CJ

UTC A-25 Plate to Line Blueprint
« on: January 10, 2019, 03:44:16 AM »
rework of old print

finding the lams could be a problem 

could fit on a 50 EI lam if you use a nylon bobbin and play with the wire sizes (drop down a gauge)

no tear down pics at this time...

https://img1.wsimg.com/blobby/go/0e07cc59-2f5a-481f-967d-12c7363b86fa/downloads/1d0thj5dj_385871.png
« Last Edit: January 11, 2019, 04:53:34 AM by CJ »
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html


scott2000

Re: UTC A-25 Plate to Line Blueprint
« Reply #1 on: January 10, 2019, 10:24:56 AM »
how is the "x" aquired? Is it a point inside? is this the air gap I've read about?
 Also, I've read about adding a virtual center tap to single ended secondaries.... Is there any way to do one on the primary side??? I'm guessing there are reasons not to... Just curious..

And why is aquired and attenuator spelled wrong here (red squiggles) ...... used to be impedance too iirc but it seems fine now???
« Last Edit: January 10, 2019, 10:47:20 AM by scott2000 »

rackmonkey

Re: UTC A-25 Plate to Line Blueprint
« Reply #2 on: January 10, 2019, 11:05:32 AM »
Cool, cool. Thanks, CJ! Keep em comin.

what method of measuring primary inductance have you settled on these days? So many techniques discussed over the years.
Whether you think you can or you think you can't, you're probably right.

CJ

Re: UTC A-25 Plate to Line Blueprint
« Reply #3 on: January 10, 2019, 07:15:52 PM »
"x" is a splice,

i used the inductance formula on this one, using a u-eff of 20,000 for 49 Ni alloy,
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

scott2000

Re: UTC A-25 Plate to Line Blueprint
« Reply #4 on: January 10, 2019, 09:52:46 PM »
Thank You!

CJ

Re: UTC A-25 Plate to Line Blueprint
« Reply #5 on: January 10, 2019, 11:20:47 PM »
fixed the print marked "splice x"  and adjusted inductance as this is a gapped core , doh on me,   :o

https://img1.wsimg.com/blobby/go/0e07cc59-2f5a-481f-967d-12c7363b86fa/downloads/1d0thj5dj_385871.png

A-26 is similar only with non gapped core  and it has a CT for P-P operation ala Pultec EQP

If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

Re: UTC A-25 Plate to Line Blueprint
« Reply #6 on: January 10, 2019, 11:39:25 PM »
<used in the Pultec MEQ-5>

Where? I though MEQ-5 used Triad HS56 and HS50. No DC.

CJ

Re: UTC A-25 Plate to Line Blueprint
« Reply #7 on: January 11, 2019, 04:56:26 AM »
man i am getting old that's right Triad HS 50,

HS 52  and UTC  A-26 in the Fairchild, A-24 in the LA2a, right?  :P

A-25 in the Collins perhaps?

don't know which chassis ,   howabout Gates, could i get a list of every transformer they ever used please?   :D
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

Re: UTC A-25 Plate to Line Blueprint
« Reply #8 on: January 11, 2019, 11:45:48 PM »
No worries. I’m getting old too. That was a “proud moment of clarity”. :P

 

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