I still have a Sinclair X10 amplifier that I built in kit form .This was 1969. Turned it on to see if it worked as I haven't run it for 20 years and it is still working. The Sinclair FM radio tuner kit same vintage was an incredible piece of work
I well remember drooling over this design in the March '79 issue of P.W. Unfortunately, I never got round to building it as I had no cash to spare at the time.
The power amplifier board has been lifted from the Hitachi application notes. This section was also available as kit from many of the retailers of the day in Edgware and Tottenham Court Road. The basic circuit could be up rated to 100 watts. A powerful amp in its day. I must have built over 15 of those kits for a number of applications. Everyone worked first time. I never had any back blown up or other faults. They sounded very good if I recall. Funny thing is, I had not heard of this complete project before. Like you I collected every issue of PW and all the other such magazines of the time. More like a Bible than a magazine.
Flippin 'eck, £110!! That's insane for a diy amp! My Pioneer SA9100 of around that time was under £100 and was way more sophisticated and powerful!! The diy kit amp that sticks in my mind was the Linsley Hood, a design that is still being cloned now, with pcbs and component sets available on ebay. I did want to build it in period but again, too expensive.
Memory lane Michael. My era. My electronics career started with getting Televisions off the tip and repairing them. Working in the controls industry now and still use the same fault finding skills on million pound machines that I learnt when I was a boy.
hi there was some A/V game made in low numbers there used to be kits you could buy back in the day there was reel to reel decks as kits and the same with recorder players maplin used to sell alot of kits you could do
I enjoy your videos as they bring back fond memories from my youth. The power amplifier section of that amp looks very like th hitachi reference design for those transistors I have built many of this design mostly the one published in the Maplin Electronics magazine it originally appeared as a part of a guitar amp but the power amp section was subsequently published in a later issues of the Maplin magazine it was published a couple of occasions later with different output transistors and more power output the original guitar amp had a power of 75 watts then the latest incarnation of the power amp was rated at 150watts with a suitable power supply. i still have one(stereo pair) of the Maplin amps in my workshop i built. that amp is still working well. This amp must be nearly 40 years old now.. Keep up the good work, Micheal. Peter Ensinger M7DTK
Very nostalgic, I designed and built a number of hi-fi amps back in the day. It would have been interesting to have connected a sig gen and a scope to check for cross over distortion when on full load. My output stages were also class AB configuration but used 2N3055's as the main drivers. SN741 op-amps were sometimes used in the pre-amp stages. I also built some impressive sub woofers using fourth order filters, 100 watt power amps and 15 inch speakers.
I do wonder what the soldering would be like using the lead free stuff we are forced to use today, fortunately I still have some military graded leaded. The toroidal transformer shows the quality.
Wow, that's a bit of a turn up isn't it Michael! I wonder what sort of record player cartridge(s) it was geared up for. When you were flicking through those PWs, I homed in on the one with the 'free nut runner'. I still have mine right here - still as orange as ever. Thank you for the trip down memory lane.
my hifi amp is home made based on the hitachi text book opamp design using genuine 2sj50 and 2sk134 i bought in early 90,s i love it ,theres only one cap in the signal path ,and it sounds so clear and detailed. it sounds a little soft on top end (gate capacitance causing slow slew rate? ) but its so livelly mids and low end even at low volume and its really noticeable how tightly it keeps even cheap speakers under control ive got heatsinks from a fruit machine and home made hand drawn pcbs the case is an old sony tape deck the only parts i needed to buy was a 300va torroid and the vmosfets i tried many times to make bipolar amps but never got thermal runaway under control, so mosfets were a godsend and sounded far more punchy aswell
I used to build quite a few projects from PW but not this one, as that was more than a months wages for me at that time, thanks Michael for the memorable moments and thanks for sharing 👍.
Your collection of stuff is a real treasure trove. I know there's been a few over the years but I'd like to see more videos just going around and taking a look at random interesting things. Do you ever plan to properly shelve / display the magazines all and put it in order?
