Clansman loudspeakers - UK Vintage Radio Repair and Restoration Discussion Forum

Andrew Sinclair · 3rd Aug 2015, 5:57 pm

Hello all,
I operate a PRC320 and (soon) a PRC351 on the amateur bands from portable locations. They also get occasional use in the shack. I thought it would be a nice idea to have a loudspeaker to use when receiving, in place of the usual handsets and headsets.
There is a 24V supply on one pin of the radio 7-pin audio connectors. It ought to be possible to build an amplifier and speaker into a box to run from this.
I know there is a loudspeaker amplifier crew box for tanks (A-AFL) etc, but this requires two units and associated cables. Do any of the standard Clansman loudspeakers contain an amplifier?
Does the sidetone cause acoustic feedback when you transmit?
73
Andrew G0AMS

ex seismic · 4th Aug 2015, 8:58 am

The Clansman "round" speaker is probably adequate for you. It doesn't have an amp in it and no volume control so might not be so good with your 351 although that itself has two levels. I use the round speaker in the shack and do not get any feedback problems. The "square" speaker is also passive but does have a volume control. The speakers are much higher impedance than you would expect so don't use a domestic 8 ohm unit.

Gordon
G7KNS

G6Tanuki · 4th Aug 2015, 9:04 am

The output stage of a PRC320 can deliver a couple of hundred milliwatts of audio - quite adequate for loudspeaker-listening in a normal shack without needing further amplification.

I use one of the plastic-cased "blue brick" Pye mobile-radio speakers (as used with Whitehalls / Westminsters etc) with my 320.

The audio sidetone on transmit isn't a problem either: it's at a very low level.

Andrew Sinclair · 4th Aug 2015, 9:22 pm

Thanks for your help. I will look out for a speaker at a rally.
Andrew

GMB · 5th Aug 2015, 9:26 am

I was given a Racal audio board which I built into a loud speaker box and use this with both Clansman and Racal sets.

The way it gets over the feedback problem is that it monitors the PTT line and mutes when it sees the transmitter being keyed.

3rd Aug 2015, 5:57 pm	#1
Andrew Sinclair Pentode Join Date: Sep 2007 Location: Fareham, Hampshire, UK. Posts: 105	Clansman loudspeakers Hello all, I operate a PRC320 and (soon) a PRC351 on the amateur bands from portable locations. They also get occasional use in the shack. I thought it would be a nice idea to have a loudspeaker to use when receiving, in place of the usual handsets and headsets. There is a 24V supply on one pin of the radio 7-pin audio connectors. It ought to be possible to build an amplifier and speaker into a box to run from this. I know there is a loudspeaker amplifier crew box for tanks (A-AFL) etc, but this requires two units and associated cables. Do any of the standard Clansman loudspeakers contain an amplifier? Does the sidetone cause acoustic feedback when you transmit? 73 Andrew G0AMS

4th Aug 2015, 8:58 am	#2
ex seismic Heptode Join Date: Sep 2009 Location: Tonbridge, Kent, UK. Posts: 687	Re: Clansman loudspeakers The Clansman "round" speaker is probably adequate for you. It doesn't have an amp in it and no volume control so might not be so good with your 351 although that itself has two levels. I use the round speaker in the shack and do not get any feedback problems. The "square" speaker is also passive but does have a volume control. The speakers are much higher impedance than you would expect so don't use a domestic 8 ohm unit. Gordon G7KNS

4th Aug 2015, 9:04 am	#3
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 14,007	Re: Clansman loudspeakers The output stage of a PRC320 can deliver a couple of hundred milliwatts of audio - quite adequate for loudspeaker-listening in a normal shack without needing further amplification. I use one of the plastic-cased "blue brick" Pye mobile-radio speakers (as used with Whitehalls / Westminsters etc) with my 320. The audio sidetone on transmit isn't a problem either: it's at a very low level.

4th Aug 2015, 9:22 pm	#4
Andrew Sinclair Pentode Join Date: Sep 2007 Location: Fareham, Hampshire, UK. Posts: 105	Re: Clansman loudspeakers Thanks for your help. I will look out for a speaker at a rally. Andrew

5th Aug 2015, 9:26 am	#5
GMB Dekatron Join Date: Aug 2003 Location: near Reading (and sometimes Torquay) Posts: 3,099	Re: Clansman loudspeakers I was given a Racal audio board which I built into a loud speaker box and use this with both Clansman and Racal sets. The way it gets over the feedback problem is that it monitors the PTT line and mutes when it sees the transmitter being keyed.