CJ

610 Input
« on: January 19, 2020, 03:59:59 PM »
1:7

pri dcr 24  sec dcr 1.3 k

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


CJ

Re: 610 Input
« Reply #1 on: January 19, 2020, 04:01:25 PM »
that was just a decoy,

upper response goes like this>
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

CJ

Re: 610 Input
« Reply #2 on: January 19, 2020, 04:06:15 PM »
sq wave into pri, scope on sec,
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

CJ

Re: 610 Input
« Reply #3 on: January 19, 2020, 04:15:08 PM »
180 phase swap at around 95 KC

this could make the preamp unstable unless compensated for,

note that this xfmr was sent because it had issues, so maybe we can rewind and retest,
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

CJ

Re: 610 Input
« Reply #4 on: January 19, 2020, 04:24:01 PM »
shield wire was just hooked to the can so probably no e shield inside, but you never know,
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: 610 Input
« Reply #5 on: January 19, 2020, 09:11:43 PM »
This was made by Cinemag yes? 
Then it should be the same as the "Winston O'Boogie" (thanks for the credit dude :) ) Cinemag that you uploaded data on a coupla days ago, with the addition of a primary tap for 50 ohm sources.
Take that bastard apart, I'm curious if it's still the same.
 

Re: 610 Input
« Reply #6 on: January 19, 2020, 09:31:03 PM »
P.S.  If it is the same beast, then it's a nice transformer.  But then, I would say that. 
 
I originally worked with Marco @ Reichenbach Engineering on this so he should probably get more credit here than me.  This was a few years before Tom took over the assets and the company became Cinemag.   
I wanted something with a beefier core than the standard  fare available at the time and I actually initially went further and had some made with EI 625  lam but, for what I wanted it for (REDD47), these 375 lams worked fine so I saved the spondoolies.

I  then used the same transformer for all the UA  pre amps I did when I went there, I just ordered something I knew worked,  with the addition of the 50 ohm tap to compete (slightly) with the Groove Tubes VIPRE.   



mjrippe

Re: 610 Input
« Reply #7 on: January 19, 2020, 10:51:06 PM »
It was made by Cinemag but dubbed the IT-610 or some other dumb name.  From a 20something UA 2-610. 

Re: 610 Input
« Reply #8 on: January 19, 2020, 11:12:20 PM »
It was made by Cinemag but dubbed the IT-610 or some other dumb name.  From a 20something UA 2-610.

OK got ya.   Then it's almost certainly a Cinemag CMMI-7C which is the same part I was prattling on about  :D

 3 X primary windings in parallel, and 2 X secondary in series. 
C.J. should absolutely find electrostatic shielding in there.   It's definitely worth rewinding/fixing anyway.
 

CJ

Re: 610 Input
« Reply #9 on: January 20, 2020, 03:13:28 AM »
might be tough to fix,

potted so we we had to cut the can,

then air dry epoxy on the lams, so all we could do was snip the tops of the e lams and remove i bars,

have to figure out a way to get the tongues out of the mouth or hook up a mandrel to the wreckage, maybe drill thru the center,

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: 610 Input
« Reply #10 on: January 20, 2020, 09:01:45 AM »
might be tough to fix,
 

A sacrificial offering,  ritualistic slaughter type thing then. 

 

Re: 610 Input
« Reply #11 on: January 20, 2020, 02:06:41 PM »
In nomine patris et filii et spiritus sancti  ;D

mjrippe

Re: 610 Input
« Reply #12 on: January 20, 2020, 02:52:41 PM »
Are UA so secretive that they would do this on purpose, Mr. O'B?  Or is it done for some reason mechanically/electrically that is beyond me?

CJ - do your worst, this is a sacrificial lamb.

Re: 610 Input
« Reply #13 on: January 20, 2020, 03:38:30 PM »
Are UA so secretive that they would do this on purpose, Mr. O'B? 

No, I don't think so.  They would certainly go so far as to have their own part number as in IT-610  over using the CMMI-7C designation, but that's common for most manufacturers to do this, throws the other guys  off the scent  :D

But they would have had no say in how it was made, nor have bothered asking Cinemag to pot the thing so it's impossible to get at.

This *may* have been something that dear departed Tom Reichenbach did to protect his products.   It's not unheard of that a company has a good winder like Cinemag make a prototype run of a transformer and then, send a few of those prototypes out to discount shops to see if it can be had cheaper.  I know for a fact this happened with other transformers initially wound by Tom and I can understand if he wanted to make that more difficult to do
Winding a few new prototypes isn't really that profitable unless you then get to sell  a larger quantity after the fact.   Try getting Jensen to make a few 1:7 large core input transformers for you to try out and you'll see.  No offence meant against Jensen's  business decisions or products intended here.

Anyway,  looking forward to seeing what C.J. turns up...

Thanks mjrippe for donating to the cause, your next pint or two is on me :)
« Last Edit: January 20, 2020, 03:41:49 PM by Winston O'Boogie »

CJ

Re: 610 Input
« Reply #14 on: January 20, 2020, 03:48:29 PM »
this is standard procedure nowadays, Jensen uses the same stuff,

wax is great but the air dry epoxy is a lot less hassle,

only complaint is you are not supposed restrict nickel lams as it can cause distortion,  but maybe the input level is too low to matter,

Ollie sent me a V76 input and i asked him if i should varnish dip it, as it had nothing around the windings, he said "please, no potting compound!" and explained all about magnetorestriction. if you look at all the V series transformers,  most do not have any type of compound used except the varnish used on the discs. but the core stays pretty much naked.
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

mjrippe

Re: 610 Input
« Reply #15 on: January 20, 2020, 04:51:04 PM »
Hey Mr. O'B, you can call me Mike.  I'm off the sauce but appreciate the gesture.  I am always looking to learn, and you have a lot of first hand knowledge so it is a pleasure to meet you here.

CJ, I have heard of magnetorestriction but as you mention it seems unlikely to be an issue at small signal levels.  Is it more of a power transformer issue or would it relate to say power amp output transformers as well as line level outputs?

Re: 610 Input
« Reply #16 on: January 20, 2020, 06:46:58 PM »
 Heya Mike, OK  pizza or a burrito or...   :)

I'd be very interested in knowing if restricting the lams is affecting things at these levels.  The V72/V76  transformers are certainly no slouches.  There must have been very good reasons for them to use larger lams,  wind them sectionally,  and leave them un-potted.  Certainly wasn't easier to make 'em that way. 


CJ

Re: 610 Input
« Reply #17 on: January 20, 2020, 07:37:33 PM »
Telefunken used a lot of Cobalt lams, Cobalt has the highest magnetorestrictive figures of all the elements, 60 microstrains, this might be the reason they did not process the lams, plus, nickel does not rust like regular steel lams,

while sanding the rough edges of the bobbin, the heat allowed the center section of the core to be pushed out so we have some Brazilian hardwood in there for a mandrel,
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

mjrippe

Re: 610 Input
« Reply #18 on: January 20, 2020, 08:35:22 PM »
Wait, Nickel... Cobalt... all we need is Aluminum and we're back to that OTHER Jensen product the AlNiCo loudspeaker magnet and magnets and coils and round and round it goes :o  So didja get it unwound yet?

CJ

Re: 610 Input
« Reply #19 on: January 20, 2020, 11:29:21 PM »
looks like the bk shield wire got shorted to the secondary splice,

so we had signal transfer as the blk lead was not grounded to any circuit,

that garbage sq wave is usually a sign that the shields are goofed up,

we measures  581 ohms blk to yel and 714 ohms blk to  grn, which would indicate a CT with thin wire as the DCR gets larger the further you get from the center.

so i bet yel is a start and grn is a finish,
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


 

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