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Old 8th Dec 2017, 7:50 am   #10
Synchrodyne
Nonode
 
Join Date: Jan 2009
Location: Papamoa Beach, Bay of Plenty, New Zealand
Posts: 2,943
Default Re: Tape to Tape recording

With two tape decks/recorders coupled by a reversing (mirror) DIN-to-DIN, there might be some signal level disparities, although perhaps not of such magnitude that they cannot be addressed by appropriate settings of the input and output gain controls.

Tape recorder DIN inputs were usually designed to accept signals from amplifier DIN outputs, which in turn were usually (but not always) of the DIN “constant current” type that typically delivered relatively lower signal levels than the by the regular (phono socket) tape recording outputs. Thus, tape recorder DIN inputs were usually somewhat more sensitive than tape recorder line inputs. On the other hand, tape recorder DIN output signal levels were usually of the about the same magnitude as the corresponding line outputs.

For the Akai 1720L, the numbers I can find are:

Line input: 30 mV, 140k
DIN input: 10 mV, 43k

DIN output: 2.5 V maximum, looking to at least 50 k.

With say a pair of Akai 1720Ls inter coupled via their DIN sockets, the output volume control of the sending unit would need to be wound back quite a bit (more than 30 dB down) to provide say around 50 mV or so for the DIN input, or whatever similar-order-of-magnitude number is required to provide a margin above 0 VU with the input gain control (of the receiving unit) at a reasonable setting.

Anyway, whilst some signal attenuation might be required with the DIN-to-DIN connection, amplification is unlikely to be required given that tape recorder DIN outputs typically deliver much more signal than is required by tape recorder DIN inputs.

On the other hand, attempting to cross-link two control units or amplifiers this way can run into difficulties, in that the signal level delivered by the DIN tape record out socket could well be noticeably less than that required by the DIN tape in socket.

Where the use of a DIN socket at each end is unavoidable when interconnecting two tape recorders, then using two standard DIN-to-4 phono leads coupled at their phono ends by barrel connectors to make up a reversing DIN-to-DIN lead has some advantage in that it is easy enough to insert attenuators between the phono plugs, if required (or if desired to obtain reasonable rather than extreme gain control settings).


Cheers,
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