What makes a API 2503 (or Profile 4804) special?

I'm in the market for more 2503 style transformers, but apparently Profile Electronics has a 100 pcs. minimum for the 4804.

I came across this blurb from the Edcor web site.

Does EDCOR Electronics do custom audio transformers?

Yes! Yes! Yes! About 50% of our transformer business are custom audio transformers. When we started designing and manufacturing transformers in 1976 all of our business was O.E.M. type or custom transformers. We primarily manufactured power transformers for the medical, large computer and related industries. The shift to audio began in the 1980?s.

Does EDCOR Electronics Charge for custom audio transformer designs?

We do not charge for custom audio transformer designs, however, we do keep the design as proprietary. There is a reason for not releasing the design information. We want to keep you as a customer and we want our competition to work hard to find our design techniques. For the most part the custom audio transformer is not large quantity and it fits our design and production techniques.

Click to expand...

So, do you guys think that a company that normally makes a $8 transformer http://www.edcorusa.com/transformers/audio/matching.htm might be able to make a decent knock off of a API 2503? They don't charge for custom designs and don't have a min. order.

Food for thought.

Cheers,

elco

Hi Elco,

I can try to answer your question "What makes a API 2503 (or Profile 4804) special"

The orginal API 2503 is a 75 ohm primary to 3 of 75 ohms secondary winding (aprox 7 ohms DC- resistance per windings)
The transformer is a quad filar type, made with litz wire winding technique and all windings are in same litz-wire as four cooper wire twisted togheter, so you have no particular primary or secondary windings, all have same behavior.

This type of transformer have very good HF-property and have a bandwidh upp to mHz, bacause the perfect phase response (aprox +/- 1 degree/10Hz to 100kHz) it have very good transient response, but the low level distortion and the high level low frequency distrotion is not so good.

I think the API 2520 op-amp that have a lot of output current, and the good transient response and maybe some THD that the 2503 transformer have, it´s the part of the famous API sound.

BTW, I have don some measurment on the "clone 4804 transformer" and it´s near same specifications as the orginal 2503, but it have some ohms higher DC-resistance per winding. (9 ohm insted for 7 ohm)

--Bo

Does anybody have that old RO thread saved where CJ disected the 4804 from James' group order. I seem to recall that CJ had all the nitty gritty details about this transformer.

elco

Bo,

Thanks for the info.

elco

Elco,

I think CJ have this great info on his hompage (I don`t remember the link)

I have some BW copy that I have save in my archive, but it is better you ask CJ.

--Bo

Yes,

"Mr Vacuumbrains" pages reveal lots of nice things:

CJ's API Pics



Mark[/url]

Hey, if EDCOR is willing to work with us, with the information we can pump into them, we just might have one heck of a supplier. It's worth asking, anyway, and it's worth a try.

I know I had no problems asking for custom windings, but it was using their existing designs. I never went as far as custom designs.

Why not just buy CJ all the tools he need then he can earn his livin' of making transformers for the group? :wink:

now that would be nice. This man deserves it.

He have been exploring the vintage transformers for a long time now.

It´s time to start manufacturing, CJ.

Count with me for donations, if you are going to buy all the tools you need.

Now this is what I call an interesting turn of events. :green:

I guess now we just have to wait and see what CJ has to say about it. :wink:

[quote author="Consul"]Now this is what I call an interesting turn of events. :green:[/quote]

Yes, but how many turns and at what impedence per turn? :razz:

Chris

Profile still manufacturing transformers with litz  available to order @  http://www.profileelectronics.com/


Profile

WAhts the price for the profile transformers!!!!???

Interesting read:

http://www.gearslutz.com/board/high-end/34975-api-transformer-legacy.html

Seems Profile screwed the pooch on the transformer and couldn't make it sound right(vs the old one with the Litz wire). AFAIK, Cinemag is doing all the API stuff now. Whether it's what is offered to consumers, i don't know...and somewhat doubt.

desol said:

Interesting read:

http://www.gearslutz.com/board/high-end/34975-api-transformer-legacy.html

Click to expand...

Ha, at gearslutz:
Currently Active Users Viewing This Thread: 7 (5 members and 2 guests)
kato, drpat, keefaz, peterc  -- hi guys

Damn... ;D Hi Kato

Wish I was in Jamaica...... Freezing my axe off here..

how compare these to CAPI 2503?

Quite an old post, but I would guess CAPI's are as true to spec as possible.  He has litz windings on offer and recently added some high-nickel content versions too.  In my humble experience of Edcor vs CAPI, you tend to get what you pay for.