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

[clintrubber]

Hi,

Nice progress!


Then this: the 'stereo-issue'.
See for instance http://www.soundonsound.com/sos/1997_articles/oct97/nightpro.html

[quote author="SOS"]The manual also recommends using the EQ3D in mastering, broadcast, post-production, live sound and home listening systems. I have a few reservations with these last applications -- not because the unit wouldn't enhance the sound quality, because it almost certainly would have a beneficial effect -- but because there is no stereo linking facility on the controls, as mentioned earlier.[/quote]
I'm not sure dual pots would guarantee this, but going for rotary switches for all bands might perhaps be a bit too much.
For a stereo air-band only this seems perfectly feasible though.

It depends of course on what applications you all have in mind.
Dual-mono or stereo ?


Bye,

Peter

 

[khstudio]

Good points.

This unit is the lower priced version (EQ3d)
It uses a switching supply
Regular pots
& no trannys

The Expensive unit (EQ3) aprox $2500-3000
Linear Power Supply
Stepped gains (ALL)
& I THINK... transformers

The circuit is the same... so there IS room for improvement.

 

[clintrubber]

[quote author="khstudio"]The question is, How can we make a board to do both, so people can have a choice.[/quote]
If the pots are not to be mounted on the PCB then it's just a matter of wiring up a pot or a switch with resistors on it. (sorry for stating the obvious)

 

[clintrubber]

[quote author="khstudio"] so there IS room for improvement.[/quote]
Reading the SOS-review made me think it'd be good to add some sort of limiting of the top-top-end of the airband.
But that might spoil part of the fun of course.
Note the review is from 1997; I'm not sure how big of a problem it still is with todays converters, see below:

[quote author="SOS"]The supplied specifications claim an overall bandwidth of 5Hz-330kHz (-3dB points),

...

Excessive boost at the top end, particularly with the AirBand set to 20 or 40kHz, can cause all sorts of horrific problems with digital recorders -- especially the earlier ones with baseband analogue anti-alias filtering. Tracks which sounded bright, crisp and full of life on the monitors during the mix often sounded absolutely terrible on replaying the DAT, because of aliasing distortions. This was caused by relatively inefficient anti-alias filtering letting a small amount of the high-level HF signals into the recorder. This breaks the Nyquist rule prohibiting audio above half the sampling rate, and the result is anharmonic distortion of the most unpleasant kind. I found an old first-generation Sony DTC1000 machine suffered the most from this phenomena, but a Sony R500 was very good in an identical situation. Modern A/D converters use a form of oversampling technology and accurate digital filtering to produce much more efficient anti-alias filtering, and the R500 proved just how much better it is!

The moral is that you should be extremely cautious with the frequency extremes. Use only very modest amounts of boost at the low end, and if your monitors don't cover the full frequency range, err towards too little! Clues to look for are meter indications that seem too loud or don't appear to relate directly to the audible programme, and loudspeaker amplifiers that get surprisingly hot or run out of steam earlier than they should. As far as the top end is concerned, the same rules apply; monitoring through your digital recorder will reveal any aliasing problems.
[/quote]

Bye,

Peter

 

[khstudio]

I have used this several times & haven't had a problem.

Like most EQ duties, a little goes a long way.

I would usually run the 40k at about 3-4 on the dial (at most)

Then sometimes lift the 2.5k fixed band up a nano nut for a little bit of definition.

The SUB is very cool too but damn... I've already got bass management issues.

ALL the bands are useful on this thing & very musical because the Q is so broad... a slight lift or pull here & there does wonders... it's a cool piece.
I would NEVER have spent this much time on it if it wasn't.

BTW, I've had at least 3 people try to buy mine from me in the past year for over $1000... one guy just offered me $1400 :shock: This is the reason I started doing this project. I wanted to clone the circuit for myself & sell him mine... win, win for me :green:

Kevin

Hey Peter,
you got those boards ready yet... all this talk is getting me excited:thumb:

 

[khstudio]

1st post updated:

Faceplate, Schematic - Rev #2, Parts list

Peter,
The pots are ALL: 500k A CCW Bourns

I fixed U5... you were even closer than I thought :thumb:

I fixed the part #'s on the list (correct on the Excel file)
The only thing NOT correct on the Excel file are the 500k A CCW Bourns Pots & the missing inductors. You can use the link on page 1 to my pictures/files.

The connection on R44 (POT) was wrong (Fixed)

Part Values were added to the original schematic (NOW Rev #2)

( I will send you the NEW Original v2 schematic so you have it & can edit it with the software. Also, let me know if you need anything else traced out from the original board.

 

[clintrubber]

[quote author="khstudio"]BTW, I've had at least 3 people try to buy mine from me in the past year for over $1000... one guy just offered me $1400 :shock: This is the reason I started doing this project. I wanted to clone the circuit for myself & sell him mine... win, win for me :green:
[/quote]

Keep on dreaming... before you know it that Malkjos(sp?)-dude that's cloning & selling G-SSLs has already sold an EQ-clone to that person :twisted:

Would it be an idea to do some registration for the schematic & PCBs for this project ? Since cloning from there on seems so easy & is low in parts-cost I'm afraid quite some bad persons are tempted to make a quick buck... :?

 

[haima]

great work kevin, peter and everyone, thanks for sharing!

i don't have much to offer as i don't have a eq3d (nor have i even seen one in the flesh..) but i've heard good things and can't wait to try the circuit out when i have a spare hour or two (mmm, yeah right!)

frequency selection is always a compromise with a fixed eq (and not having used the unit i don't know how it sounds) but i imagine having access to some extra frequencies, such as around 60Hz and 450Hz etc, might be useful - we could experiment with adding some extra switchable freqs...

anyway... i better butt out now, keep up the good work! :sam:

haima

oh, here's some evilbay links with some pics and info for those who don't have one of these units:

eq3-d ebay - with pics

eq3-d ebay - with a copy of a magazine review

 

[khstudio]

[quote author="clintrubber"][quote author="khstudio"]BTW, I've had at least 3 people try to buy mine from me in the past year for over $1000... one guy just offered me $1400 :shock: This is the reason I started doing this project. I wanted to clone the circuit for myself & sell him mine... win, win for me :green:
[/quote]

Keep on dreaming... before you know it that Malkjos(sp?)-dude that's cloning & selling G-SSLs has already sold an EQ-clone to that person :twisted:

Would it be an idea to do some registration for the schematic & PCBs for this project ? Since cloning from there on seems so easy & is low in parts-cost I'm afraid quite some bad persons are tempted to make a quick buck... :?[/quote]

What does that mean DUDE :? "Keep on Dreaming"
If my plans were to make money I would NEVER have posted it in here.
I thought some of you guys may enjoy the project as much as me... If it becomes a problem I'll just pull all the info & schematics.

The "REAL EQ3d's" sell for over $800 at least on eBAY & don't show up too often. My plans are to clone for myself, share, then sell my original unit.

I know nothing about

registration for the schematic & PCBs

I DO NOT want to get in the middle of any BS over this.

Should I put a "Gyraf" style disclaimer on the 1st post :?:

Kevin

 

[khstudio]

x

 

[chrissugar]

Kevin,
the decoupling capacitors for each opamp are important to be connected close to the + and - pins of each opamp. In your PCB picture the decoupling caps are close to the opamps but the ones on the negative rail are connected to one trace and the opamps to another so they don't do what they are supposed to do.

 

[khstudio]

x

 

[chrissugar]

Wow :shock: It makes no sense. Are you sure there are no traces under the opamps on the component side that connect the decoupling direct to the opamp pins? Even if that would be the case it looks strange to have two separate traces for the minus rail. :?

chrissugar

 

[clintrubber]

[quote author="khstudio"][quote author="clintrubber"][quote author="khstudio"]BTW, I've had at least 3 people try to buy mine from me in the past year for over $1000... one guy just offered me $1400 :shock: This is the reason I started doing this project. I wanted to clone the circuit for myself & sell him mine... win, win for me :green:
[/quote]

Keep on dreaming... before you know it that Malkjos(sp?)-dude that's cloning & selling G-SSLs has already sold an EQ-clone to that person :twisted:

Would it be an idea to do some registration for the schematic & PCBs for this project ? Since cloning from there on seems so easy & is low in parts-cost I'm afraid quite some bad persons are tempted to make a quick buck... :?[/quote]

What does that mean DUDE :? "Keep on Dreaming"
[/quote]
Hi Keven,

That 'Keep on dreaming... ' wasn't meant like you have understood it. It's the wording I used after seeing yet another G-SSL-clone by that Malkjos-person and I think it'd be a real pity if the reversed engineered circuits & upcoming PCBs would fall into his greedy hands as well.

So that 'Keep on dreaming... ' was partly out of fustration about that G-SSL-eBay-mass-producer and was partly in jest. So my words may have given you a wrong impression of what I was meaning, I regret that and let me add my apologies for the part of the confusion that's to blame on me.

If my plans were to make money I would NEVER have posted it in here.
I thought some of you guys may enjoy the project as much as me... If it becomes a problem I'll just pull all the info & schematics.

That's all clear, you're not after a quick buck and you selling your original unit later on is in no way objectionable of course.

I know nothing about

registration for the schematic & PCBs

I DO NOT want to get in the middle of any BS over this.

My main point was that since this unit seems to have such a high ratio of desirability vs ease & low cost of making (after the hard work of tracing & PCB-making), I'd really hate to see it going the route the G-SSL-PCBs have gone for Malkjos-types.
What could be done about that ?

Should I put a "Gyraf" style disclaimer on the 1st post :?:

While it won't guarantee much I'm afraid, I still think it's a good idea. At least it gives something to point at once the quick-buck-clones start appearing on eBay.

Best regards,

Peter

 

[khstudio]

The more I thought about it I thought you may be just venting "in General"

Ya... all that work for that would suck

I just spent another night working on it... still waiting to hear from Peter about his progress & opinions... I think he's working on the FULL PCB :wink:

We'll see.

Send me your email & I'll send you all the current files... like the raw PCB files so you can see what's up & or etch your own. There are some extras missing in the schematic that you can see on the original (cloned) PCB.

I would recommend that anyone who takes these files remember... it may NOTE be %100 but SHOULD be very close. You can help by using the MAIN PCB file, parts list & Schematic to reference the project & find errors, if any.

I'd like to see a group effort for a new cool easy EQ :grin:

Thanks, Peter (#2)
Kevin

 

[khstudio]

x

 

[okgb]

Thanks for sharing your work & effort Kev , i appreciate it

I'm in for a board if anyone is making some ,

regards Greg

 

[MrZpliff]

[quote author="okgb"]Thanks for sharing your work & effort Kev , i appreciate it

I'm in for a board if anyone is making some ,

regards Greg[/quote]

Me too !

Great job on this one :thumb: :thumb: :guinness:

 

[khstudio]

I'm getting set up for etching right now so well see if this thing works pretty soon... wish me luck :green:

I did fix the errors & will repost the PCB.

Is a CCW Audio pot a Reverse Audio Taper :?: :?: :?:


Kevin

 

[peterc]

Is a CCW Audio pot a Reverse Audio Taper

Probably not, the taper is usually specified after the value. You said the value was 500kA, the A value is log taper usually. O dont know where the CCW comes from. Is it printed on the pot?

Peter