Boombox speaker/amp upgrade

Discussion in 'Tech talk' started by richlooker, Jun 12, 2021.

  1. richlooker

    richlooker New Member S2G Supporter

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    I have a JVC RC-838 and a Panasonic RX-5500. Both are big, bold and beautiful, and they sound nice. But, compared to what even smallish bluetooth speakers of today can do, they don't have much oomph in the bass division. I wonder if it's doable to enhance the bass output by replacing the amp output stages and maybe the speaker drivers.

    I'm thinking of something like this; a class D module that runs on 12V, in theory this should be much more efficient than the existing class AB amps, and make available a lot more power.
    https://www.ebay.com/itm/123278969283

    With more power available, it should be possible to drive better speaker units, with bigger magnets - less efficient but with better abilities in the lower frequency region. Maybe something like the Visaton BG 17:
    https://www.visaton.de/en/products/drivers/fullrange-systems/bg-17-8-ohm

    Has anyone tried anything like this? Any thoughts?
     
  2. radiorich

    radiorich Active Member

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    Hello Richlooker,
    Far as that boombox goes I like using Visaton brand speakers when I am restoring my radios and car audio they are make some great speakers and I find that they are fairly Efficient and so can great on units with lower power .
    If I were you my first step would to replace The electrolytic capacitors before doing anything else you will see am improvement I am currently restoring a 1970s Sony radio I tested all the Electrolytic capacitors and they were bad .
    I have been repairing electronics as a living since the 1980s I use to do warranty work on JVC and Panasonic gear both of them have made some great stuff over the years .
    I don't know your background but I went to school and got degree in electronics plus I have ran my own shop since the 80s .

    sincerely Richard
     
  3. Longman

    Longman Well-Known Member S2G Supporter

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    I fitted Alpine speakers into a Sharp boombox, after my attempt at replacing the rubber surrounds failed.
    http://www.stereo2go.com/topic/index.php?content_oid=523725846035377387&board_oid=193392314111653319
    Prior to that I had seen pictures of a GF777 someone had done the same to.

    While bigger magnets etc sounds to be a great idea I would be very careful to make sure there is enough room inside the box for them to fit.
    I only just got those to fit, and as you can see that was at one particular angle.
     
  4. richlooker

    richlooker New Member S2G Supporter

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    Sounds reasonable; these are probably AC-coupled all over with 40+ years old electrolytics. I'll start there. Simultaneously, I have a wreck RX-5500 that I can use as testing grounds for speaker/amplifier replacements.

    Cool, I'll look into Alpine speakers as well, more expensive than Visaton, but I suspect a coax car speaker will be even better, if I can make it fit. I will make careful measurements before ordering anything.

    Cheers, Richard
     
  5. radiorich

    radiorich Active Member

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    Hello Richlooker,
    Sounds good and let us know what you find out just make sure if you do use car speakers that your amp is ratted for 4 ohm speakers check out parts express they have tons of speakers to choose from .
    I have a 1980s Phillips boombox that I want to restore .
    Sincerely Richard
     
  6. Emmett Langley

    Emmett Langley New Member

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    I have a GE 3-5257a boombox from 1984. It looks and sounds great. I was wanting to install a more powerful amplifier and speakers so it's more powerful. Any ideas on what type of amplifier, woofers, tweeters I need to this project. here is a picture of it. If anyone can think of anything, please let me know. I'm really wanting louder sound and powerful bass.
     

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  7. Longman

    Longman Well-Known Member S2G Supporter

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    Speakers. - Whatever will fit and matches the amplifier
    Amplifier - They have moved on quite a bit. One minute Googling found me https://www.ebay.co.uk/itm/204669814427
    or for a stereo box
    https://www.ebay.co.uk/itm/397247116387

    Bear in mind that the PSU might be the limiting factor even with the original amp. All 1980s boomboxes I have seen used a simple Transformer - Rectifier - Capacitor set up.
    I got a B&O boombox for cheap because "the sound was distorted". I then found it didn't happen running from batteries. Changing the main reservoir capacitor stopped it happening on mains.
     
  8. Emmett Langley

    Emmett Langley New Member

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    ok so could i have a technician just put a better amplifer and speakers in and have to plug it up in order to use it? Because it power source's are 6 d size batteries or 120 ac
     
  9. Mister X

    Mister X Moderator Staff Member

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    If it works you'd be better off selling it and buying parts for a DIY boombox, a shop would probably laugh at you, maybe a car audio place might be able to help? It get pretty involved splicing existing switches to the new equipment and you'd have to pretty much carve out the insides for it. Parts Express might be a good source for parts and ideas if you go that route. I've bought a friend one of the Lepai's when they were cheap an hot years ago.

    https://www.parts-express.com/brand...9P4uThxiejGCRDIFuiIQg6EUAynd6_hGaYgqWOqxb7ppN

    upload_2026-1-22_12-11-22.png

    Rampage has this killer tiny sub that even looks cool, it's 2.32" in depth, made for RC cars.
    https://www.b2audio.com/produkt/rampagerc2/

    upload_2026-1-22_12-10-53.png


    I spent the 80's building DIY boomers using tossed car stereos and speakers, it was pretty fun, check out this guys box, the website gives insight into the build.
    https://karilavikka.fi/supaghettoblaster.php


    [​IMG]

    If you carry the GE around, I highly recommend getting rechargable batteries. Most are AA but you can buy adapter shells that will hold either 1 or 3 AA's. IKEA is a great source for cheap rechargeables and chargers, I don't think they have the D-cell adapters.
     
  10. Reli

    Reli Well-Known Member S2G Supporter

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    The RX-5500 is already a great sounding boombox, with crystal clear vocals and strings. And it can go loud too, it has more power than the JVC.
    Inside, it's packed very well, so I doubt you'll be able to put bigger magnets in it.
    If you want better bass, there's better radios to focus on. Radios with more room inside the case to amplify the bass waves.
     
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  11. Mister X

    Mister X Moderator Staff Member

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    Old thread Reli, Richlooker seems to be long gone.

    Personally I'd never cut into those iconic boxes unless they were already basket cases. The Star Wars Boombox (RC-838) is so unique looking but close to the movie I wonder if George Lucus had issues like he did with Battlestar Galactica whom he sued for copying.
     

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