Located - source of NOS transistor audio transformers

Post new topic   Reply to topic

Go down

Located - source of NOS transistor audio transformers Empty Re: Located - source of NOS transistor audio transformers

Post by Codar on Wed Apr 03, 2019 2:57 am

I would just measure the resistance, the bottom end (as I call it) ten we have a few turns to the centre tap and then lots of turns to the top end, an internal cap usually around 180pF is under the can which is connected across top and bottom.

Now then, some circuits have the collector going to the centre tap, the supply going to the 'bottom end' the top end is left unused the 'tuned winding' other circuits may have the supply going to the centre tap while the collector is connected to the 'bottom end' as I call it.


The  mouser 455Khz 'cans'  The White IF can is - from bottom to centre pin is 2.7R, bottom to top is 6.4R while the secondary is 2.2R.... these figures will vary somewhat and gives a clue which end is the 'top' end.

The Red 'Ossy' coil I have, again from bottom end as I refer is 0.2R to the centre tap and from bottom to top is 3.9R, while the secondary is 0.22R, as you probably know these oscillator coils don't have an internal capacitor.


I've never tried passing 50mA through em' I'd be tempted just to measure the resistance because the wire is mighty thin.

I've got a Bonex and Cirkit catalogue with a load of Toko coil data in, if you want me scan some into a pdf file, let me know, they give all the turns, 'Q' and internal capacitors info.

Toko have stopped making coils, Spectrum is your best bet, http://www.spectrumcomms.co.uk/, they make identical Toko RF coils, not sure if they do I.F cans though, look under 'components.'

Dave.

Codar

Posts : 6
Join date : 2019-02-18
Age : 70
Location : Nr. Manchester

View user profile

Back to top Go down

Located - source of NOS transistor audio transformers Empty Re: Located - source of NOS transistor audio transformers

Post by Admin on Tue Apr 02, 2019 8:26 pm

Hello Dave,
I also have loads of 455kHz IF cans, but I am lacking data, or to be more accurate, I have conflicting data for the same type of cans.
I would really appreciate the e-mailed document.

I was seriously thinking about passing 50mA through the windings and measuring the voltage drop to find which end was which, then pulsing the current to find the winding directions.
In the batch I bought I received two 10mm "yellow" cans and it seems that they are the same but one has a tuned primary and the other has a tuned secondary.

Perhaps I should build a little AM IF amplifier to test them out? It would be a nice little project for me right now with limited facilities.  Idea

But I am still seeking the RED oscillator cans.

Very best regards and thank you for thinking about me.
/Harry - SM0VPO (EA/SM0VPO)

PS
british.inteligence.sweden@sm0vpo.com
or
hotmail@sm0vpo.com

(Do NOT correct them. They are spelled correctly. Both are genuine Arrow )
(Spammers don't reply to the first. People don't believe the second)

_________________
They say that money cannot buy you happiness. But if you want to prove this by experiment, then I volunteer to be the test-rabbit :-)
Admin
Admin
Admin

Posts : 732
Join date : 2012-11-24
Age : 67
Location : Märsta, Sweden

View user profile http://www.sm0vpo.com

Back to top Go down

Located - source of NOS transistor audio transformers Empty Re: Located - source of NOS transistor audio transformers

Post by Codar on Fri Mar 29, 2019 8:50 pm

I got some I.F cans from  Mouser... and some Red and Blue audio output /driver transformers. Got the data sheet, I'll Email to you.

Dave

Codar

Posts : 6
Join date : 2019-02-18
Age : 70
Location : Nr. Manchester

View user profile

Back to top Go down

Located - source of NOS transistor audio transformers Empty Located - source of NOS transistor audio transformers

Post by Admin on Tue Mar 19, 2019 9:22 pm

Hi you guys,
I am still seeking a source for the RED local oscillator coils used in the old MW transistor radios.
Located - source of NOS transistor audio transformers Cans-5

I managed to find the 455kHz IF cans, but yesterday I hit gold-dust  Very Happy

Remember the old two-transformer audio amplifiers? Well I found them in the UK. https://www.cricklewoodelectronics.com 
They are a little bit "pricey" but affordable. Based and delivers from the UK, so no "China Tax" like we have in Sweden or the USA.
Located - source of NOS transistor audio transformers LT44web
https://www.cricklewoodelectronics.com/LT44-Miniature-Audio-Driver-Transformer-20K-ohms-to-2-x-1K-ohms.html

This is the blue transformer upon which I based a phased SSB exciter to feed a four-phase RC ladder for the four-phase balanced modulator(s), see http://213.114.131.21/tx/p-ssb.htm. Now you have a source for them.

And the 3Ω output transformer:
Located - source of NOS transistor audio transformers LT700
https://www.cricklewoodelectronics.com/LT700-Miniature-Audio-Output-Transformer-1000-ohms-to-3.2-ohms-3.2-ohms.html

Very best regards from Harry - SM0VPO

_________________
They say that money cannot buy you happiness. But if you want to prove this by experiment, then I volunteer to be the test-rabbit :-)
Admin
Admin
Admin

Posts : 732
Join date : 2012-11-24
Age : 67
Location : Märsta, Sweden

View user profile http://www.sm0vpo.com

Back to top Go down

Located - source of NOS transistor audio transformers Empty Re: Located - source of NOS transistor audio transformers

Post by Sponsored content


Sponsored content


Back to top Go down

Back to top

- Similar topics

Post new topic   Reply to topic
 
Permissions in this forum:
You can reply to topics in this forum