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Main => Everything Else => Topic started by: david656 on July 03, 2008, 05:27:33 pm

Title: 1W Maplins DIY Amplifier kit
Post by: david656 on July 03, 2008, 05:27:33 pm
i bought one of these things yesterday and started to make it at midnight and finished around 3am and then today connected up the wires to a MP3 and speaker and well the results are some what shocking ! the static on the line is awful and out powers the weak sound anyway and makes it a total waste of my time and money ! does anyone know why it could be putting so much static buzzing out onto the line ?

1W Amp with a set gain of 50
Requires a 4 - 12v power supply


my favorite part is its not suitable for under 3 year olds  :laugh2:  :soapbox:  :censored: i mean ! when have you EVER seen a four year old casually soldering a PCB ? making his own tap on night light etc !!!


any hints would be nice

http://www.maplin.co.uk/module.aspx?ModuleNo=2921&doy=3m7

PS that looks NOTHING like the one i have ! even though its ment to be the same thing ! and the picture on the box is different to the components inside the box ! i mean they have changed colour and shape a bit !

(except resistors of course !
Title: Re: 1W Maplins DIY Amplifier kit
Post by: Level42 on July 04, 2008, 05:35:32 pm
What were you drinking that it took 3 hours to solder 3 caps, 3 resistors, 1  IC and 1 pot ? :D

Are you sure all solderings are 100%. No shorts ?

What are you using as a power supply ?
Title: Re: 1W Maplins DIY Amplifier kit
Post by: Ed_McCarron on July 04, 2008, 05:36:31 pm
Its not the most advanced amp, from the looks of the pic.  Make sure your power supply is clean.  If you're using a wall-wart, toss an electrolytic cap (rated for 2x your voltage, maybe 3300uf-ish) across the power leads to smooth the DC out.

Try powering it from a decent sized battery and see if the problem goes away.
Title: Re: 1W Maplins DIY Amplifier kit
Post by: Level42 on July 04, 2008, 05:41:23 pm
Yep, that's why I asked about the power supply...good suggestions.

I incidently built this amplifier. I use it on my Mario Bros. cab and works great (running from the Nintendo Power Supply):

(http://www.vellemanusa.com/images/products/0/k4001.jpg)

http://www.velleman.be/product/view/?lang=en&id=9181
Title: Re: 1W Maplins DIY Amplifier kit
Post by: Blanka on July 04, 2008, 06:01:15 pm
I'm about to use an amp like this:
(http://www.briangt.com/gallery/albums/lm3886amp/3886_065.sized.jpg)

2x65 watt gainclone. Serious stuff  ;D
1 watt will do for Space Invaders, but later titles sound much better with a little beef in the amp.
Title: Re: 1W Maplins DIY Amplifier kit
Post by: Level42 on July 04, 2008, 06:37:31 pm
Yup:

(http://forum.arcadecontrols.com/index.php?action=dlattach;topic=42798.0;attach=17631;image)



http://forum.arcadecontrols.com/index.php?topic=42798.0
Title: Re: 1W Maplins DIY Amplifier kit
Post by: Blanka on July 05, 2008, 04:39:38 am
@topicstarter:
Its a pre-amp. You cannot use that for powering speakers. Sure it will sound crap.
Title: Re: 1W Maplins DIY Amplifier kit
Post by: Level42 on July 05, 2008, 08:06:47 am
Quote from: Blanka on July 05, 2008, 04:39:38 am
@topicstarter:
Its a pre-amp. You cannot use that for powering speakers. Sure it will sound crap.

Hah ! Now how  did I overlook that ! :D
Title: Re: 1W Maplins DIY Amplifier kit
Post by: Ed_McCarron on July 05, 2008, 10:17:36 am
Quote from: Blanka on July 05, 2008, 04:39:38 am
@topicstarter:
Its a pre-amp. You cannot use that for powering speakers. Sure it will sound crap.

Ha!  Sure, go ahead and actually READ the page he posted...  Thats cheating.   :D