khstudio

My 3 DUAL PULTECs - EQP-1a3 - Solid State
« Reply #60 on: October 16, 2008, 02:46:19 AM »
CJ,
Good info. :thumb:

Quote
kh, did you fix the clipping, or do you just watch your levels on the hybrid input?


Well, it's not really clipping, I just can't turn the high boost up as high or I do like you said & watch my input levels.

I did some general measurements & it seems that with the original Input TX setup, with the 620 secondary loading, the level drops approx 3-5dB.
So... 2 things happen from this:
1 - you hit the circuit  & Inductor a little harder
2 - the output amp levels have to be turned down to compensate for "Unity Gain" from input to output.

Pat said the original had a slight boost when going thru the unit in bypass... I think 1dB or so.

I set mine up with NO boost.

I tried to add the 620ohm resistor after the HYBRID & NOTHING happened.
Joe said this is right... that the HYBRID is so strong that the 620 does nothing but add distortion & pulls the amp out of class A towards AB.

For those of you who are building a Pultec or Passive EQ:::


There are SO many items that add up to the "Mojo"
I never planed on making mine exact but did want to try to get as close as I could. & I can say without a doubt, that my "BLUE" unit definitely has some "Mojo" that my other units don't!
But , they don't suck & are Killer too, just different, which is why I keep saying the circuit/passive EQ is just cool & you can set it up SOooooooooooo many different ways & STILL have a great piece of gear.

Take it from me... DON"T sweat all the details UNTIL you actually build one :!:  :!:  :!:
It doesn't matter if it's "Just like a Pultec" or not, as long as YOU have a working unit to try out different components & hear the changes yourself.
You will never understand what the different caps, inductor, TX's, etc... will sound like until you try it yourself. :wink:

You'll learn a lot & be able to tune it the way YOU like.

I expected to like my BLUE unit so much more than the others that I'd want to make them ALL the same... I was wrong.
But don't get me wrong... the BLUE units high boost (using the inductors I wound) is my favorite of the high boosts of all three units.

These 3 stereo Pultecs/Passive EQ's are among my absolute favorite pieces of gear I've built... & I've built a LOT of stuff.
I used EVERY channel on the last 3 mixes I did... just Killer!!!
Kevin ~ KHStudio


CJ

My 3 DUAL PULTECs - EQP-1a3 - Solid State
« Reply #61 on: October 16, 2008, 04:03:13 AM »
A triple bypass would be great.
No, not heart surgery, although I could probably use some, I mean a rotary switch:

1)  Total Bypass
2)  Line Amp Only
3)  Eq Section and Line Amp


Yes on just build something.

Remember when everybody was hot on the Calrec with the Tants?
Freaked me right out.

I would not have guessed that the order you put the filter components in would affect the sound.

Since this is AC we are dealing with, the signal hits cap first, inductor first.

So would not it be the same?

Manleys has it opposite.
I built mine stock.

Maybe because of the single ended nature of the filter section...
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

khstudio

My 3 DUAL PULTECs - EQP-1a3 - Solid State
« Reply #62 on: October 16, 2008, 03:53:40 PM »
Quote from: "CJ"


I would not have guessed that the order you put the filter components in would affect the sound.

Since this is AC we are dealing with, the signal hits cap first, inductor first.

So would not it be the same?

Manleys has it opposite.
I built mine stock.

Maybe because of the single ended nature of the filter section...


There is a definite difference in the sound when you change the order... I remember posting about it a few times.
Are you referring to my comments about the order or did you try it yourself?

BTW... it's good to see you back CJ.
You seem pretty chill lately.   :cool:
Kevin ~ KHStudio

CJ

My 3 DUAL PULTECs - EQP-1a3 - Solid State
« Reply #63 on: October 16, 2008, 04:18:53 PM »
Yes I am all better now.

Less BS, which will be more boring, but easier on the forum members.
 :green:
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

noulou

My 3 DUAL PULTECs - EQP-1a3 - Solid State
« Reply #64 on: October 16, 2008, 04:33:27 PM »
Quote from: "khstudio"


Pat said the original had a slight boost when going thru the unit in bypass... I think 1dB or so.



Maybe
this has something to do with the fact that so many people seem to love original pultecs on bypass! According to my experience 1dB louder always sounds better.

Just a thought.

khstudio

My 3 DUAL PULTECs - EQP-1a3 - Solid State
« Reply #65 on: October 16, 2008, 04:42:23 PM »
Quote from: "noulou"
Quote from: "khstudio"


Pat said the original had a slight boost when going thru the unit in bypass... I think 1dB or so.



Maybe
this has something to do with the fact that so many people seem to love original pultecs on bypass! According to my experience 1dB louder always sounds better.

Just a thought.


Trust me... it's not just the added gain.
You've got several components like a 2520, Tant cap, Large 1uf cap + in & output TX's the signal is passing thru (I'm referring to the SS Pultecs myself) the TUBE version has even more & different components... like Tubes, for one  :razz:
Kevin ~ KHStudio

khstudio

My 3 DUAL PULTECs - EQP-1a3 - Solid State
« Reply #66 on: October 16, 2008, 05:21:15 PM »
Quote from: "CJ"
Yes I am all better now.

Less BS, which will be more boring, but easier on the forum members.
 :green:


It's all about balance. You can be so damn helpful & one of the smartest people around here. It took me a long time to understand you... so don't change too much... you just don't have to be so mean (like one thread I read.)

I've learned a lot from your posts & appreciate the time you take to share your knowledge.  :thumb:

Hey, when you say the NEW cores are a lot stronger... are talking Ferrite or Iron Powder core?

The Cinemags are much more... ahh, "Linear" sounding - Cleaner, more accurate to me.
But these Iron Powder Core's with 1300 windings have this flavor that is Very Musical & will "Break-up or "drive" when pushed (in a cool way).

Also, Pats Original Pultecs has the Cap BEFORE the inductor.
But a friend of mine let me rip open his TUBE TECH Unit & it had the Inductor 1st.

Both sound cool but different... I really wanted to put a switch on mine but didn't. :sad:  Very easy mod to add.
& for anyone that missed my comment about this:

The Inductor first sounded more "Vintage" & mid-range focused or colored.
& the Cap first was more "Open" sounding & seemed to (maybe) be a little more useful all around... if that makes sense.

BTW... I THINK Pat said that the LANG "May" be  Inductor first... like the Tube-Tech. Have to ask him again to be sure.
Kevin ~ KHStudio

CJ

My 3 DUAL PULTECs - EQP-1a3 - Solid State
« Reply #67 on: October 16, 2008, 07:10:12 PM »
I still have this, I think Rafa is to thank, maybe Canadia Greg, I forgot:

No wait, IJR, right!
Where the heck is he anyway, working for Hesbola   or something?

http://i37.tinypic.com/25ix0dx.gif

Since we like to split atoms on all our DIY, which is why we are the best in town, which side does the foil lined up in the Pultec caps, I bet Pat wrote it down.
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

khstudio

My 3 DUAL PULTECs - EQP-1a3 - Solid State
« Reply #68 on: October 16, 2008, 10:30:56 PM »
CJ... that's cool. :thumb:

I've been trying to get Pat back around here but he's so damn busy... He does live around Arnold so...... "He'll be bock"
Kevin ~ KHStudio

CJ

My 3 DUAL PULTECs - EQP-1a3 - Solid State
« Reply #69 on: October 17, 2008, 01:59:30 AM »
Yeah he's putting the finishing touches on that Papa Roach live album.

There was talk about the Torwico being the Pultec core also.

There is a thread around here somewhere about that.
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


khstudio

My 3 DUAL PULTECs - EQP-1a3 - Solid State
« Reply #70 on: October 17, 2008, 08:17:57 PM »
CJ... I need your help!

Sent you a PM yesterday. Did you get it yet?

Anywho,

I just got a pair of the Sowter 9820 & can't find any info about HOW they should (or shouldn't) be Loaded on the secondary.

Are they meant as a "Drop In" replacement in the API 312?

Meaning - Should the ZOBEL network be set up the same as the original 2622 TX???

I have spoke with a few guys that just use the original Zobel values & No secondary loading but it's never been mentioned ANYWHERE if the Sowter 9820 input TX needs different loading or compensation.

I thought you might be able to help me because (I Think) you helped Brian with these.

Thanks man,
Kevin
Kevin ~ KHStudio

CJ

My 3 DUAL PULTECs - EQP-1a3 - Solid State
« Reply #71 on: October 17, 2008, 08:37:56 PM »
You can do a freq plot of the transformer out of circuit, see if it has a bad rise that needs squishing.
Don't bother with the bass, just sweep it from 10K to 100K.

If the Sowter has the same peak,  put it back in the circuit and tweak the zobel values til you get a compromise between lost mid range and no major resonant peaks.

Here is the orig freq plot, out of circuit.
Sweep the Sowter and see if it matches.
If so, then just slap the stock network on there.

I think he tries to get the vintage stuff as close as time and materials permit.
Although sometimes he improves the iron if the original had stuff that could be made better.
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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