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 Post subject: Connecting phones across Radiola 64 reproducer cone coils
PostPosted: Mar Sat 09, 2013 7:24 pm 
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Joined: Jan Wed 26, 2011 10:19 pm
Posts: 190
Location: Carmel, Indiana 46033
I'm looking at the uy 227 tube with the five prongs facing me and the prong that's spaced away from the others at 6 oclock, with the other prongs at 1, 3, 9, and 11 oclock. At which positions are the heater prongs?

I'm also reading the 1928 neutralization steps for the Radiola 64. In part it says: "Connect a pair of phones across the cone coil of the reproducer unit." I think this means an old pair of headphones, which I don't have. I don't understand why phones were to be connected. What can I use instead? Is there some level of resistance I should connect across the speaker cone coil, or is there some other reason for doing this?

Hey, thanks. Dan


Last edited by ivorydan on Mar Sat 09, 2013 9:25 pm, edited 1 time in total.

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 Post subject: Re: UY227 Tube Heater Prong location and another question
PostPosted: Mar Sat 09, 2013 7:29 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 3145
Location: Northern Panhandle, WV
Here is the info on the 27 tube Dan:
http://www.nj7p.org/Common/Tube/SQL/Tub ... hp?Type=27

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Carl


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 Post subject: Re: UY227 Tube Heater Prong location and another question
PostPosted: Mar Sat 09, 2013 8:58 pm 
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Joined: Jan Wed 26, 2011 10:19 pm
Posts: 190
Location: Carmel, Indiana 46033
OK, thanks Carl, so it looks like 1 and 5 are the heater prongs.

Now anybody have any ideas about the phones? Dan


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 Post subject: Re: Connecting phones across Radiola 64 reproducer cone coil
PostPosted: Mar Sun 10, 2013 12:23 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 5076
Location: Ortonville, Michigan
From your question, it sounds to me like you are attempting to perform the alignment and neutralization of the set. It is a genuinely important operation.

In the days that the Radiola 64 was built, the only impedance of headphones was in the order of 1500-2500 ohms. They are quite sensitive, if you should connect them to almostany signal source, even today.

The reason that you need to use phones on the set's output, is to be able to accurately detect the absolute null in signal when you are doing the neutralization part of the I.F. alignment. You can't rely on hearing the null from the speaker. I've done it on several of the Radiola 60 family

Normally, you are cautrioned about running the set with speaker disconnected. It's a good way to blow an output transformer, if the volume should be set a bit too high. But, at the low signal levels that are used to detect null sihnal in the alignment process, the danger isn't a problem.

You'll be amazed at what a performer those Radiolas 60 through 67 sets are. And there is probably none that doesn't need alignment.


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 Post subject: Re: Connecting phones across Radiola 64 reproducer cone coil
PostPosted: Mar Sun 10, 2013 1:21 am 
Member

Joined: Jan Wed 26, 2011 10:19 pm
Posts: 190
Location: Carmel, Indiana 46033
OK, thanks. I'll try to find some with app 2000 ohms impedance. Dan


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