[lou]

Hi!
Would appreciate some help.

Was thinking of using a tube car radio at home. Specs read current
consumption 1.5A (at .5W).
The fuse is 5A.

DC power supply should be at least 1.5A but can I go up to 4A without
harming the radio?
Not sure if I would gain any improvement in sound.

Thanks!

Please cc: my email address if possible.

Louis

[Peter Wieck]

On Jan 27, 4:45*am, lou wrote:
Hi!
Would appreciate some help.

Was thinking of using a tube car radio at home. Specs read current
consumption 1.5A (at .5W).
The fuse is 5A.

DC power supply should be at least 1.5A but can I go up to 4A without
harming the radio?
Not sure if I would gain any improvement in sound.

Thanks!

Please cc: my email address if possible.

Louis


Amperage will have no effect on the radio - with the presumption that
you fuse it correctly so that the fuse burns before it does if some
sort of internal short happens.

Note that most tube-type car radios have a vibrator to make B+ through
a transformer - be sure that it is working properly, and/or has been
replaced with a SS type. When they fail it can be quite spectacular
especially if not properly fused.

Gary Taymen from the "other" group (rec.antiques.radio+phono) will
give you many further details on vintage car radios.

Peter Wieck
Wyncote, PA

[Peter Wieck]

On Jan 27, 7:53*pm, Bret Ludwig wrote:

*Usually people prefer to use a external or stuff-it-in-there AC
supply with a regular B+ and filament supply and not run the vibrator,
when using car tube radios for regular indoor use. Elsewise you will
need a beefy supply that will usually be inefficient and take up a lot
of space.

*Old Sears Schumacher battery chargers make nice DC supplies, by the
way

Try reading the OP... . And someone sophisticated enough to have a VPS
to make the B+ would not be making such a post.

So, answer the direct question, don't dispute the direct answer - as
to the requirement of the P/S, if it makes 1.5A @ 13.6V. it will do
just fine, any of several supplies from the likes of even Radio Shack
are capable of that. No need to use a battery charger which are not
known for being particularly quiet in this sort of application.

Peter Wieck
Wyncote, PA

[RapidRonnie]

On Jan 27, 8:17 pm, Peter Wieck wrote:
On Jan 27, 7:53 pm, Bret Ludwig wrote:

Usually people prefer to use a external or stuff-it-in-there AC
supply with a regular B+ and filament supply and not run the vibrator,
when using car tube radios for regular indoor use. Elsewise you will
need a beefy supply that will usually be inefficient and take up a lot
of space.

Old Sears Schumacher battery chargers make nice DC supplies, by the
way

Try reading the OP... . And someone sophisticated enough to have a VPS
to make the B+ would not be making such a post.

So, answer the direct question, don't dispute the direct answer - as
to the requirement of the P/S, if it makes 1.5A @ 13.6V. it will do
just fine, any of several supplies from the likes of even Radio Shack
are capable of that. No need to use a battery charger which are not
known for being particularly quiet in this sort of application.

Assuming he is talking about building a regular transformer B+ and
filament supply instead of a regulated lab supply, I'm with Bret on
this one.

Linear regulated supplies are very inefficient. If you are using a
typical variable bench supply to provide 6 or 12 volts you are looking
at 30 to 60 percent efficiency at the terminals of the supply , plus
the substantial inefficiency of the vibrator pack supply. In contrast
an unregulated transformer B+ supply is about 75 percent efficient and
if the heater chain can be run on AC 85 percent efficiency is possible
if not more.

If, like me, you are a heavy radio listener the power bill will add
up fast.

To build such a supply you will need a conventional power
transformer , some diodes and filter caps plus a choke or a power
resistor (the choke is more efficient). Most 1945-55 car radios will
run on about the same B+ current as a Fender Princeton or Super Champ
amplifier. A new power transformer for one of these can be had for $30
or less. The diodes are a few cents each (I like to series and
parallel them for redundancy with series resistors) and filter caps if
you use PCB types a couple bucks. Seven or eight bucks for the choke.

Considering the saved A/C load in the summer it will pay for itself
in a year or two versus the power draw if a big old high current HP or
Lambda supply is used even if you already have the supply.

Of course you can creatively use salvaged transformers as well.

A cheat is to get a one piece prebuilt supply out of certain surplus
military equipment.

[Eeyore]

lou wrote:

Hi!
Would appreciate some help.

Was thinking of using a tube car radio at home. Specs read current
consumption 1.5A (at .5W).
The fuse is 5A.

DC power supply should be at least 1.5A but can I go up to 4A without
harming the radio?

Any load will draw only as much current as it needs. You can't 'force'
current into a load because the label says 4A instead of 1.5A. It's a
popular misconception.

Graham

[Peter Wieck]

On Jan 27, 11:37*pm, RapidRonnie wrote:

*Assuming he is talking about building a regular transformer B+ and
filament supply instead of a regulated lab supply, I'm with Bret on
this one.

Assuming that, sure.

But I believe the OP is requesting an opinion of whether a 4A @
(nominal) 12V rated power-supply will run his radio with a nominal
load of 1.5A. It will. If he wants to go further at it, then perhaps
he should get into a more sophisticated approach.

But, again, from the OP, it appears that he wants to run a tube car
radio as a tube car radio, but inside his house, not inside his
vehicle. For whatever reason a simple 12V P/S will do the trick right
off the shelf without agony. My suggestion to him was to be sure of
the mechanics and electrics of the radio - but not necessarily to mess
with it beyond that.

Pays you money, takes you chances.

Peter Wieck
Wyncote, PA