Retro Gadgets: I Swear Officer, I Was Listening To 45

May 9, 2023 by Al Williams 15 Comments

Audio in cars has a long history. Car radios in the 1920s were bulky and expensive. In the 1930s, there was the Motorola radio. They were still expensive — a $540 car with a $130 radio — but much more compact and usable. There were also 8-tracks, cassettes, CDs, and lately digital audio on storage media or streamed over the phone network. There were also record players. For a brief period between 1955 and 1961, you could get a car with a record player. As you might expect, though, they weren’t just any record players. After all, the first thing to break on a car from that era was the mechanical clock. Record players would need to be rugged to work and continue to work in a moving vehicle. As you might also expect, it didn’t work out very well.

It all started with Peter Goldmark, the head of CBS Laboratories. He knew a lot about record players and had been behind the LP — microgroove records that played for 22 minutes on a side at 33.3 RPM instead of 5 minutes on a side at 78 RPM. He knew that a car record player needed to be smaller and shock-resistant. Of course, in those days, it would have tubes, but that could hardly be helped.

The problem turned into one of size. A standard 10- or 12-inch disk is too big to easily fit in the car. A 45 RPM record would be more manageable, but who wants to change the record every three or four minutes while driving?

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Bluetooth Record Player Puts A New Spin On Vinyl

November 24, 2021 by Kristina Panos 73 Comments

You know, we were just discussing weird and/or obsolete audio formats in the writers’ dungeon the other day. (By the way, have you ever bought anything on DAT or MiniDisc?) While vinyl is hardly weird or (nowadays) obsolete, the fact that this Bluetooth record player by [JGJMatt] is so modern makes it all the more fantastic.

Not since the Audio-Technica Sound Burger, or Crosley’s semi-recent imitation, have we seen such a portable unit. But that’s not even the most notable part — this thing runs inversely to normal record players. Translation: the record stands still while the the player spins, and it sends the audio over Bluetooth to headphones or a speaker.

Inside this portable player is an Arduino Nano driving a 5 VDC motor with a worm gear box. There really isn’t too much more to this build — mostly power, a needle cartridge, and a Bluetooth audio transmitter. There’s a TTP223 touch module on the lid that allows [JGJMatt] to turn it off with the wave of a hand.

[JGJMatt] says this is a prototype/work-in-progress, and welcomes input from the community. Right now the drive system is good and the Bluetooth is stable and able, but the tone arm has some room for improvement — in tests, it only played a small section of the record and skidded and skittered across the innermost and outermost parts. Now, [JGJMatt] is trying two-part arm approach where the first bit extends and locks into position, and then a second arm extending from there and moves around freely.

Commercial record players can do more than just play records. If you’ve got an old one that isn’t even good enough for a thrift store copy of a Starship record, you could turn it into a pottery wheel or a guitar tremolo.

Know Audio: Get Into The Groove

November 18, 2021 by Jenny List 62 Comments

The legendary Technics SL1200 direct-drive turntable, as used by countless DJs. Dydric [CC BY-SA 2.5)], via Wikimedia Commons. — The legendary Technics SL1200 direct-drive turntable, as used by countless DJs. Photo by Dydric CC-BY-SA 2.5

For me, the vinyl record player is the spiritual home of my audio listening experience, probably because I’m of the last generation to grow up when vinyl was king. The 12″ album, with its full-size sleeve and copious sleeve notes, used to be an integral part of musical enjoyment that hasn’t been adequately replicated in the age of streaming.

And like anyone who became an adult while CD players were still expensive luxury items, I started my journey into Hi-Fi with a turntable set-up that sounded pretty good. Since a new generation have in recent years rediscovered vinyl, it’s once again something that should be part of any review of audio technology.

I would have started this piece with a full run-down of the constituent parts of a good turntable, but since that’s a piece that I wrote back in 2017, it’s time to investigate some of the audiophile claims about vinyl recordings. It’s fair to say that this is an area where a lot of complete rubbish is spouted by people who should know better, and that’s something I find immensely entertaining to poke fun at. Buckle up. Continue reading “Know Audio: Get Into The Groove” →

Guitar Effect Built From An Old Record Player

December 9, 2019 by Tom Nardi 4 Comments

With little more than a gutted record player, a light bulb, and the legendary 555 timer IC, [Jacob Ellzey] has constructed this very slick optical tremolo effect for his guitar. By modulating the volume of the input signal, the device creates the wavering effect demonstrated in the video after the break.

The key is a vinyl record with large tabs cut out of it. As the record spins, these voids alternately block and unblock a small incandescent bulb. A common GL5537 photoresistor, mounted on the arm that originally held the player’s needle, picks up the varying light levels and passes that on to the electronics underneath the deck. An important note here is that different spacing and sizing of the cutouts will change the sound produced by the effect. [Jacob] has already produced a few different designs and plans on experimenting with more now that the electronics are completed.

Under the hood there’s a voltage divider and low gain amplifier connected to the photoresistor, and also a 555 timer circuit that’s driving the incandescent bulb. Once he was done fiddling with them, the circuit was moved to a neat little protoboard. A pair of potentiometers mounted through the side of the record player allow for adjusting the depth of the effect itself, as well as the output volume. Naturally, there’s also an external foot pedal that allows keying the effect on and off without taking your hands from the guitar.

As is usually the case, everything was going well on this project until the final moments, when [Jacob] found that the circuit and bulb were both browning out when powered from the same transformer. As a quick fix, he gutted a Keurig and used its transformer to drive the light bulb by itself. With independent power supplies, he was ready to rock.

Of course this isn’t the first time we’ve seen a piece of consumer electronics modified into a guitar effect, but if you’re looking for something a bit more built for purpose, there’s plenty of high-tech options to keep you busy.

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Repairing A Desktop Jukebox

September 11, 2018 by Al Williams 4 Comments

Although vinyl records have had a bit of resurgence, they are far away from their heyday. There was a time when 45 RPM singles were not just how you listened to music at home, but they also populated the jukeboxes you’d find in your local malt shop or anywhere else in public. [Fran] has an old 45 RPM “desktop jukebox” from RCA. It really isn’t a jukebox, but an automatic record changer dating from the 1950s. The problem is, the cartridge was toast. Replacing it wasn’t a big problem, even though replacing it with an exact duplicate wasn’t possible. But, of course, that was just the start.

You can see in the video below, that there were some weight problems with the cartridge, but the changer part would not work. She tears it down and makes some modifications. She even pulled out the schematic which had three tubes — one of which was just a rectifier.

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A Victrola For The 21st Century

April 9, 2018 by Jenny List 12 Comments

We’ve lost something tangible in our listening to music, as we made the move from physical media through MP3 players to streaming services on our mobile devices. A 12″ vinyl disc may be slightly cumbersome, but there is an undeniable experience to pulling it from the sleeve and placing it on the turntable. Would you like to recreate that? [Castvee8] would, because he’s created a 21st-century version of a wind-up gramophone, complete with a turntable and horn.

Under the hood is an Arduino-controlled MP3 player, while on the surface is a 3D-printed turntable and horn. On the turntable is placed a CD, and a lead screw moves the horn across it during play to simulate the effect of a real turntable. An Arduino motor controller shield drives the turntable and lead screw, and at the end of each song, the horn is automatically returned to the start of the CD as if it were a record.

The effect is purely aesthetic but should make for an unusual talking point if nothing else. Surprisingly this project is not the first of its type, in the past, we’ve shown you another one that played a real CD in the place of the record on the turntable.

Wood Finish From Old Records

August 23, 2017 by Adam Fabio 36 Comments

Next time you’re working on a project that needs a durable wood finish, don’t grab the polyurethane. Follow [Victor Ola’s] advice and raid your grandparent’s record cabinet for some old 78 records. Modern records are made from vinyl. The stiff, brittle old 78’s from the 1960’s and earlier were made from shellac. Shellac is a natural material secreted by the female lac bug. It can be thought of as a natural form of plastic and was used as such for years until man-made plastics became commodity items.

Older 78 RPM phonograph albums are usually made entirely from shellac. [Victor] started by taking a few old cracked records and pulverizing them with a hammer. The shellac crumbs were then poured into a mason jar along with some isopropyl alcohol. The alcohol dissolves the shellac, creating a thick goo. More alcohol will thin the slurry down to a paintable consistency. The mixture is then ready to be painted on any wood surface. Wiping off the excess will reveal the wood grain.

Shellac is normally amber in color. Records are black because carbon is added to the mix. This makes the shellac stain dark and makes it a flat finish. While it would be fine to leave it this way, [Victor] added a coat of lacquer over his shellac stain to achieve a glossy finish on his upcycled gramophone.

If you’re getting into woodworking, don’t worry – anyone can do it. Just make sure you have sharp tools.

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