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On Saturday, January 19, 2019 at 4:44:49 PM UTC-6, Big Bad Bob wrote:
On 01/05/19 16:48, wrote:
On Mon, 31 Dec 2018 11:48:34 -0800, Big Bad Bob
wrote:

On 12/29/18 17:07, wrote:
I have a new power transformer, which says "for Eico Stereo". But that
is all I know. It's just a hand written label, stuck on the bottom.

The case has these numbers stamped on it. 30002-3 (there is a "H" below
that).

It has 5 wires on the secondary. Two are 6.3v filament. The others are
the high voltage with roughly 285 volts on each side of the center tap.
(570v total).

I'd like to find out what model Eico stereo it's from, so I can
hopefully find a schematic and see what tubes it was made to power.

It's a fairly large transformer. Not as big as the old ones onthe old
tube tv sets, but still large.


hmmm... I'm guessing it's for a console stereo with maybe 10W per
channel. Most of the heater supply would be for the FM radio, all of
those IF amplifier tubes and stereo detector. The final stage might be
6BQ5 or similar, maybe even single-ended. I've seen that, actually...

The output DC would be around 320V probably, coming out of the rectifier
tube [unloaded], good enough for 6BQ5-based amplifiers which aren't
supposed to exceed 300V (from what I read). With a proper load on it,
the running DC volts would be around 300V or so, and cathode bias on the
output tubes would make them operate within their limits. But yeah this
would be a typical config for a home stereo system from the late 50's or
early to mid 60's.

Interesting it's made by Eico. I had an Eico tube preamp ages ago that
was originally a kit. I used it with a tube power amp for decades
before the output transformer went out in one channel and I had no
source for replacements...

online searches show vintage tube equipment by them that might use the
transformer you have.

I'm gonna answer my own question. After alot of research online, this
transformer is for an Eico 315 Signal Generator. So it's not an
amplifier at all. The good news is that I have a 315 Signal Gen. So I
had the schematic right here all the time, and it lists that part
number..... I doubt I will ever need to replace the transformer, but I
do have a spare....

I might build a variable power supply with it. Just a thought.....

Searching for transformers on google is frustrating. I saw more of those
stupid plastic toys called "transformers", than the ones used in
electronics. Grrrrrrrr....


You should try these places:
hammond catalog, and amplifiedparts.com, and also mouser electronics.
Occasionally e-bay will have stuff like that as well.

places like that have lots of tube-related stuff, including drop-in
replacement power and output transformers for guitar amps,
potentiometers, appropriately-voltaged capacitors at reasonable prices,
tube sockets, etc. i.e. the things that google might not quickly give
you search results on.

You can also add things like "site:amplifiedparts.com" to your google query.
--
(aka 'Bombastic Bob' in case you wondered)

'Feeling with my fingers, and thinking with my brain' - me

'your story is so touching, but it sounds just like a lie'
"Straighten up and fly right"