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

[Harpo]

my pleasure. The hardest part in excel is optical polishing and making it foolproof. This sheet for shure is ugly and without any safety belts. :green:
As you substitute the rev.log 470k and R-series with the calculated values for your switched thingy, you could lower the feedback resistor R30 to something like 10k to 20k. (Make R48 the same value for bypass.) Using a non shorting switch may help the otherwise ~+6dB increasing level between step position.
-Harpo

 

[rob_gould]

Excellent - more great information. This looks pretty foolproof even for me!

Non-shorting switches it is.

Thanks Harpo

:sam: again!

 

[Harpo]

Hi Rob,

thanks for the :sam: . Just uploaded a 2nd chart if you also like to limit the max.cut between switching, otherwise the frequency range of the switched filteramp would be missing for the blink of an eye. ..for what its worth. :green:

 

[rob_gould]

Ah OK - that addition makes sense.

A couple of questions:

What effect will lowering the value of feedback resistor R30 have on the circuit?

The table gives a total value for RV + Rseries. Does this mean I should just jumper all the Rseries positions on the boards and use one resistor for each step that combines both values. Does this make sense?

Thanks,

Rob

 

[Harpo]

[quote author="rob_gould"]What effect will lowering the value of feedback resistor R30 have on the circuit?[/quote]
lower resistive noise, as also Rin (=RV+Rseries) get lower by the same factor.
For your desired +6dB boost and Rfeedback 10k, Rin will be in the same range as the original version at full boost, but resistive noise is about 80% lower. No idea, if you will notice the difference.

[quote author="rob_gould"]The table gives a total value for RV + Rseries. Does this mean I should just jumper all the Rseries positions on the boards and use one resistor for each step that combines both values.[/quote]
Yes. If you want to keep your Rseries, subtract its value from the chart value. If you lower Rfeedback, your Rseries will also have a different/lower value. The drawing in the excel-sheet should explain it.

 

[dagoose]

Hi there!

I have my nite eq running for a while now and still love it!
The only thing is it's not running at unity gain.. In normal use it's no problem but i just build a switch box for my mastering with 3 eq inserts (extended pultec, sontec and nite) and when switching to the nite eq the level drops about 3 db.
What resistor should be changed to what value?
Have checked this thread but couldn't find it and before i just flip in different resistors for experimenting it might be worth checking out before doing that.

 

[Harpo]

[quote author="dagoose"].. the nite eq the level drops about 3 db.
What resistor should be changed to what value?..[/quote]
There are various spots to tweak this.
Measure the exact level drop, giving maybe -3.18dB. Flip the sign as you want to boost your signal by this amount, giving +3.18dB. Convert this dB reading to an AV-factor =power(10;(3.18/20)), giving 1.4421.
In case you have constant level with all freq.pots centered and air-band in off-position, compared to bypass position, it would be easiest to increase R3 and R4 from 4k99 to (4k99 x 1.4421) =7k196 for the example above.

Next possible spot is increasing the feedback resistor R30 and bypass resistor R48 by this same factor.
Next possible spot is the voltage divider R24/R25.
Next ... :green:

 

[khstudio]

[quote author="dagoose"]Hi there!

I have my nite eq running for a while now and still love it!
The only thing is it's not running at unity gain.. In normal use it's no problem but i just build a switch box for my mastering with 3 eq inserts (extended pultec, sontec and nite) and when switching to the nite eq the level drops about 3 db.
What resistor should be changed to what value?
Have checked this thread but couldn't find it and before i just flip in different resistors for experimenting it might be worth checking out before doing that.[/quote]

This doesn't sound normal... are you SURE you have the jumpers installed correctly :?: They not only lift pins for Bal or Un-Bal operation but they also change the GAIN!

Or is it your "Center point" of the pots your referring to???

 

[dagoose]

[quote author="khstudio"][quote author="dagoose"]Hi there!

I have my nite eq running for a while now and still love it!
The only thing is it's not running at unity gain.. In normal use it's no problem but i just build a switch box for my mastering with 3 eq inserts (extended pultec, sontec and nite) and when switching to the nite eq the level drops about 3 db.
What resistor should be changed to what value?
Have checked this thread but couldn't find it and before i just flip in different resistors for experimenting it might be worth checking out before doing that.[/quote]

This doesn't sound normal... are you SURE you have the jumpers installed correctly :?: They not only lift pins for Bal or Un-Bal operation but they also change the GAIN!

Or is it your "Center point" of the pots your referring to???[/quote]

OK, will check the jumpers, it's been some time that i've build it so i'm not sure if they are in ok then.
I'm running it all balanced BTW.
The center points are set correctly, i did it the hard way; check every band with RMAA untill it was flat and then centered the knob, took me about 1 to 2 hours but it's completly flat when set to the center position.

I'll keep you posted! Thanks. :thumb:

 

[dagoose]

ok... checked the jumpers but they are all set correctly (balanced) and still have about 6db of gain loss which looks like it is indeed connected unbalanced (6db)
Any idea?

 

[radiance]

Do you also have 6dB lower gain when the EQ is in bypass mode?

 

[dagoose]

[quote author="radiance"]Do you also have 6dB lower gain when the EQ is in bypass mode?[/quote]

Yep, it's not a hard bypass so it still goes through the circuit then.
Must be something in the summing (5532/5534) so i guess it's just a matter of changing resistors but sure which and what value.

http://www.khstudio.us/DIY PICs/Alternate output view.bmp[/url]

 

[dagoose]

Nobody? :sad:

Ok... i'll drop my nite eq then and go for this option: http://www.bteaudio.com/products/PEQ3/PEQ3.html :wink:

 

[khstudio]

I'm not having this problem so I'm not sure how to help you. :?

 

[peterc]

Not really a fix but a work-around:

Try increasing the 56k2 (R30) resistor to 68k or 82k, this should give a few db boost overall.

Peter

 

[Harpo]

[quote author="dagoose"][quote author="radiance"]Do you also have 6dB lower gain when the EQ is in bypass mode?[/quote]

Yep, it's not a hard bypass so it still goes through the circuit then.
Must be something in the summing (5532/5534) so i guess it's just a matter of changing resistors but sure which and what value.

http://www.khstudio.us/DIY PICs/Alternate output view.bmp[/url][/quote]
so your loss is not ~-3dB but -6dB. Most probably not in the summing stage. (your connecting cables are wierd ballanced for shure?) Doublecheck value of R1, R2, R3, R4, R26, R27, R47 and for no short between U4 Pin6-7 (this is U6 Pin 6-7 on pcb). Case all these are OK and you don't want to search further for a maybe mislabled resistor, you can fix this following my previous posting.

 

[radiance]

[quote author="dagoose"]Nobody? :sad:

:[/quote]

Sorry, forgot to check this post lately...but answers have been given yet.

Your problem is most likely found in R30, R1, R2, R3, R4, R26, R27 or R47.

How's the crush & blend progressing btw?

 

[dagoose]

[quote author="radiance"][quote author="dagoose"]Nobody? :sad:

:[/quote]

Sorry, forgot to check this post lately...but answers have been given yet.

Your problem is most likely found in R30, R1, R2, R3, R4, R26, R27 or R47.

How's the crush & blend progressing btw?[/quote]

I'm going to check that tonight or tomorrow, must indeed be something with resistors tough i'm almost sure i have the right ones in there.
Might change some resistor values as stated in some post before (r3 / r4) which i missed in some strange way, my mistake .

C n B is also on my todo list but still waiting for some free time..
i need longer day's or shorter nights.. :green:

BTW: how about that nite VST? :shock:

 

[Harpo]

[quote author="dagoose"]..., must indeed be something with resistors ...[/quote]
not neccesarily. With signal present measure AC-voltage at your jumperd for ballanced xlr-output. Between xlr-pin3 and 0V should read the same value as between xlr-pin2 and 0V (flipped polarity doesn't matter). Case not, remove the short at U6 Pin6-7 (this is U4 Pin6-7 on schematic).

-Harpo

 

[radiance]

[quote author="Harpo"] remove the short at U6 Pin6-7 (this is U4 Pin6-7 on schematic).
[/quote]

Is this a usual suspect for F*@K ups?


Don't see no short on the scematic.....