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AES type of Battery Eliminator has hum in B+
#10

Rod

Yes, your standard TO-220 LDO is good for 0.7 - 1.5W dissipation (more with a heatsink) and a small current with a large dropout (which in this specific case is...what...55V) will get you that.

Now, they simply took a typical voltage egulator circuit and implemented it using discretes. Using a good enoughg transistor with some heatsink will give you a good regulator.
Also, you could simply take that LDO and couple it with a larger transistor, beefing it up.

But the output cap, a small one that will take care of small ripple and stability, is still needed.
Large cap should not be used as it could create a short but large dissipation and destroy the transistor (an integrated LDO is typically thermally-protected). At small currents 10-20uF would be enough.


Also, it is a good idea, especially with the bi-polar transistor as the power element, to put a reverse diode across its E/C (it is often done with LDOs): this protects it if the output capacitance discharged slower than input ones and a reverse voltage develops across it. Of course if tehre is no output capacitor, this is not a problem.

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.


Messages In This Thread
RE: AES type of Battery Eliminator has hum in B+ - by morzh - 03-31-2025, 10:11 AM
SMPS for tube radios - by toptip - 12-06-2025, 09:22 PM



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