off topic, I think. 5AR4/5AS4 etc

[Neil Morrison]

You could always add a PTC (if you can find one) to the B+ line. That
would delay the application of B+. More complex ways are possible
also.

Neil

----- Original Message -----
From: "Murray Grandy" <mgrandy at TELUS.NET>


> It's amazing what you miss when you're trying to go the cheep
route. Of
> course I am aware of these differences and they make sense. Just
didn't
> think. Guess that is why 5AR4's sell for several times the cost of
5U4's and
> other similar rectifiers. I was going to use the 5AS4 in a Dynaco
ST-70.
> Guess I will look for the real thing. Thanks to all for the great
info.
> Murray
>
*********************************************************************
*******
> ***********
> The 5ar4 cathode is indirectly heated - meaning it takes 15-30
seconds to
> start working - the 5as4 filament is the cathode - heating up in a
few
> seconds.  5ar4 is a good idea as the other tubes in the piece of
equipment
> have warmed up and will be ready to draw current when the rectifier
warms
> up.  The prevents the high voltage from attempting to rise to a
much higher
> value as it would with a directly heated rectifier or solid state
diode -
> therefore stressing the filter condencers until the other tubes
have warmed
> up sufficently to draw current.
>
> Regards,
>
> Bill Riches, WA2DVU
> Cape May, NJ

-----------------------------------------------------------
Products bought, sold or traded here is the responsibility of the
parties involved.  This list and the City of Tempe are not responsible
for losses or misrepresentations of any kind.  Buyer beware!

-----------------------------------------------------------
This list is a public service of the City of Tempe, Arizona
-----------------------------------------------------------

Subscription control - http://www.tempe.gov/lists/control.asp?list=HEATH
To post - HEATH at LISTSERV.TEMPE.GOV
Archives - http://interactive.tempe.gov/archives/HEATH.html