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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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22nd Apr 2017, 6:01 pm | #1 |
Heptode
Join Date: Mar 2014
Location: Leeds, West Yorkshire, UK.
Posts: 899
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Hacker RP38 with Fane speaker
Hi all.
Can anyone tell me what speaker should be in this set and what Ohms it should be? There's a Fane speaker in there at present but it's been damaged by a leaking battery making it sound bad. Don't know if this makes any difference but it's the Hunter with just a tone control. The last photo is of another speaker I have that will fit but it's 15 Ohms. |
22nd Apr 2017, 9:08 pm | #2 |
Dekatron
Join Date: Jul 2007
Location: Evesham, Worcestershire, UK.
Posts: 4,241
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Re: Hacker RP38 with Fane speaker
That's a very early Hunter. The last one I have on record with a Fane loudspeaker is 3700. There's lots more detail about the model's evolution in this thread: http://www.vintage-radio.net/forum/s...d.php?p=922240 - I wouldn't mind knowing more about your set to help with my research.
It's a 15 ohm unit, so if your replacement fits physically, then I dare-say it'll do the job. Personally, I can't help feeling the magnet will foul the chassis, but fingers crossed I can't see any battery damage anywhere. Is it a rubbing voice coil? If so, you might be able to correct it by *carefully* bending the chassis. Play a pure sine wave tone at about 100Hz though the speaker, and firmly pull the magnet in various directions while listening to see if the tone becomes purer. If so, you can use a lump of wood and a hammer to bend the chassis legs as needed. Actually much easier to do than describe. Good luck, Mark |
22nd Apr 2017, 9:44 pm | #3 |
Heptode
Join Date: Mar 2014
Location: Leeds, West Yorkshire, UK.
Posts: 899
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Re: Hacker RP38 with Fane speaker
Hi Mark.
You may already have this set on your books so to speak, it's serial number is 03700. It's one of two sets that belonged to my parents the other being a white Sovereign 11. The Fane speaker looks OK but there is corrosion on one of the thin leads that goes from the paper cone to the terminal strip. I have tried to repair it twice in the past but after a while it breaks. You say the speaker should be 15 Ohms but when I put a meter across it it's only showing 12 do you think this could be a problem? |
22nd Apr 2017, 9:47 pm | #4 |
Heptode
Join Date: Mar 2014
Location: Leeds, West Yorkshire, UK.
Posts: 899
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Re: Hacker RP38 with Fane speaker
Sorry Mark. Just realized its the same set.
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22nd Apr 2017, 9:49 pm | #5 |
Dekatron
Join Date: Jan 2005
Location: Oxford, UK.
Posts: 17,820
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Re: Hacker RP38 with Fane speaker
12 ohms is the DC resistance, the AC impedance will no doubt be nearer 15 ohms. So, no, not a problem.
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22nd Apr 2017, 10:06 pm | #6 |
Dekatron
Join Date: Aug 2013
Location: Wigan, Greater Manchester, UK.
Posts: 9,427
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Re: Hacker RP38 with Fane speaker
I used to repair the flexible leads on speakers with the braiding from small diameter coax, forgotten the coax type number. I threaded nylon drive cord through the braid, it worked and didn't give problems.
Frank |
22nd Apr 2017, 10:39 pm | #7 |
Dekatron
Join Date: Jul 2007
Location: Evesham, Worcestershire, UK.
Posts: 4,241
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Re: Hacker RP38 with Fane speaker
Ah - so the Fane-equiped models remain as elusive as ever! If I'd looked properly at my records, I would have seen that 3700 was yours
Yes, the DC resistance is always a bit lower than the AC impedance. In fact, the AC impedance varies wildly with frequency - for example: http://sound.whsites.net/tsp-f1.gif - and that curve changes when you put the thing in an enclosure. So the stated impedance can only really be a nominal figure. As has been said, repairing braids is feasible. I'd be tempted to try, given the rarity of the set. |
23rd Apr 2017, 6:49 pm | #8 |
Heptode
Join Date: Mar 2014
Location: Leeds, West Yorkshire, UK.
Posts: 899
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Re: Hacker RP38 with Fane speaker
Will give it a go and let you know how it turns out.
Thanks for the advice. |
27th Apr 2017, 6:58 pm | #9 |
Heptode
Join Date: Mar 2014
Location: Leeds, West Yorkshire, UK.
Posts: 899
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Re: Hacker RP38 with Fane speaker
Hi All.
I took your advice and cannibalised some of the braided wire from a duff speaker and soldered it onto the existing wire on the Fane making what was there longer and I have to say it seems to have worked. Incidentally the replacement speaker I have will fit even though its magnet is larger so I will keep it safe just in case. Thanks for the usual excellent advice. K |
27th Apr 2017, 9:33 pm | #10 |
Dekatron
Join Date: Jul 2007
Location: Evesham, Worcestershire, UK.
Posts: 4,241
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Re: Hacker RP38 with Fane speaker
Excellent news
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