3D "AIR" EQ - "Night EQ" PCB's Complete!

[Whoops]

oh Kevin,
thanks for clearing that out.

I understood that you were using a 15-0-15 transformer, but I thought that you had your rails also +15v and -15v.

So do your rails measure + and - 18 even though you are using an 15-0-15 transformer?

thanks

 

[khstudio]

So do your rails measure + and - 18 even though you are using an 15-0-15 transformer?

YES... & this is what's important!!!

You NEED enough headroom for the Regulators to work properly & I'm on the edge I'm sure.

Remember, me AC out of my TX was higher than 15v.

 

[SALSA]

Hi Whoops,

You might want to check out this very useful tool of Samuel

http://www.groupdiy.com/index.php?topic=21307.0

Cheers,

Mike

 

[outoftune]

sorry if this have been covered already, but...i have many questions. i built one of these myself and am finishing up 3 for a friend! very interested in this circuit and I really like the sound of it.

i've seen pics of this one ( http://www.electrical.com/item.php?page=5&pic=pictures/5-0.jpg )and a few other eq3's with different faceplates, just wondering if they are all the same internally? is the eq3 the same circuit as the eq3d, except with stepped pots? any other magic going on inside those?

has anyone here attempted to build one with the stepped gain controls?

i know khs said the mid point of his pots measured 47k, just wondering if this is with the pots in the circuit or disconnected?

also, regarding opamp selection for the eq3d: i know KHS said it uses JRC 5532's for the lower bands, and signetics for the 2.5k/air & the 5534. i have only been able to find NJM 5532's, no one seems to sell the JRC ones. are these essentially the same thing? i have TI 5532's in there now, but im interested to try something else. anyone have some JRC5532's they'd be willing to sell me?

one last thing, anyone happen to have a scanned copy of the manual for this? i would love to have a look.

and finally THANKS TO KHS, PETER C AND EVERYONE ELSE FOR THIS PROJECT!!! it sounds great, the air band is on all my vocal tracks! i've also had success with using this for some DIY mastering. even with the fixed bands, it can definitely help to clear things up.

 

[Whoops]

So do your rails measure + and - 18 even though you are using an 15-0-15 transformer?

YES... & this is what's important!!!

You NEED enough headroom for the Regulators to work properly & I'm on the edge I'm sure.

Remember, me AC out of my TX was higher than 15v.

Hi Whoops,

You might want to check out this very useful tool of Samuel

http://www.groupdiy.com/index.php?topic=21307.0

Cheers,

Mike

Thanks a lot for the information and for the link.

I was not even aware of regulators headroom.
I always assumed that if you wanted, for example + and - 18V, you needed a transformer with the secondaries 18-0-18.

I going to study more this subject now, and learn a bit.

thanks a lot

 

[outoftune]

sorry if this have been covered already, but...i have many questions. i built one of these myself and am finishing up 3 for a friend! very interested in this circuit and I really like the sound of it.

i've seen pics of this one ( http://www.electrical.com/item.php?page=5&pic=pictures/5-0.jpg )and a few other eq3's with different faceplates, just wondering if they are all the same internally? is the eq3 the same circuit as the eq3d, except with stepped pots? any other magic going on inside those?

has anyone here attempted to build one with the stepped gain controls?

i know khs said the mid point of his pots measured 47k, just wondering if this is with the pots in the circuit or disconnected?

also, regarding opamp selection for the eq3d: i know KHS said it uses JRC 5532's for the lower bands, and signetics for the 2.5k/air & the 5534. i have only been able to find NJM 5532's, no one seems to sell the JRC ones. are these essentially the same thing? i have TI 5532's in there now, but im interested to try something else. anyone have some JRC5532's they'd be willing to sell me?

one last thing, anyone happen to have a scanned copy of the manual for this? i would love to have a look.

and finally THANKS TO KHS, PETER C AND EVERYONE ELSE FOR THIS PROJECT!!! it sounds great, the air band is on all my vocal tracks! i've also had success with using this for some DIY mastering. even with the fixed bands, it can definitely help to clear things up.

anyone?

 

[SALSA]

profusionplc.com for JRC's

Cheers,

Mike

 

[Whoops]

Hi,
did anyone ever finished the Night EQ using stepped switches instead of Pots?

 

[rob_gould]

Nope but it's on my list!  I was going to use 1x12 Lorlins with 1db steps. 

The issue here is that using Elma / Grayhill 1 x 24 switches would just be too expensive for this project.

 

[Whoops]

Nope but it's on my list!  I was going to use 1x12 Lorlins with 1db steps. 

The issue here is that using Elma / Grayhill 1 x 24 switches would just be too expensive for this project.

yes I know.
I would like to do mine with 0,5dbs steps.

I've read the whole thread on this project but I still get a bit confused with the Pot subject.

If I use the 470 rev log pots from Audiomaintenance, I have to adjust the center value (0dbs) changing some resistor values, is that right?

Has anyone done this successfully?

 

[MrZpliff]

I changed my pots to 12 step lorlins.
that way I get around 5dB +/- for each freq.
I did match the pots with resistors, but I want to use it as a stereo EQ, mastering style.

Got 12 pots with center click for sale

 

[Whoops]

I changed my pots to 12 step lorlins.
that way I get around 5dB +/- for each freq.
I did match the pots with resistors, but I want to use it as a stereo EQ, mastering style.

Got 12 pots with center click for sale

Thant's really nice,
what resistor values did you use for the steps?

do you have any docs or info you could provide that could help us?

 

[Harpo]

Stepped gain could be calculated using my ugly excel chart
good luck
-Harpo

 

[Whoops]

Stepped gain could be calculated using my ugly excel chart
good luck
-Harpo

Thanks a lot Harpo,
unfortunatly I'm a newbie and although your document looks great I don't know how to use it.

 

[Harpo]

less great than ugly, but its not that hard to do. See the little wiring sketch on the right side. The resistors for each step position at the switches are listed in the green cells, with a resistor in parallel (value in the orange cell) to get it less jumpy between switch positions. Each of these building blocks substitute a 470K rev.log. pot (RV36, RV38, .., RV44) with its 5.62K series resistor (R37, R39, .., R45) for each freq.band gain setting part of the summing amp.

Maybe you want to use a 12 pos. lorlin type switch instead, limited to 11 pos. for a center position at step 6, so you just replace the default value '23' with '11' for 'step positions' in the yellow cell. Maybe you want a different cut/boost range (within limits), so replace the default values '5.5' and '-5.5' with maybe '5' and '-12.487' for 'max.boost' and 'max.cut' in the yellow cells. Each time you update a value in the yellow cells for your needs, the whole chart is recalculated and resistor values picked for the closest E96 value to match your plan.

 

[Whoops]

Thanks a lot Harpo for explaning
it makes totally sense now.

I think 12pos are a little bit limited, but the 24 pos switches seem too big to fit into a 1U rack case.

If I use the 470k rev log pots with center ident,
what's the process that I have to do to make sure the center is correct?

 

[Harpo]

some pages back (~01/2008) my pot tweaking chart might help you.

 

[Whoops]

some pages back (~01/2008) my pot tweaking chart might help you.

Oh my God,
are you the real Harry Potter?

thanks harpo

 

[Whoops]

Hey, does anybody have a photo showing how the lorlin is wired?

I think I understand, but the photo from the link here (http://www.groupdiy.com/index.php?topic=19789.520) seems to be gone...

I'm also having problems in wiring the switch, and I've read this full thread and all the explanations.
The Photo is gone also.

My Lorin Switch has 2 Pins in the middle.
A and C

around those theres 12 Pins, marked from 1 to 12


SO:

"A" (Board) should connect to "A"  (center Pin)

B (Board) should connect to  "C" (center Pin)

2 to 2
3 to 3
4 to 4
5 to 5
6 to 6

How about 2-6 ? how should I connect this?

Pins 1 , 7 , 8 ,9 ,10, 11 and 12 are not connected at all?

 

[peterc]

From the old post (edited):

First half of the rotary switch:
The hole marked 'a' goes to the inner pin of a 2 x 6way rotary. The hole marked '2-6' goes to the pins 2-6 (joined on the switch). Shown by the 2 white wires in this pic.

The second half of the rotary:
The hole marked 'b' goes to the other inner pin of the rotary. The individual wires marked 2 to 6 go to pins 8-12 on the switch. Shown by the coloured wires in the pic.

So the first thing to do is to make sure the switch is a 2x6 way. Then check against the circuit diagram.....

I will try & find the pic on my other PCs

Peter