Thorn synchro-amp. Would love some advice please. - UK Vintage Radio Repair and Restoration Discussion Forum

TunstheTuner · 14th Oct 2022, 8:28 pm

Hello

Thanks for letting me join.

I'm really after some advice and I'm hoping this is the best place. So here goes.

Recently someone was having a house clearance and getting rid of a load of clutter. I stumbled across something called Thorn synchro-amp and it just looked too good to be thrown out. I work with a lot of old electrical equipment in my job and this thorn synchro-amp definitely caught my eye.

Ive tried googling it but only came across one video but I'm wondering if anyone can shed any light on it please?
Thanks

Reelman · 14th Oct 2022, 10:13 pm

Another member, Julie_M, gave this explanation previously:

It's for use with a four-track recorder with an accessory socket; which provides power, ground and a connection to the unselected tape head.

The "monitor" socket is for a pair of (probably high-impedance) headphones, so you can listen to the soundtrack while recording pulses at the appropriate points on the pulse track. When you swap the tracks and play the tape with the soundtrack through the recorder's speaker and the pulse track through the synchro-amp, the latter closes a contact whenever a pulse is detected, which starts the projector's slide-change cycle. (Short pulse to go forwards, long pulse to go backwards?)

The "stereo" socket is for connecting another amplifier and speaker in order to listen to stereo tapes. The 3.75 / 7.5 switches will be to select the correct de-emphasis for the tape speed.

All the above is from memory, so may well be incomplete or incorrect ...

I believe this is correct, it may also allow sound-with-sound recordings; record on one track whilst listening to another so that both can be replayed in synchronisation.

Peter

14th Oct 2022, 8:28 pm	#1
TunstheTuner Diode Join Date: Oct 2022 Location: Darlington, County Durham, UK. Posts: 1	Thorn synchro-amp. Would love some advice please. Hello Thanks for letting me join. I'm really after some advice and I'm hoping this is the best place. So here goes. Recently someone was having a house clearance and getting rid of a load of clutter. I stumbled across something called Thorn synchro-amp and it just looked too good to be thrown out. I work with a lot of old electrical equipment in my job and this thorn synchro-amp definitely caught my eye. Ive tried googling it but only came across one video but I'm wondering if anyone can shed any light on it please? Thanks

14th Oct 2022, 10:13 pm	#2
Reelman Octode Join Date: Aug 2008 Location: Rotherham, South Yorkshire, UK. Posts: 1,723	Re: Thorn synchro-amp. Would love some advice please. Another member, Julie_M, gave this explanation previously: It's for use with a four-track recorder with an accessory socket; which provides power, ground and a connection to the unselected tape head. The "monitor" socket is for a pair of (probably high-impedance) headphones, so you can listen to the soundtrack while recording pulses at the appropriate points on the pulse track. When you swap the tracks and play the tape with the soundtrack through the recorder's speaker and the pulse track through the synchro-amp, the latter closes a contact whenever a pulse is detected, which starts the projector's slide-change cycle. (Short pulse to go forwards, long pulse to go backwards?) The "stereo" socket is for connecting another amplifier and speaker in order to listen to stereo tapes. The 3.75 / 7.5 switches will be to select the correct de-emphasis for the tape speed. All the above is from memory, so may well be incomplete or incorrect ... I believe this is correct, it may also allow sound-with-sound recordings; record on one track whilst listening to another so that both can be replayed in synchronisation. Peter