Where might I go for basic audio amplifiers?

All I want is something that has a 3.5mm input jack, and speaker connectors.
Everything else, perhaps even a volume control, is extra.

Something around 20W.

This would be for miscellaneous household audio.
At the moment I've got various stereo units doing this, but they are rather
large, and a neater solution would be nice.

Thanks.

Maplin do all sorts of modules if you are able to wire these up to a PSU.

"Ian Stirling" wrote in message
...
Where might I go for basic audio amplifiers?

All I want is something that has a 3.5mm input jack, and speaker
connectors.
Everything else, perhaps even a volume control, is extra.

Something around 20W.

This would be for miscellaneous household audio.
At the moment I've got various stereo units doing this, but they are
rather
large, and a neater solution would be nice.

Thanks.

Ian Stirling wrote:

Where might I go for basic audio amplifiers?

All I want is something that has a 3.5mm input jack, and speaker connectors.
Everything else, perhaps even a volume control, is extra.

Something around 20W.

This would be for miscellaneous household audio.
At the moment I've got various stereo units doing this, but they are rather
large, and a neater solution would be nice.

Thanks.

Depending upon how much you want to pay and how much you want to DIY,
you could try Maplins (www.maplin.co.uk)- eg, N66AW 18W mono amp for
£9.99, though obviously PSU, connectors enclosure and pre amp (if
needed) would be on top of this.

HTH,

Chris

--
cut along the dotted line to reply

"Ian Stirling" wrote
| Where might I go for basic audio amplifiers?
| All I want is something that has a 3.5mm input jack,
| and speaker connectors. Everything else, perhaps even
| a volume control, is extra.
| Something around 20W.

Hmm, real watts or music power watts?

| This would be for miscellaneous household audio.
| At the moment I've got various stereo units doing this,
| but they are rather large, and a neater solution would
| be nice.

Those amplified speakers used for computers. I don't know how many W my
Altec Lansings with a subwoofer pump out, but they do the business on a
Roland Virtual Guitar. Many people will have spares from buying new PC
systems.

Alternatively for something a bit more gutsy than the typical maplin modules

http://www.bkelec.com/Diy/pp50.htm
50 W amp module, GBP 60. Includes power supply, just fits to back of a
cabinet.

http://www.bkelec.com/Professional/A...ssD/ClassD.htm
600 W Class D amp module. Okay that one's not cheap :-)

Owain

Owain wrote:
"Ian Stirling" wrote
| Where might I go for basic audio amplifiers?
| All I want is something that has a 3.5mm input jack,
| and speaker connectors. Everything else, perhaps even
| a volume control, is extra.
| Something around 20W.

Hmm, real watts or music power watts?

Actual real RMS watts.

The inventor of peak music power should be burnt at the stake.

| This would be for miscellaneous household audio.
| At the moment I've got various stereo units doing this,
| but they are rather large, and a neater solution would
| be nice.

Those amplified speakers used for computers. I don't know how many W my
Altec Lansings with a subwoofer pump out, but they do the business on a
Roland Virtual Guitar. Many people will have spares from buying new PC
systems.
snip

I have speakers, I am just looking for the amps.
Thanks for the references, I was wondering if such a thing existed
already boxed, as it's in the range of a 1 chip class D amp, which could
do it lots cheaper than with linear amps, as well as using less power, and
needing less heatsinking.

"Ian Stirling" wrote in message
...
I have speakers, I am just looking for the amps.
Thanks for the references, I was wondering if such a thing existed
already boxed, as it's in the range of a 1 chip class D amp, which could
do it lots cheaper than with linear amps, as well as using less power, and
needing less heatsinking.


Most of the IC suppliers have demo boards using their amplifier chips -
perhaps you could tie one of these to a big wallwart.

In article ,
G&M wrote:
Most of the IC suppliers have demo boards using their amplifier chips -
perhaps you could tie one of these to a big wallwart.

You'd be talking about a very weedy amp if a wall wart would power it.

--
*The e-mail of the species is more deadly than the mail *

Dave Plowman London SW 12
RIP Acorn

Dave Plowman wrote:
In article ,
G&M wrote:
Most of the IC suppliers have demo boards using their amplifier chips -
perhaps you could tie one of these to a big wallwart.

You'd be talking about a very weedy amp if a wall wart would power it.

You can get surprisingly powerfull SMPS wall-warts.
The biggest I remember off-hand is around 30W.

The key is to run the transformer at a really high frequency, so you can
fit more power through.

Easily enough to power a gigawatt of speakers (Peak Invented Music Power).

In article ,
Ian Stirling wrote:
You'd be talking about a very weedy amp if a wall wart would power it.

You can get surprisingly powerfull SMPS wall-warts.
The biggest I remember off-hand is around 30W.

The key is to run the transformer at a really high frequency, so you can
fit more power through.

You've still got the problem of the reservoir caps though - these need to
be a decent size for adequate 'music power' ;-)

--
*The more I learn about women, the more I love my car

Dave Plowman London SW 12
RIP Acorn

"Dave Plowman" wrote in message
...
In article ,
G&M wrote:
Most of the IC suppliers have demo boards using their amplifier chips -
perhaps you could tie one of these to a big wallwart.

You'd be talking about a very weedy amp if a wall wart would power it.

100W PSU running at 450 kHz internally. Alcatel make it for small telecomms
products.

"Ian Stirling" wrote in message
...

Actual real RMS watts.

Grrr - this is a common and seemingly self-perpetuating error. You don't
mean RMS watts, you mean mean (i.e. average) watts, for a sine wave, into a
resistive load. You mean the product of the RMS output voltage and current
into the load. This is the average value of the power delivered - the
'heating power' in other words. That's the whole point of using RMS values
for voltage and current, but it's nonsensical to talk about "RMS power".

--
Andy

"Dave Plowman" wrote
| Most of the IC suppliers have demo boards using their amplifier
| chips - perhaps you could tie one of these to a big wallwart.
| You'd be talking about a very weedy amp if a wall wart would power it.

Amps are like computers - real ones have 3-phase hardwired in. Anything less
is consumer gear :-)

Owain

In article ,
Huge wrote:
I'd be inlcined to buy something off eBay. Much easier than building it.

The actual building of an amp can be ok - especially if a kit - but making
it look good is a different matter.

--
*Cover me. I'm changing lanes.

Dave Plowman London SW 12
RIP Acorn

Andy Wade wrote:
"Ian Stirling" wrote in message
...

Actual real RMS watts.

Grrr - this is a common and seemingly self-perpetuating error. You don't
mean RMS watts, you mean mean (i.e. average) watts, for a sine wave, into a
resistive load. You mean the product of the RMS output voltage and current
into the load. This is the average value of the power delivered - the
'heating power' in other words. That's the whole point of using RMS values
for voltage and current, but it's nonsensical to talk about "RMS power".

Yes, strictly one should speak of RMS power into a n ohm load, which is
sensiblke.

Ian Stirling wrote:

Owain wrote:

"Ian Stirling" wrote
| Where might I go for basic audio amplifiers?
| All I want is something that has a 3.5mm input jack,
| and speaker connectors. Everything else, perhaps even
| a volume control, is extra.
| Something around 20W.

Hmm, real watts or music power watts?


Actual real RMS watts.

The inventor of peak music power should be burnt at the stake.

| This would be for miscellaneous household audio.
| At the moment I've got various stereo units doing this,
| but they are rather large, and a neater solution would
| be nice.

Those amplified speakers used for computers. I don't know how many W my
Altec Lansings with a subwoofer pump out, but they do the business on a
Roland Virtual Guitar. Many people will have spares from buying new PC
systems.

snip

I have speakers, I am just looking for the amps.
Thanks for the references, I was wondering if such a thing existed
already boxed, as it's in the range of a 1 chip class D amp, which could
do it lots cheaper than with linear amps, as well as using less power, and
needing less heatsinking.



Its within range of a bridged single chip car stereo type chip actually.

Especially if run off 15-18v DC. And being used for audio rather than
sine waves or guitars.Where avreage power is probably less tahn a watt,
and smaller heastinks will work.

3 suggestins

(i) skip. Find any old cheapo radios etc and adapt them.

(ii) as pointed out computer speakers if you want the speaker as well.

(iii) roll your own PCB including supply etc - useful if you need 10plus.

Dave Plowman wrote:

In article ,
Huge wrote:

I'd be inlcined to buy something off eBay. Much easier than building it.


The actual building of an amp can be ok - especially if a kit - but making
it look good is a different matter.



Put itin with the speaker in a veneered MDF box.

The Natural Philosopher wrote:
Ian Stirling wrote:

Owain wrote:

"Ian Stirling" wrote
| Where might I go for basic audio amplifiers?
| All I want is something that has a 3.5mm input jack,
| and speaker connectors. Everything else, perhaps even
| a volume control, is extra.
| Something around 20W.

Hmm, real watts or music power watts?


Actual real RMS watts.

The inventor of peak music power should be burnt at the stake.

| This would be for miscellaneous household audio.
| At the moment I've got various stereo units doing this,
| but they are rather large, and a neater solution would
| be nice.

Those amplified speakers used for computers. I don't know how many W my
Altec Lansings with a subwoofer pump out, but they do the business on a
Roland Virtual Guitar. Many people will have spares from buying new PC
systems.

snip

I have speakers, I am just looking for the amps.
Thanks for the references, I was wondering if such a thing existed
already boxed, as it's in the range of a 1 chip class D amp, which could
do it lots cheaper than with linear amps, as well as using less power, and
needing less heatsinking.



Its within range of a bridged single chip car stereo type chip actually.

Especially if run off 15-18v DC. And being used for audio rather than
sine waves or guitars.Where avreage power is probably less tahn a watt,
and smaller heastinks will work.

Yeah.
I'd like a fairly bullet-proof device, and am not really keen on
smaller heatsinks.

I was just wondering if someone had stuck a nice class D amp in a little
box.
The Maplin 50W 6 channel amp for 45 quid would almost suit, but i'd really
like the amps seperate.

(I have signal wiring, but not speaker wiring to the speaker locations).

Oh well.

I suspect I'll watch ebay for a while, to see if anything very suitable
pops up.
Thanks.

"Ian Stirling" wrote in message
...

Yes, strictly one should speak of RMS power into a n ohm load, which
is sensiblke.

No, you've missed the point completely. You should speak of mean power into
a given load.

--
Andy

"Steve Firth" wrote in message
...
Dave Plowman wrote:

You'd be talking about a very weedy amp if a wall wart would power it.

I have a 240W wallwart, well actually it's a dangly A6 size three mm
thick PSU. Thinnest and smallest I've ever seen.

Who makes it ? Always on the lookout for better PSUs.

In article ,
Steve Firth wrote:
You'd be talking about a very weedy amp if a wall wart would power it.

I have a 240W wallwart, well actually it's a dangly A6 size three mm
thick PSU. Thinnest and smallest I've ever seen.

You must have some very large sockets if something A6 size fits them.

--
*If I throw a stick, will you leave?

Dave Plowman London SW 12
RIP Acorn

In article ,
Steve Firth wrote:
You must have some very large sockets if something A6 size fits them.

It dangles. Short flexible lead to a 13A plug top.

Not a wall wart, then. Simply an external power supply.

--
*Why is the time of day with the slowest traffic called rush hour?

Dave Plowman London SW 12
RIP Acorn

"Ian Stirling" wrote in message
...
The Natural Philosopher wrote:
Ian Stirling wrote:

Owain wrote:

"Ian Stirling" wrote
| Where might I go for basic audio amplifiers?
| All I want is something that has a 3.5mm input jack,
| and speaker connectors. Everything else, perhaps even
| a volume control, is extra.
| Something around 20W.

Hmm, real watts or music power watts?


Actual real RMS watts.

The inventor of peak music power should be burnt at the stake.

| This would be for miscellaneous household audio.
| At the moment I've got various stereo units doing this,
| but they are rather large, and a neater solution would
| be nice.

Those amplified speakers used for computers. I don't know how many
W my
Altec Lansings with a subwoofer pump out, but they do the business
on a
Roland Virtual Guitar. Many people will have spares from buying new
PC
systems.

snip

I have speakers, I am just looking for the amps.
Thanks for the references, I was wondering if such a thing existed
already boxed, as it's in the range of a 1 chip class D amp, which
could
do it lots cheaper than with linear amps, as well as using less
power, and
needing less heatsinking.



Its within range of a bridged single chip car stereo type chip
actually.

Especially if run off 15-18v DC. And being used for audio rather
than
sine waves or guitars.Where avreage power is probably less tahn a
watt,
and smaller heastinks will work.

Yeah.
I'd like a fairly bullet-proof device, and am not really keen on
smaller heatsinks.

I was just wondering if someone had stuck a nice class D amp in a
little
box.
The Maplin 50W 6 channel amp for 45 quid would almost suit, but i'd
really
like the amps seperate.

(I have signal wiring, but not speaker wiring to the speaker
locations).

Oh well.

I suspect I'll watch ebay for a while, to see if anything very
suitable
pops up.
Thanks.

If you're handy witha soldering iron you could try this site:-

http://sound.westhost.com/pcb/pricelist.html

Neil

"Steve Firth" wrote
| Dave Plowman wrote:
| You must have some very large sockets if something A6 size fits them.
| It dangles.

That's not a wart. It's a scrotum.

Owain

Ian Stirling wrote:

The Natural Philosopher wrote:


Its within range of a bridged single chip car stereo type chip actually.

Especially if run off 15-18v DC. And being used for audio rather than
sine waves or guitars.Where avreage power is probably less tahn a watt,
and smaller heastinks will work.


Yeah.
I'd like a fairly bullet-proof device, and am not really keen on
smaller heatsinks.



Believe me, it doesn't matter. Those all in one chips have thermal
shutdown anyway.

I spent a large part of my life designing audio power stuff. For disco
or gutauisr/keyboarsd use, yes, the bugers run em at full power
contnsuoly. For PA or music uses below the level of gross distortion,
teh peak to mean levels are something like 3-10:1.

I actually think that 'music power' is indeed a meaningful thing. Its
possible to design an amp that may have an RMS rating of 20W, that
sounds as loud for teh same distortion as a 100W true RMS amp.

It depends on what you want it for. For HiFi use I'd rather have peak
power than RMS power, tho both togther are nice.


I was just wondering if someone had stuck a nice class D amp in a little
box.
The Maplin 50W 6 channel amp for 45 quid would almost suit, but i'd really
like the amps seperate.



Class D sucks by and large. Not very hifi - even today.


(I have signal wiring, but not speaker wiring to the speaker locations).

Oh well.

I suspect I'll watch ebay for a while, to see if anything very suitable
pops up.
Thanks.



Someone was selling a mixed bag of car radio chips on there. These are
really incredibly easy to get working - just follow the manufactureres
design notes. Fed from a 12v AC transformer/rectifier/capacitor (about
4700uF) to give about 16-18v DC, (could use nice LV lamp toroids etc)
you get either 5W stereo into 4ohms, or 20W mono in bridge format. Perrt
clean power - usually around the 0.2% distortion at sensible power
level...couple that up to a decent car speaker in a box, and you have a
nice localised sound source. Anyway 5W to 20W is only 6dB, and you can
get 6dB by buying a better than average loudspeaker...
Not sure what the final application is - I asume some way to spread Jazz
FM throughout the house?

Second hand car radioscan be pirated as well.