FS: Piece of Maplin history MA 310 A Very High Quality 40W Stereo Amplifier' - diyAudio
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Old 4th November 2012, 09:04 PM   #1
Flibble is offline Flibble  United Kingdom
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Default FS: Piece of Maplin history MA 310 A Very High Quality 40W Stereo Amplifier'

I got this from a very nice guy who was giving up electronics and having a clear out, hed had it from new (about 30 years ago!) and never got round to finishing it off. When I got it there were a few minor probs (dodgy joints on power PCB, bridged track on one of the input boards, wrong resistor value on one of the tone boards and some dodgy wiring between the pots and tone boards), also the amp boards were shot and all the power wiring between the power boards, caps, fuses and amps boards was missing. I sorted all this out (and made all the mains wiring safe! Currently has a blue light behind the red the filter which makes it purple, but at least youre not risking your life taking the lid off with it plugged in) I had a couple of the same amp boards from a project I made in school so they went in and now its working great (no crackle from the pots, all knobs and buttons doing the right things as far as I can tell). I should point out that since it was only finished a couple of weeks back its been played for about 1 hour in the past 30 years . The amp boards were re-capped with new electrolytics and wima reds (polystyrene caps were left in) fairly recently, and some resistors swapped for matching ones. I didnt bother wiring up those two smaller amps for headphones but I think theyre both working fine and the wiring is there (just tidied out of the way).

Ive got the original paper instructions, Ive put them online for posterity here and the Maplin mag article for the 50 watts amps is here.

I got it for a project and now its finished Ive too many other projects and not enough space so it needs to go. Id really like to see it go to someone whod appreciate it and not take it apart for bits If I could get 40 for it (to cover the build cost of an ESP Project 101 ) that would be really awesome, otherwise make me an offer. The thing is really really heavy so its going to cost about 15 to courier it UK mainland, payment would have to be paypal or cash on collect, PM or reply if you're interested. The black bits in the knobs are just black paper and two fell off . I've not managed to find any mention of this amp anywhere on the internet, I guess it pre-dates mainstream web!

Cheers, Dan.
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Old 12th July 2013, 10:58 AM   #2
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Default Maplin MA310 Stereo Amp

I built this amp back in 1985 and have used it virtually everyday since (playing Radio 2 as I type)!! A superb amp. I have had to replace one of the 6.2 zeners and a couple of pots that became noisy, and that's it. I did later modify the mono/stereo left/right facility. I loved the idea of mono left or right (great for listening to early Beatles stuff!!), but there was no option for mono left & right - which mine now has!!
I bet the MA310 would still give modern stereo amps a good run for their money in terms of sound quality.
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Old 12th July 2013, 11:04 AM   #3
Mooly is offline Mooly  United Kingdom
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I remember an older family friend building this when I was just getting seriously into electronics. Very nice amp from what I remember. A lot could probably be done to uprate it nowadays. I seem to remember it used a few opamps (quads) with an unusual pin out.

Shame all that real diy aspect disappeared from the likes of Maplin etc.
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Old 12th July 2013, 11:17 AM   #4
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Default Maplin MT310

At the same time as building the MA310 I also built the MT310 4 Band Stereo Tuner. It was a but clunky to use but looked great with the MA310 in the stereo unit!! Tuners have certainly moved on since - internet radio & iTunes now feed my old faithful MA310.
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Old 12th July 2013, 11:23 AM   #5
Mooly is offline Mooly  United Kingdom
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Hmm... don't just remember that one.
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Old 12th July 2013, 02:18 PM   #6
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Default The MT310 Tuner

The MT310 4 Band Stereo Tuner - and I still have it!!
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Old 31st July 2013, 10:23 PM   #7
Flibble is offline Flibble  United Kingdom
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Really great to hear you guys have fond memories of this amp! Ended up flogging it on ebay in the end. Those Maplin 50 watt power amp modules sound great, the gigantic preamp section I'm less convinced about (although this could be down to the guy who built this one originally )

Cheers, Dan.
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Old 27th August 2013, 01:17 AM   #8
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Quote:
Originally Posted by Flibble View Post
Really great to hear you guys have fond memories of this amp! Ended up flogging it on ebay in the end. Those Maplin 50 watt power amp modules sound great, the gigantic preamp section I'm less convinced about (although this could be down to the guy who built this one originally )

Cheers, Dan.
My first amp build was the Maplin 50 watt amp.
I was amazed when it worked.
I had intended it for disco use but it simply wasn't loud enough outside of a home.
So I built he Maplin 225WRMS 2n3055/mj2955 amplifier.
To save on transistor insulators I bought 2 heatsinks and mounted them in a wooden box. The amp worked great for a good few years until I eventually sold they disco.

I keep looking for old Maplin amps on ebay but they sometimes go for silly money. I was lucky enough to get a couple of 50 watt amps for a few pounds. One was working the other had a wrong transistor and few transistors missing but it was fun getting it working. When I got them powered up I had forgotten just how good they sound.
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