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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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2nd Jun 2010, 3:54 pm | #1 |
Heptode
Join Date: Mar 2003
Location: Waiheke Island, New Zealand
Posts: 503
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Osram Four New Music Magnet
Hi could someone please advise the voltages for the supply
LT 2V SG? HT+ GB- I can't find the circuit on disks 1-3 (as supplied by Paul.) Thanks |
2nd Jun 2010, 4:50 pm | #2 |
Retired Dormant Member
Join Date: Sep 2003
Location: Bristol, UK.
Posts: 808
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Re: Osram Four New Music Magnet
I can't remember the specific voltages quoted for this set but The HT is almost certainly 120v. The SG is about 90v but 60v might also be OK. The GB will depend on the valve used but will probably be round about -3v or -1.5 volts. The original grid bias batteries had taps at 1.5 volt steps and I think the intention was to use trial and error. It would be less than 9v as this was the usual max voltage of the batteries.
The 9v batteries might even be later than the Music magnet, because it was normally used with a variable Mu valve as a volume control (RF gain) |
2nd Jun 2010, 5:42 pm | #3 |
Retired Dormant Member
Join Date: Jan 2007
Location: Westbury, Wiltshire, UK.
Posts: 2,451
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Re: Osram Four New Music Magnet
On the (3 valve) set I am playing with it has two grid bias battery connectors and from what I can see two is normal, one for the output stage and one for the earlier stage(s)
The bias volts are giving on the valve museum site if you are not sure. Dave |
2nd Jun 2010, 7:14 pm | #4 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,637
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Re: Osram Four New Music Magnet
MM4 installation Instructions part 1
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2nd Jun 2010, 7:21 pm | #5 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,637
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Re: Osram Four New Music Magnet
MM4 installation Instructions part 2
For some reason, they are uploading as thumbnails, not attachments. On my PC they can be read quite easily. If you PM your Email address, I'll send them direct. |
2nd Jun 2010, 9:04 pm | #6 |
Dekatron
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,171
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Re: Osram Four New Music Magnet
Hi PWH, just a note of caution. Do not adjust the GB tappings with the LT supply ON as this can damage the valves.
Ed |
3rd Jun 2010, 9:20 am | #7 |
Heptode
Join Date: Mar 2003
Location: Waiheke Island, New Zealand
Posts: 503
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Re: Osram Four New Music Magnet
Thank you all, I now have the information I need
For the reference of others HT is 120V, SG is 72-60V depending on volume (lower voltage = greater battery economy) GB is -9 to -3V as the LT battery dies away... |
30th Aug 2010, 7:38 pm | #8 | |
Retired Dormant Member
Join Date: Dec 2007
Location: Southampton, Hampshire, UK.
Posts: 2
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Re: Osram Four New Music Magnet
Quote:
I've just come across your very helpful post. Having just written a short article for the BVWS Bulletin on the restoration of my Osram Four New Music Magnet, without the benefit of the pages you've scanned, I must recall my article and make some changes, even from what I can see in the thumbnails. Would it be possible for you to email me higher resolution scans? In particular have you any comment on the "Super Power" P2 valve suggested as an alternative audio amplifier? many thanks Gwyn G3ZIL BVWS member |
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31st Aug 2010, 7:24 pm | #9 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,637
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Re: Osram Four New Music Magnet
Hello Gwyn,
Send me your Email address by PM and I'll send by return. Regards, Bill PS as regards the super power valve it's just a more powerful triode as far as I know, hence the higher HT consumption. It was also popular to replace the last valve with a pentode at this time, necessitating replacing the four pin holder with a five. |
1st Sep 2010, 5:54 pm | #10 |
Retired Dormant Member
Join Date: Dec 2007
Location: Southampton, Hampshire, UK.
Posts: 2
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Re: Osram Four New Music Magnet
Bill
Many thanks. Will PM you my email address in a moment. Thanks for the comment re the P2 super power valve. I had got confused, in that I remembered that a P2 was a bright emitter valve, but on delving deeper, this was a Cossor valve, and Marconi used P2 for their equivalent of the Mullard PM202. The set was very confusing as I received it, for there was a KT2 in the output valve position, in a 5 pin socket, with the screen unconnected, and a 220OT in the detector position! But, all sorted now. Would it be OK with you if I quoted from the material you've scanned in the article I've written for The Bulletin, I will of course credit you as the source. regards Gwyn |
3rd Dec 2015, 10:35 pm | #11 |
Triode
Join Date: Aug 2011
Location: Bagshot, Surrey, UK.
Posts: 38
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Re: Osram Four New Music Magnet
Bill AC/HL I'm restoring an Osram 4 New Music Magnet, is there any chance of getting hold of the scans of the original instruction manual in high resolution as I can't read the ones on the forum very well - Alan
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4th Dec 2015, 12:47 am | #12 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,637
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Re: Osram Four New Music Magnet
Hi Alan,
PM your email address & I'll send what I have, I can't claim high res. but it is better. |
4th Dec 2015, 1:20 am | #13 |
Heptode
Join Date: May 2015
Location: Bradford, West Yorkshire, UK.
Posts: 510
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Re: Osram Four New Music Magnet
Hi AC/HL Bill.
I am always interested in these older radios, could you PM me the manual etc please. Andrew
__________________
worried about the electrons entering the circuit and the smoke leaving Andrew |
4th Dec 2015, 2:40 am | #14 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,637
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Re: Osram Four New Music Magnet
Of course Andrew, PM your email address.
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4th Dec 2015, 4:35 pm | #15 |
Triode
Join Date: Aug 2011
Location: Bagshot, Surrey, UK.
Posts: 38
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Re: Osram Four New Music Magnet
Many thanks bill for the higher resolution scans they are just what I need. - Alan
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12th Dec 2015, 1:48 pm | #16 |
Retired Dormant Member
Join Date: Dec 2015
Location: Chipping Norton, Oxfordshire, UK.
Posts: 11
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Re: Osram Four New Music Magnet
Hi Bill,
I have just joined and have an Osram New Music magnet 4 without any instructions. Could you send me some better resolution scans? kind Regards Dave |
12th Dec 2015, 2:48 pm | #17 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,637
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Re: Osram Four New Music Magnet
Hi Dave,
As above, send me a PM with your email address. |