CJ

31267 optimal wiring in the solid state Pultec
« Reply #40 on: January 30, 2007, 05:55:48 AM »
Have you ever seen a picture of Tiger Woods?
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


hejsan

31267 optimal wiring in the solid state Pultec
« Reply #41 on: January 30, 2007, 06:29:30 AM »
If I'm deciphering CJ correctly, there is more to the 31267 than this datasheet you have is telling, so try hooking it up like he suggests..

hejsan
Just remember -- if the world didn't suck, we would all fall off.
Quote from: "Butterylicious"

CJ

31267 optimal wiring in the solid state Pultec
« Reply #42 on: January 30, 2007, 06:40:18 AM »
I was being a smartass leading down the road of Tigers Nike shirt.
What's the Nike slogan- just do it, but I can see that it was turning into a long trip for little.

Its right there on the data sheet.
Pri Par-2.4 K
Sec Ser 2.4 K

2.4 K is not the impedanxe of the transformer, it is the impedance of what was originally hooked up to the input of the transformer, which was probably a resistor ladder of some sort.

So ignore the 2.4 K
Get a Sharpie and write "600" on it if it makes you feel better.

Only the turns are not exactly 1:1, so you get a 10 percent bonus.

You could also flip it for 1:2 if you need more gain.
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

Purusha

31267 optimal wiring in the solid state Pultec
« Reply #43 on: January 30, 2007, 07:35:43 AM »
I know, sometimes ego can get in the way  :green:

OK, that sounds more clear now, thanks for the tip.  :thumb:  :thumb:  :thumb:
Regards as always, Purusha

CJ

31267 optimal wiring in the solid state Pultec
« Reply #44 on: January 30, 2007, 08:24:36 AM »
"I know, sometimes ego can get in the way "

No, sometimes lack of brain power can get in the way.
If I wanted to be egotistical, I would have laid some of this on ya to try an explain the change in sound, but linear algebra comes after differential equations which comes after calculus, which comes after trig, which comes after algebra 2 which comes after geometry which comes after algebra one which comes after grade school math, where are you on the food chain so I know how to talk?

Take the determinent of line four, and you will have your answer.

 :grin:



I mean, here is 700 pages of heavy stuff, just on the metal the lams are made out of:

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

Purusha

31267 optimal wiring in the solid state Pultec
« Reply #45 on: January 30, 2007, 08:40:30 AM »
CJ, I wasn't thinking to add my remark in a bad or negative way :grin:

But it's true that sometimes people who got better brain from God look
down on others (like me) with much less brain . But this is all so temporary,
one life time you have brain like Einstein, next life time you are a brainless
frog, it's all just good and bad karma and the brain is a gift from God anyway
so one should never be proud of what he's got cause he may loose it in one second.

Back on the topic. I admire your waste knowledge CJ and appreciate it when ever I get
some little information and knowledge here. I think this forum was meant for this in the
first place.  :thumb:

Peace  :grin:
Regards as always, Purusha

CJ

31267 optimal wiring in the solid state Pultec
« Reply #46 on: January 30, 2007, 08:44:17 AM »
Don't worry, Im still in wise ass mode, not trying to be mean, just using your thread to brag about all the cool xfmr books I found today at Stanford Eng.
Check this action:

and its 5:48 am over here, so I feel weird.

Check this action:





Heck, even I cant understand a word of this guy, waaay to thick.
My brain, that is.



Look at this, a whole book just on core loss:



And another one!



This one gets the weirdest  xfmr book of the year" award:

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

Purusha

31267 optimal wiring in the solid state Pultec
« Reply #47 on: January 30, 2007, 09:11:28 AM »
I am not impressed at all :green:

Check out my literature  :grin:



It's all about the one who is behind this material creation and his existing laws  :wink:
Regards as always, Purusha

31267 optimal wiring in the solid state Pultec
« Reply #48 on: January 30, 2007, 09:16:35 AM »
Quote from: "CJ"
They have 36 CD's with the Feynman Lectures.


man i love those discs for roadtrips, my old roommate/goodfriend has them on mp3.   awesome lectures.

anyway....   check this out purusha....  if you hook up a transformer output micpre with a true, exact, 600 ohm ouput (source) impedance into the pultec, and your pultec is wired 2k4:2k4, than the pultec will, after that transformer, see 600 ohms (for the most part.)

If you have the same scenario, but with a a real and true 10k ouput impedance source, and put it into the pultec wired 2k4:2k4, the pultec, after the input transformer, will see 10k (more or less).

transformers dont have an actual impedance...  the reflect whatever you put into them.   HOWEVER...  this "inductance" that gets brought up is a measure (in Henries) of the transformers core.  If you have too few Henries, you will get bass loss and things like that *if* your output impedance in the stage before is too high.

so the number they put on the transformer is a measure of inductance really, and the idea is that if you stay under (preferably 1/10th, if you don't wanna do any serious math) the rated impedance, you'll be ok and you'll get full voltage transfer and your entire signal will pass correctly.

so consider those numbers maximums.  now heres the clincher on passive eqs and the pultec filter section.  passive eqs must be designed for a particular impedance for them to work correctly.  the pultec filter section is designed for 600 ohms.  if you are *over* that, at the point between the first pot of the filter and the secondary of the input transformer, it won't work the way it should, regardless of how the transformer is wired up.

the idea with this pultec stuff is that sometimes you'll be coming out of modern equipment that can't drive a true 600 ohm load.  when that happens, the filter won't work correctly if the transformer is wired 1:1.  but if you have a 10K impedance output, and you want the pultec to work the right way, you'll need a 10K:600 transformer.    It coul also be 2k4:150.  The point is that its a 4:1 ratio transformer, which transforms impedance to the square, so 16:1.  

The point is insurance that regardless of the equipment that is right before the pultec, it will work correctly.  You may have to makeup more gain because of the stepdown, but the usefulness of the eq in the long run with different gear will be way more worth it than compromising for available gain.  gain is cheap.  strange sonics, if you have clients to please, is not cheap.

i'm not the expert by any means, but i would do one of two things... either wire for max stepdown on the input transformer and get more gain, OR, wire it 2k4:2k4, but be prepared to drive it with gear that can (and does) drive 600 ohms.

a buffer box of some sort could come in handy in the latter scenario.  something that steps down impedance and possibly also retores that lost gain. (line amp)

for the times when it sounds wierd and doesnt make any sense.

i tried......    tell me if i have to edit any mistakes up there

Purusha

31267 optimal wiring in the solid state Pultec
« Reply #49 on: January 30, 2007, 09:28:18 AM »
Thanks for the explanation enthalpystudios.  :thumb:

Quote
i'm not the expert by any means, but i would do one of two things... either wire for max stepdown on the input transformer and get more gain, OR, wire it 2k4:2k4, but be prepared to drive it with gear that can (and does) drive 600 ohms.


So wiring it -6db would be a bad choice? Didn't understand you on this one.
Regards as always, Purusha


CJ

31267 optimal wiring in the solid state Pultec
« Reply #50 on: January 30, 2007, 09:29:36 AM »
You think that  sounds weird, look at this.
Great post BTW:

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

hejsan

31267 optimal wiring in the solid state Pultec
« Reply #51 on: January 30, 2007, 09:43:23 AM »
I have one question then, since the EQ is designed to sound correct with 600 ohms, and will sound bad *over* that, can I assume it will sound just normal *under* that?
Like if I used a 10k:600 which was then driven by a true 600 ohm output of some other gear, it would look like ~40 ohms to the eq section..right? or is it 150?

Thanks for the small essay enthalpystudios, it makes the fact that some manufacturers only list the impedance ratio much clearer.
Just remember -- if the world didn't suck, we would all fall off.
Quote from: "Butterylicious"

Purusha

31267 optimal wiring in the solid state Pultec
« Reply #52 on: January 30, 2007, 10:12:05 AM »
I followed what CJ suggested by wiring it 1:1 and compared the sound to -6 wiring
... damn it really gives the extra mojo when freqs are boosted. I can't hear any difference
when freqs are on 0 boost but you can hear nice difference when you boost them.
Definitely gives more bass and up in the face highs. I like it :razz:

I think I will just keep it like this. Thanks guys.  :thumb:  :thumb:  :thumb:

One last question. How will I know if the impedance is too high for the 1:1?
Should I hear weird change in the sound immediately when I turn on the Pultec
but without boosting any freqs or when freqs are boosted? Inserted in my Midas it
sounds fine but u never know what gear will I connect before the unit in the future.
Regards as always, Purusha

31267 optimal wiring in the solid state Pultec
« Reply #53 on: January 30, 2007, 02:26:38 PM »
i honestly dont know about that one...  not sure how much of an effect there will be when the input is being loaded down...  BUT if you notice any funniness, loss of bandwith, or loss of level, than think about what gear is preceding.  if it sounds ok on your inserts, than you shouldnt have too many troubles ;]

besides, looks to me like the ouputs on the midas consoles are for the most part designed to a 75ohm output impedance.

so if you ever have a problem, say you have a compressor that you want to go into the nevetec, and it sounds f'ed up, just know that your board will work...  go out of the comp (or whatever) into a channel, and direct out into the nevetec, and then back to wherever it should go.  a little extra crap, but thats what i would do if i had an impedance issue with that eq, and if i had that board.


 

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