Sub Sonic Posted December 22, 2012 Share Posted December 22, 2012 I was having a look at this home made amplifier module, and was wondering if anyone recognises it? It is built in dual mono, has 66V rails, and looks to be an Electronics Australia board. One channel is blowing fuses, I suspect it may be a bridge rectifier. It was originally used as a PA amp, and I was eyeing off the enclosure and parts for another amp project but was wondering if it's worth keeping as it is. Pics: Cheers! SS 1 Link to comment Share on other sites More sharing options...
Green Wagon Posted December 22, 2012 Share Posted December 22, 2012 The outputs are old mosfets. The numbering on the bottom of the board tells you everything you need to find its origins. EA 89 M 11. So, designed by Electronics Australia in 1989. Have search for EA magazines (library ?) around the 1989 1990 era. Link to comment Share on other sites More sharing options...
Sub Sonic Posted December 22, 2012 Author Share Posted December 22, 2012 Thanks, I did do an online search but did not come up with anything. Unfortunately I don't have any EA magazines and was hoping someone here might be able to help. Other than that, the library might be the next step. Cheers! SS Link to comment Share on other sites More sharing options...
Sierra Posted December 22, 2012 Share Posted December 22, 2012 This is the EA Playmaster Pro Series One Power Amplifier. 140 WRMS per channel @ 8 Ohm, 180 WRMS per channel @ 4 Ohm Here are pictures of the one I built when the kit first came out circa 1989 I built both the Pro Series One Power Amp and the Pro Series Two Pre Amplifier ... these served as my main amps for nearly two decades. I still have them ... although they are retired now from active duty 3 Link to comment Share on other sites More sharing options...
Sub Sonic Posted December 22, 2012 Author Share Posted December 22, 2012 Thanks Sierra! That's definitely the same one, I think I might keep it original. How do they sound in comparison to more modern amps? Regards, SS Link to comment Share on other sites More sharing options...
Sierra Posted December 22, 2012 Share Posted December 22, 2012 You're Welcome SS It's agood amp ... operationally it's quiet and it has plenty of grunt. Many years ago it fried the woofers of my Audax speakers (that I still use today) during a party we had when someone turned the volume up a little bit too much after some alcoholic beverages Sound wise it's not in the same league as my Valve amp or even my old Marantz 4140. While it sounds nice enough it misses out on the finer nuances of better quality amps. I guess maybe a good way to describe it is if you threw a veil over your speakers ... the music is there but it just doesnt "engage" you if you know what I mean. Link to comment Share on other sites More sharing options...
Sub Sonic Posted December 22, 2012 Author Share Posted December 22, 2012 Thanks Sierra, I know what you mean, it sounds like it might find itself back on the shelf. Unfortunately, no matter how much I like an amp or pair of speakers, if the SQ isn't up there it just won't get used. I might fix it up and have a listen just out of curiosity though. Regards, SS Link to comment Share on other sites More sharing options...
Sierra Posted December 22, 2012 Share Posted December 22, 2012 Yeah ... I know what you mean SS. If you are able to fix it for not too much cost then you should do it and have a listen for yourself. Link to comment Share on other sites More sharing options...
trainfan1981 Posted May 9, 2015 Share Posted May 9, 2015 Hi SS. Did you find some schematics for your Playmaster Pro Series amp? Researching the application of the Hitachi TO-3 and TO-3P MOSFETS, I managed to purchase a set of magazines and have scanned the amplifier articles. I also have the later Pro Series 3 using the 2SJ162/2SK1058 and the 300 watt version using 3 pairs. Let me know if you need a file. Link to comment Share on other sites More sharing options...
Equaliser Posted May 9, 2015 Share Posted May 9, 2015 (edited) Those Hitachi 2SJ49's are very hard to short even when pushing the amplifier beyond its rated limits. First amplifier looks like a simple dual mono design but with no relays or protection with output and anything that will drift into red zone so watch out for how loud you push the amp. Edited May 9, 2015 by DefQon Link to comment Share on other sites More sharing options...
Monkeyboi Posted May 10, 2015 Share Posted May 10, 2015 This is the EA Playmaster Pro Series One Power Amplifier. 140 WRMS per channel @ 8 Ohm, 180 WRMS per channel @ 4 Ohm Here are pictures of the one I built when the kit first came out circa 1989 I built both the Pro Series One Power Amp and the Pro Series Two Pre Amplifier ... these served as my main amps for nearly two decades. I still have them ... although they are retired now from active duty Pro Series 1 01.JPG Pro Series 1 02.JPG Pro Series 1 03.JPG Pro Series 1 04.JPG Pro Series 1 05.JPG Lovely neat and clean build there. So nice to see you took considerable care in its construction. Easy to see why it lasted over two decades and still going strong. Cheers, Alan R. 1 Link to comment Share on other sites More sharing options...
Wicked_XR Posted September 29 Share Posted September 29 Just rebuilding mine after 30 years Link to comment Share on other sites More sharing options...
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