53 years ago I was an intern in the Solid State Physics Lab -- lab rat -- my job was to build stuff from Scientific American "Amateur Scientist" articles -- like a PLL. I also fixed the Tektronix scopes (535, 525?), attended to the McIntosh amplifiers they used and built some low noise pre-amplifiers.
On my own I built a regulated power supply for my Eico 753 transceiver, a horrible rig which I still have. Thinking of George's transistorized supply, I acquired the matching Eico mobile supply for it, a working AC supply and the Eico Keyer. I blew the original Eico AC supply, a local ham gave me a mil-surplus transformer for it. Somewhere there is a picture of it.
My SWTP "Plastic Tiger" blew up immediately upon powering up.
On my own I built a regulated power supply for my Eico 753 transceiver, a horrible rig which I still have. Thinking of George's transistorized supply, I acquired the matching Eico mobile supply for it, a working AC supply and the Eico Keyer. I blew the original Eico AC supply, a local ham gave me a mil-surplus transformer for it. Somewhere there is a picture of it.
My SWTP "Plastic Tiger" blew up immediately upon powering up.
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Did yours have the two piece dust cover where the top hinged on the back? It was nearly impossible to close that thing without making the record skip, so I left it open while playing records. The spinning shiny thing was too much of a temptation for a curious cat so the two tangled, and the cat won.
I never built any of the SWTPC amps from their kits. I copied the PCB from the magazine article and stuffed them with free silicon from the Motorola Semiconductor sales engineer. The Plastic Tiger and the Universal Tiger were the versions we made the most of, well into the 80's. Some were used in guitar amps and a few were used in HiFi systems, but thanks to my "Electric Bagel" power supply, (I didn't choose the name) most went into car or van amps.
I sold the remains of my collection of random parts and PC boards to another member here 10 or 12 years ago. Since then, I found the "Master Blaster" amp I built for my car in the 90's as an "analog design project" for school in quest of an engineering degree. I can't find it now though. It had 4 X Plastic Tigers in it, powered by a "new improved" power supply that used a cup core transformer, so it could not be called an electric bagel.
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Then 45 years ago or so when the first of the small fry arrived ....I used to pick up "Hi Fi News and Record Review" at Hotalings bookstand in NYC on 42nd Street -- also got Elektor and some French hi fi mag there.
From one of these I built the second "DaLine" which used a B110 and T27. It sounded pretty good with my Pioneer SX-838.
I gave the DaLine to my brother who was in college as I got my hands on a pair of AR AR3a's. I still have the AR's which one of my sons had for a few decades. He returned them to me with the driver surrounds and pots replaced (didn't pass the WAF test). They are now on stands and still sound pretty good!
From one of these I built the second "DaLine" which used a B110 and T27. It sounded pretty good with my Pioneer SX-838.
I gave the DaLine to my brother who was in college as I got my hands on a pair of AR AR3a's. I still have the AR's which one of my sons had for a few decades. He returned them to me with the driver surrounds and pots replaced (didn't pass the WAF test). They are now on stands and still sound pretty good!
We mostly put Grace 707s on those. Here is the one i built 43 years ago:
The look on people’s faces when the lowly Connoisseur outperformed the top end Technics and Denon DDs (with same arm and cartridge)was priceless.
dave
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Had one of those as well. 128K Macintosh with Imagewriter, $4300 CAD, but nothing compared to the LaserWriter, $11k plus a later $3k upgrade.
Stillhave it, only the shell and frame is original, now a 4 MB, 16MHz 68020 with room to install internal drive.
dave
We sold a few of those. Noit the greatest TT. A valid attempt at giving a pivoterd arm linear tracker chops.
dave
I quickly learned the best place for teh dustcover wa snot on the table, this became my dustcover.
dave
The calculator wars were a time of very rapid advancement. I had a SR-56 by 1976 and a TI-59 by 1977. I still have the TI-59. It was the pinnacle of the calculator era.
I designed and built my first Z-80 computer in 1978.
Ed
If the question isn't limited to audio and audio-related devices, I can add my opinion. I'm 55 so 50 years ago I was a small boy. But 40 years ago, at my 16's I made my first AM transmitter and receiver for the 80m amateur band.
TX was a 6DQ6 choque modulated by another, a 6U8 oscillating at 1700KHz apx. and a 6BQ5 as frequency doubler. Audio was a 12AX7 and a crystal mike. A 5U4 and 5Y3 for rectifiers with separate power traffos for final stage, running 500V at 6DQ6 anode supply. Pi tank with 410pF at plate side and 3 x 410 at antenna load side.
RX was a 6BZ6 (RF), 6BE6(Converter), 2 x 6AU6 (IF) 6AV6 (detector and 1st audio), 6AQ5 (audio out), 6AL5 (Noise reduction), 6C4 (beat oscillator) and 80 (rectifier). Speaker was an electrodynamic unit 1500 Ohm field and 6" cone.
As with 16 I could't get my ham licence, a guy from the radioclub told me I can use the radioclub call LU1EEE during tests. This guy was the president of such RC.
TX was a 6DQ6 choque modulated by another, a 6U8 oscillating at 1700KHz apx. and a 6BQ5 as frequency doubler. Audio was a 12AX7 and a crystal mike. A 5U4 and 5Y3 for rectifiers with separate power traffos for final stage, running 500V at 6DQ6 anode supply. Pi tank with 410pF at plate side and 3 x 410 at antenna load side.
RX was a 6BZ6 (RF), 6BE6(Converter), 2 x 6AU6 (IF) 6AV6 (detector and 1st audio), 6AQ5 (audio out), 6AL5 (Noise reduction), 6C4 (beat oscillator) and 80 (rectifier). Speaker was an electrodynamic unit 1500 Ohm field and 6" cone.
As with 16 I could't get my ham licence, a guy from the radioclub told me I can use the radioclub call LU1EEE during tests. This guy was the president of such RC.
I still have mine and it still works. Was $400 CDN in 1974. Doesn't get much use but I can't part with it.
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I used the 6DQ6A single tube transmitter which I built from the ARRL Handbook. The article said it could get 30W on 80, 40 and 15 meters, I don't know if that claim is true, but it did light up a 25W bulb pretty good! It had a voltage regulated screen and didn't chirp. I never got it "officially" on the air, and spent my time on 6M until I got my general class license.
One of my favorite tubes from the era remains the 6360 dual tetrode which I operated on 6M
An ex girlfriend ended up with the charger. IIRC i paid $250 (U of A bookstore) CAD in 1972.
dave
I always hate CW thus never use it as CW TX.
I remember (fully ignorant about magnetism and inductance) that the modulating choke was a rewound choke from dual cores ferromagnetic resonant stabilizators for TV. But as I believed that more inductance was better, I used the core without air gap. Colleagues told me that I had
I used bulbs as dummy load too, and a way to check if modulation was positive or negative (improperly adjusted TX's sometimes modulate negative).
So colleagues said me I had nasal voice when transmitting. Over it, the core was too much saturated that was capable of attract a screwdriver and keep it vertical. Old good times where the bigger problem was to discover why the TX had nasal audio. But several DX to about a KM using the window grid as antenna.
I remember (fully ignorant about magnetism and inductance) that the modulating choke was a rewound choke from dual cores ferromagnetic resonant stabilizators for TV. But as I believed that more inductance was better, I used the core without air gap. Colleagues told me that I had
I used bulbs as dummy load too, and a way to check if modulation was positive or negative (improperly adjusted TX's sometimes modulate negative).
So colleagues said me I had nasal voice when transmitting. Over it, the core was too much saturated that was capable of attract a screwdriver and keep it vertical. Old good times where the bigger problem was to discover why the TX had nasal audio. But several DX to about a KM using the window grid as antenna.