check for errors? as far as i know, it is completely correct.
(http://img96.imageshack.us/img96/2617/eq7qc.png)
(http://img206.imageshack.us/img206/6440/eq24xd.png)
from here (http://www.mitedu.freeserve.co.uk/Circuits/Audio/3band.htm)
;D
oh and I need someone to copy this into a transferable format... I'll email you the original file if needed.
Does that actually count as an equalizer? Isn't it just a three knob tone stack?
dave.
I think it is considered a bad idea to run traces between the pins of an IC? Thinks look a bit tight tolerance wise. If you have any thoughts of making more than one, you might want to look at having ExpressPCB make the boards, especially with tolerances that tight, and the ground plane design. If you can fit four circuits on a 3.8"X5" miniboard, it brings the per-board cost down to under $5@ (3 miniboards for $59).
Kerry M
Quote from: StickMan on March 13, 2006, 12:49:14 AM
Does that actually count as an equalizer? Isn't it just a three knob tone stack?
dave.
It counts. I would count it since it is an active 3band EQ. If it was just the 3 bands that cut, I would probably refer to it as a tone stack. But in all reality, even that is an equalizer.
Quote from: bwanasonic on March 13, 2006, 01:10:28 AM
I think it is considered a bad idea to run traces between the pins of an IC? Thinks look a bit tight tolerance wise. If you have any thoughts of making more than one, you might want to look at having ExpressPCB make the boards, especially with tolerances that tight, and the ground plane design. If you can fit four circuits on a 3.8"X5" miniboard, it brings the per-board cost down to under $5@ (3 miniboards for $59).
Kerry M
it's a ground trace though... didn't know there were any special trace guidelines for (relatively) low voltage applications like this.
Here's a good description of how to get around all the trash in ExpressPCB and print out a transferable layout:
http://www.robotroom.com/PCB.html (http://www.robotroom.com/PCB.html)
I haven't done too many boards, but I agree that running that trace between the pins might be a challenge if you're etching this board at home. Mostly about tollerances and trace widths. Try switching the orientation of the two caps at top left and the resistor (and a lot more stuff I'm sure) The idea being to bring the two branches of that trace together on the left side of the chip so you won't have to run that trace between the pins. Sorry if this isn't helpful, but I don't have the time today to try my hand at the layout.
Chester
Nice layout No One Ever! I want to hear it.
Just what I was looking for, how timely - me want to build!
I volunteer make a transfer for this. And output a gif or pdf file (like the ones on GGG) for use with PnP Blue.
I would want to make a few boards for personal use.
Perhaps a jumper on the component side for that trace going between IC pins.
Message me if you would like me to post my transfer.
Pushtone
I just saw the link to the schem. ::)
Problem is the freq. centers of 50Hz, 1kHz and 10kHz are not so great for guitar.
Can these be tuned to more guitar friendly frequencies by changing caps?
I'm thinking 200Hz, 630Hz and 2kHz depending on how wide these filters are.
I could learn something by building this.
Pushtone
Quote from: no one ever on March 13, 2006, 06:13:00 PM
Quote from: bwanasonic on March 13, 2006, 01:10:28 AM
I think it is considered a bad idea to run traces between the pins of an IC? Thinks look a bit tight tolerance wise. If you have any thoughts of making more than one, you might want to look at having ExpressPCB make the boards, especially with tolerances that tight, and the ground plane design. If you can fit four circuits on a 3.8"X5" miniboard, it brings the per-board cost down to under $5@ (3 miniboards for $59).
Kerry M
it's a ground trace though... didn't know there were any special trace guidelines for (relatively) low voltage applications like this.
Why even bother routing the ground with a trace when you have it connected to the copper everywhere anyway?
--john
Quote from: johngreene on March 14, 2006, 06:52:34 PM
Quote from: no one ever on March 13, 2006, 06:13:00 PM
Quote from: bwanasonic on March 13, 2006, 01:10:28 AM
I think it is considered a bad idea to run traces between the pins of an IC? Thinks look a bit tight tolerance wise. If you have any thoughts of making more than one, you might want to look at having ExpressPCB make the boards, especially with tolerances that tight, and the ground plane design. If you can fit four circuits on a 3.8"X5" miniboard, it brings the per-board cost down to under $5@ (3 miniboards for $59).
Kerry M
it's a ground trace though... didn't know there were any special trace guidelines for (relatively) low voltage applications like this.
Why even bother routing the ground with a trace when you have it connected to the copper everywhere anyway?
--john
exactly! new layout coming out in a bit (shorter height, longer width, as this is designed to be mounted on the side wall of an enclosure, along with other improvements)
Quote from: Pushtone on March 14, 2006, 02:05:32 PM
Nice layout No One Ever! I want to hear it.
Just what I was looking for, how timely - me want to build!
I volunteer make a transfer for this. And output a gif or pdf file (like the ones on GGG) for use with PnP Blue.
I would want to make a few boards for personal use.
Perhaps a jumper on the component side for that trace going between IC pins.
Message me if you would like me to post my transfer.
Pushtone
that would be great! thanks for offering ;D
i'm sure a few R/C value changes will make this more guitar friendly. i'm short of time to do the math right now though.
here ya go! thicker traces, more clearance.
(http://img458.imageshack.us/img458/9712/slimeq6no.png)
Cool I'll do the trace tonight.
So this is to go on the wall of the enclosure. If so, it should be no taller than say... 22mm for a 1590B. Your layout will be taller than that by the looks of it.
Quote from: Pushtone on March 15, 2006, 03:01:34 PM
Cool I'll do the trace tonight.
So this is to go on the wall of the enclosure. If so, it should be no taller than say... 22mm for a 1590B. Your layout will be taller than that by the looks of it.
I'm putting it on the wall of a 2" high enclosure (univibe, smalbear 1690ns)... I believe I have breathing room in that case?
Quote from: no one ever on March 15, 2006, 07:03:22 PM
Quote from: Pushtone on March 15, 2006, 03:01:34 PM
Cool I'll do the trace tonight.
So this is to go on the wall of the enclosure. If so, it should be no taller than say... 22mm for a 1590B. Your layout will be taller than that by the looks of it.
I'm putting it on the wall of a 2" high enclosure (univibe, smalbear 1690ns)... I believe I have breathing room in that case?
yep i do (checked)
Here's the transfer. Did I get it right?
http://www3.telus.net/david65/pedal-pics/3BandEQ-PCB-FOROUTPUT.pdf
(http://www3.telus.net/david65/pedal-pics/3BandEQ-PCB-FOROUTPUT.pdf)
Oops I already see two traces that are too close together.
Please check it before I update it.
Thanks
Pushtone
Would I be wrong to think this circuit would have an input impedance of around 10k?
I'm thinking a buffer before the EQ would be a good idea.
It would add 2 or 3 cm to the legnth.
Quote from: Pushtone on March 16, 2006, 10:41:47 PM
Here's the transfer. Did I get it right?
http://www3.telus.net/david65/pedal-pics/3BandEQ-PCB-FOROUTPUT.pdf
(http://www3.telus.net/david65/pedal-pics/3BandEQ-PCB-FOROUTPUT.pdf)
Oops I already see two traces that are too close together.
Please check it before I update it.
Thanks
Pushtone
Thank you very much, Pushtone!
I'll get on the buffer...
whew! quickest layout i've ever made. thanks Jack for hosting such a plethora of schematics.. including buffers :icon_biggrin: (see miniboost page at muzique for schem)
(http://img358.imageshack.us/img358/3039/buffereq3qs.png)
and trace
(http://img20.imageshack.us/img20/5524/buffereqtrace8so.png)
oh and a note: this layout uses the inverting output... should I have used the non-inverting second output?
Quote from: no one ever on March 18, 2006, 04:31:10 PM
(see miniboost page at muzique for schem)
oh and a note: this layout uses the inverting output... should I have used the non-inverting second output?
Do you mean to say you used the mini-booster for the buffer? I just built one a while back and it wouldn't be my first choice for this application. I love the sound of the mini-booster but I think this circuit calls for a clean 1:1 buffer. The mini-boostr is half to three quarter the way to a fuzz box. Its a dirty preamp, or should I say, sounds like tube grit, which is what it's suppose to do. I'm going to call mine True Grit because if John Wayne had played guitar, he would of used a mini-booster.
Anyway..., is there anyway I could talk you into a layout using a TL072? The IC buffer at GGG perhaps?
About the non-inverting output... yeah it should not invert the phase unless there is to be another inverting amp used after the EQ circuit. I f I understand right, this little EQ could be inserted after a BSIAB circuit to boost bass respone or something. SO, if this is right, it should have a high impedance input (buffered) and a low impedance, non-inverted output.
Quote from: Pushtone on March 18, 2006, 05:33:34 PM
Do you mean to say you used the mini-booster for the buffer? I just built one a while back and it wouldn't be my first choice for this application. I love the sound of the mini-booster but I think this circuit calls for a clean 1:1 buffer. The mini-boostr is half to three quarter the way to a fuzz box. Its a dirty preamp, or should I say, sounds like tube grit, which is what it's suppose to do. I'm going to call mine True Grit because if John Wayne had played guitar, he would of used a mini-booster.
Anyway..., is there anyway I could talk you into a layout using a TL072? The IC buffer at GGG perhaps?
About the non-inverting output... yeah it should not invert the phase unless there is to be another inverting amp used after the EQ circuit. I f I understand right, this little EQ could be inserted after a BSIAB circuit to boost bass respone or something. SO, if this is right, it should have a high impedance input (buffered) and a low impedance, non-inverted output.
hmm.. alright then. the article says the output is unity gain, but i'll whip up an alternate buffer anyways. :icon_biggrin:
GGG IC Buffer
(http://img213.imageshack.us/img213/7601/gggbuffereq9wk.png)
trace
(http://img232.imageshack.us/img232/203/gggbuffereqtrace7rw.png)
crap.
looking at datasheets... tl071's max input V is 15 and the lf351's input resistance (impedance?) is 1012ohms!
thinking of replacing the lf with the tl071 and putting in one of those voltage regulators-on-a-chip thingies.
but, then the power scheme within the vibe would be strained, i think.. the single 15v regulator will feed the eq circuit and the vibe's signal path, and the straight 18v will go to the LFO of the vibe... cross my fingers, i guess.
:icon_neutral:
Quote from: no one ever on March 18, 2006, 11:14:46 PM
crap.
looking at datasheets... tl071's max input V is 15 and the lf351's input resistance (impedance?) is 1012ohms!
thinking of replacing the lf with the tl071 and putting in one of those voltage regulators-on-a-chip thingies.
but, then the power scheme within the vibe would be strained, i think.. the single 15v regulator will feed the eq circuit and the vibe's signal path, and the straight 18v will go to the LFO of the vibe... cross my fingers, i guess.
:icon_neutral:
well, they're pin for pin matches, so a new layout isn't a problem.
whew! ah the wonders of paint.
(http://img65.imageshack.us/img65/2118/bugger1ix.png)
hope somebody besides me finds this useful. :icon_biggrin:
I'm thinking of building one of these..can you post the shematic you used for the buffer?
And what replacement caps might sound better for guitar?
Quote from: rockgardenlove on March 22, 2006, 07:22:29 PM
I'm thinking of building one of these..can you post the shematic you used for the buffer?
And what replacement caps might sound better for guitar?
here (http://www.mitedu.freeserve.co.uk/Circuits/Audio/3band.htm) you are, sir.
and the cap question is pending. :icon_biggrin:
No, I meant the shematic for the buffer...like it needs to go Buffer->EQ->Amp right? Or else it will load the pickups wrong.
Quote from: rockgardenlove on March 22, 2006, 07:58:03 PM
No, I meant the shematic for the buffer...like it needs to go Buffer->EQ->Amp right? Or else it will load the pickups wrong.
ah. yes. here (http://generalguitargadgets.com/pdf/ggg_ic_buffer.pdf) ya go. (pdf)
and the buffer is before the eq anyway, so no worries. input is on the left, as is the buffer circuit.
The confusion is about words only: I think I see a mosfet buffer stage, not a minibooster (which is a jfet muamp, uses two jfets). You should be ok, although my guess is that stuck on the output of a reasonably low output impedance effect, a bipolar buffer would work fine, without biasing issues. Did you look at Jack's buffers article?
Ben
Quote from: Ben N on March 23, 2006, 03:27:41 AM
The confusion is about words only: I think I see a mosfet buffer stage, not a minibooster (which is a jfet muamp, uses two jfets). You should be ok, although my guess is that stuck on the output of a reasonably low output impedance effect, a bipolar buffer would work fine, without biasing issues. Did you look at Jack's buffers article?
Ben
well the third layout is the minibooster w/ buffer mod, using the inverting output. i'll have to modify that one for non-inverting output.
the latest layout uses the simple ic buffer from ggg.
i agree with your 'low impedance' statement, i think i'll remedy that with the minibooster instead of the ggg buffer. its a clean enough boost/buffer for me.
The Mini-Booster is half to three quarters the way to a fuzz box. :icon_eek:
I can get a Fender type clean sound out of my new Fat Boostered with the aid of the VOL and GAIN controls but the Mini-Booster is always at least "gritty" when at unity gain. Maybe mine is F*#@-Up?
On second thought, it sounds too good to be that.
But thanks for the 3-band with the GGG buffer as I have parts for that.
I have to admit, the 6-band EQ poster after your 3 band kinda kill the buzz I was feeling about the 3-band. But I'm back into it as I really want a small circuit that can go into an existing stompbox to add bass, or whatever.
Hey no one ever- do you need me to trace any of these and output a pdf?
Quote from: Pushtone on March 23, 2006, 06:48:48 PM
The Mini-Booster is half to three quarters the way to a fuzz box. :icon_eek:
I can get a Fender type clean sound out of my new Fat Boostered with the aid of the VOL and GAIN controls but the Mini-Booster is always at least "gritty" when at unity gain. Maybe mine is F*#@-Up?
On second thought, it sounds too good to be that.
But thanks for the 3-band with the GGG buffer as I have parts for that.
I have to admit, the 6-band EQ poster after your 3 band kinda kill the buzz I was feeling about the 3-band. But I'm back into it as I really want a small circuit that can go into an existing stompbox to add bass, or whatever.
Hey no one ever- do you need me to trace any of these and output a pdf?
nah, thats fine. i figured out a way to output a gif and i just scale it in word. thanks for your help though, pushtone! :icon_biggrin:
although in my experience, the minibooster hasn't sounded dirty at all... hmmm. oh well.
Quote from: no one ever on March 23, 2006, 06:22:29 PM
Quote from: Ben N on March 23, 2006, 03:27:41 AM
The confusion is about words only: I think I see a mosfet buffer stage, not a minibooster (which is a jfet muamp, uses two jfets). You should be ok, although my guess is that stuck on the output of a reasonably low output impedance effect, a bipolar buffer would work fine, without biasing issues. Did you look at Jack's buffers article?
Ben
well the third layout is the minibooster w/ buffer mod, using the inverting output. i'll have to modify that one for non-inverting output.
the latest layout uses the simple ic buffer from ggg.
i agree with your 'low impedance' statement, i think i'll remedy that with the minibooster instead of the ggg buffer. its a clean enough boost/buffer for me.
Nope, that is not a minibooster, although it may be an AMZ Mosfet boost in buffer mode. Go back to AMZ, and you will see that they are two completely different circuits, and the idea expressed here that the minibooster can act as a distortion is misplaced in relation to this circuit (although of course anything with gain can distort if pushed).
Quote from: Ben N on March 24, 2006, 09:49:06 AM
Nope, that is not a minibooster, although it may be an AMZ Mosfet boost in buffer mode. Go back to AMZ, and you will see that they are two completely different circuits, and the idea expressed here that the minibooster can act as a distortion is misplaced in relation to this circuit (although of course anything with gain can distort if pushed).
right you are! whoopsies. my bad on my faulty naming conventions :icon_rolleyes:. mosfet boost is what i meant all along. and yes, its in buffer mode.
good catch!
So has anyone worked out those capacitor substitutions?