value and sound
ideal for my application.

I am tempted to try to perhaps use a higher voltage tolerant device (higher
power) and use an unregulated supply from a transformer/bridge/cap. Sounds
a little dangerous but would be lower in cost. These ICs seem to have a
very good PSRR. I need to do the sums for any saving.

Many thanks.
 
F

Fred

Jan 1, 1970
0
Georg Acher said:
|> I would like to take the easy way out and design in a power amp module. It
|> must have a 30W rms output into 8 ohms. Can anyone suggest a source for an
|> affordable amp module?

Not really a module, but easy to handle (no self oscillation, only a few
additional components), very robust (short-circuit/over-temperature) and a lot of
power (60W RMS@8Ohm):

TDA7294

http://www.st.com/stonline/books/pdf/docs/1057.pdf

I've build a few amps with it (some single, some bridged), no problems at all.


Many thanks.

Unfortunately the ST website doesn't give a clue to their cost.
 
G

Georg Acher

Jan 1, 1970
0
<TDA7294>
|> Many thanks.
|>
|> Unfortunately the ST website doesn't give a clue to their cost.

Avnet-Marshall lists them at about 5-8$ a hundred or so. A few years ago I
bought them for about 12DM (~6-7$) for ten pcs.
 
M

Mike Diack

Jan 1, 1970
0
There seems a consensus here that the Nat Semi range is good value and sound
ideal for my application.

I am tempted to try to perhaps use a higher voltage tolerant device (higher
power) and use an unregulated supply from a transformer/bridge/cap. Sounds
a little dangerous but would be lower in cost. These ICs seem to have a
very good PSRR. I need to do the sums for any saving.

Many thanks.
Sounds like a job for the Nat Semi LM3886 then
Cheap as chips and you can even get a fully insulated version and
avoid the pesky mica washer. VCC tolerant to over 80 volts so you can
forget the PSU regulator. I've used these by the bucketload and my
only (minor) complaint is slightly ragged clipping (clip-stick!)
M
(They will send you a couple of samples if you ask them)
 
N

N. Thornton

Jan 1, 1970
0
Fred said:
There seems a consensus here that the Nat Semi range is good value and sound
ideal for my application.

I am tempted to try to perhaps use a higher voltage tolerant device (higher
power) and use an unregulated supply from a transformer/bridge/cap. Sounds
a little dangerous but would be lower in cost. These ICs seem to have a
very good PSRR. I need to do the sums for any saving.

Many thanks.


Hi.

This would be the normal way to do audio power amps, with no regulation.

Regards, NT
 
J

John Fields

Jan 1, 1970
0
I am tempted to try to perhaps use a higher voltage tolerant device (higher
power) and use an unregulated supply from a transformer/bridge/cap. Sounds
a little dangerous but would be lower in cost. These ICs seem to have a
very good PSRR. I need to do the sums for any saving.

---
That's how it's done. :)

All you have to do is make sure that the reservoir cap(s) can never
discharge to the point where you run out of headroom under load.

Also, if you run positive and negative rails you can get rid of the
output capacitor and, instead, include a reservoir cap for the -supply.

Use a transformer with a center-tapped secondary, a full-wave bridge to
get your + and - voltages and two reservoir caps and that's pretty much
the whole supply!
 
F

Fred

Jan 1, 1970
0
John Fields said:
---
That's how it's done. :)

All you have to do is make sure that the reservoir cap(s) can never
discharge to the point where you run out of headroom under load.

Also, if you run positive and negative rails you can get rid of the
output capacitor and, instead, include a reservoir cap for the -supply.

Use a transformer with a center-tapped secondary, a full-wave bridge to
get your + and - voltages and two reservoir caps and that's pretty much
the whole supply!

Many thanks. I was thinking along those lines. I accept the comment by NT,
just that regulation of a power supply is a bit of an unknown until you
build one.
 
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