14-06-2022, 05:58 PM
It just for me trying to get some better transformers on the 1920/30's style radio, there is not a lot of volume to play with so trying to minimise the losses.
The simple triode output valves I am using are more than likely to have an Ra between 3.5 K to 6 K Ohms so although it works with higher ratio transformers I am just not able to drive the speaker coil, hence wondering what output transformers had what ratios so I could scan the auction sites for suitable single ended output ones.
At present I think I would need something like an 0.75 Ohm speaker!
So really looking for the likes of 30 to 40:1 ratios. From what I can glean many of the speakers of the time would be quite high impedance in the region of a few hundred Ohms, which I do not have, only the typical 4 to 8 ohm jobs to hand so the old 5:1 ratio transformers would not help as I would be loading it heavily, not that I had any.
Hope that makes sense and to why I was asking about transformer ratios.
Adrian
The simple triode output valves I am using are more than likely to have an Ra between 3.5 K to 6 K Ohms so although it works with higher ratio transformers I am just not able to drive the speaker coil, hence wondering what output transformers had what ratios so I could scan the auction sites for suitable single ended output ones.
At present I think I would need something like an 0.75 Ohm speaker!
So really looking for the likes of 30 to 40:1 ratios. From what I can glean many of the speakers of the time would be quite high impedance in the region of a few hundred Ohms, which I do not have, only the typical 4 to 8 ohm jobs to hand so the old 5:1 ratio transformers would not help as I would be loading it heavily, not that I had any.
Hope that makes sense and to why I was asking about transformer ratios.
Adrian
Learning as I go!
Youtube EF91 Valve
Youtube EF91 Valve
