Retrofitting analogue volume control

Seeing as I like Absolute 80s I've got DAB Radio Alarm, but the problem with these things is the crappy incremental push button volume control. The lowest setting is too loud for me in the morning. I've looked at putting one of those USB charged mini speakers in, but I'd forget to keep it charged. I'm not averse to a bit of dismantling, drilling & soldering, but what component would I need? A varialble resistor of some sort from Maplin/RS that has a stick to fit a disc or similar on it, but which one to get?

Cheers

CD

Reply to
CD
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Won't be that easy I suspect. The internals will be all designed around digital inputs. About the easiest will be a series resistor in the speaker line to drop the minimum volume to an acceptable level, and then hope there is enough volume for other uses at the maximum end of the range.

Reply to
Bob Minchin

Assuming it has an analogue power amp, fitting a normal volume control isn't impossible. But a machine built surface mount PCB can be tricky to modify.

Reply to
Dave Plowman (News)

Track cutting required.

Actually SM power chips are not small things ..

Reply to
The Natural Philosopher

If it has a single chip amp it might be easy to snip a pin and insert a pot. Or it might not. Difficult to know without seeing it.

Reply to
Dave Plowman (News)

This is what I was thinking, inserting something variable on the speaker wire.

Reply to
CD

Chances are it has a EEPot or similar connected to a three wire bus under control of the micro controller. If you can have a look round the board, looking up component ids on the web, you may be able to identify the device and pinout. At which point you know where you could connect your pot and a likely value for it.

Reply to
John Rumm

Or stick some felt type material over the speaker grill on the radio?

Reply to
Gazz

poor way IMHO

Reply to
The Natural Philosopher

The term "put a sock in it comes to mind". :-)

Reply to
whisky-dave

Well this very much depends on the device. Often, there are one chip devices around which means there is no place for an analogue volume control. If you are lucky and the amp and the radio are seperate devices, then you can wire it as you would any volume control. I'd say if the amp is made with bipolar transistors or a chip, you need to break thelive audio feed somehow, fit a large electrolytic on the end of the amp end, and put a 10K Log pot across it. Then a small resistor, say 1k, from the slider to where the audio emerges. You will probabbly need to make the volume right up on the buttons to accomodate any losses, and I would think the min 1k ought to not damage the output.

If you wanted to go back though, you might have aproblem. Of course the pot needs to be stereo if the signal is stereo, and it might sound better if the

1k was a little bigger. Brian
Reply to
Brian Gaff

As I said before, you really need to see what the circuit is. I'd be very careful with series resistors, some amps do not like high impedances on their speaker connections. However if its a standard speaker then something around 12 ohms 1 watt is probably a place to start. Brian

Reply to
Brian Gaff

That would also work ;-)

Might tend to lose the treble response a bit though...

Reply to
John Rumm

But probably by far the most practical. It's not what you'd do with a hi-fi audio system - but here we're talking DAB Radio Alarm!

Reply to
Ian Jackson

In article , Brian Gaff scribeth thus

If you can get any info of course!..

Come on it is DAB, Mono is the standard operation mode!...

Reply to
tony sayer

Find the audio signal path by touching connections with a short bit of wire with both ends bare - avoiding any mains of course! If it does have audio outside of the chip/s somewhere, a 10k pot should do the job. If not you'd need to resort to cruder methods like a series R in a speaker wire.

NT

Reply to
meow2222

In my case a t-shirt, which also covers the too bright display, but this method doesn't give the fine adjustment I wan't, the volume has to be just low enough...

Reply to
CD

More to it tham I imagined!! I'll look for a DAB clock radio with a traditional volume control..... Yeah right.

I think an X-Mini in the earphone jack is the way to go, having had a root around the radio there is a mini USB socket, which having RTFM is for firmware updates, but will do fine as an X-Mini charger.

Thanks for the insightful advice.

Reply to
CD

What was that? Class B? (stretching the memory).

These days I suspect all the amplifiers come on a chip and will be protected against just about everything except excessive voltage.

Reply to
newshound

I had a similar problem with a laptop, where the volume control didn't affect error beeps from the speaker.

For that I just used adhesive tape over the speaker grille to muffle the sound.

Reply to
BartC

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