khstudio
Well-known member
Don't leave me now :green:
3D "AIR" EQ - "Night EQ" PCB's Complete!
- Thread starter khstudio
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Purusha
Well-known member
Ah, just copy the damn thing to the bones :green:
khstudio
Well-known member
[quote author="Purusha"]Ah, just copy the damn thing to the bones :green:[/quote]
I never said I wouldn't... just wanted to make a simpler version... that's all.
It's been a very long & frustrating day. Thank god my other 1272 etched good but I don't think I left the EQ board under the lamp long enough... it's not looking good.
I WILL be doing the full... gone too far to stop now.
Kevin
I never said I wouldn't... just wanted to make a simpler version... that's all.
It's been a very long & frustrating day. Thank god my other 1272 etched good but I don't think I left the EQ board under the lamp long enough... it's not looking good.
I WILL be doing the full... gone too far to stop now.
Kevin
peterc
Well-known member
Kevin
You could probably run a resistor in parallel to the single band you wanted to use. Actually a pot would be better for testing purposes, then you could vary the pot to find the value that gives the same signal amplitude to the EQ band you want to use.
Then take the pot out of circuit, measure its value & sub in a resistor.
Peter
You could probably run a resistor in parallel to the single band you wanted to use. Actually a pot would be better for testing purposes, then you could vary the pot to find the value that gives the same signal amplitude to the EQ band you want to use.
Then take the pot out of circuit, measure its value & sub in a resistor.
Peter
peterc
Well-known member
I'll have a go at this...
R4 on the input opamp just goes to ground. Confusing the way it has been drawn, but no signal goes to the output via this path. The audio path is all via the output of this opamp, from pin 1, through both the "bypass" path, & the "to all Q's" path.
Then the relevant path is selected by SW7 & routed to the - input of U5. U5 & U4(b) then act as the output buffers & balancing cct.
I will try & run a sim tonite to determine the value of the "bypass" resistor, it might have to be an all-pass opamp stage.
Peter
R4 on the input opamp just goes to ground. Confusing the way it has been drawn, but no signal goes to the output via this path. The audio path is all via the output of this opamp, from pin 1, through both the "bypass" path, & the "to all Q's" path.
Then the relevant path is selected by SW7 & routed to the - input of U5. U5 & U4(b) then act as the output buffers & balancing cct.
I will try & run a sim tonite to determine the value of the "bypass" resistor, it might have to be an all-pass opamp stage.
Peter
khstudio
Well-known member
x
khstudio
Well-known member
I got one board almost loaded but left out the U1b section... waiting for advise.
What's the word :?:
Kevin
What's the word :?:
Kevin
khstudio
Well-known member
x
[quote author="khstudio"]:sad:
I'm pretty bummed out... I was hoping for a lot more help & interest in this project.[/quote]
:sad: Sad to say I simply doesn't have the knowledge to help you, but I'm very interrested and willing to support you in any way I can (whatever that may be)
atleast I'll try to cheer ya up ! :thumb: :thumb: :thumb: :guinness: :guinness: :green: :grin: :green:
I'm pretty bummed out... I was hoping for a lot more help & interest in this project.[/quote]
:sad: Sad to say I simply doesn't have the knowledge to help you, but I'm very interrested and willing to support you in any way I can (whatever that may be)
atleast I'll try to cheer ya up ! :thumb: :thumb: :thumb: :guinness: :guinness: :green: :grin: :green:
gar381
Well-known member
Kevin
Hang in there... :thumb:
I think there is a lot of interest in this. Lots
of us are following this thread. Please keep
up the good work!
GARY
Hang in there... :thumb:
I think there is a lot of interest in this. Lots
of us are following this thread. Please keep
up the good work!
GARY
chrissugar
Well-known member
Kevin,
You can spare yourself alot of time and effort if you try what I asked you. Desolder all the resistors in series with the pots except one band , and listen to what it does (how it measures and how it sounds) at minimum, mid and maximum position. Do it with all bands, and you will draw the right conclusions.
Of course, you can simulate the circuit or we can speculate but nothing compares to some real world data.
chrissugar
P.S. I'm sorry I don't have the time to be actively involved in this project. I would really like to help more than giving just some ideas.
You can spare yourself alot of time and effort if you try what I asked you. Desolder all the resistors in series with the pots except one band , and listen to what it does (how it measures and how it sounds) at minimum, mid and maximum position. Do it with all bands, and you will draw the right conclusions.
Of course, you can simulate the circuit or we can speculate but nothing compares to some real world data.
chrissugar
P.S. I'm sorry I don't have the time to be actively involved in this project. I would really like to help more than giving just some ideas.
khstudio
Well-known member
x
peterc
Well-known member
I'm tied up at the moment, but try this. To make the hi shelf an all pass stage, just short out C51 & C3. Should make it a non-inverting amp with a gain of about 8.
But I think one of the previous posts is right about a single band will work. In the sim, it looks like a single band will actually pass the audio above & below the peaks made by the caps. I have only simulated a single band without the summing parts, but have a look at the pic.
I know circuitmaker has been critisized here before, but it looks pretty convincing......
Hope it helps
Peter
But I think one of the previous posts is right about a single band will work. In the sim, it looks like a single band will actually pass the audio above & below the peaks made by the caps. I have only simulated a single band without the summing parts, but have a look at the pic.
I know circuitmaker has been critisized here before, but it looks pretty convincing......
Hope it helps
Peter
khstudio
Well-known member
I'm about an hour or less from firing it up :grin:
Thanks Peter,
Just wondering... will it work OK the way I designed it too???
Your idea definitly sticks to the original more & seems much easier. :thumb:
Kevin
Thanks Peter,
Just wondering... will it work OK the way I designed it too???
Your idea definitly sticks to the original more & seems much easier. :thumb:
Kevin
Harpo
Well-known member
Hi Kevin,
some input to your hard work (hoping it is useful). :thumb:
your summing resistor R37 is part of the summer U5. Increase R37 to 56k to set this inverting stage to AV = -1. (AV=-R30/R37).
The modified Full Band will need an AV of about 10 to behave as your airband so R11 at 10k and R9 at 1k will set this AV. (AV=1+(R11/R9))
The full schemo has a minor error at R47. This resistor is switched in parallel to R26 when in Balanced mode and C14 can block DC offset.
For usual the 22pF C13 is a compensation cap and for NE5534 (U5) close between pin 1 and 8 (trace-side?) or use this cap as shown in the feedback path for the dual NE5532 witch has no compensation pins.
The 2.5k shelf band is drawn as 1.2k shelving, so leave out C51 or set C3 and C51 to 470nF each. (-3dB hpf = 1 / (2pi * R9 * C3||C51).
Calculating from your shemo the airbands are at 2kHz, 4kHz, 8kHz, 17kHz and 36kHz, so a bit off the frontpanel labeling, may be correct with real world caps.
all the best
Harpo
some input to your hard work (hoping it is useful). :thumb:
your summing resistor R37 is part of the summer U5. Increase R37 to 56k to set this inverting stage to AV = -1. (AV=-R30/R37).
The modified Full Band will need an AV of about 10 to behave as your airband so R11 at 10k and R9 at 1k will set this AV. (AV=1+(R11/R9))
The full schemo has a minor error at R47. This resistor is switched in parallel to R26 when in Balanced mode and C14 can block DC offset.
For usual the 22pF C13 is a compensation cap and for NE5534 (U5) close between pin 1 and 8 (trace-side?) or use this cap as shown in the feedback path for the dual NE5532 witch has no compensation pins.
The 2.5k shelf band is drawn as 1.2k shelving, so leave out C51 or set C3 and C51 to 470nF each. (-3dB hpf = 1 / (2pi * R9 * C3||C51).
Calculating from your shemo the airbands are at 2kHz, 4kHz, 8kHz, 17kHz and 36kHz, so a bit off the frontpanel labeling, may be correct with real world caps.
all the best
Harpo
clintrubber
Well-known member
[quote author="peterc"]But I think one of the previous posts is right about a single band will work. In the sim, it looks like a single band will actually pass the audio above & below the peaks made by the caps.[/quote]
Yep, all those amps for the indiv. bands are non-inverting so the gain outside of 'the filtered band of interest' can never be less than unity (0 dB)
(as long as they're configured with some kind of negative feedback)
Bye,
Peter
Yep, all those amps for the indiv. bands are non-inverting so the gain outside of 'the filtered band of interest' can never be less than unity (0 dB)
(as long as they're configured with some kind of negative feedback)
Bye,
Peter
clintrubber
Well-known member
[quote author="khstudio"] but I had this idea of the AIR band only version from the start & now I have to stop & learn which is always a good thing.
[/quote]
Did you catch what I wrote last Monday ?
[quote author="clintrubber"]
...
On the other hand, I can see how the air-band could be used as a stand alone thing when used in say a subgroup insert. You do your main-mix as usual and route some channels to the subgroup as well. The subgroup-faders control the added air.
Or even better yet, use it like you would a reverb, so with FX-sends from the channels. Receive the result on an FX-return.
(Check topology for signal-polarity).
Bye,
Peter [/quote]
So the straigh-on dry path is provided by your mixing-desk...
...for the time being, or as a permanent way of using the air-band. The latter will mean the dry signal doesn't need to leave & enter your mixer.
Bye,
Peter
[/quote]
Did you catch what I wrote last Monday ?
[quote author="clintrubber"]
...
On the other hand, I can see how the air-band could be used as a stand alone thing when used in say a subgroup insert. You do your main-mix as usual and route some channels to the subgroup as well. The subgroup-faders control the added air.
Or even better yet, use it like you would a reverb, so with FX-sends from the channels. Receive the result on an FX-return.
(Check topology for signal-polarity).
Bye,
Peter [/quote]
So the straigh-on dry path is provided by your mixing-desk...
...for the time being, or as a permanent way of using the air-band. The latter will mean the dry signal doesn't need to leave & enter your mixer.
Bye,
Peter
khstudio
Well-known member
[quote author="Harpo"]Hi Kevin,
some input to your hard work (hoping it is useful). :thumb:
your summing resistor R37 is part of the summer U5. Increase R37 to 56k to set this inverting stage to AV = -1. (AV=-R30/R37).
The modified Full Band will need an AV of about 10 to behave as your airband so R11 at 10k and R9 at 1k will set this AV. (AV=1+(R11/R9))
The full schemo has a minor error at R47. This resistor is switched in parallel to R26 when in Balanced mode and C14 can block DC offset.
For usual the 22pF C13 is a compensation cap and for NE5534 (U5) close between pin 1 and 8 (trace-side?) or use this cap as shown in the feedback path for the dual NE5532 witch has no compensation pins.
The 2.5k shelf band is drawn as 1.2k shelving, so leave out C51 or set C3 and C51 to 470nF each. (-3dB hpf = 1 / (2pi * R9 * C3||C51).
Calculating from your shemo the airbands are at 2kHz, 4kHz, 8kHz, 17kHz and 36kHz, so a bit off the frontpanel labeling, may be correct with real world caps.
all the best
Harpo[/quote]
Awesome :thumb: :green:
#1
You are right about R47. I rechecked it against the REAL PCB. I will fix that ASAP.
#2
I do not think U1 is an inverting stage :? 5 I think is... how would raising that value affect the other summer from the AIR BAND (5.6k)???
#3
C13 does NOT connect to pins 1 & 8 on the PCB... not sure what you mean there???
If you don't have the PCB I drew of the REAL EQ3d I will send you the file & you can open it with the free software www.expresspcb.com.
THANK YOU for getting involved... I am very excited about this project... when you guys get involved it gives me a jolt to keep going.
Kevin
some input to your hard work (hoping it is useful). :thumb:
your summing resistor R37 is part of the summer U5. Increase R37 to 56k to set this inverting stage to AV = -1. (AV=-R30/R37).
The modified Full Band will need an AV of about 10 to behave as your airband so R11 at 10k and R9 at 1k will set this AV. (AV=1+(R11/R9))
The full schemo has a minor error at R47. This resistor is switched in parallel to R26 when in Balanced mode and C14 can block DC offset.
For usual the 22pF C13 is a compensation cap and for NE5534 (U5) close between pin 1 and 8 (trace-side?) or use this cap as shown in the feedback path for the dual NE5532 witch has no compensation pins.
The 2.5k shelf band is drawn as 1.2k shelving, so leave out C51 or set C3 and C51 to 470nF each. (-3dB hpf = 1 / (2pi * R9 * C3||C51).
Calculating from your shemo the airbands are at 2kHz, 4kHz, 8kHz, 17kHz and 36kHz, so a bit off the frontpanel labeling, may be correct with real world caps.
all the best
Harpo[/quote]
Awesome :thumb: :green:
#1
You are right about R47. I rechecked it against the REAL PCB. I will fix that ASAP.
#2
I do not think U1 is an inverting stage :? 5 I think is... how would raising that value affect the other summer from the AIR BAND (5.6k)???
#3
C13 does NOT connect to pins 1 & 8 on the PCB... not sure what you mean there???
Will my NEW setup that I drew (posted above) work? I already hooked it up but I can change it if need be. With the 100k pot maxed & 10k resistor to GND should give me 10x right?
If you don't have the PCB I drew of the REAL EQ3d I will send you the file & you can open it with the free software www.expresspcb.com.
THANK YOU for getting involved... I am very excited about this project... when you guys get involved it gives me a jolt to keep going.
Kevin
khstudio
Well-known member
x
clintrubber
Well-known member
Cool, enjoy ! :thumb:
[quote author="khstudio"]
I'm an eager student
Kevin[/quote]
Even more :thumb:
BTW, I like the drawing style of your schematics better than what I use (Simetrix). So I'm curious, which program are you using ?
And can you run a circuit simulation from it (either directly or after some exporting of the netlist).
Thanks,
Peter
[quote author="khstudio"]
I'm an eager student
Kevin[/quote]
Even more :thumb:
BTW, I like the drawing style of your schematics better than what I use (Simetrix). So I'm curious, which program are you using ?
And can you run a circuit simulation from it (either directly or after some exporting of the netlist).
Thanks,
Peter
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