Bring That Old Hi-Fi Into The 2020s

It’s a distressing moment for some of us, when a formerly prized piece of electronic equipment reaches a point of obsolescence that we consider jettisoning it. [Jon Robinson] ran into this dilemma by finding the Kenwood Hi-Fi amplifier his 17-year-old self had spent his savings on. It was a very good amp back in the day, but over two decades later, it’s no longer an object of desire in a world of soundbars and streaming music boxes. After a earlier upgrade involving an Arduino to auto-power it he’s now given it an ESP32 and an i2S codec which performs the task of digital audio streaming as well as a better job than the Arduino of controlling the power.

Inside the case is a piece of stripboard with the ESP and codec modules, but there was still the problem of seamlessly integrating it with the amp’s distinctly analogue-era controls. The output from the codec is wired into an audio input – quaintly labelled for a DAT player – and a simple cam on the input selector switch operates a microswitch to select the ESP32.

If you’re dipping your toe in decent audio then an old amp from decades past can make an excellent purchase, but you might wish to educate yourself through our Know Audio series.

41 thoughts on “Bring That Old Hi-Fi Into The 2020s

    1. I have audio gear going back many years, including a Teac/Tascam 4-track reel to reel professional studio tape deck with Dolby noise reduction. I currently have a 31 year old Kenwood integrated amp and a straight line tracking phone deck. All my stuff is in mint condition. Just because it’s. Old doesn’t mean it’s obsolete.

  1. This is an interesting item. I still have my Kenwood Amp and tuner from a separates system I bought 32 yrs ago.
    (The twin cassette desk and 6 disc CD player didn’t survive). I may well look into doing something similar…

    1. Pioneer SX 1010 – 48 pounds of 100wpc a d big current amp from 1973! Nothing comes close in tone and pure power. Paid $750 new in 1973. Technics SL 1300 turntable. So sensitive, mfrs had to suspend it from ceding with wire to check specs and avoid the ambient room vibrations on table. $425 in 1973. Technics RS676US single bay cassette deck. Pro Series player/recorder. Multiple gain and tone controls. It’s huge for a cassette player. $$25 in 1973. These three pieces play amazingly well together with AR 94 floor standing speakers about 35 years old. Bad news – No Remote Control for any of these units – BooHoo!

      1. For quite a while I yearned to have a Pioneer 909 reel to reel, or even a 707. But I could only afford one of their cassette decks.
        (Come to think of it, I still can’t afford a 909 B^)

        1. i know what you mean, i got a pineer rt-1020l about 2yrs. ago from a flea market, paid about $200 only had to clean the heads, and it still working fine, i’d still like to find an rt-707 though.

  2. It does seem easier to simply plug in a streamer if that’s what it’s missing. My Lafayette LA-40 plays (or *played* until Grace Digital disabled it) Pandora through the 12″ 3-way floor standing speakers I spent my life savings on as a youth by being connected to a streaming radio. It also has a Kodi player that channels in any of my digital music.

    I was relieved to see that this wasn’t another article about removing the guts from old equipment and replacing with new. Some of the old stuff has a sound quality that you simply don’t get from the cheap Chinese electronics. I have a 90s era Kenwood that sounds gorgeous so I hope Jon keeps the original sound in addition to the front end work.

    1. About ten years ago I paid $7 for somebody’s stereo receiver at a garage sale. It was decent enough.

      I hooked it to the computer. Amplification for the speakers, which were much better than many “computer speakers”. A phono preamp. It came with circuitry for two tape decks, so I coukd use one for my cassette deck, the other to the soundcard, so I could feed the turntable or cassette deck into the soundcard. And I had the radio.

      These wren’t obsolete, people simply want “small and simple” and they’re willing to give up the working fine equioment that they paid money for.

    2. I was happy that the guts weren’t removed, old equipment normally sounds better than newer cheap designs. Friend of mine found an old Brionvega RR126 and had it serviced by a a former authorized Brionvega repair, and got a BT recever inside added simply with wires soldered on the back of the tape DIN socket and a power supply. The receiver was recapped, needle and belt replaced and record player cleaned and regreased. The only irreversible upgrate are the loudspeakers, because the original ones have the cone destroyed and aren’t actually high quality so a modern coaxial 3-way speaker is put instead

    3. I have an old marantz ki signature amp, but don’t use it. I do use the Cambridge audio sr20 amp though, and stream over wi-fi through its mp3 selector. Spotify is the main one I use them phone, it’s sounds ok through my mission Floor standing speakers

    4. This. I have a bunch of chromecast audios in use around the house. One attached to a 50’s stereo console which sadly/not sadly has been gutted and updated to all digital amps and all new drivers with a built in sub.

      On the flip side, breathing new life into old components with clickable non remote powered on/off switches can easily be remedied by a smart outlet. So a CCA + smart outlet can do wonders. If it’s new enough to have toslink, you can do digital from the CCA to the receivr/amp. The CCA will have better sound quality than other streamers out there and integrate with Google home.

      Sure, you can go all Frankenstein on it if that’s your thing, but there are many other projects I would rather spend my time on. Two quick plug ins, and I can say, “hey Google, play…” and not think twice about it.

      Though I was thinking of picking up a hybrid tube amp for the console and fabricate a plexiglass frame for it so when the console is open, you could see the recessed tubes lit up and give the console a little nostalgia besides it’s casing.

  3. I know this is Hackaday, and part of the reason people do these things is just to see if they can, but I have to admit in this case I would personally have just gotten a commercial Bluetooth receiver. Even if I tucked it into the receiver’s case and powered it from the main PCB like he’s done here, it still seems like a more reliable approach than a dev board running Arduino code.

    Now had he put something like a Pi Zero in there and was streaming online radio right into the amp over i2S, that might have been another story. But it says he specifically DID NOT want to do that, so who knows.

    I understand the MCU is also doing some power management stuff, which is fine. But I still would have offloaded the audio streaming to a dedicated device.

  4. I bought a Bluetooth streaming device which has aptX (high bitrate) capability and a proper DAC. The cost was a little less that $200, but it was well worth it. You simply plug the device into the RCA jacks reserved for a tape deck or CD player, and that’s it. My vintage system is modernized.

  5. I have done similar. Bought a Ifi Bluetooth unit, pair with my ipad and now I can play on my Kyocera R651 . It makes my Kef 104.2’s sound amazing. The Kyocera looks and sounds like new. Didn’t want to get rid of the Kyocera so this was a perfect solution.

  6. Good timing. I’ve had two surround receivers bite the dust; a SONY after about 7 years, and the PIONEER unit that replaced it. The PIONEER’s main digital/DSP board failed. Which means there’s a big fat power supply and 5 power amps left with nothing to do. I might repurpose this as a stereo bi-amp with an active crossover.

    I also have amps approaching 50 that still sound fine, give or take a crackly volume pot, which are easily replaced. Modern isn’t always better.

    1. I bought two second hand sony receivers, both died from protection faults within a few years. I wasn’t impressed and the next amp I bought was a cambridge audio axa25. it’s all through hole, and quite basic inside so I hope to rock and roll with it for some time, with a new set of speakers to be on the safe side. I found the sony dsp equaliser to be quite watery sounding, and no way to disable it either.

  7. While I appreciate the “tinker value” of the project, I use a cheap, well-worn Android tablet and a 46 year old Sansui amp ($99 was real money to a starving student!) via the headphone jack as my “garage stereo” and the amp will likely outlive me.

    1. As long as you have a subwoofer with reasonable size the rest of the frequencies can be reproduced by very small speakers very well. And even good sub frequency response doesn’t need massive boxes the way it once really did, can get pretty good, useable for most rooms but not hugely loud sub frequency from matchbox sized speakers…

      Never bought into the soundbars as a concept though – all that ‘surround sound’ processing – if you want the fully positional audio just put some damn speakers up for it, they don’t need to be large and you will get a good or even great result… And if music is all you care about a couple of small cabinet speaker somewhere is all you need, probably easier to fit into any space than the stupidly long soundbar that covers everything on largish bit of furniture, and likely sounds better too…

      Seems to me a sound bar is just what the TV should have had built in…

  8. These days you don’t really need to open up your classic audio component and modernize its guts in a half assed attempt to make it relevant for today’s streaming purposes. If your vintage stereo component has an auxiliary port, all you need is to either purchase a DSD with Bluetooth, Network media streamer, roll your own Pi based audio streaming device, or something just as simple as a USB DAC to connect to your computer /tablet to get your audio system on the Spotify / Pandora bandwagon. Most of these streaming devices have RCA outputs that will connect to your auxiliary input of your stereo system. There’s No need to bastardize your prized stereo component just for this functionality.

    If you’re not sure or understand about the streaming devices I’m talking about, go look on AliExpress and search for DSD. There are hundreds of different media streaming devices with different select features that satisfies bringing your vintage stereo component into the modern age.
    I have a DSD 512 that also does media streaming on various music platform sites as well as just simple Bluetooth and hi-res audio. I use it for my vintage Sony STR-V7 stereo receiver. The only thing modern my Sony receiver has are newer audio and filter capacitors.

  9. I’ve used an esp32 as a Bluetooth audio receiver with an i2s DAC and it wasn’t a good experience. It had constant weird disconnects and pretty frequent stuttering. I ended up switching to a $25 aptx/ldac module and a atmega48 for logic and I’ve never had issues with it.

  10. You kids these days just don’t know how to throw money at a problem. I’ve been running my Kenwood KR5600 for years with alexa and a smart plug to turn it on and off, and a Sonos Connect to drive audio to it.

  11. i have plugged a £2.50 car bluetooth adapter in to a spare aux port on my 1990’s sony amp. the adapter is the size of a dongle, it has a micro usb for power and a jack plug for sound out. I use it to stream music from my phone. it sounds loads better than the numerous bluetooth speakers I’ve tried.

  12. I use a Google chrome cast 2nd gen to stream audio from the Internet through my 30 year old hifi set up..

    I can also play tracks stored on my phone with just a few button tapps..

    Also my old hifi and speakers are connected to my TV using the headphone out socket and everything playing on the TV is like being at the cinema..

    The chrome cast has given my old hifi a new lease of life..

    Shame they don’t make them anymore…

    1. I’m pretty sure you have a Chromecast Audio as they were the only ones to do audio output via the headphone jack. You can also get an optical 1.8mm to toslink cable to go digital instead of analog.

      You can find the CCA’s on ebay for about $50. You can also use the regular chromecasts with an hdmi audio extractor or if your receiver is newer, just plug it in to an hdmi for audio only. And I believe the Xiaomi MiBox (a Google TV device) has a separate audio out if you wanted to go that route.

      It is a shame Google discontinued them to push their inferior speakers when many have much better home audio options the CCA could breath new life into.

  13. Using Pioneer HPM 60 speakers from 1978, true bass reflex sound. Spinning vinyl on a Pioneer PL 518 turntable. Plenty of sound is provided by a Luxman 35 watt receiver.
    Can’t even turn up the receiver more than half way in my living room.

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