Adding Bluetooth Audio Receiver to 1940s Tube Radio Using SW/MW Switch for Input

Hi I am playing around with an old 1940s radio. It runs 230V and 60 watts. I would like to add bluetooth to the tube amp using the sw/mw switch to connect the bluetooth module and then run into the 6 vacuum tube amplifier. Can anybody enlighten me on this please as I would like to be able to bluetooth music to this and get the old sound for new music. Is it possible as I cant find anybody that has done it yet and am I going about it the right way? Could someone please advise me?....

Thank you much appreciated

It needs and audio input somewhere, but mostly you are going to need schematics. Usually those old radios have a schematic pasted on the fiberboard of the speaker panel.

If you don't have a schematic you should scower around the internet to get one and also you should provide a list of the tubes in the radio. There will be an audio pre-amp tube, that would be where you would connect the bluetooth audio input signal.

Personally if I had a radio from the 40s, I would kill someone who would butcher it up with bluetooth. But this is your radio, do as you wish.

You can buy tube amps and do what you want leaving that radio alone. The other thing is that the radio has very very old capacitors and if you screw up one of those without a schematic, you are screwed, because it will likely not work again unless it is restored by a professional.

So 1st you need a schematic, then you need to identify the pre=amp tube, then adding an audio input to that sectio is not that difficult.

Good luck and hopefully the radio survives.

Hi yes I can help you with this what you need is a Bluetooth Class 2 module with Audio capability
I’m busy on working a similar approach for an adaptation myself at the moment so I understand your needs fully

Module comes shipped with the following profiles

A2DP - Advanced Audio Distribution Profile
Stereo streaming with SBC, MP3, AAC, APT-X
compression options. Source or Sink profile.
• AVRCP - Audio Video Remote Control Profile
Standard remote audio playback controls.
Controller or Target profile

Features
• CSR BlueCore5 chip set
• Bluetooth v3.0
• Class 2 radio, range typically exceeds 20m
• +8dB PA Output RF Gain
• High speed wireless data rate up to 3Mbps
• Digital & analog stereo input
• Digital & analog stereo output
• 16-bit ADC/DAC stereo CODEC
• 9 programmable digital I/O pins
• 16 Mbit flash memory
• USB, UART, I2C, I2S, PCM, and SPDIF interfaces


The module concerned needs a 4v5 volt supply which you can derive from the amplifier it is also capable of other profiles that are inbuilt but this will suite your immediate needs

If you would like more info please contact me via the site Id be only to happy to try and assist you

The bluetooth audio aspect is a slam dunk, this is dime a dozen, commodity. The challenge is integrating it into a vintage collectable radio. I personally went out and got myself a A2DP compliant Bluetooth module ($30 or so), and installed it in my sister's car so she could have hands free iPhone. Her car didn't have an aftermarket upgrade radio. No it didn't have all the bell/whistles mentioned below but where and how it's connected is the challenge, not the bells/whistles.

Most people on this blog don't understand analog, much less analog RF, much less tubes & 70, 70 year old hardware!

I just hope the owner of this collectable takes the radio to a person who restores these and gets professional installation. Best case, the installation would be reversible.

Just for the heck of it, Callum, could you take a photo of the radio to share with the rest of the folks. Would like to see it.

Ahh I think you will find that changed considerably now Earl Bluetooth modules produce high fidelity sound now They are not early frontier science anymore Most radios now have Bluetooth , sd card readers , usb , and dvd all in one The sound quality is superb !! These are quite up to date market commodities not available to consumer only to trade and I have read the specs on this and obviously asked lots of questions

I would as you suggested love to see the pictures of the unit I also like valve equipment believe it or not

See this page for details of how to build your own with modern day electronics

http://schematic-diagram.blogspot.co.uk/search/label/TUBE HI-FI AMPLIFIER



http://www.harrington.force9.co.uk/ValveAmps/EL156_Valve Amp.html

I think this will provide lots of interest for you as well Earl

http://www.harrington.force9.co.uk/Projects/ElectronicProjects.htm

You don’t have much of choice these days , not that I think its all good either it’s the regrettable price we pay for modernization is some aspects but we progress society within the world or at least we hope to strive to break new frontiers all the time

You either find a way to combat the market with respect to the car manufacturers and the £3000 pound touch in the in car hi fi market and come out with a Bluetooth module or you face massive depression with respect to one shop closing after another

These days you can stream live video content and mobile phone content via smart phone Again the quality is well , you would have a hard job beating this

You can say the same for the in house audio market you can incorporate modern technology along side old technology and still arrive at unsurpassable sound or you demolish an entire industry

So you have to move this way otherwise we going to face closures left right and center so there is no point fighting against this anymore

You either move with this and not against it whilst keeping business open and running

What’s important, Employment , keep the wheels turning, otherwise what do we face ?

I think you know the answer to this already Just that’s its very difficult to deal with this at times I agree

Hi guys here is the picture of my project currently restoring same model though.

Thanks for the feed back guys!

Hi callum
Pics didnt come out might need to upload these again or possibly change the type of file your are uploading example gif or jpeg There are conversion programes on the net foc for download to do this

hope these work for picture they are .Jpg

OK s I have identified where you would connect the audio. It is not as straight forward as one would imagine but can be done. I have done this before, and it will work. May require some tinkering to get the audio quality acceptable. You should know that these old radio/audio devices don't have a flat 20HZ to 20KHz frequency response. So it will not sound as good as your usual audio.

Although when you get down to it MP3 files, most Bluetooth is really poor, poor audio quality, if you are a true audio file. In other words if you are into quality audio you would not listen to MP3 or Bluetooth audio, you just wouldn't.

So I have included the file for reference.

I said you could do this , although you wouldnt exactly get fantastic audio from radio Lets be honest
For its intended puposes yes it would work beutifully

I would put a switch on thier as well and make a slight adjustment so you can select input external or internal, also enure that you shield your bluetooth device and assocaited out put circuitry with a decent power supply so as to reject the mains born hum that is normally present on older radios of this type with decent screened leads and you want to *decouple the input via a capacitor rated at 50 volts dc* around about 10uf will be ok Safety reasons !!

So bluetooth with mp3 would sound magnificant on this mans radio

Actually what I have done in the past with my Father's help as a kid, (I was the kid) I took the volume control loose from the circuit, disconnect it, connect it up to a microphone. Take the audio output that goes to the speaker and hook it up to the IF stage (it's in the schematic). So what the heck would that do?

It turns a receiver into a transmitter. I also hooked up my phonograph, similar to a CD except with scratches, and I was my neighborhood DJ, master of disaster, in the mix, etc.

Got paid for playing my friends favorite tunes, Radio had a range of about a 1/2 mile radius. It was all free, didn't cost a penny on my part. Stuff was old salvage electronics that neighbors threw out.

well I would really question your definition of magnificent. !st of all you'll get lot's of 60Hz humm/buzz because of the poor power rectification/filtering and 2nd MP3 files, common as we know them say like iTunes SUCK, horrible quality, not even close to true fidelity.

That can be proven with a spectrum analyzer looking at the original source vs the reproduced digital MP3.

the reason they suck is that most people don't know true fidelity and don't care as long as they can get 1 million songs on a postage stamp. So give the masses what they want. Make money, not quality sound.

That's ok if that's what people will accept and are will ing to pay. Same can be said for video quality, look at an iPad, talk about sucking. Well that's another project.

Thank you for the adice guys. I will see how I get on. Im going to source a A2DP reciever module tomorrow.

I’ve got a good supplier for you

KC Wirefree very helpful man who will assist you in what ever you need


I should have also mentioned it might be an idea to double check chassis potential with respect to the ground of your finalised Bluetooth circuit to ensure no voltage differences or that the radio isn’t at half mains potential

Use a DVM to do this with this set to 250 volts range or more Make sure you do this before connecting otherwise you might wind up with a severe electrical shock or and extremely loud bang with huge sparks etc

Just to be on the safe side

See datasheets below

Very good point because I don't see any designed method that provides true isolation. Also given this is 70 years old and that's truely amazing the caps still function, caps get ohmic, leaky. Now the audio should be cap coupled, the AC/DC power supply for the Bluetooth is isolated so you are covered there., should be anyway.

Just make sure the AC injected is AC coupled, that should insure safety.

Again good point to know EXACTLY what potential the chassis is relative to Earth, (water pipe stove, etc), just so no one gets a rude hello, how are you today, ZZZZZZZZZ.

Oh BTW, I might just have to go out and get me a couple of these puppies ( inclosed files). I'm sure I can find a use somewhere, or make a use!

Good stuff!

Which Audio module would you personally use for this project just the KC6112 w internal arial class two should do the job hey?

I would use the one that has the most power and alows for an antenna.

So many time Bluetooth advertises and doesn't deliver because of the whimpy power and the lack of an antenna.

You get 10 feet away and it cuts out, you do not want that. I understand that the Bluetooth protocol limits the range but one can fine tune that to maximize it, I believe (without the aid of the latest standard in my hands) 30 feet is the range, but what does that mean? With error correction, other techniques, you can get around data lapses, errors in tx/rx, but audio is another issue unless you have a huge buffer. Another issue is that when errors are detected, the tx rate is slowed which means a reduction in already poor audio quality.

So high power with an antenna (which could actually be fitted with a directional reflector if needed.


Good stuff!!

I have a pretty good tx/rx from GE, that has a diapole antenna and it's not bad.

The Kc6112 is the best of the lot

There is also on the way another patent regards this module which is currently pending via KC Wirefree

This will also be on offer but as and when this happens I don’t know as yet but am advised that this will be a simple software upgrade via the net

Bluetooth isn’t all about power in terms of RF out

Its a short distance unlicensed medium for transmission with which , if your are very clever or do some consistent research and lots of practice, can write applications for which makes this very interesting

Bluetooth is about services or what we term profiles So the power of Bluetooth is not in its RF out as would have been expressed as being a good transmitter years ago

Its what you can use this for which makes this so very interesting especially within the field of data communications

Some examples are the famous
"See Lego Mindstorms (Lego Mind Storms)":http://mindstorms.lego.com/en-us/Products/default.aspx


Your Mobile phones for example, Modem communications It has also been implemented in many other areas of the medical industry and further as an aid for handicapped people so that control over lighting systems and also other key areas can be easily accessed

Lots of scope for development in these areas if you can write software or design embedded systems Ill let you think on this as well


Then more oviously the A2DP – Advanced Audio Distribution Profile ,Stereo streaming with SBC, MP3, AAC, APT-X and AVRCP – Audio Video Remote Control Profile as in your particular needs Car radio for example, Indoor Hi Fi another example Very hard to beat Im telling you the quality is out of this world

If i thought for one moment it was rubbish I would have no hesitation is saying this

I’m a little upfront and blunt when I make recommendations My recommendations are on what I know to be true not a pack of well “*****” and the normal proverbial which is why I’m not a good salesman

I say what I want to say regardless “Be warned!!” So if it’s good I say it’s good otherwise expect rotten , horrible comments i prefer to admire the engineering of electronics rather than the physical casing which surrounds or encapsulates the apparatus Im not to interested in looks but its internal workings , its layout , and its biuld quality plise its final delivery It can be pink , green with spots on or black i couldnt care less as to its looks

I want to know if it works and hus justification in the engineeting world

It’s a shame you didn’t read my comments on the Bluetooth competition that would have explained this in full for you where I talked about the Bluetooth stack and its software, hardware interaction plus the history of Bluetooth


It’s a shame you didn’t read my comments on the Bluetooth competition that would have explained this in full for you where I talked about the Bluetooth stack and its software, hardware interaction plus the history of Bluetooth

Aaaah Thats down to your sound card earl and codecs different story that altogether but Im aware of what yout discussing having had to progress through this path myself

Mark:

I don't know who the , "It's a shame," comments are directed.

I will say this. It is a shame there are many devices out there that claim Bluetooth and can make the claim. It's a shame we don't have a better yard stick when measuring those claims. It's a shame that Bluetooth audio sucks in general.

You have mentioned devices with lot of bells & whistles, none of that matters if the basic audio is bad. I use wireless remote speakers in my house. my wireless isn't bluetooth and it isn't bluetooth because of all the inherent limitations.

And yes when it comes to wireless and distance, power is a very important consideration which implies the antenna is important by default. You don't appreciate that, is that a shame, who cares if you don't. The principals in the RF of the 70 year old radio and the Bluetooth are exactly the same, no difference.

I will say this in closing, your blog goes on, and on, you are doing your best to lecture. To lecture in a public forum is INSULTING.

Mark, don't lecture/insult folks if you want to be taken seriously.

I’m not being insulting Earl I think you take this the wrong way sometimes but there is a legal limit to Bluetooth and yes the audio is good but then as i said and if you read the specification on bluetooth its not intended for long distances and wasnt designed for long distances

Sony use Bluetooth ,Pioneer use Bluetooth

Lots of other manufacturers of hi fi use Bluetooth

If it was that bad why is is then that the likes of Sony , Pioneer , to name a but a few inclusive JVC are the top market brands amongst audio hi fi fanatics

If it was that bad and the quality that lousy don’t you think people wouldn’t pay that much more for their products rather than choose an unknown brand which does sound bad

I hear your point but its a case of move with the times

I think the trouble is Earl you don’t like new technology because you would rather stay with the old technology perhaps rephrased i'ts costing people jobs, I agree its is ! You are correct but Why because they don’t want to accept new technology where as if they did they would still be employed possibly but might have to diversify their skills accordingly and retrain but that would be all they have to do

Which means your old skills are important but you have to re adjust to take on bourd new skills

Again I hear your point understand how you feel sometimes about this modern era ,so to speak, but you wont beat the quality of this equipment

I wouldn’t say this if I didn’t mean what I said and I do mean it

Everyone is having to do exactly the same now and thats take on bourd new skills and re adjust

They dont have a choice either

On the plus side of things earl

You can at least use a computer otherwise you wouldn’t be posting here would you ? You can upload images and you can adjust images to give information and that means that you have PC skills which means Earl your really don’t have too much to be concerned over your well over halfway there already without even realizing this

That’s quite a lot more than an awful lot of people can manage in this country

They are in diabolical circumstances and really do need help and are not getting help at all from any government authority which I think is disgusting ,

You could redirect your comments to those in power and ask them what’s going on and more importantly ask them why Earl


Id love to see what answers you get from them , if any , that’s if you want to know what insulting is all about ,

or Earl you could spend the last 4 months sending email after email with applications for work and sit and hope for a reply and not even get an answer

or

You could if you like phone these companies up and have the phone slammed down in your face or you could also be one of these companies or customers for that matter who cant even get thier money back

So i dont think I'm at all insulting and thats being very polite