Small amp <5w for portable radio

hedphones

Member
2013-02-11 3:25 pm
Hi! I'm building a mono speaker out of an old analog radio.. Basically ripping all the insides out, and replacing with a small amp to drive the speaker from MP3 source, with 1/8" or rca cables. Now the radio has this nice analog sound quality which i'm trying to replicate. What kind of amp should I look for? Will regular cheap TDA's sound good with the sensitive vintage speaker? Class A design, I think, would be preferred. I'm looking to spend 20-30£ max for this project, so probably no tubes.
 
Look at this catagory of farnell amps stocked in UK.
Audio Amplifier Dev Kits | Video Decoder Dev Kits | Farnell element14 UK
They also have warehouses in sweden and Germany, but I don't speak the language there.
Beware type T and D amps need to be put in a steel box with chokes on inputs and outputs to keep RF from leaking out into other circuits.
We had some ST brand boards here in the US that were even cheaper but there is no sense shipping a chi***** product across the atlantic with double custom fees.
I expect any amp you buy preassembled, will be D, T, or AB.
mcmelectronics.com a division of farnell has some cheaper kits here in Ohio, but I don't know how you would buy those over there.
Power supply is another issue. Farnell tends to be expensive on power supplies.
Another supplier with a warehouse in in scandanavia is mouser, I believe.
 

hedphones

Member
2013-02-11 3:25 pm
Look at this catagory of farnell amps stocked in UK.
Audio Amplifier Dev Kits | Video Decoder Dev Kits | Farnell element14 UK
They also have warehouses in sweden and Germany, but I don't speak the language there.
Beware type T and D amps need to be put in a steel box with chokes on inputs and outputs to keep RF from leaking out into other circuits.
We had some ST brand boards here in the US that were even cheaper but there is no sense shipping a chi***** product across the atlantic with double custom fees.
I expect any amp you buy preassembled, will be D, T, or AB.
mcmelectronics.com a division of farnell has some cheaper kits here in Ohio, but I don't know how you would buy those over there.
Power supply is another issue. Farnell tends to be expensive on power supplies.
Another supplier with a warehouse in in scandanavia is mouser, I believe.

From your link I found this, which would be more than suitable size and power wise: PMODAMP2 - DIGILENT - MODLUE, PMOD, AUDIO AMP, 2.5W, CLASS D | Farnell element14 I think it would also be quite easy to insulate such small amp.

If you are after an older type of sound, and you want simple, and you want to DIY the amplifier - I'd suggest a simple classic design from the 1970's, first type of amp I ever built: http://www.diyaudio.com/forums/solid...amplifier.html
I guess that is slightly too powerful tho for this application ?

Let me clarify :D The radio is a small old Grundig Satellit radio from 1964. There's lots of sound demos on youtube. I simply heard one in real life and kind of fell in love how this old crappy thing sounded! The amplifier had sort of "soft clipping" sound to it. I'm currently bidding on a similar radio which has a broken amp, which I then need to replace.

So I need to get the kind of vintage sound. Is there any discrete small amps available? I probably don't need more than 2-3 watts of power.