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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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2nd Jul 2019, 10:16 pm | #1 |
Triode
Join Date: May 2017
Location: Malmö, Sweden
Posts: 31
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Vintage car radio to amp
Hi, I have a MGB GT from the 1960s with a vintage mono radio fitted (I think it is a blaupunkt Hldesheim). The radio is connected to a 6X4 inch speaker mounted below the dashboard in the dedicated space in the middle. The sound is surprisingly loud, but the character is rather harsh and lack power/base. Now I know these old time radios are not audiophile, but I am hoping to find a way to improve the sound somewhat. I tested the speaker in another setting and it seems much of the harshness comes from the speaker so I have decided to change it.
I was hoping to receive some tips, experiences and recommendations on speakers and possibly amps too. I am particularly curious on how to best connect an amp to the radio. I would be using the speaker output from the radio so I suspect a low power converter would be needed? My concern is if the radio will be able to handle this? From what I understand, the radio should have about 4 watt max output and recommended to operate a speaker at 4 ohms. I found this used 6X9 speaker with an integrated amp from a chrysler that seems I might be able to squeeze in to the dashboard: http://www.2040-parts.com/infinity-6...73ab--i604115/ But the question is, would I be able to hook it up to the MG? And if so, could I connect it straight to the speakers, or would I need a converter? Any thoughts on this would be appreciated. Tips on other speakers/settings also welcome. Thanks, Gunnar |
2nd Jul 2019, 10:23 pm | #2 |
Nonode
Join Date: Jun 2016
Location: Bognor Regis, West Sussex, UK.
Posts: 2,301
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Re: Vintage car radio to amp
First question, is the MG negative or positive earth?
Peter |
2nd Jul 2019, 10:25 pm | #3 |
Triode
Join Date: May 2017
Location: Malmö, Sweden
Posts: 31
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Re: Vintage car radio to amp
Hi, thanks Peter. I forgot to mention that. It has been converted to negative earth.
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3rd Jul 2019, 7:50 am | #4 |
Rest in Peace
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Location: N.W. Oxfordshire(Chipping Norton)
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Re: Vintage car radio to amp
It's quite possible that the amplified speaker in your link has a line level input, in which case it cannot be connected to the speaker terminals on your Hildesheim Radio. I'd be inclined to ask the seller for more information about that speaker first.
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3rd Jul 2019, 8:00 am | #5 |
Heptode
Join Date: Oct 2008
Location: Aalborg, Denmark
Posts: 903
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Re: Vintage car radio to amp
It is necessary to know exactly WHAT Hildesheim radio you have.
Hildesheim alone says nothing about what the radio contains or how it's built. Some are made from the factory with an output to be used with an external amplifier, others not. Look at the label on the side of your radio and report the number starting with 7, followed by at least 2 groups of numbers each with 3 digits. That should pinpoint the version and open a way to find the correct schematic. I've attached a file with 2 schematics for Hildesheim to show how big a difference there can be between two Blaupunkt radioes with the same name. One radio (upper schematic) is made for connection to external amplifier, the other not. The lower schematic shows a Hildesheim suitable for both 6 and 12V supply with negative or positive chassis. |
3rd Jul 2019, 8:22 am | #6 |
Octode
Join Date: Dec 2018
Location: Llandeilo, West Wales, UK.
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Re: Vintage car radio to amp
Hi Gunnar,
If you believe the speaker is the problem, why not start by testing another, better, 4 ohm speaker in the car first? Old AM radios do not sound anything like the FM and DAB you might be used to today. If the sound quality is poor to start with, adding another amplifier will not improve it. Alan
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3rd Jul 2019, 8:25 am | #7 |
Dekatron
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
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Re: Vintage car radio to amp
I have exactly the same problem with the Radiomobile 1070 fitted in my 1968 MGBGT.
The original speaker baffle, if you could call it that is more decorative than functional. The 7X4 speaker is designed to be sensitive rather than give a good bass response. It is a typical 'television' type of the period. The radio performs well with plenty of volume and sounds good when connected to a decent speaker /enclosure but no bass with the car kit. As there is very little on the radio today that interests me I'm not too bothered but it looks nice in the dashboard. Regards, John. |
3rd Jul 2019, 9:12 am | #8 |
Dekatron
Join Date: Oct 2003
Location: Southport Lancashire, UK.
Posts: 3,237
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Re: Vintage car radio to amp
I think that Alan and John have hit the nail on the head. Firstly AM is not a good sound source, particularly these days when the signal is compressed and generally manipulated to be nothing like the original. Secondly radios in cars were much less common in "classic" days and the car manufacturers didn't put much or any effort into maximising the potential when they decided where to put and how to mount the speaker. Many cars had a single speaker mounted under the rear window pointing upwards to the roof lining - not the best listening experience for the driver.
In my experience the output from the amplifier in all but the cheapest car radios is pretty good if it has a good source such as FM or a CD. I have a Rover P4 which originally had a very similar set up. I managed to fit speakers into the panels on the outer side of both foot wells and this has made them sound better as they are more enclosed. It isn't anything like perfect due to the positioning of the speakers but it is better than it was originally. Fortunately Radio Lancashire is still broadcast on MW so there is something to listen to but one forgets how the signal fades near to power lines, under bridges etc, etc when using AM.
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3rd Jul 2019, 9:34 am | #9 | |
Triode
Join Date: May 2017
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Re: Vintage car radio to amp
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Thanks, Gunnar |
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3rd Jul 2019, 9:35 am | #10 |
Rest in Peace
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Location: N.W. Oxfordshire(Chipping Norton)
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Re: Vintage car radio to amp
If the Hildesheim is similar to the first schematic in 'tri-comp's' link, then an added amplifier with line input could be connected by removing the blanking plug from the DIN socket and connecting the added amp's input to pin 1 of said socket, using a screened lead, with the screen going to pin 3. However, as others have said, you are never going to get high quality sound from an AM Radio. B.T.W., John, your Radiomobile 1070 looks as if it 'belongs' in that MGBGT. I'm not knocking the Hildesheim. Blaupunkt made some very good radios, but BMC would have fitted, or offered as an optional extra, Radiomobile or Motorola Radios. Gunnar, yes you could use one of those speaker to line level converters to match the radio's output to the amplifier's input.
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3rd Jul 2019, 9:45 am | #11 | |
Triode
Join Date: May 2017
Location: Malmö, Sweden
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Re: Vintage car radio to amp
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3rd Jul 2019, 9:53 am | #12 | |
Triode
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Re: Vintage car radio to amp
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3rd Jul 2019, 10:13 am | #13 | |
Triode
Join Date: May 2017
Location: Malmö, Sweden
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Re: Vintage car radio to amp
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3rd Jul 2019, 10:18 am | #14 | |
Triode
Join Date: May 2017
Location: Malmö, Sweden
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Re: Vintage car radio to amp
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/Gunnar |
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3rd Jul 2019, 10:28 am | #15 |
Heptode
Join Date: May 2009
Location: Birmingham, West Midlands, UK.
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Re: Vintage car radio to amp
Something like this would give you access to the modern world.
https://tinyurl.com/y4mom2mp You could then connect what you like..even a Bluetooth transmitter and one of those cheap but usually good Bluetooth speakers available at some supermarkets etc. Obviously, any old age deficiencies in the old radio maybe magnified but the modern attachments will probably reduce noise. If you can nail down what model it actually is and somebody can provide a circuit diagram, it could well be possible to place a modern amp module inside the radio itself which will do it's best with the output of the receiver section. |
3rd Jul 2019, 1:02 pm | #16 |
Dekatron
Join Date: Oct 2003
Location: Southport Lancashire, UK.
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Re: Vintage car radio to amp
I fitted two speakers only because I briefly used a stereo FM radio in it. It was negative earth whereas the car is positive earth. I took a lot of precautions to isolate it but in the end my confidence in it ran out and I reverted the Radiomobile that came with it. I think that the point is that my speakers are now in an enclosed area which helps with the bass response. They are also better speakers than the original.
Part of my +ve/-ve earth precautions were to build a wooden box to enclose the radio. Could you make an enclosure for your speaker which would fit into the space? This might help with the bass response. Even something like an ice cream container might help, if only to try. I don't think that any sort of separate amp would help much if the speaker is mounted on a small, open baffle.
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Paul |
3rd Jul 2019, 3:48 pm | #17 |
Dekatron
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Re: Vintage car radio to amp
There seems to be room in that original fibreboard speaker enclosure for a larger speaker.
Car Scrappers/Breakers will usually have many 9" x 6", 4 ohm units which is a popular auto size. These are liable to have a roll surround to the cone for an improved Bass. If there is a concentric tweeter, this could be disconnected/removed to achieve a more "mellow" sound.
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Edward. |
3rd Jul 2019, 4:12 pm | #18 | |
Triode
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Re: Vintage car radio to amp
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3rd Jul 2019, 4:20 pm | #19 | |
Triode
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3rd Jul 2019, 4:28 pm | #20 | |
Triode
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