16-03-2015, 07:36 PM
Thanks guys for reading and responding to my post with so much helpful information.
I have got some LT700 audio transformers, but was sceptical as to whether the circuits I outlined in option 2 & 3 above were strictly necessary, and are likely to provide any discernible improvement in performance over option 1. The general consensus is that option 1 would provide satisfactory results. Alistair D suggested that perhaps a blocking cap would be a worthwhile addition - presumably as I've shown in the updated diagram below? (I don't know how come the values of 4k7 for the two resistors arose).
It was my son who asked me about this - he shares my interest in vintage radios and has a small collection, but doesn't himself have any that have gram input sockets. (He has a couple of Ekco A22s, and uses a 'spitfire' with them). He'd asked whether direct connection of i-pods to radios that do have gram sockets was possible and I said yes, without considering the aspect of stereo to mono. It caused me to consider whether it's advisable to simply join the two channels of the I-pod output together in parallel to feed this into a mono gram socket, or whether doing so would have an adverse effect on the I-pod (or whatever other gizmos people use today).
As to 'pantry transmitters', fine if a radio doesn't have a gram input socket, or is AC/DC, but no required if a gram socket or 'aux' input is present.
I have got some LT700 audio transformers, but was sceptical as to whether the circuits I outlined in option 2 & 3 above were strictly necessary, and are likely to provide any discernible improvement in performance over option 1. The general consensus is that option 1 would provide satisfactory results. Alistair D suggested that perhaps a blocking cap would be a worthwhile addition - presumably as I've shown in the updated diagram below? (I don't know how come the values of 4k7 for the two resistors arose).
It was my son who asked me about this - he shares my interest in vintage radios and has a small collection, but doesn't himself have any that have gram input sockets. (He has a couple of Ekco A22s, and uses a 'spitfire' with them). He'd asked whether direct connection of i-pods to radios that do have gram sockets was possible and I said yes, without considering the aspect of stereo to mono. It caused me to consider whether it's advisable to simply join the two channels of the I-pod output together in parallel to feed this into a mono gram socket, or whether doing so would have an adverse effect on the I-pod (or whatever other gizmos people use today).
As to 'pantry transmitters', fine if a radio doesn't have a gram input socket, or is AC/DC, but no required if a gram socket or 'aux' input is present.
Regards, David.
BVWS Member.
G-QRP Club Member 1339.
'I'm in my own little world, but I'm happy, and they know me here'
BVWS Member.
G-QRP Club Member 1339.
'I'm in my own little world, but I'm happy, and they know me here'
