Tandberg reel to reel series 15 - UK Vintage Radio Repair and Restoration Discussion Forum

Tractorfan · 15th Aug 2012, 10:08 am

Hi,
I recently bought the above machine for 4€ with its carrying case and it works well after a bit of TLC. The belts are a little stretched, but not too much of a problem for now. It has been dropped at sometime in its past as there was damage to one corner of the wooden case and the screws holding the deck in were bent

. No mechanical damage though.
Anyway, to my question: I notice that there's a small low value (3.9 ohms, I think) wire wound resistor in series with the three ohm Tandberg speaker. The speaker & resistor are original and the machine has not been "got at" in any way.
I was just curious as to why the resistor was fitted. Any ideas chaps?
Cheers, Pete

TIMTAPE · 15th Aug 2012, 11:46 am

I think the power amp in those models could do about 10 watts undistorted which I guess would be too much for the small internal speaker, hence the rather crude but effective power limiting resistor.

Tim

Tractorfan · 15th Aug 2012, 6:16 pm

Hi,
Of course! Silly me,

I remember now. It's mentioned in the user's handbook. Doh!
It says that the internal amp is ten watts, but the speaker is only three watts. A matching extension speaker was available as an accessory.
Many thanks for that kick up the memory, Tim!

Cheers, Pete

15th Aug 2012, 10:08 am	#1
Tractorfan Dekatron Join Date: Mar 2008 Location: St. Frajou, l'Isle en Dodon, Haute Garonne, France.(Previously: Ellesmere Port, Cheshire, UK.) Posts: 3,183	Tandberg reel to reel series 15 Hi, I recently bought the above machine for 4€ with its carrying case and it works well after a bit of TLC. The belts are a little stretched, but not too much of a problem for now. It has been dropped at sometime in its past as there was damage to one corner of the wooden case and the screws holding the deck in were bent . No mechanical damage though. Anyway, to my question: I notice that there's a small low value (3.9 ohms, I think) wire wound resistor in series with the three ohm Tandberg speaker. The speaker & resistor are original and the machine has not been "got at" in any way. I was just curious as to why the resistor was fitted. Any ideas chaps? Cheers, Pete __________________ "Hello?, Yes, I'm on the train, I might lose the signal soon as we're just going into a tunn..."

15th Aug 2012, 11:46 am	#2
TIMTAPE Octode Join Date: Jul 2006 Location: Perth, Western Australia Posts: 1,969	Re: Tandberg reel to reel series 15 I think the power amp in those models could do about 10 watts undistorted which I guess would be too much for the small internal speaker, hence the rather crude but effective power limiting resistor. Tim

15th Aug 2012, 6:16 pm	#3
Tractorfan Dekatron Join Date: Mar 2008 Location: St. Frajou, l'Isle en Dodon, Haute Garonne, France.(Previously: Ellesmere Port, Cheshire, UK.) Posts: 3,183	Re: Tandberg reel to reel series 15 Hi, Of course! Silly me, I remember now. It's mentioned in the user's handbook. Doh! It says that the internal amp is ten watts, but the speaker is only three watts. A matching extension speaker was available as an accessory. Many thanks for that kick up the memory, Tim! Cheers, Pete __________________ "Hello?, Yes, I'm on the train, I might lose the signal soon as we're just going into a tunn..."