AP2503

[Walrus]

The 325 boards are dark blue and are a mixture of Rev 3 and Rev 4 with Huntingdon and Melvilles on. Although one R4 has a "Studio Systems Division" on it. Don't know what era they were, but it looks like the original one. Unfortunately, most of my 325 boards are minus the 2520 as they were bought years ago from an old desk as spares.

The 312's are also dark blue and are Rev 4. Again these were bought for the 2520's and most are missing said item. Interestingly, the input transformer is an AP2169 and not a AP2622!

Can't see any notches in the xfr bobbins.

 

[safe as milk]

hi
nice one,

the studio systems 2520 is before meville which is before huntington,

ive never seen a 312 with a 2169 on it?

re the bobbin gap that's only on certain ones(but it's on both 312+325)
they must have changed these 2503's every couple of years,

anyone else got diff. revisions or litz2503's out there?


cheers

 

[CJ]

OK, I rewound the sample safe as milk sent, had to scrape the varnish off the lams with an exacto, and take the varnish off the wire so I could get it all back on the bobbin.
To take the varnish off the wire, I used a super clean iso alchohol.
Did not want to remove the enamel!

The quad wire was strung down the building, then split apart, cleaned, and spooled up for winding:

]http://vacuumbrain.com/The_Lab/TA/API/AP2503/rewind_b.jpg

Then I made a wire guide with a 0.016' end mill, so the wires can not cross over in the guide, and wide enough for just 4 wires:
]http://vacuumbrain.com/The_Lab/TA/API/AP2503/rewind_a.jpg

I managed to get all the lams and wire back together.
Did a sweep test, everything the same, but, the leakage capacitance went from about 8100 pf down to 4100 pf.

Banging my head against the wall, all I came up with is the varnish.

I will have this thing dipped down at the local xfmr shop to see if the capacitance goes back up.
Varnish is supposed to add capacitance, as it acts like a dialectic when it gets between the wires, more so than air.
You can see the keeper lam is rounded, so as not to cut wire when lacing up the core.
It also extends further to overlap the loose I bars on the outside.
I should have ordered some for the last kits, but they are not grain oriented, and therefore represent a slight loss of inductance, so there is a tradeoff.

http://vacuumbrain.com/The_Lab/TA/API/AP2503/rewind_c.jpg

So time to spool up a twist-tite version and do some side by side testing.
Then that should be it for the API output.

That's good, because look what Silent Arts just sent me.
My oh my, a man of my heart!
Best x-mas gift so far!
Thanks SA!

http://vacuumbrain.com/The_Lab/TA/API/AP2503/sa_1.jpg

 

[radiance]

I've seen that black Haufe trannie before...
I think it was in this thread

http://www.groupdiy.com/index.php?topic=6463&highlight=haufe+3000

A transformer with an opamp inside...he he whadayaknow

 

[ruairioflaherty]

Hey CJ,

I missed this thread first time around as I was away on location doing a TV shoot. I have a loose 2503, not sure of the vintage. Any tests I can do for you to add to the confusion. It's wrapped really tight so I cannot tell if the winding is twisted or not,

cheers,
Ruairi

 

[[silent:arts]]

[quote author="CJ"]That's good, because look what Silent Arts just sent me.
My oh my, a man of my heart!
Best x-mas gift so far![/quote]
:grin: - I will send you bigger ones for eastern :green:
(have you seen the V74 iron on eBay ??? - crazy)

 

[CJ]

Holy Cow, Volker, do you want that output back?


Ruairi, you could do a dc ohms test, that might tell me something without shipping it away to be traumatized.

You can also cut the tapoe off the back, look at the wire, and re tape.

This vintage from safe as milk had strapping tape like you buy for shipping, holding the leads down.
That is not a coomon adhesive in the xfmr biz.
Also, the outer tape looked like black electrical tape with a poly insulator.

 

[[silent:arts]]

[quote author="CJ"]Holy Cow, Volker, do you want that output back?[/quote]
no :green:

 

[CJ]

I got the 2503 back from the varnish tank and the capacitance went back up to 8000 pf, so it was the processing that makes the difference.
I will wire the leads back up and send it back to Safe as mILK, THANKS AGAIN.
CJ

 

[safe as milk]

hi cj
sorry to bother you, but are you getting my pm's?

 

[clintrubber]

[quote author="safe as milk"]hi cj
sorry to bother you, but are you getting my pm's?[/quote]
And sorry to bother you...

... but that's a pretty nice'n'weird avatar you've got there :thumb: :green: :guinness:

(I think I bagot it :thumb: )

 

[safe as milk]

hi
yeah i've got ssltech to thank for that!
it was on a funny website he posted a link to.
to me it does'nt mean anything, just a funny image
although i am an englishman that loves french films/music.

 

[clintrubber]

[quote author="safe as milk"]
to me it does'nt mean anything, just a funny image
although i am an englishman that loves french films/music.[/quote]

Oopla :roll: :grin:

You must be pulling my leg, but OK, I'll bite:

Please gimme the link to that funny site!

 

[safe as milk]

hi
that makes it look like im anti-french,
i cant be, im in love with audrey tautau..(who is'nt?)
i thought it was just funny,
should i take it down? i don't want people to get the wrong idea.

i cant remember the site, it was like a spoof news thing.
hopefully ssltech will remind us

 

[clintrubber]

[quote author="safe as milk"]hi
that makes it look like im anti-french,
i cant be, im in love with audrey tautau..(who is'nt?)
i thought it was just funny,
should i take it down? i don't want people to get the wrong idea.

i cant remember the site, it was like a spoof news thing.
hopefully ssltech will remind us[/quote]
Nothing anti-french in that if you ask me.

I like that movie (and the old original better than the Rocky-remake),
so MC with the baguette was pretty funny :thumb:

 

[SSLtech]

Yeah, "Get" / "Baguette". Pun.

I remember that the unedited Get Carter was pretty brutal. Some nudity and LOTS of violence, when violence still affected the viewer, prior to the desensetization of these days... though perhaps part of the reason.

Keith

 

[clintrubber]

Don't know if I've seen the unedited or not (DVD).
The beach-scene at the end (where he's simply shot) a bit of a strange ending...
Nice soundtrack.

Hmm, I forgot if in the remake Rocky was shot as well.

 

[safe as milk]

hi
that's all cool then,

just been looking & i can't believe i did'nt
bookmark the site where it came from.
do you have that link again please ssltech?

 

[deveng]

CJ,

Since 2503's are getting difficult to find these days, I'd like to try and build some myself. I searched all posts on these builds (at least I think I found them all!).

Am I correct that at least some versions were non twisted quadfilar, 29 gauge wire? I've got the links to the suppliers for the bobbins and lams from the other threads.

Do you still have any 625 EI M6 lams and keepers left? If you do and don't mind mailing me some, please PM me with cost for lams and effort.

By the way, I must say your transformer de-constructions are entertaining and informative!!

Jeff

 

[deveng]

sorry, double clicked and somehow got 2 messages