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

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Here's the deal on PCB's:

Peter is supposed to be working on the FULL version PCB but I don't know the time frame or statis... he will have to chime in. His plans were to have PCB mounted components (pots & switch)


x
 
Hi Kevin,

I really like and appreciate your idea and efforts. I'm going to check with Fabio and see if he would be willing to do these. He's been extremelly busy, so I can't promisse. But in the mean while, have you checked www.4pcb.com ? They have a $500 off your first order. and aftet that you can still use other discounts towards you next few. I had some neve boards made with them and I ended up with 10 boards free. Also, your second order doesn't have the tooling charge. It's worth a shot.

I personally would like an "AIR" only version. No shelves, or anything else. I'm still a little confused with this eq, I'm not sure if the shelving selector is actually part of the AIR circuitry or not. Could you clarify?

thanks
Gil
 
This is really cool... haven't been excited about DIY for a Couple months -- thanks for reigniting the flame....

The "Air" Version is all I want to make -- hopefully someone will PCB the thing..

Cheers
 
Hi Kevin,

I would keep all the power supply stuff out of the board. It would shrink the size and let people use their own supplies.

So If I understand correctly, you select the frequency you want the AIR to work on, right?? uhmmmm interesting

Gil
 
[quote author="BR"]Hi Kevin,

I would keep all the power supply stuff out of the board.  It would shrink the size and let people use their own supplies.  

So If I understand correctly, you select the frequency you want the AIR to work on, right??  uhmmmm interesting

Gil[/quote]

The "ADDITIONAL" filtering is part of the ORIGINAL design & MAY be needed for LOCAL stability on EACH board! Remember, this EQ gets up there in frequency.

#2 It's a selectable high shelf with a volume control... AIR is the 40k, but all the setting have a nice usable flavor & really blew the shit out of my mixing boards EQ when comparing... I was shocked.

I WILL NOT be straying too far from the original (known to work) circuit unless A- it's an added feature or B- it's an un-needed component that will not effect the already proven performance.

Although, you guys can do what you want.

The only thing I added to the original was a switch on the front to choose Balanced or un-balance operation... taking the top off was NOT an option... even a switch on the back would be better. The jumpers are needed because they change the circuit... I do not think it's possible to just ground or lift pin 3, etc...
 
Progress is being made :green:

Just wanted to thank Harpo :thumb:

He has been extremly helpful with this project & has made some VERY important recommendations which will be implemented into the schematic & PCB's... Some are un-needed component changes or value adjustments & some are additional PADs - added for user options.

I'm currently working on a direct comparison with the original & also trying to determin wether the 2.5k band can be added or not... if not, that stage will be used for the PEAK detection circuit.

Note: the PEAK circuit may also be added either way.

Kevin
 
[quote author="gyraf"]
There's also 2 (regular looking) green resistors with (Brown, Black, Brown - GOLD)... 3 bands & Green... never seen that, any idea's Question

Inductors for RF-protection. 100uH?

Jakob E.[/quote]

I need help with this one :oops:

I've never had to order inductors before & don't know which ones to get???

Are these OK :?:

http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=205455&Row=586083&Site=US
M7837-ND 78F101J CHOKE CONFORMAL COATED 100UH
100µH ±5% 78F Axial Bulk Epoxy
JW Miller A Bourns Company

http://www.digikey.com/scripts/DkSearch/dksus.dll?Filter

Thanks,
Kevin
 
It's neat that these inductors were added but if you'd ask me I'd skip them for now if they're delaying progress. They're not essential for the functioning.
You would want to add holes for them on the PCB of course (if not already there) so that they can be added later eventually.

Cheers,

Peter
 
[quote author="khstudio"] but I don't really totally understand why they were there or do I have the test equipment to see if there needed or not... maybe for keeping the 20k & 40k clean??? :oops: [/quote]

Hi Kevin,

It's about L1 & L2 at the output, correct ? (as in the schematic on page 1)

Jensen sells a ready-to-go version and calls it a load isolator:
http://www.jensentransformers.com/datashts/oli3.pdf

OUTPUT LOAD ISOLATOR
DECOUPLES CAPACITIVE LOADS AT HIGH FREQUENCIES
* Prevents oscillation and instability in line driving op-amps
* Maintains much lower output impedance than "build-out" resistors
* Non-ferrous core inductor eliminates added distortion
* No effect on audio frequency response or transient performance
* Less than 0.01 dB insertion loss in a 600 Ohm line

The load isolator is designed to isolate op-amp outputs from capacitive loads such as a long cables. Its series impedance is about 0.3 Ohm across the audio spectrum, but increases to about 40 Ohms at RF frequencies to prevent amplifier instability or oscillation while preserving a low audio output impedance.

Without coils added I'd still keep the same values for R29 & R32.

Cheers,

Peter
 
[quote author="khstudio"]... I HATE ordering parts... I think it's the worst part of DIY :mad: Kevin[/quote]

Worst part is paying for parts you orderd wrong that wont be of any use the next decades :green:

I think, maybe wrong, the inductors should reduce rf from the switching supply that is built in the original unit. Leave them out, but place pads as in clintrubber's previous post.
 
[quote author="Harpo"][quote author="khstudio"]... I HATE ordering parts... I think it's the worst part of DIY :mad: Kevin[/quote]

Worst part is paying for parts you orderd wrong that wont be of any use the next decades :green:

I think, maybe wrong, the inductors should reduce rf from the switching supply that is built in the original unit. Leave them out, but place pads as in clintrubber's previous post.[/quote]

DAMN... one more thing that has to do with that F*#kin switching Supply that is not needed. Why would people even use them if they need so much compensation... I DO NOT GET IT! It surely can't be a COST saving issue by the looks of it.

But if this is the case... it's more good news along with the 470uf's being too large... it makes for more room & cheaper parts/values :thumb:

kevin
 
[quote author="khstudio"]DAMN... one more thing that has to do with that F*#kin switching Supply that is not needed. Why would people even use them if they need so much compensation... I DO NOT GET IT! It surely can't be a COST saving issue by the looks of it.

But if this is the case... it's more good news along with the 470uf's being too large... it makes for more room & cheaper parts/values :thumb:
kevin[/quote]

Think it's a cost issue. They've been small manufacturers selling products that have to meet CE/TÜV/CAN-CSA... much less hassle and cost with prebuilt modules that have this confirmed. Not an issue with DIYers for home use (meeting this specs for shure is obligatory), but that malkjos :twisted: -style cloners may get into severe trouble someday.

Both have their pro's and con's.
a transformer is specced for a constant source voltage (115/230V) which in not a constant in real world. It will introduce more or less hum at 50/60Hz that unfortunately is within the audio band. A switching supply at the same load will be smaller in size and may produce less heat but introduce rail noise in it's switching band.

INPUT SPECIFICATIONS
Source Voltage 85-264 Voltage AC
Frequency Range 47-63 Hz
Source Current
True RMS 1A At 85V Inputut
Peak Inrush 40A
Efficiency .68 -.72 (Varies by model)
ENVIRONMENTAL SPECIFICATIONS
Ambient Operating Temperature Range 0oC to +70oC Derating: See Power Rating Chart
Ambient Storage Temperature Range -40oC to +85oC
Temperature Coefficient Outputs 1-4: 0.02%/oC
Conducted Emissions EN 55022 Class B

SAFETY SPECIFICATIONS
GENERAL SPECIFICATIONS

General Protection Class: I

Overvoltage Category: II

Pollution Degree: 2

Underwriters
Laboratories
File E137708 UL 60950, Third Edition
UL Recognition Mark for Canada
File E137708 CAN/CSA-C22.2 No. 60950:00
TUV EN 60950:2000
Low Voltage Directive
Dielectric Strength
Reinforced Insulation 4242 VDC, Primary to Secondary, 1 Sec.
Basic Insulation 2121 VDC, Primary to Ground, 1 Sec.
Operational Insulation 500 VDC, Secondary to Ground, 1 Sec.
Mean Time Between Failures 150,000 Hours min., MIL-HDBK-217F, 25oC, GB
Weight 1.00 Lbs. Chassis and Cover
0.50 Lbs. Open Frame
 
[quote author="khstudio"]

BTW, The FULL PCB is looking good :wink: Peter sent me a draft last night :green:

Still working out a few details but I think it's safe to say it's on the way.

I'm ordering parts for about 6 projects including this one... I HATE ordering parts... I think it's the worst part of DIY :mad:

Kevin[/quote]

I'm in for 2 full PCB:s when they're ready. I ahven't got the time right now to build it anyway... even if I'm thinking of building the "air-section" on perfboard.. I've never bothered to get that etching stuff. I'm too lazy I guess :oops:

I agree about ordering parts... when building the La-2a I had to order from about half of the western world. Wich when you think of it is a really great thing for us DIY'ers. Without the net I guess much of these projects wouldn't be possible :grin: at least not for me.
 
[quote author="khstudio"]DAMN... one more thing that has to do with that F*#kin switching Supply that is not needed. [/quote]
I'm not sure which inductors are under discussion here, but if it's indeed those at the audio-output (L1,2 in the schematic on page 1) then it's not related to the kind of supply but because of the reasons I quoted from the Jensen-datasheet of the load isolator.


Why would people even use them if they need so much compensation... I DO NOT GET IT! It surely can't be a COST saving issue by the looks of it.
W.r.t. switching-supplies: a TX for 50 or 60 Hz is big, bulky & expensive.

A switch mode power supply works at much higher frequencies and avoids having to use that big iron. It uses a smaller TX of different core-material.
Despite using more parts & being more complex it's still cheaper. And as said by Harpo, those switching modules are made in massive quantities for tons of applications so can be even more cheaper.

Bye,

Peter
 
[quote author="khstudio"]I'm ordering parts for about 6 projects including this one... I HATE ordering parts... I think it's the worst part of DIY :mad: [/quote]
I'm not impressed :wink:
I mean, it's easy to mention a few more parts of DIY that are worse than this:

#1. doing the metalwork

#2. having to STOP ordering parts ('cos time for sleep, social stuff, work etc)

#3. having to quit DIY for a while to use the gear you made (to justify making this stuff altogether) :thumb:


Cheers,

Peter
 
Good Points :green:

But I'd rather do the Metalwork any day... I sit behind a computer enough.

+ about 5 KEY pieces I needed are not in stock :mad:

I can't believe a 5k audio taper pot will be out of stock for a month, Damn Mouser. I was also missing 2 items & had 1 bag labled correctly with the wrong shit in it. I like Mouser but come on. This scares me when it comes to resistors.

OK, Back on track :wink:

Kevin
 
Back
Top