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Old 23rd Feb 2008, 9:16 pm   #21
Dean Huster
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Default Re: What is your oldest Homebrew / Kit still in everyday use?

My first kit which I still have and use was an Allied Radio Knight-Kit KG-620 vacuum tube voltmeter, built around 1965 or so. It has never needed a repair, although I did swap out the 1.5v "C" cell for the ohmmeter with a rectifier and filter off the heater winding.

Had a transistor tester than was homebrew back in 1967 that I ended up relegating to the junk bin when I acquired a Tektronix semiconductor curve tracer. It was a circuit that originally appeared in Radio-TV Experimenter, a U.S. magazine of that era. I still have the magazine, I know, but don't know which one it was in. I've never thrown away a hobbyist electronics magazine in the 40+ years I've been in the hobby.

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Old 24th Feb 2008, 1:57 am   #22
tsgunnell
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Default Re: What is your oldest Homebrew / Kit still in everyday use?

The tube booster tester from television by alan wilcox television 1987 .i used it just the other day bought a few tubes back to life over the years
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Old 24th Feb 2008, 1:12 pm   #23
'LIVEWIRE?'
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Default Re: What is your oldest Homebrew / Kit still in everyday use?

I still have, although it needs an overhaul, a Shortwave Receiver, using Denco Plug-in Coils, and OC170 transistors, built to a design by David Gibson, published in Practical Wireless in 1972 or 73.
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Old 24th Feb 2008, 9:41 pm   #24
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Default Re: What is your oldest Homebrew / Kit still in everyday use?

I have got an old crt booster which I first put together back in 1977. It was based on a Practicle Television designed mono crt booster using a 100w lightbulb for the heater supply and a 15w Pygmy bulb on the HT feed to the grids. A year or so later I modified it to boost colour tubes this meant replacing the 100w light bulb with a suitable transformer. It was used frequently but does not see much service now.
I still have an RC oscilator which produces a 330Hz sine or square wave output. This was built at Bath College back in 1977 as part of our laboratory studies. It still works and is still occasionally used.
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Old 2nd Mar 2008, 11:45 am   #25
Trevor
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Default Re: What is your oldest Homebrew / Kit still in everyday use?

Here are 2 pictures of a diy amplifier I made about 30 years ago It still works and I am about to make some upgrades to It
The design is a nominal 30 watts into 8 ohm per channel class a/B
output stage is inverted darlingtons with constant current source on the vas and diff front pair
Offset is under 4mv on each channel
The amp was origionaly used as a miband amp on a 3 way triamped system
So heatsinking was not an isui
The mods that I intend to to are by Renardson a "new aproach to class b design" Wireless world 1998 The work of a marvel he has in my opinion managed to perfect the class A/B output stage and it can be found by Googling
I wil keep you posted re the mods etc
regards Trev
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Old 2nd Mar 2008, 7:59 pm   #26
'LIVEWIRE?'
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Default Re: What is your oldest Homebrew / Kit still in everyday use?

I might add that I still have, in daily use in my workshop, a variable voltage, current limited PSU(5 to 25v @ 2A Max), built around a 741 opamp, with series pass darlington transistor(BC238 & 2n3055). I built it in, I think, 1972 or 73, based on another PW design with a few mods. Never to my knowledge given any trouble.
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Old 3rd Mar 2008, 12:17 am   #27
Phil G4SPZ
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Default Re: What is your oldest Homebrew / Kit still in everyday use?

Quote:
Originally Posted by 'LIVEWIRE?' View Post
I might add that I still have, in daily use in my workshop, a variable voltage, current limited PSU...
I made a similar unit of my own design that I still use, virtually every day. It is one of the most useful bits of kit in my shack, although it is limited to 0.5 amp at 0-25 volts. It has twin voltage and current meters, and its most useful feature is a variable constant-current source. From memory, this uses a 741 op-amp to sense the voltage drop across a 1-ohm resistor, and applies a bias to the series regulator (2N3055).

Contrary to Livewire's, mine has suffered two faults over the years. The voltage control pot, a standard component driven through a 6:1 reduction drive, went o/c and had to be replaced. More recently, the 1-amp potted bridge rectifier went s/c and I think it was originally under-rated, although the original lasted over 35 years...

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Old 5th Mar 2008, 12:46 am   #28
Tim
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Default Re: What is your oldest Homebrew / Kit still in everyday use?

Quote:
I made a similar unit of my own design that I still use, virtually every day. It is one of the most useful bits of kit in my shack, although it is limited to 0.5 amp at 0-25 volts. It has twin voltage and current meters, and its most useful feature is a variable constant-current source. From memory, this uses a 741 op-amp to sense the voltage drop across a 1-ohm resistor, and applies a bias to the series regulator (2N3055).
That sounds good. Er, may I have the circuit please, as I have been wanting to build a low voltage variable bench supply for some while.
Thanks
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Old 6th Mar 2008, 11:48 am   #29
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Default Re: What is your oldest Homebrew / Kit still in everyday use?

I still have a couple of old transistor radio kits I built in the early '60s. I can't say I use them bery often, but I believe they still work. They are Elegant 7s sold by R&TV Components Acton. They do have 7 transistors, but are not very elegant! The date would be prpobably1963.
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Old 6th Mar 2008, 9:11 pm   #30
Phil G4SPZ
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Default Re: What is your oldest Homebrew / Kit still in everyday use?

Quote:
Originally Posted by Tim View Post
...may I have the circuit please, as I have been wanting to build a low voltage variable bench supply...
Tim, you have a PM.

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Old 3rd Apr 2008, 12:01 am   #31
AndrewH
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Default Re: What is your oldest Homebrew / Kit still in everyday use?

A PSU I made in the early eighties based on the PW Marchwood design. It used 9 2N3055's instead of the 5 in the PW one. It is built into a 19" rack and is not what you would call compact. It works well though.
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Old 21st Apr 2008, 12:19 am   #32
Oldtimer74
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Default Re: What is your oldest Homebrew / Kit still in everyday use?

I built my "Elizabethan" transmitter to the design by G5RV in 1955 and I still use it regularly for AM transmission. It lay idle in the rack for about 35 years until I decided last year to get it going again. I had to replace 1 valve and 1 resistor only!! Shows something of the quality of the ex-Govt parts from which it was entirely built.
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Old 8th Jun 2008, 7:03 pm   #33
Trevor
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Default Re: What is your oldest Homebrew / Kit still in everyday use?

I was recently called a life long friend of mine to replace the cartridge on his turntable
This gave me the opportunity to take a few photos of the preamplifier/amplifier combination I made this about 28 years ago and can say that it is still in use and is played a few times a week
The phone gain and equlisation is done in two stages spread over 2 TL072 stages per channel This was done after a deal of thought that led me top the conclusion that most preamps at the time were not capable of driving there own equalisation networks
The line stage is another TL072 this giving a gain of 20 db
Their are only 2 controls on the preamp a vol control and a push button
Input selection is bu the push button that was connected to a cmos 4017b/4016 quad gate that sequenced both the inputs and power on off to the power amp turnatble etc
This was all new at the time and has proven to be very durable
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Old 10th Jun 2008, 12:23 pm   #34
camtechman
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Default Re: What is your oldest Homebrew / Kit still in everyday use?

Having just found this thread & seeing the PW digital clock, I couldn't resist showing you my PW digital clock.

Whereas the OP's clock is LED display & uses a clock chip, mine was from the earlier PW 2-Part Article by J.G.Mercer (possibly 1968?) and uses only 7441 & 7490 ICs & RS Numicator Tubes.

I built in a new equipment case that I obtained from where I worked at that time (GEC-Marconi).

It still works and is now some 40 years old and to think, I nearly threw it away a few years back....perish the thought!
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