UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Radio (domestic)

Notices

Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only.

Reply
 
Thread Tools
Old 13th Mar 2019, 6:33 pm   #1
Colin1949
Diode
 
Join Date: Nov 2018
Location: Newbiggin-by-the-Sea, Northumberland, UK.
Posts: 4
Default Bush DAC90A query

I'm trying to identify the + terminal on the speaker, green wire or, I think the other wire is mauve colour.
Than you.
Colin1949 is offline   Reply With Quote
Old 13th Mar 2019, 7:15 pm   #2
Paul JD
Tetrode
 
Join Date: Oct 2018
Location: Coventry, West Midlands, UK.
Posts: 96
Default Re: Bush DAC90A query

I can't help with the wire colours but with the speaker disconnected you can determine the phase by briefly touching a 9v battery to the speaker terminals and observing which way the cone moves. If the cone moves outwards the terminal that the battery + is touching is the + terminal.

As it is a mono radio with a single speaker it is irrelevant which way the speaker is connected though
Paul JD is online now   Reply With Quote
Old 13th Mar 2019, 8:00 pm   #3
Ian - G4JQT
Heptode
 
Ian - G4JQT's Avatar
 
Join Date: Jun 2004
Location: Reading/Fakenham, UK.
Posts: 872
Default Re: Bush DAC90A query

It doesn't matter. There is no DC going through a speaker when driven through a transformer. In fact there should never be any DC going through a loudspeaker in a conventional set up, so it never matters.

Ian
Ian - G4JQT is offline   Reply With Quote
Old 13th Mar 2019, 8:11 pm   #4
Stylo N M
Heptode
 
Join Date: Jul 2012
Location: Derby, Derbyshire, UK.
Posts: 571
Default Re: Bush DAC90A query

Hi,

looking at the DAC90A radio's i have here, the original rubber covered wire colours were green and yellow. The yellow being the positive from the output sound transformer.


As Paul JD has already exsplained, it doesn't really matter wich way round the speaker is connected, it will run quite happily eather way.

I would be a bit carefull about placing a fully charged 9 volt battery directly accross the speaker terminals, as the susspension of the voice coil, could easily be damaged, due to it's age brittleness and fragility.

Paul
Stylo N M is offline   Reply With Quote
Old 13th Mar 2019, 8:24 pm   #5
Paul JD
Tetrode
 
Join Date: Oct 2018
Location: Coventry, West Midlands, UK.
Posts: 96
Default Re: Bush DAC90A query

Quote:
Originally Posted by Ian - G4JQT View Post
It doesn't matter. There is no DC going through a speaker when driven through a transformer. In fact there should never be any DC going through a loudspeaker in a conventional set up, so it never matters.
It matters if you have more than one speaker, either stereo or twin speaker mono. If they are out of phase you will get signal cancellation.

Quote:
Originally Posted by Stylo N M View Post
I would be a bit carefull about placing a fully charged 9 volt battery directly accross the speaker terminals, as the susspension of the voice coil, could easily be damaged, due to it's age brittleness and fragility.
Good point, with an older small speaker such as this probably best to use a 1.5v battery.
Paul JD is online now   Reply With Quote
Old 13th Mar 2019, 10:28 pm   #6
Mike. Watterson
Heptode
 
Join Date: Dec 2014
Location: Limerick, Ireland.
Posts: 505
Default Re: Bush DAC90A query

1.5V is enough for almost anything. Works even for 2000 + 2000 ohms earphones wired in series. Maybe not for Electrostatic speakers.
Mike. Watterson is offline   Reply With Quote
Old 14th Mar 2019, 1:36 am   #7
Colin1949
Diode
 
Join Date: Nov 2018
Location: Newbiggin-by-the-Sea, Northumberland, UK.
Posts: 4
Default Re: Bush DAC90A query

Thank you all for quick response. The answers. Make everything much clearer.
Colin1949 is offline   Reply With Quote
Old 30th Mar 2019, 12:53 pm   #8
Ian - G4JQT
Heptode
 
Ian - G4JQT's Avatar
 
Join Date: Jun 2004
Location: Reading/Fakenham, UK.
Posts: 872
Default Re: Bush DAC90A query

Quote:
Originally Posted by Paul JD View Post
Quote:
Originally Posted by Ian - G4JQT View Post
It doesn't matter. There is no DC going through a speaker when driven through a transformer. In fact there should never be any DC going through a loudspeaker in a conventional set up, so it never matters.

Ian
It matters if you have more than one speaker, either stereo or twin speaker mono. If they are out of phase you will get signal cancellation.
Yes, quite correct - that's when it does matter. But not for mono radios with just one speaker like the DAC90A.
Ian - G4JQT is offline   Reply With Quote
Reply

Thread Tools



All times are GMT +1. The time now is 8:10 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Copyright ©2002 - 2019, Paul Stenning.