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

[Script]

Example:
If you have 50k for R38, you need to change R39 to 562R -- and this for all filter stems.

Also you need to scale down R30 by factor 10 and then scale up C13 for same filter response. Calculate it.

Finally, I made R48 a trimmer to address difference in volume when switching from bypass. You might not need this. Can do any time later.

 

[NorthernLight]

Again you confuse me

First you say I should not bother with 50K, and then you point me to 50K dual gang potentiometers and the resistors to be replaced. The resistor values I asked for and your answer is appreciated, thanks.

My concern with the dual gang potentiometers is that they have a tolerance of 20%, and I am unsure about the matching of the two gangs. I can't find that in the datasheet either. I know the dual gang pots are a really cost-effective solution, but I'm not looking for the cheapest option per sé. I kind of like the stepped switch idea and the precision it brings.

Let me assume that you indeed mean that the conversion to 50K potentiometers (or switches) is not necessary and that a stepped switch with a value of 500K is fine. If I proceed to enter these values into Harpo's excel I get the following data:

	corresponding part
R feedback	R30	56200​	ohms (if you change it, also change R48 for bypass to the same value)
max.boost	R37,39,41,43,45	5​	dB
max.cut	RV36,38,40,42,44	-5​	dB
step positions		21​	(2 to 25 positions)
max.cut between switching	-6​	dB (must not be higher than regular max.cut)
R in parallel		112134​	ohms	closest E96 value	113000​
Step	Boost/Cut value in dB	this is voltage gain	required R in (to substitute Rseries+RV)	with 'R in parallel' the R at the switch is	closest E96 value in ohms
1​	-5,000​	0,5623​	99939​	864643​	866.000
2​	-4,500​	0,5957​	94349​	571628​	576.000
3​	-4,000​	0,6310​	89071​	420620​	422.000
4​	-3,500​	0,6683​	84088​	328651​	332.000
5​	-3,000​	0,7079​	79385​	266860​	267.000
6​	-2,500​	0,7499​	74944​	222532​	221.000
7​	-2,000​	0,7943​	70752​	189239​	191.000
8​	-1,500​	0,8414​	66794​	163349​	162.000
9​	-1,000​	0,8913​	63057​	142671​	143.000
10​	-0,500​	0,9441​	59530​	125807​	127.000
11​	0,000​	1,0000​	56200​	111806​	113.000
12​	0,500​	1,0593​	53056​	100015​	100.000
13​	1,000​	1,1220​	50088​	89966​	90.900
14​	1,500​	1,1885​	47286​	81312​	80.600
15​	2,000​	1,2589​	44641​	73793​	73.200
16​	2,500​	1,3335​	42144​	67211​	66.500
17​	3,000​	1,4125​	39787​	61409​	61.900
18​	3,500​	1,4962​	37561​	56263​	56.200
19​	4,000​	1,5849​	35460​	51676​	51.100
20​	4,500​	1,6788​	33476​	47568​	47.500
21​	5,000​	1,7783​	31604​	43875​	44.200

I'm not sure what the "max cut between switching" means. Does it perhaps mean the behaviour when using a break-before-make" switch? Is it important?

I think the rightmost column holds the resistor values that need to go between the switch steps. The "max cut between switching" influences the values in this column, so I would like to confirm I'm doing this right, before ordering bespoke stepped switches and potentially wasting a lot of money .

 

[Script]

Haven't looked at your math. Here's mine.

Those custom-made rotaries cost USD200 for 8 pieces. They are hand-made (so a reasonable price) and sure also worth supporting the seller.

Yet, for USD200 one could buy 250 pieces of dual taper pots for 0.8 a piece at Tayda and look for closest match from pins 1 to 3 across decks, and then in a second step from pin 1 to eyeballed mid position. Should be able to find 6 duals that match closely enough across decks. The remaining ones go to charity.

Anyway, once jam is pumping and crowd hopping , pot mismatch is a rather unlikely reason for complaints

But agreed, my math doesn't compute cos those pots are out of stock at Tayda. Haven't checked whether they have 500k, nor what other have on offer.

 

[NorthernLight]

You have a valid point about buying a surplus of those pots and matching them by hand; I did not think about that. I did check their site and they have the 500K version on stock in fact. Thank you for this perspective.

However, it feels a bit wasteful to buy 200+ potentiometers in order to find 6 useable specimens. I would like to make an effort in keeping the world sustainable, spending a bit more on a product and/or person to reduce the use of resources and/or generating waste is part of that. So the stepped switches have not left my mind yet, and if someone can confirm the values in the table in my prvious post (3D "AIR" EQ - "Night EQ" PCB's Complete!) that would be wonderful.

 

[Script]

Charity -- maybe even thru this forum? -- ain't waste

 

[Script]

Oh, and wouldn't need 250 to find 6.

 

[lisex]

Hi all,
does anyone have PCB for PSU?
I found here this one but it doesnt looks like at finished projects.

 

[Script]

Any +/-15V PSU would do the job here.

 

[Whoops]

Hi all,
does anyone have PCB for PSU?
I found here this one but it doesnt looks like at finished projects.

That PSU was sold by PeterC at the time, but you will not find it at the present.
When I did my Night Eq I used the SSL9K PSU, that was a very popular project around here and there were plenty of those PCB's around.

At the moment you can buy a PCB psu from Silent Arts,
get the POSNEGPSU-rev02 and you will be sorted:

POSNEGPSU-rev02: EUR 6,50 each + shipping + VAT where applicable

https://groupdiy.com/threads/51xaudio-by-silent-arts.39570/

 

[lisex]

That PSU was sold by PeterC at the time, but you will not find it at the present.
When I did my Night Eq I used the SSL9K PSU, that was a very popular project around here and there were plenty of those PCB's around.

At the moment you can buy a PCB psu from Silent Arts,
get the POSNEGPSU-rev02 and you will be sorted:

POSNEGPSU-rev02: EUR 6,50 each + shipping + VAT where applicable

https://groupdiy.com/threads/51xaudio-by-silent-arts.39570/

Thank You Whoops, I will try to find SSL9K PSU and if I fail - then will order from Silent Arts

 

[lukas]

I do something like this. can be with attenuation pot, or jumper. Input INA134, and DRV134 output(...can be THAT...).

 

[Script]

I see alternative slots for "shelf adjust trimmers". That absolutely splendid.

 

[lukas]

I add new position 15kHz too. Simetrical input can be like early version on 5532, or THAT1240 for your choose. Two push switches, one for ByPass, second for SHelf on/off...i have few pcb, if someone intersted...

 

[macleod69]

Thank You Whoops, I will try to find SSL9K PSU and if I fail - then will order from Silent Arts

You can find a psu for this project here.

 

[meteoric]

I add new position 15kHz too. Simetrical input can be like early version on 5532, or THAT1240 for your choose. Two push switches, one for ByPass, second for SHelf on/off...i have few pcb, if someone intersted...

My inbox doesnt work - i dont know why... please message me. Thank you

 

[1wildthing]

Hi guys, I'm trying to build this eq starting from the prodigy nite eq 500 schematic from audiomanteinance that I found at page 37 of this thread. I would like to add an attenuator pot to tame the input level.
Do you think I can get away with this simple solution even on a balanced input or I need something more sofisticated? It's a simple 10k pot between + and -.

 

[Whoops]

Hi guys, I'm trying to build this eq starting from the prodigy nite eq 500 schematic from audiomanteinance

Before going to the attenuation question, I just want to let you know that my advise is that you build this project using the PCB's that were provided by PeterC, you have everything setup there, will be pretty easy to build and the input attenuation will be easy to implement.

Many people has those PCB's untouched and will be willing to sell them, just ask in the Black Market or do a search over there

 

[djmiggymigz]

Bringing this thread back in summer of 2024! Just read thru no joke the entire thread and learned so much. Huge thanks to khs, Peter, harpo, and everyone else for all work and sharing of knowledge here.

Not entirely sure what happened but it seems the DIYRacked version of this has some bad blood behind it? Wish I’d read thru this prior as I’m currently working on building this from diy racked. The design and build of this diy buildout seems far more efficient.

Regardless, as the diy noob I am, I’m currently running into issues. All my pcb’s are stuffed and plugged in. Unit powers in fine and passes audio just fine in bypass. When eg is engaged, L channel goes MIA. R channel seems to be working more or less (getting noise introduced into the signal as I boost above 7-8 on the faceplate.

However, my main issue that I’d love input on is in the PSU. Running at +- 18V using a toroid, 317/337 regs, and 2 5k trimmers to calibrate for the +-18v. Problem I’m having is I can’t figure out how to get the correct voltage at the dc output terminals that feed the pcb’s.

Can someone please tell me where to measure from. With my VM red probe on the +/- output terminals, I get vastly different readings based on where the black probe is. Black probe on dc ground terminal, I’m reading -.5v on the positive side and -39v on the negative. Black probe on the main AC ground (screw holding the torpid in place) I’m sitting perfectly at +-18v. Thinking I may have the toroid primaries and secondaries wired into the pcb incorrectly.

 

[djmiggymigz]

Bringing this thread back in summer of 2024! Just read thru no joke the entire thread and learned so much. Huge thanks to khs, Peter, harpo, and everyone else for all work and sharing of knowledge here.

Not entirely sure what happened but it seems the DIYRacked version of this has some bad blood behind it? Wish I’d read thru this prior as I’m currently working on building this from diy racked. The design and build of this diy buildout seems far more efficient.

Regardless, as the diy noob I am, I’m currently running into issues. All my pcb’s are stuffed and plugged in. Unit powers in fine and passes audio just fine in bypass. When eg is engaged, L channel goes MIA. R channel seems to be working more or less (getting noise introduced into the signal as I boost above 7-8 on the faceplate.

However, my main issue that I’d love input on is in the PSU. Running at +- 18V using a toroid, 317/337 regs, and 2 5k trimmers to calibrate for the +-18v. Problem I’m having is I can’t figure out how to get the correct voltage at the dc output terminals that feed the pcb’s.

Can someone please tell me where to measure from. With my VM red probe on the +/- output terminals, I get vastly different readings based on where the black probe is. Black probe on dc ground terminal, I’m reading -.5v on the positive side and -39v on the negative. Black probe on the main AC ground (screw holding the torpid in place) I’m sitting perfectly at +-18v. Thinking I may have the toroid primaries and secondaries wired into the pcb incorrectly.

Okay I’ve since learned that it’s only the secondaries that get wired into the psu AC INPUT. Thought maybe I had those connected wrong, swapped them, and was able to probably calibrate to +18v however the negative rail won’t go “higher” than -7v

 

[peterc]

Our old friend DIYRacked.....
He took my PCB design and added relay bypassing and sold it as his own.
I would not run it at +-18v, in my past experience +-16v will be fine.
What power supply PCB are you using?
Pics maybe