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Vintage Telephony and Telecomms Vintage Telephones, Telephony and Telecomms Equipment |
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29th Mar 2018, 11:33 am | #1 |
Heptode
Join Date: Oct 2006
Location: Leeds, West Yorkshire, UK.
Posts: 597
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Is it possible to get more receiver volume from BT Statesman and Viscount phones ?
I'm planning to convert one or the other to binaural headset use but so far I find the earphone volume isn't really sufficient for two 300 ohm earphones. Apart from adding a battery-powered inline amplifier is it feasible, for example, to remove or replace some components from the circuit board ? Would something like that help ?
All suggestions gratefully read. Thankyou. |
29th Mar 2018, 3:45 pm | #2 | |
Dekatron
Join Date: Jul 2007
Location: Penrith, Cumbria, UK.
Posts: 3,687
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Re: Is it possible to get more receiver volume from BT Statesman and Viscount phones
Quote:
You could use a matching transformer (or transformers) to adjust the impedance to your headset, but you'd need to find them small enough to fit in your phone.
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Regds, Russell W. B. G4YLI. |
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29th Mar 2018, 5:09 pm | #3 |
Heptode
Join Date: Oct 2006
Location: Leeds, West Yorkshire, UK.
Posts: 597
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Re: Is it possible to get more receiver volume from BT Statesman and Viscount phones
Russell, the plan is to simply use the circuit board of whichever phone, so no handset or keypad and a BT1000 lever key as a hook switch. The headset has two 300 ohm rocking armature earphones wired in parallel and a dynamic microphone, altogether replacing the handset.
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29th Mar 2018, 6:33 pm | #4 |
Dekatron
Join Date: Jul 2007
Location: Penrith, Cumbria, UK.
Posts: 3,687
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Re: Is it possible to get more receiver volume from BT Statesman and Viscount phones
Try the receivers in series before considering other options to see if that makes an improvement.
__________________
Regds, Russell W. B. G4YLI. |
29th Mar 2018, 9:16 pm | #5 |
Heptode
Join Date: Apr 2011
Location: Edinburgh, UK.
Posts: 805
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Re: Is it possible to get more receiver volume from BT Statesman and Viscount phones
The circuits used in amplifying handsets and powered from the carbon transmitter voltage may give you some inspiration
http://www.samhallas.co.uk/repositor...1000/N1840.pdf http://www.samhallas.co.uk/repositor...1000/N1842.pdf http://www.samhallas.co.uk/collectio...3_variants.htm |
30th Mar 2018, 11:16 am | #6 |
Heptode
Join Date: Oct 2006
Location: Leeds, West Yorkshire, UK.
Posts: 597
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Re: Is it possible to get more receiver volume from BT Statesman and Viscount phones
I just happen to own one of those amplifier circuits from the old GPO handsets. The snag is that they are powered by the same source as the carbon transmitter on a type 746. The Statesman and Viscount don't have that power provision.
Ideally I was hoping for a solution along the lines of removing or replacing a resistor in the receiver circuit to boost the volume. Thankyou for your responses folks. |
30th Mar 2018, 11:47 am | #7 |
Dekatron
Join Date: Jan 2005
Location: Oxford, UK.
Posts: 17,843
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Re: Is it possible to get more receiver volume from BT Statesman and Viscount phones
Seems a shame to spoil a Statesman or Viscount with no guarantee of success.
I could send you a BT Relate 300 phone with loudspeaking provision (powered by AA batteries) FOC if you wish - it came from moderator Graham originally. The display's on the way out but it functions perfectly in other respects and would be an ideal candidate for what you're trying to do, I would have thought. Just pay P&P. Cheers, Nick. |
30th Mar 2018, 12:29 pm | #8 |
Heptode
Join Date: Oct 2006
Location: Leeds, West Yorkshire, UK.
Posts: 597
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Re: Is it possible to get more receiver volume from BT Statesman and Viscount phones
Thanks for your kind offer Nick but I'll pass. The Statesman and Viscount were almost scrap when I bought them so there's no need to worry ! I'll persevere.
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