Partygram!

Posted on


So much for the 6BW6…along came…Solid State Technology! Yes! Transistors!

By this time I was working as an Apprentice at Telefusion Ltd on the front line of Technology. So my next project was to improve the original Stereo amplifier and bring in Solid State Devices (Transistors) My friend Neil had just built a slimline amplifier based on an amplifier in Practical Wireless, the Partygram.

The Partygram was a Mono Amplifier that used two high power transistors (AD161 and AD162) in Push-Pull Mode to give an output of 10 watts rms. Two of these amplifiers built in the same box would give high quality stereo! I was dead impressed with Neil’s Amp, so I set about building one myself. I managed to obtain most of the parts from work, but the most expensive item was the mains transformer. The drivers and pre-amps used BC108’s and equivalent PNP devices. I built a case from aluminium and my Dad built a wooden surround, all the controls were mounted on the front. This was a superb project, we could have audio separates (Amplifier, Deck, Speakers) and was used at home and later when I got married right up until about 1980 with a pair of wall mounted Bush Denon Speakers (actually Warfedales)

Later, I used the case of the amp to house another amplifier, a FET 100 watt disco amp from Maplin which to this day is still used…in fact I used it yesterday at school for the Christmas Disco!

I still have an original copy of Practical Wireless with the Partygram circuit and details, how sad am I?

Advertisements

What’s a 6BW6?

Posted on

Well, here it is the famous 6BW6 valve!

What’s a valve? you Digital Natives may ask… Click HERE!

This versatile little beast could produce around 10 watts at Audio Frequencies and great for my first attempt at a stereo amplifier.

Our ‘record player’ built by my Dad, sat in the corner of the front room with a speaker built in the front. It sounded nice!
Hi-Fi was the ‘in thing’ back in 1969 and records and LP’s were now going STEREO so my Dad and I decided that we would build a stereo record player!
The original amplifier in the box came from an old radio that my Dad had used as an amplifier, not bad kit really, 6V6 valve amp provided a fair old sound. I decided at first to strip down the amp and use the chassis to build the new one…a bit of task really as it was my first project with valves! After a lot of drilling, filing and wiring the new stereo amp began to take shape, meanwhile, Dad was building the new wooden speaker cabinets…tall, slim and dark.
OK…I had a few teething problems with the amp, the pre-amp needed to be quite sensitive because we planned to have a deck with Magnetic Cartridges and this caused a lot of instability in the amp, so much so that the poor 6BW6 would glow red!!

Bought the record deck from Barry, G3WIS, a real piece of engineering, super heavy and stable complete with Magnetic Cartridge.

At last we were all ready to hear STEREO for the first time. To test the equipment we used a record that was made to demonstrate the effects of STEREO…I can still hear it now…”June is bursting out all over” and the train whizzing from one speaker to the other! I had just bought ” Bridge over troubled water” and this sounded great on the new system.

Hi-Fi at last, thanks to a couple of 6BW6 valves!

Later, the 6BW6 along with the 5763 and EL84 valves gave me the power to build transmitters that could transmit Radio Frequencies 160m and 80m!

Morse Code

Posted on

This is the very same Morse Key in the photo taken by Dad of me when I was 17! It came originally from M. Dzubias in a big green box for about 50p! I still use it!

Today, Morse Code is simply ‘past it’s user date’ , slow, inefficient and what the hell is it anyway? Children can ‘text’ on their mobile phones, but have never heard of Morse Code!
Well, here is my story from the days when Morse Code was the tried and tested way of communicating in even the most difficult environments, when radio operators on ships used Morse Code as part of their everyday life and Radio Amateurs had to learn it (like it or not) to gain a Class A licence.

In 1971 I passed my Radio Amateur Exam in May, my next target was to learn Morse Code at 12 Words Per Minute in order to pass my Morse Test to achieve my Class A licence.
George (G3ZQS) was an ex navy operator, he taught me everything I know about learning Morse. He would come around to my house in his slippers and teach me the G3ZQS way of learning morse. George was a real character, did so much to inspire me to go for it and also to bring so much pleasure to others learning the code. George made his own tapes, using the ‘George method’ I was able to learn Morse Code up to 20 WPM before taking my test. (A real acheivment for me at the age of 16!) George’s methos involved grouping letters together with similar sounds and rhythms (Q – God save the Queen – dah dah dit dah)

It worked for me!

Soon I was on my way to the Liver Buildings in Liverpool with my Dad to take my Morse Test. I even had to get time off work for this. The day itself I can remember like yesterday, we got lost in Liverpool trying to find our way and asked a man near the Docks, gave us directions and explained how the Dockers were all on strike!
In the Liver Building we walked up several flights of stairs to the place where the test was to held. I was shown into a room with several different Morse Keys to choose from, I chose the shiny brass one, and asked to practice for a bit. Then I had to listen to a passage of text in Morse Code and write it down, following that I had to send a passage in Morse Code. I was allowed three errors! Scary stuff!

Well…I passed!

I could at last send for my Class A licence!

A word about George, G3ZQS:

  • Can listen to morse like we listen to words!
  • Can send Morse Code on a broken hacksaw blade at 60WPM!
  • Can send and receive Morse Code at 60 WPM after drinking several brown ales!
  • Can drive a big car with his slippers on!

A man of many talents!

So now, in the digital world where children, grown ups and digital natives send text messages daily, I have one advantage….

Text messaging is really Morse Code….and I can send it faster than they can text it!!

NEV CAM

Posted on

You have heard of a WebCam?

Well, back in the early 70’s I did some experimenting with Amateur Television (more about this in a later post) Along came Barry (G3WIS) and offered me this small and compact NEV Camera with a ‘C’ Mount lens for 10 quid! I couldn’t resist so I bought it. It was a super camera, 405 lines, Black and White and good definition. The camera was used to transmit true 405 line television pictures on 70cm between my friend Neil and myself. This was unheard of at the time…we were pioneers! (and analogue natives)

The camera itself had two printed circuit boards stacked one above the other. The circuit used quite old and noisy transistors, so I decided to rebuilt the camera by modifying the circuit to include BC type transistors and make new printed circuit boards from scratch. The camera actually worked, and worked well! The only problem was the connectors on the edge of the boards which became a bit intermittent.

Im have never been able to find out about the original camera from the Internet, but it was certainly a nifty little camera for it’s time. I can’t remember what happened to the camera, in the days of 625 lines the cam became obsolesent and disappeared forever. Maybe someone, somewhere, has one of these in a museum!

Here is classic link for the old magazines!

Modern Radio

Posted on




My first memories of Modern Radio bring cold, dark Saturday afternoons, long queues and the cigar smoke! Back in 1967 the shop counter was a small, crowded area with the man with the cigar (I always thought he must be rich!) and the lady with the glasses. I wanted to be served by the lady because she was always nice to me and helpful. Sometimes Diane (the daughter) would serve to help out. I always remember waiting…and waiting, men in front with handfulls of valves wanting to be tested on their renowned valve tester, long lists of components and technical sounding questions. I was about 13 at the time, somehow I didn’t fit, I came with pocket money to spend, not a pro! I can still picture the cabinet on the wall on the left hand side full of valve boxes that never seemed to move.
Modern Radio was handy, my school bus stopped right across the road, so I would call in on my way home from school, sometimes just to look in the window. Compared to the shop on Deane Rd, prices were not cheap and God forbid if you had to order something which came from RadioSpares! When I built my first Topband Transmitter I needed a fairly sturdy tuning capacitor which had to be ordered, when I came the price was devastating! I really couldn’t afford to buy it and had to spend about three weeks pocket money to pay for it.

Modern Radio is an institution! I can’t imagine the shop ever closing. I still call in to buy my bits and I love the same atmosphere when I walk in the door. Diane runs the shop now with her daughters and you can still get those components. I pass Modern Radio a lot and still enjoy parking and spending time looking in the window.

Autobiography?

Posted on

Have you been into a book shop recently? It seems that everyone who is famous, not so famous and was famous are writing their biography! How can someone like Wayne Rooney, Amir Khan and the like have a biography long enough for a book?
I would like to have my own biography, why not? My own analogue biography of the days of wine and roses, glowing valves, hot soldering irons and OC71’s!
Although I have not got the time or patience to write a book about my analogue native days, the blog will let me ‘drip feed’ my past and in a few years time I will collect it all together and publish it as my analogue biography!

This does just as well!

Posted on

In 1967 when I first became interested in Electronics I knew nothing about shops that sold components. In my first project I was working with a multivibrator circuit kit and earpiece that produced ‘tones’. To change the tone I needed to change the value of one of the resistors, so I went along to the local T.V. shop who sold me a 1.2k resistor for 6p! What a rip off!

Then I found out about the shop at the bottom of Deane Rd owned by a great guy called M. Dubias with the patience of a saint! I used to love getting off the school bus and running down to the little shop on Deane Rd to buy my bits (resistors 1p) Electrolytic Capacitors…if I went in to ask for a capacitor he would say “10 microfarad…electrolyic?…. I have 8 microfarad…it will do just as well!” He was always right! Found out later that his name is Michael, the shop moved to Bradshawgate, right next to the bus stop so a lot of time was spent visiting his shop. Michael always had time for me, told me about any bargains he had and would explain and help solve problems when it didn’t work. If I turned up with a list of components that I needed for my project he would always come up with something that would do just as well, then he would round off the price to give me a good deal, never felt ‘ripped off’.

The shop closed on Bradshawgate back in the late 70’s without a trace. Thanks Michael Dubias …wherever you are!