Hello all , I have come into possession of a 1970's Australian made amplifier .Its a thingy smith kit in an enclosure that was designed for the kit . All the wires have been cut and the board has been damaged a little but that's repairable . There are a couple of pots that will need replacing as well. The question is does anyone know what power these amps have as I get conflicting information from the all knowing internet. I also have a 50 watt as yet unbuilt kit of the same era by thingy Smith . It doesn't look at all like this one .
Can you identify the four power transistors on the heat sink (the photo is too fuzzy)? At least this may give an indication of what the output possibly could be. The heat sink looks like it's been weathered a bit - the transistors' performance is suspect. A power transformer is not evident in the pictures of the board - its core size may/may not be an indicator of how much power it could provide to the final amplifier stage. What is the kit nomenclature (cannot read it from the photos) - somewhere in internet land there must be someone with an old D--- Smith catalog with a description of this amplifier.
Ok , I'm home . Sorry for the confusion. There are two numbers on the circuit board . 80sa10 and cat H8386 (not "K") . The number on the transformer mounting plate is MO152 , I'm not sure if this number has any relation to the actual transformer or not . Some blurry pics and test results to follow tomorrow . The name D--K SMITH ELECTRONICS is also printed on the board . A lot of these builds came with permission from Australian Electronics Magazine , when analog electronics was huge in this country......sad to see that its not that popular anymore .
Hello again , unfortunately one of the transistors is unreadable , two are clearly marked 2SK133 OD1 , 2SJ48 1B1 .One is only partially readable ...K133or8 1L?. All are Hitachi branded .Sill haven't gotten around to testing transformer outputs , more info forthcoming .Cheers , Dave.
With a dual set of these transistors (assuming stereo left channel, right channel) of that max rating on that heat sink, the amplifier must have been capable of producing some earth shaking tunes. Does the 50 watt unit you have from thingy Smith bear any electrical similarity to this one? In any event, you might first test the transistors - it may affect your decision to go ahead with making this a restoral project or just scavenge it for parts. For what it's worth, if you are still lacking a schematic, there is an example of a monaural 2SK133-2SJ48 guitar amp at www.plexoft.com/SBF/mounted/0tube.html
Last Edit: Nov 6, 2016 16:11:29 GMT -8 by radioman
Hi , thanks Radioman , I'm have a problem uploading pics of the transformer and the other 50 watt circuit , it seems that the 50 watt kit is convertible to 100 watts ( its tiny compared to the unknown one...about a quarter or less the size . Hope I can sort this error problem ! Cheers , Dave.
frustrated with win 10. I cant upload any more pics as windows is messing with my laptop . Its really sickening the way MS has hijacked lots of peoples online lives including mine . The combination of a crappy ASUS laptop model F553M and an even crappier OS windows 10 has pretty much ruined my on and offline experience . I'm going to visit a tech and have the hard drive replaced and loaded with windows 7 . I'm going to burn the old hard drive at the stake after running it through with a screwdriver a couple of times , just to make me feel better ! Sorry for the rant but ive really had enough of this garbage. Windows even hides administrative tools from you so as to try to discourage any alterations .Its basically MALWARE .Now ive passed the cut off time to revert to a previous OS (8.1) which is almost as bad as win 10 .So new hard drive and win 7 it is .....sigh. Again ,I apologize for carrying on .....just so frustrated.!!!!
Hey Dave, I can relate to everything you've said about Win 10, beginning with the way MS forced most Win 7 users to "upgrade" to it. Also, I don't like the way MS forces one to install all upgrades, even the ones for which you don't need. When I get some time, I'm going to install Linux on a laptop (which runs slower with Win10) and see how well it can run the MS suite. Linux may be easier to run; seems like it becomes more popular each year. An recent article about Linux (versus Windows 10) from PC World is attached.