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

[Harpo]

I measured the resistance( U5 pin 2) to  (U1,U2,U3 pins 1 and 7)  and The smallest value was 31k6 and the biggest was ~660k witch is the total value of the pot, Is this wrong?

Sorry, but wrong. You seem to have every resistor from the excelsheet wired in a series string of resistors (resistor between each switch step, instead of one side of the resistors connected to a switches throw lug and all resistors other side to a common ring). As already said and from the calcsheet, for +/-5dB smallest value would be 31K6 and biggest value 100K for the total value, but this is an easy fix.

 

[sedit1]

I measured the resistance( U5 pin 2) to  (U1,U2,U3 pins 1 and 7)  and The smallest value was 31k6 and the biggest was ~660k witch is the total value of the pot, Is this wrong?

Sorry, but wrong. You seem to have every resistor from the excelsheet wired in a series string of resistors (resistor between each switch step, instead of one side of the resistors connected to a switches throw lug and all resistors other side to a common ring). As already said and from the calcsheet, for +/-5dB smallest value would be 31K6 and biggest value 100K for the total value, but this is an easy fix.

Harpo, this is the best news in this week! So problem solved and now everything seems to be working like it should, I was thinking about this kind of mistake because it was my first stepped switch and  english is not my native language so it's easy to misunderstand some instructions.

Huge thanks to you! It's great that there is people like you in this board who are willing to give great advices and help to the people who need it. I'm going to make a donation to the forum right away!

 

[Leonardo_007]

Hello,

is there one pcb left for me, please?

 

[glbaudio]

is possible to have 2 PCBs?

 

[peterc]

Sorry guys, all out at the moment. No plans for a re-order at the moment.

Peter

 

[druu]

I'm also very interested in PCB's! I need this EQ. Anyone know of any online PCB fabricators that don't have a minimum order?

 

[dagoose]

Finally decided to make my nite EQ stepped because i love the sound but for mastering it is pretty much useless without switches, and that is a shame.
Just wondering what will be best because i see 2 versions in the sheet from Harpo.
One with a resistor in parallel with BBM switches and one without the parallel resistor and with a MBB switch.
Which one will be best? I will go for simple lorlins with max 5db boost and cut

 

[dagoose]

No one?
Also wondering about the airband since it is just a positive value. I want 5db max boost with 0.5 db steps (= 11 steps) is it just a matter of using the sheet and set the cut value to 0 and max boost to 5? something like this?

Step "Boost/Cut
value in dB" "this is
voltage gain" "required R in
(to substitute Rseries+RV)" closest E96 value in ohms
1 0,000 1,0000 56200 56.200
2 0,500 1,0593 53056 53.600
3 1,000 1,1220 50088 49.900
4 1,500 1,1885 47286 47.500
5 2,000 1,2589 44641 44.200
6 2,500 1,3335 42144 42.200
7 3,000 1,4125 39787 40.200
8 3,500 1,4962 37561 37.400
9 4,000 1,5849 35460 35.700
10 4,500 1,6788 33476 33.200
11 5,000 1,7783 31604 31.600

 

[Harpo]

...I will go for simple lorlins...

...that you can get as a BBM or as MBB switching type. Use the config that matches your type of switch.

Airband is always adding (no cut) and because of range overlap (the 2.5kHz shelfing band is part of the airband), you won't get a +0.5dB airband boost step without some cut of the corresponding shelfing band. All frequency stages aren't filters but bandwidth limited non-inverting gain stages with a 1st order -6dB slope that won't drop below unity gain, so the overall range of cut is limited to about -5dB .. -6dB when all bands get summed up.

 

[druu]

Anyone have any PCB's for this?

 

[RATMNL]

It's in the white market thread.... a lot of these have gone missing lately, so I don't know if Peter C. will ship them out still.. check the market, ask him!

 

[dagoose]

...I will go for simple lorlins...

...that you can get as a BBM or as MBB switching type. Use the config that matches your type of switch.

Airband is always adding (no cut) and because of range overlap (the 2.5kHz shelfing band is part of the airband), you won't get a +0.5dB airband boost step without some cut of the corresponding shelfing band. All frequency stages aren't filters but bandwidth limited non-inverting gain stages with a 1st order -6dB slope that won't drop below unity gain, so the overall range of cut is limited to about -5dB .. -6dB when all bands get summed up.

OK, great! i ordered BBM switches so i'll know what to do then I was already thinking of getting BBM in the first place, don't like the idea of open contacts. ;-)
But still wondering about the air band boost: what if all the bands are at 0 and you want the air boost to work from 0=off to + 5.5 db max in 0.5 db per step. What would be the way to calculate that? I'm a bit lost on the airband. All the other bands are clear.

 

[dagoose]

...I will go for simple lorlins...

...that you can get as a BBM or as MBB switching type. Use the config that matches your type of switch.

Airband is always adding (no cut) and because of range overlap (the 2.5kHz shelfing band is part of the airband), you won't get a +0.5dB airband boost step without some cut of the corresponding shelfing band. All frequency stages aren't filters but bandwidth limited non-inverting gain stages with a 1st order -6dB slope that won't drop below unity gain, so the overall range of cut is limited to about -5dB .. -6dB when all bands get summed up.

OK, great! i ordered BBM switches so i'll know what to do then I was already thinking of getting BBM in the first place, don't like the idea of open contacts. ;-)
But still wondering about the air band boost: what if all the bands are at 0 and you want the air boost to work from 0=off to + 5.5 db max in 0.5 db per step. What would be the way to calculate that? I'm a bit lost on the airband. All the other bands are clear.

anyone? what did you guys use for the airband?

 

[Autophase]

hi Guys,
I have done a couple of DIY builds in the past, I really would like to add a nice hardware EQ to my mastering chain, I really like the look of the Nite EQ, the fixed frequencies seem perfect for my needs.
Being that I will be using 2 of these in stereo for mastering, I figure I'll need to make stepped attenuators for all of the boost cut pots, is there anyone else who has done it this way who can offer any advice?

Thanks

 

[dagoose]

ok.. what am i missing here? I just build one switch with + 5 (31k6) and -5 (100k) max boost/cut and i only get something like 1.5/2db of max boost and cut.  (testing it on the 650hz band)
With the potmeter i get something like 20db boost/cut so the circuit is Ok (it has been racked up for quite some time without problems).
If i use something like 5k6 for the boost i get (IIRC) 10db of boost.
Am i missing something here? 0 position is 0, it's just the max boost and cut that are way out of the range the sheet says.  :-[

 

[Harpo]

Rseries (R39 for the 650Hz band) still in place instead of shorted out ?

 

[dagoose]

Rseries (R39 for the 650Hz band) still in place instead of shorted out ?

hmm.. so that is what i'm missing here.  :-[
They are indeed.. totaly missed that!
Thanks! 8)

EDIT: i shorted r39 and now i get a bit more boost (max 2.5 db) but still no 5db as it should be with 31k6.  ???
When i replace the 31k6 with 10k i get something like 5.5 db boost which is good. If i use the sheet with 10k max in the boost it says it's boosting 15db, which is totally different then the 5.5db i see.
With 330k for cut (= -15db according sheet) i get a cut of something like 3.5/4 db but with the 100k= -5db (according top sheet) i get only about 1db of cut.

anyone? I really don't get it..

 

[Autophase]

Hi guys,
I have got a pair of boards & PSU all stuffed now.
I intend to use this EQ in stereo for mastering, so I will be opting for rotary switches for all cut/boost controls.
From reading through the forum I think I need 1 pole 12 way rotary switches, limited to 11 positions, position 6 being the centre.

Can you guys confirm if I've got that right?

Thanks

 

[rob_gould]

Yup that's right.  This is the plan for mine too, though it has been sitting in a  box half finished for the last three years.

You just need to decide the size of the steps for cut and boost.  There's a spreadsheet floating round somewhere on this thread which allows you to calculate resistor values which determine the size of the steps.  Courtesy of Harpo I believe.

 

[Autophase]

Yes I have seen the resistor tables, ill probably do the same as harpo and have 5x 1db steps each way.

Would anyone be able to clarify another thing for me please, i spent the afternoon reading most of this thread. To my understanding of stepped attenuators, each resistor goes a a lug on the switch then the other resistor leg goes to a common point, usually a ring or the same trace on some stripboard.
But I have seen in this thread some people wire the attenuator in series, so each step increase introduces another series resistor into the signal path, my concern with the series method is that it introduces more noise with each additional resistor in the signal path.

please can you clarifiy which is the correct / most accrate method for this eq? If I am missing something please fill me in, afterall the building is only half the reason I am here, the other half is to learn (and hopefully help someone else in the future)  ;D

sorry for bump, but I could do with some assistance on this please