06-19-2015, 01:03 PM
Pages: 1 2
06-19-2015, 01:03 PM
06-19-2015, 01:25 PM
Did anyone else notice this is a 25-40 hz chassis? It has the over-sized transformer. I recently picked up a 1st (early) run model 90 chassis from a low boy and it has the same 'white' decal instead of the 'gold' decal on the end of the tube shield.
Does anyone know if these 25-40 hz chassis sold here in the US are early chassis? The Canadian versions always seem to have the metal tag instead of the gold or white decals,
David
Does anyone know if these 25-40 hz chassis sold here in the US are early chassis? The Canadian versions always seem to have the metal tag instead of the gold or white decals,
David
06-19-2015, 03:16 PM
Yeah, the 25-40 cycles makes a 70 into a 70A.
06-19-2015, 04:38 PM
The 25-40 cycle 70A sets were sold in the USA as well as Canada. No, just because a set is a 70A does not necessarily mean it is an early production set.
06-19-2015, 06:53 PM
Nice console. Do you have to change anything to use it in an AC 60Hz line?
06-19-2015, 08:47 PM
(06-19-2015, 06:53 PM)Mike Wrote: [ -> ]Nice console. Do you have to change anything to use it in an AC 60Hz line?
Thanks. From what I understand, no changes have to be made.
06-19-2015, 09:26 PM
That is correct. You can run a 25 cycle power transformer with 60 cycle AC...but the reverse is not true.
06-19-2015, 09:36 PM
Actually there are many advantages to owning a set equipped with a 25 cycle compatible power supply, as most have noticed the power transformer is larger, because the core is larger in order to avoid saturation at the lower line frequency. However in addition to the power transformer they would add electrolytic caps of a larger value and often add extra filter chokes or increase the size of the field coil or of the filter chokes to eliminate the 25 cycle ripple. So if you run a 25 cycle set on 60 cycles the transformer will run cooler, can tolerate more abuse, and there will be next to no hum.
Regards
Arran
Regards
Arran
06-19-2015, 09:41 PM
(06-19-2015, 09:36 PM)Arran Wrote: [ -> ] Actually there are many advantages to owning a set equipped with a 25 cycle compatible power supply, as most have noticed the power transformer is larger, because the core is larger in order to avoid saturation at the lower line frequency. However in addition to the power transformer they would add electrolytic caps of a larger value and often add extra filter chokes or increase the size of the field coil or of the filter chokes to eliminate the 25 cycle ripple. So if you run a 25 cycle set on 60 cycles the transformer will run cooler, can tolerate more abuse, and there will be next to no hum.
Regards
Arran
Wahoo!
06-19-2015, 10:21 PM
06-20-2015, 12:51 PM
I think you have a good one to restore. Pretty clean and looks like only light surface rust on top of chassis, nice and roomy underneath and only 6 bakelite blocks to restuff.
06-20-2015, 06:51 PM
(06-20-2015, 12:51 PM)Mike Wrote: [ -> ]I think you have a good one to restore. Pretty clean and looks like only light surface rust on top of chassis, nice and roomy underneath and only 6 bakelite blocks to restuff.
Yeah, i think so too! Thanks.
Pages: 1 2