drpat

Solid state Pultec EQP1A power supply... New
« on: June 12, 2007, 07:07:14 PM »
...
« Last Edit: September 17, 2010, 09:46:26 AM by drpat »
I use the LA2a on very hot signals like lead vocal.


Kamel

Solid state Pultec EQP1A power supply...
« Reply #1 on: June 13, 2007, 02:39:35 AM »
the output B+ of the gyraf pultec is given by the ac output of the second transformer, and the voltage drop of the 3k3 2W,increase the ac value to have more than 325v, around 350v rectified and calculate with ohm's law tne value of the drop resistor to get 325 with the current needed, be carefull to take right voltage caps and right diode or bridge rectifier voltage

drpat

Solid state Pultec EQP1A power supply... New
« Reply #2 on: June 13, 2007, 04:46:59 AM »
...
« Last Edit: September 17, 2010, 09:46:44 AM by drpat »
I use the LA2a on very hot signals like lead vocal.

Kamel

Solid state Pultec EQP1A power supply...
« Reply #3 on: June 13, 2007, 05:23:23 AM »
9 to 220 or 2x110 is fine too, and easier to find
that's real the 2nd transformer will overheat a little beat, but i'll do that in the G9 to get more HV, 220-15v--->12v-220v as it's write inthe G9 meta thread, and i've got no problem
Jakob is a pragmatic man, and he found a lot of good tips, thanks Jakob :guinness:

CJ

Solid state Pultec EQP1A power supply...
« Reply #4 on: June 13, 2007, 01:24:12 PM »
just put the rectifiers in there, fire it up for a few seconds so the caps don,t blow, recoed the B+, if it's under the cap rating, let it go like that.
You will only gain more headroom and less noise with the higher B+.

The engineers would have loved to get the voltage higher, but they were told that the transformer has to be cheap!
(less sec turns) so db wise, the went for bottom dollar.

use the octal socket/plug connecotrs, available at Allied.
8 and 11 pin, for stereo/crosstalk.
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

drpat

Solid state Pultec EQP1A power supply... New
« Reply #5 on: June 13, 2007, 08:46:10 PM »
...
« Last Edit: September 17, 2010, 09:47:19 AM by drpat »
I use the LA2a on very hot signals like lead vocal.

Sender

Re: Solid state Pultec EQP1A power supply...
« Reply #6 on: June 14, 2007, 12:43:03 AM »
Quote from: "drpat"
I'm taking on the daunting task of shrinking a 3space EQP-1A clone into a single rack space. My question is actually a two part question...

1. I want to forego the tube supply for a solid state supply. This will require a 325V feed and 6.3V to the heaters. Has anybody built a supply of this sort that has some insight or a simple way to go about this?

2. I want to make the power supply external for noise and real estate purposes. I know that this is done for tube mics all the time, I'm just looking for insight on adequate connectors and cable to carry the 325V to the EQ.

I've looked at the METAs, and the GYRAF Pultec power supply is the closest thing I've found, but the voltages are much lower that the requirements that a Pultec needs. Any help will be appreciated, and harsh truths are especially appreciated...


Manley makes several one rack space pultec style eq's that are one rack space, with the power supply included. Perhaps you can go there for inspiration??

I don't know if it's solid state or not....

drpat

Re: Solid state Pultec EQP1A power supply... New
« Reply #7 on: June 14, 2007, 04:12:36 AM »
...
« Last Edit: September 17, 2010, 09:47:35 AM by drpat »
I use the LA2a on very hot signals like lead vocal.

Sender

Re: Solid state Pultec EQP1A power supply...
« Reply #8 on: June 14, 2007, 12:13:01 PM »
Quote from: "drpat"
Yes, I've used them, and was very UNinspired...

Besides the Manleys, there are a lot of other one rack space EQs out there that don't sound like Pultecs, but decided to put the name on there anyways. I think some of them (Manley "Pultecs")  are even transformerless :? That's like building a transformerless Neve, and slapping the slogan "Neve style EQ" on the front panel! Pure marketing BS to lure the idiots to buy something that says "Pultec" on it. I would guess that the majority of people who bought these things have never heard a Pultec, so what they don't know, won't hurt them, right?

What does all this ranting have to do with anything here? I don't know, I'll shut up now...

Do you have a schematic :green:


The first 100 were made w/o a transformer. The later ones have a three way switch on the back. Two of the positions are phase flip and the other one is xformer bypass.

I don't, let me see if I can get one.


btw, I like them! :green:

CJ

Solid state Pultec EQP1A power supply...
« Reply #9 on: June 14, 2007, 02:40:49 PM »
I'll trade you a brand new HS 29 for that beat up 217!!!
Please! Pretty frikin please!
I will resign Papa Roach to your studio, Beverly Hills is doing them in.
 :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


drpat

Solid state Pultec EQP1A power supply... New
« Reply #10 on: June 14, 2007, 04:54:39 PM »
...
« Last Edit: September 17, 2010, 09:48:04 AM by drpat »
I use the LA2a on very hot signals like lead vocal.

CJ

Solid state Pultec EQP1A power supply...
« Reply #11 on: June 14, 2007, 05:13:37 PM »
FIY, I A/B ed the Sowter rerplacement against the HS 29, and heard no difference. This is partly due to the relaxed ratio, 1:2, or similar.
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

drpat

Solid state Pultec EQP1A power supply... New
« Reply #12 on: June 14, 2007, 09:15:54 PM »
...
« Last Edit: September 17, 2010, 09:48:18 AM by drpat »
I use the LA2a on very hot signals like lead vocal.

CJ

Solid state Pultec EQP1A power supply...
« Reply #13 on: June 18, 2007, 06:56:56 PM »
the only transformer not in my closet is the 217 D.
Thats all I am interested in. Kayaking, and the 217 D.
Nothing else matters.

I paid Andy 250 bones for that HS 29.
I took one apart even. The thread is around here somewhere.
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

drpat

Solid state Pultec EQP1A power supply... New
« Reply #14 on: June 18, 2007, 11:56:22 PM »
...
« Last Edit: September 17, 2010, 09:45:49 AM by drpat »
I use the LA2a on very hot signals like lead vocal.

CJ

Solid state Pultec EQP1A power supply...
« Reply #15 on: June 19, 2007, 06:55:34 PM »
sowter actually sounded better, but don't tell anybody.
i dont want this 29 to de preciate.
something about a little more twinkle on the high end.
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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