Heathkit Mohican model GC-1U - UK Vintage Radio Repair and Restoration Discussion Forum

Ian G Bennett · 5th Jan 2007, 3:34 pm

Trying to restore a Mohican radio.
I am short of the internal speaker which according to the wiring diagram is 35 ohms.
The fixings on the cabinet side would suggest its about 6 inches, maybe elliptical.
Does anyone have one or know of a supplier?

dsergeant · 5th Jan 2007, 7:28 pm

Well I have an old Mohican which has been extensively modded then canibalised over the years. It was my very first amateur receiver, bought when I was at Uni in 1968. Just had a quick look at it and found it was in an even sorrier state than I remembered with lots of things missing and hanging off. Sadly the speaker has also long disappeared, but if there is anything else you are looking for I may be able to help.

Dave

Ian G Bennett · 6th Jan 2007, 5:38 pm

Thanks for looking Dave.
My Mohican is virtually mint, no scratches on front or rear or case & by fitting new electrolytics it workis quite well.
Oh I forgot it also has its original Heathkit cardboard box.
Why the speaker should be missing is very odd.
The other thing missing is the whip aerial.
By any miracle does yours have the aerial?
Ian M3IGB

dsergeant · 6th Jan 2007, 6:56 pm

Quote:

Originally Posted by Ian G Bennett

By any miracle does yours have the aerial?

No sorry Ian, just the rubber grommet left....

Dave

Ed_Dinning · 6th Jan 2007, 9:45 pm

Hi Ian, you could try some old TV speakers for the Mohican. Philips used 35 ohn types in their early transistor sets. They were generall quite small speakers to. It would be possible to use a 3 ohm unit and make a small impedance matching transformer for it. PM me if yiu have no joy and I'll tell you what's involved.

Ed

Ian G Bennett · 12th Jan 2007, 3:01 pm

Thanks Ed,
Finding a 35 ohm speaker is proving very difficult.

In the mean time to get loudspeaker sound out of it can you give me an idea what is involved in getting it to work on an 8 ohm speaker (which seems to be the standard now)

Ian M3IGB

Ed_Dinning · 12th Jan 2007, 8:02 pm

Hi Ian, the simplest way is to fit about a 22R resistor in series and accept that the souns will be much reduced, perfectly OK for a quick test. It would be possible to run an 8R speaker with it, again reduced output and not to be prolonged.
Note that in this instance Resistance and Impedance are somewhat different.
For a simple matching transformer use an old heater or output transformer and wind about 50 turns of 0.3mm wire to a tapping point; wind a further 50 turns to the finish.
Connect start and finish to set output (35R), connect 8R speaker to start and tapping.

Ed

5th Jan 2007, 3:34 pm	#1
Ian G Bennett Retired Dormant Member Join Date: May 2005 Location: Whitley Bay, Tyne & Wear, UK. Posts: 57	Heathkit Mohican model GC-1U Trying to restore a Mohican radio. I am short of the internal speaker which according to the wiring diagram is 35 ohms. The fixings on the cabinet side would suggest its about 6 inches, maybe elliptical. Does anyone have one or know of a supplier?

5th Jan 2007, 7:28 pm	#2
dsergeant Octode Join Date: Mar 2006 Location: Bracknell, Berkshire,UK. Posts: 1,175	Re: Heathkit Mohican model GC-1U Well I have an old Mohican which has been extensively modded then canibalised over the years. It was my very first amateur receiver, bought when I was at Uni in 1968. Just had a quick look at it and found it was in an even sorrier state than I remembered with lots of things missing and hanging off. Sadly the speaker has also long disappeared, but if there is anything else you are looking for I may be able to help. Dave

6th Jan 2007, 5:38 pm	#3
Ian G Bennett Retired Dormant Member Join Date: May 2005 Location: Whitley Bay, Tyne & Wear, UK. Posts: 57	Re: Heathkit Mohican model GC-1U Thanks for looking Dave. My Mohican is virtually mint, no scratches on front or rear or case & by fitting new electrolytics it workis quite well. Oh I forgot it also has its original Heathkit cardboard box. Why the speaker should be missing is very odd. The other thing missing is the whip aerial. By any miracle does yours have the aerial? Ian M3IGB

6th Jan 2007, 9:45 pm	#5
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,195	Re: Heathkit Mohican model GC-1U Hi Ian, you could try some old TV speakers for the Mohican. Philips used 35 ohn types in their early transistor sets. They were generall quite small speakers to. It would be possible to use a 3 ohm unit and make a small impedance matching transformer for it. PM me if yiu have no joy and I'll tell you what's involved. Ed

12th Jan 2007, 3:01 pm	#6
Ian G Bennett Retired Dormant Member Join Date: May 2005 Location: Whitley Bay, Tyne & Wear, UK. Posts: 57	Re: Heathkit Mohican model GC-1U Thanks Ed, Finding a 35 ohm speaker is proving very difficult. In the mean time to get loudspeaker sound out of it can you give me an idea what is involved in getting it to work on an 8 ohm speaker (which seems to be the standard now) Ian M3IGB Last edited by Darren-UK; 29th Jan 2008 at 2:20 am. Reason: Removed 'wanted' request.

12th Jan 2007, 8:02 pm	#7
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,195	Re: Heathkit Mohican model GC-1U Hi Ian, the simplest way is to fit about a 22R resistor in series and accept that the souns will be much reduced, perfectly OK for a quick test. It would be possible to run an 8R speaker with it, again reduced output and not to be prolonged. Note that in this instance Resistance and Impedance are somewhat different. For a simple matching transformer use an old heater or output transformer and wind about 50 turns of 0.3mm wire to a tapping point; wind a further 50 turns to the finish. Connect start and finish to set output (35R), connect 8R speaker to start and tapping. Ed