Would a 385 VA transformer with two 38 volt secondaries work for the unregulated supply diagrammed in the Zen V4 article? Do I need to change the supply circuit to use this transformer? Thanks.
G
G
38v should be okay. Use the secondaries parallel, that should give you 38 - 0 @ 770VA (instead of 38 - 0 - 38 @ 385 VA).
If it is a 385 VA transformer with two secondaries at 38 VAC then the two secondaries in parallell will give you a single 38 VAC at 385 VA. This will in turn correspond to roughly 50-52 VDC (single rail) after rectification and with load. The voltage may be slightly higher than the one with a 36 VAC transformer as stated in the article which will run your regulator slightly warmer but everything is well within limits IMHO.
This is pushing it a little for a stereo ZV4 (which would be happier with say 500+ VA)but will most likely work OK with the transformer running a little bit warm which is OK for some and unacceptable for others...
Tazzy,
the rating for the transfomer is 385 VA (provided that is correct) which means 385 VA for the WHOLE transformer which gives 192.5 VA per secondary which then makes available the whole 385 VA when using them in parallell for the single rail output.
/UrSv
This is pushing it a little for a stereo ZV4 (which would be happier with say 500+ VA)but will most likely work OK with the transformer running a little bit warm which is OK for some and unacceptable for others...
Tazzy,
the rating for the transfomer is 385 VA (provided that is correct) which means 385 VA for the WHOLE transformer which gives 192.5 VA per secondary which then makes available the whole 385 VA when using them in parallell for the single rail output.
/UrSv
I am using a 45-0-45 750VA transformer (in paralel) that gives after rectification 65V. It is a bit too much and the FET of the PSU runs warm. I think it is best to use a IRFP240 or something like that here, because of the extra heat.
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