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[IN STOCK] L-1 Quad VC EQ. Eurorack. (Mouser cart p.4)
MUFF WIGGLER Forum Index -> Music Tech DIY  
Author [IN STOCK] L-1 Quad VC EQ. Eurorack. (Mouser cart p.4)
L-1
Now is time for announces. I too decided not to break away from the team.

I'm working now on the Quad VC Equalizer/Resonator. Already finished simulation works.

Your comments/critique are welcome.

I used as reference 'Digitally-Controllable Audio filters and Equalizers' paper of Gary K. Herbert and Fred Floru.
http://www.thatcorp.com/datashts/AES13-031_Digitally_Controllable_Audi o_Filters.pdf

The device has four identical bands with BP filters. Also first band is switchable to HP mode and fourth band to LP to make low and high shelves. Also each band is switchable to boost or cut modes.

Every parameter has voltage control, also I plan master CV ins for all bands.

Controls are:

FREQUENCY is peak frequency of a band. Range is 10 octaves. V/oct responce and initial frequency are trimmable with trimpots. CV range is 0...10V.

BANDWIDTH range is from 2 octaves to 0.06 octave at 3dB point. CV range is -5....5V.

LEVEL range is 14dB. CV range is 0...5V.

LM4040 precise voltage source for all offset voltages.

Temperature compensation.

Filters are based on hi-end quality THAT2180 chips. VCA for resonance gain (level control) is discrete.

Chips used:

8 x THAT2180
2 x THAT300
3 x TL074 (for CV)
12 x dual opamps for audio. I will use OPA2604 but TL072 possible.

24HP Eurorack.




Here are simulation plots:

BANDWIDTH

from -5V to 5V CV in 1V steps. Level CV is 5V. Freq CV is 5V.

Simulation is made for 5V amplitude modular input signal level (14dB).

I didn't changed level for cut mode but for boost mode I decreased level from 14 to 0 dB to have headroom for boosting.

cut:



boost:





LEVEL

From 0 to 5V CV in 0.5V steps. Bandwidth CV is -5V. Freq CV is 5V.

cut:



boost:





FREQUENCY

From 0 to 10V CV. Bandwidth CV is -5V. Level CV is 5V.




I expect a bit of selfoscillation on high frequencies for thin bandwidth.
This is plots for 3 last volts of frequency and 3 last volts of bandwidth.




LOW AND HIGH SHELVES

They are not shelvig filters really but HP for low self and LP for high shelf.
So if we want to cut low freq, we need to swith in boost position.
We can very effectively cut (or boost) low (or high) freqencies. Bandwidth setting changes slope in this case.
On the plots bandwidth setted to min, middle, max (-5V, 0V, 5V). Freq setted to min for low shelf, to max for high shelf.










TEMPERATURE COMPENSATION.

I made temperature compensation for the filters, it affects to frequency and bandwidth.
But I didn't made tempco for level. It makes 1dB loss from 25 to 75 °C. I think it's not so important.

Plots for 25, 50, 75 °C.

Without tempco:




With tempco:

Dogma
before I explode Alex how long till production?

I cant wait to show off my L1 rack....bring on the ADSR and now this!
horstronic
Awesome!
albmoya
Impressive. Good job!
jules
I know that you don't have anymore space on your panel (and it's already big), but individual outs for the bands would be cool. Maybe leave some easy to access jumpers/connectors at the back of the PCB.
albmoya
Quote:
I know that you don't have anymore space on your panel (and it's already big), but individual outs for the bands would be cool. Maybe leave some easy to access jumpers/connectors at the back of the PCB.

+1
It would be cool applause
L-1
albmoya wrote:
Quote:
I know that you don't have anymore space on your panel (and it's already big), but individual outs for the bands would be cool. Maybe leave some easy to access jumpers/connectors at the back of the PCB.

+1
It would be cool applause



It's not so easy really. To have cut mode, bands must be connected in series.
So individual out of each band must be normalled to individual in of next band. An expander is impossible.
I'm thinking to make bipolar CV for level. Negative voltage will make cut, positive - boost. It allows to avoid boost-cut switches and to place individual in-outs for each band at these places. I think it must work but will make the module more complex and expensive. It means worst sales for me...
But it will allow to make interesting modulations..
So, I have what to think hmmm.....

I'm thinking about CD4066 electronic switches..

albmoya
Do you mean something like the "Band" and "Notch" outputs on the Cwejman RES-4? That would be nice, too.
synthdiy
Nice work @L-1. I've shared it to synthdiy subreddit.
jules
Bipolar CV control to go from cut to boost is a great idea.

Then your next module will then be a joystick so you can plug CV level cut/boost on the Y axis, and bandwidth CV control on the X axis.
(Or you make a theremin to control of these 2 parameters).
I guarantee some happy customers.
L-1
albmoya wrote:
Do you mean something like the "Band" and "Notch" outputs on the Cwejman RES-4? That would be nice, too.



Boost mode = "band".

Cut mode = "notch".

Just same phenomenon called differently.


jules wrote:
Bipolar CV control to go from cut to boost is a great idea.


OK, will work on it.
cranleigh
Absolute definite build for me! the poor man's res-4!
Rockin' Banana! Rockin' Banana! Rockin' Banana!
sonicwarrior
cranleigh wrote:
the poor man's res-4!

I hope it pings as well.
synchromesh
Looks fantastic! The banana jack conversion might be a bit tight, but that's fine...
CLee
Nice work, looks really interesting.
fluxmonkey
very nice, i have a few eq's in various formats, but none w/ VC.

having the bandwidth control going from wide (fully counterclockwise) to narrow (clockwise) seems backwards to me... no big thang, just saying
L-1
fluxmonkey wrote:
very nice, i have a few eq's in various formats, but none w/ VC.

having the bandwidth control going from wide (fully counterclockwise) to narrow (clockwise) seems backwards to me... no big thang, just saying


OK will make backwards, it's possible.
CLee
L-1 wrote:
fluxmonkey wrote:
very nice, i have a few eq's in various formats, but none w/ VC.

having the bandwidth control going from wide (fully counterclockwise) to narrow (clockwise) seems backwards to me... no big thang, just saying


OK will make backwards, it's possible.


Makes sense to me. Its like the Q control on an eq
Kashyyyk
i want the first serial number the 0001 love
ben_hex
Looks great, having Shelves, the Serge Res EQ and Ladik E-110 I'm an EQ in the rack fan smile
Reality Checkpoint
Any update on this?
L-1
Now I spent all money on VCADSR and PSU + Busboard projects.
PSU + Busboards will be full kits, include transformers.
So this VCEQ will be autumn project.
Reality Checkpoint
L-1 wrote:
Now I spent all money on VCADSR and PSU + Busboard projects.
PSU + Busboards will be full kits, include transformers.
So this VCEQ will be autumn project.


Roll on the autumn!!
Paradigm X
man sooner or later im going to have to give up and go eurorack. these no wiring projects look so easy. And theres actually a fair bit of wiggle room for the knobs, which is my usual complaint about euro.

Looks awesome smile

Great feature set, switchable HP/LP/BP on the end two bands is great!

Cheers
Funky40
personally i would add a bypass switch on such a module.
....i see there some tiny space left on the left side of the out jack.
Any FX module and any filter should have a bypass switch.
.......makes experimenting around ALOTS faster !.....and patching and jamming more flexible.

i also would add some vertical lines on the bottom row of jacks for better distinguishing between the four filter units and their jacks.

i know, it would take a little away of the symmetrical optics. at least a switch more.
personally i rate functionality much higher than optics wink...but thats me lol
Endorfinity
please make individual outputs for stereo operation MY ASS IS BLEEDING
fragletrollet
jules wrote:
Bipolar CV control to go from cut to boost is a great idea.


OK, will work on it.[/quote]

Yes please!

Looking forward to this!
komyta
4-band parametric EQ in Eurorack...
I've been dreaming about it !

spinning
L-1 wrote:
I'm thinking to make bipolar CV for level.

Great move !
That would make it much easier to operate, in my opinion.
fragletrollet
Not to be talking about using it more drastically in sound-design. Love slow modulating eq on chords through delays/rev...
komyta
Yes, being able to use it that way would be great !

I'm pretty sure most people would appreciate the Bipolar CV for Level.
woodenbox
This thing looks amazing - any soundclips? how does it respond to pinging?
DomMorley
Any updates on this? hyper
cranleigh
Yeah, still interested too!
L-1
I have correct working channel on DIY PCB.
Now routing the PCBs for the final prototype. Will show soon.
L-1
I built correct working channel. It sounds perfect! thumbs up

Also I already routed the PCBs. Construction is similar to L-1 VC Stereo Mixer.

L-1 Quad VC EQ features:

- four independent channels with full voltage control.
- first channel switchable to low shelf, fourth channel switchable to high shelf.
- independent ins and outs for every channel. Out of previous channel is connected to in of next channel via IN jack's switched pin.
- DIP switches turn on resonance loop and filters start to oscillate sine waves when LEVEL is positive. It's for v/oct trimming and just to use as sine oscillator if needed.
- frequency v/oct responses and initial frequencies (offsets) are trimmable via trimpots at the back.
- temperature compensation for Frequency and BW controls.

Controls are:

FREQUENCY - potentiometer range = CV range = 10V = 10 octaves.

BANDWIDTH - potentiometer range = CV range = -5V...+5V = 0.8....24 semitones.

LEVEL - potentiometer range = CV range = -5V...+5V = -16....+16 dB

IC's used:

8 of THAT2180
12 of OPA2604 (TL072 possible) - audio chains opamps.
8 of TL074 - CV chains opamps.
2 of DG412 analog switches.
2 of THAT300 or BCM847BS or matched 2N3904 pairs.

Prototype top - looks ugly but sounds cool:



Prototype bottom - a bit of shamanizm:




PCB1 - control board:



PCB2:

fragletrollet
Looks Nice, but is the high shelf on the left and low shelf on the right? Seems opposite to me...?

But Else i love the input and output configuration and feature set!
L-1
fragletrollet wrote:
Looks Nice, but is the high shelf on the left and low shelf on the right? Seems opposite to me...?

But Else i love the input and output configuration and feature set!



Pictures drawn wrong maybe. It switches from BP filter to LP at the first channel, and to HP filter at the fourth channel.
L-1
Corrected frontpanel:

prscrptn
^ wow, this looks great! w00t
indigoid
How many cycles are those DIP switches rated for? Is there no other dual switch that fits?

Otherwise, looks fantastic.
fragletrollet
indigoid wrote:
How many cycles are those DIP switches rated for? Is there no other dual switch that fits?

Otherwise, looks fantastic.


Agree!
L-1
0,75 € Multicomp switch has golden contacts and 2000 cycles.
http://ru.farnell.com/multicomp/mcnds02/switch-dil-2-pos-spst/dp/94721 26


2,67 € C & K COMPONENTS switch has golden contacts and 10000 cycles.
http://ru.farnell.com/c-k-components/bd02/switch-2-way-spst-tht/dp/231 9977


$0.17 switch in Tayda promises gold contacts but I doubt.
http://www.taydaelectronics.com/electromechanical/switches-key-pad/dip -switch/dip-switch-2-positions-gold-plated-contacts-top-actuated.html


I see no problem with that. Everyone can choose. 10000 cycles is much more than enough.
I will install Multicomp ones on assembled by me modules.
The purpose of this switch is to turn a filter in selfoscillation. May be used twice per year for v/oct trimming and sometimes to get sinewaves.
richard
wow

bring it on

also not keen on the dip switches

but I will buy one anyway
cranleigh
Rockin' Banana!
excellent, will get one without question
cranleigh
How do the outputs work? Is output 4 the sum of all bands if the other outputs are not tapped?
And any chance of more master outputs with bandpass/notch/etc modes?

It's peanut butter jelly time!
Endorfinity
DOPE screaming goo yo
L-1
cranleigh wrote:
How do the outputs work? Is output 4 the sum of all bands if the other outputs are not tapped?
And any chance of more master outputs with bandpass/notch/etc modes?

It's peanut butter jelly time!


Channels are connected in series. Out of previous channel is connected to in of next channel via IN jack's switched pin. So if you connect a new signal says in the IN3, you disconnect channels 1 and 2 from the OUT4 (sum out).

Bandpass mode = LEVEL is positive. Notch mode = LEVEL is negative.
cranleigh
L-1 wrote:
Bandpass mode = LEVEL is positive. Notch mode = LEVEL is negative.


Great -so does that mean an LFO into the Level jack will create a morph between the modes?
L-1
cranleigh wrote:
L-1 wrote:
Bandpass mode = LEVEL is positive. Notch mode = LEVEL is negative.


Great -so does that mean an LFO into the Level jack will create a morph between the modes?


yes correct.
there is an electronic switch. It creates tiny clicks at zero crossing but they are practically non-audible at work.
cranleigh
Brilliant, that sounds really fun. When do you think the boards/panel will be available?
L-1
cranleigh wrote:
Brilliant, that sounds really fun. When do you think the boards/panel will be available?


Small batch PCBs is ordered for testing. Will see...
Emalot
IS it hard to put main NOTCH OUTPut?
L-1
Emalot wrote:
IS it hard to put main NOTCH OUTPut?


Negative level makes notch. I second time answer this on one page.

L-1
I've assembled the prototype module. It works correct but I stupidly confused LEVEL control direction. So need to order another boards.

First record here. Photos - tomorrow.

Two mixed waves from L-1 Basic VCOs. I modulate all CV inputs with LFOs.
Download the WAV file for normal quality.

[soundcloud url="https://api.soundcloud.com/tracks/234731348" params="auto_play=false&hide_related=false&show_comments=true&show_use r=true&show_reposts=false&visual=true" width="100%" height="450" iframe="true" /]
Reality Checkpoint
Excellent progress! Will definitely be on my to buy list.
cranleigh
Animal! Animal! Animal! Animal! Animal! Animal!
sounds great -really growly and alive toward the end of the demo.
L-1
I forget to post the photos. They are here (no panels yet):









jules
Really like the holes on the 2nd board for the lytics and power header!!
It make it make look like a smily face.

It's going to be a bit of work though. Thats a lot of SMT to solder.
samuraipizzacat29
They come from Aleksei pre-done. Besides, 1206 is easier to hand solder than through hole anyway thumbs up
L-1
jules wrote:
Really like the holes on the 2nd board for the lytics and power header!!
It make it make look like a smily face.

It's going to be a bit of work though. Thats a lot of SMT to solder.


L-1 VC Stereo Mixer has the same holes smile

And yes, I offer boards with all SMDs installed for little additional money.
FetidEye
this project is awesome!
VanEck
Looking good! Looking forward to this one. Just wish it could do stereo with an expansion.
jules
EDIT: Answered question.
sorry, it's on the first page, size: 24HP.
guitarfool
Good job! Looks like another "must have" module Euro "Standard" ftl
Emalot
Some News?
L-1
The VC Equalizer is ready! Sounds perfect!
Ordering a batch. Will be in stock in one month.
Now have 3 kits for sale. Write in comments who want.

Pricing:

2 PCB - 2mm thickness, gold platted, black mask. $35 x 2 = $70

Two panels - 24HP front & back. Anodized alu, black print. $45

SMD parts + soldering. $30

8 tempco resistors $10

Standoffs

Shipping per set: $5 - only boards, $10 - boards+panels.

TOTAL for complete set with shipping: $165

Assembled module $680.






Special edidtion board with silver mica capacitors. Sounds better.
Also there is two options on transistor pairs - or THAT300 or BCM847BS (not installed in kits).





Dogma
sounds absolutely brilliant on the demo wink i reckon i will use this a lot more than i would a Res-4 (be nice to have both but id have this first)

Theres a fair bit of expensive chips in here - wondering if a group buy might be an idea?
Puzzler
I want one. Miley Cyrus
hendrkf
I would like to order an assembled module. Please email me at: hendricks2018@gmail.com
koshi
Hey guys just heads up, I managed to get factory build of this module by Alex.
w00t
This thing sounds amazing. Got really cool drum sounds out of it, leads, bass. Not to mention it rocks as master EQ. Really cool for bringing out the textures in the patches. I linked it with Modcan Quad LFO and they work great together, it likes lots of CV. Panel layout it great, lots of space, not too cramped.
thumbs up
Here is few demos of it, with patch notes. Feel free to download the files.

[soundcloud url="https://api.soundcloud.com/tracks/250484010" params="auto_play=false&hide_related=false&show_comments=true&show_use r=true&show_reposts=false&visual=true" width="100%" height="450" iframe="true" /]

[soundcloud url="https://api.soundcloud.com/tracks/250661333" params="auto_play=false&hide_related=false&show_comments=true&show_use r=true&show_reposts=false&visual=true" width="100%" height="450" iframe="true" /]

[soundcloud url="https://api.soundcloud.com/tracks/250486074" params="auto_play=false&hide_related=false&show_comments=true&show_use r=true&show_reposts=false&visual=true" width="100%" height="450" iframe="true" /]

[soundcloud url="https://api.soundcloud.com/tracks/250486075" params="auto_play=false&hide_related=false&show_comments=true&show_use r=true&show_reposts=false&visual=true" width="100%" height="450" iframe="true" /]
cranleigh
Sounds killer. Will be building one of these when I get the time...
mOBiTh
Looking great Alex!

The Filter Q/curve should get more pointy with clockwise direction IMO
noisefor
I'll take one!
FetidEye
i'll take one
Dogma
When is the VEQ gonna be on your site Alex? And your bloody handy Mouser carts? You have no idea how helpful they are - this is gonna be so so so good smile
Emalot
Somebody try to ping it?
cranleigh
Any updates on when this will be on your site, Alexi?
L-1
I've assembled two test devices. Everything works OK. So I start sales.

http://l-1.su/VCEQ.html



PCB1 bare:




PCB2 bare:




PCB1 with SMDs:




PCB2 with SMDs and tempcos:

L-1









cane creek
Is it ok to experiment with the capacitors, like 8 X K71-7 4.7NF or Sprague Vitamin Q instead ?
L-1
cane creek wrote:
Is it ok to experiment with the capacitors, like 8 X K71-7 4.7NF or Sprague Vitamin Q instead ?


Experiments are always OK SlayerBadger!

I've tried silver micas there but it's expensive but sounds better imho. Small ones from Banzai fit.

synchromesh
L-1 wrote:
I've assembled two test devices. Everything works OK. So I start sales.


Lovely work as always Alex! we're not worthy

I'm building my Eurorack with banana jacks, so I would like to ask you how many normalled jack sockets you have here.
L-1
synchromesh wrote:
L-1 wrote:
I've assembled two test devices. Everything works OK. So I start sales.


Lovely work as always Alex! we're not worthy

I'm building my Eurorack with banana jacks, so I would like to ask you how many normalled jack sockets you have here.


The inputs of 2, 3, 4 channels are normalled from the outputs of previous channels.
Daisuk
Any sound demos of this floating about? cool
samuraipizzacat29
There's a handful in the previous pages of the thread. I don't think there are a whole lot of these built out in the wild just yet. Working on mine in the near future.
L-1
Sounds good. I use it for every voice and two on master. Really good.
With mica caps is a bit better than with polystyrenes. For audiophiles.
padski
Hi Mr L-1, Do you have any calibration instructions or do we wing it?
I've just finished one for someone smile
Very nice, by the way smile
Padski
L-1
Calibration is V/oct and offset.
Turn first channel in selfoscillation. LEVEL - max, BANDWITH - min, DIP switch to reso.
V/oct and offset trimming is the same as for other oscillators and filters.
Send a note, says C1. Trim offset to C1 exact. Then check C2 C3 C4 C5. If pitch goes higher, trim v/oct in direction where pitch goes more higher. Return to C1, trim offset again exact. Repeat until you will have exact tracking.

Turn LEVEL on zero (center), swith back. Go to next channel.
cranleigh
Do you have a mouser cart for this one ALex?
koshi
Loving this module!
@Daisuk Here is another short demo with Modcan Quad LFO as voice source.
[soundcloud url="https://api.soundcloud.com/tracks/280485244" params="auto_play=false&hide_related=false&show_comments=true&show_use r=true&show_reposts=false&visual=true" width="100%" height="450" iframe="true" /]
FetidEye
Have you experimented with feedback?
(selfpatching or with audio thru)

I'm wondering about the sounds it can make.
I really like the Serge resEQ feedback sounds (I have 2 of those)
especially with drumsounds or drones
koshi
Actually I didn't yet. Mainly because i also use ResEQ for feedback and indeed its fantastic for that. Combined with Wave Multiplier! Dead Banana

I use L-1 EQ mainly at the end of the patch or part of the patch great with digital stuff like Harvestman. It works great with ResEQ as well actually. It sounds more expensive, less rough if that makes sense compliments it really well. Kind of like mastering EQ.

Gotta try feedback patch now you mentioned it.

thumbs up
L-1
koshi Thanks for the demo!


cranleigh Working on a cart now. Hope tomorrow will post here.



L-1
L-1 Quad VC Equalizer - Mouser shopping cart

http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=edf38 e2226

MERCHANDISE TOTAL: $137.76 (USD)

Parts not included in Mouser shopping carts:

12 OPA2604 - included in the cart but non-stocked now, therefore not calculated in total. TL072 or your favorite dual opamps can be used.

8 4700p (4.7n) polystyrene capacitors. Mouser has only radial ones but axial needed. Lenght 18mm max, high 10mm max. Banzaimusic has in stock, also they have mica caps, blue ones, they fit by size, sound better but expensive. Also Banzai has genuine OPA2604.

12 50K linear 9mm PC mount potentiometers
12 knobs
23 inline jacks

These buy at Thonk (UK) or Erthenvar (US). Thonk has center detent pots, good for Level.
koshi
@FetidEye

Here is quick feedback patch for you. It makes really nice voice. I think I need two of them now Dead Banana
Tracks really well. Works great in resonance mode. I've put the switches up for all the filters and sequenced with SH MK2 modulated with Maths and Modcan Quad LFO, no extra sources or processing. It gets brutal like ResEQ
thumbs up

[soundcloud url="https://api.soundcloud.com/tracks/281406005" params="auto_play=false&hide_related=false&show_comments=true&show_use r=true&show_reposts=false&visual=true" width="100%" height="450" iframe="true" /]
Dogma
koshi wrote:
Loving this module!
@Daisuk Here is another short demo with Modcan Quad LFO as voice source.
[soundcloud url="https://api.soundcloud.com/tracks/280485244" params="auto_play=false&hide_related=false&show_comments=true&show_use r=true&show_reposts=false&visual=true" width="100%" height="450" iframe="true" /]


Lord that was awesome! i think this module just got bumped up the schedule!

NOTE: Thanks for heads up Alexi - Banzai looks the best place to get the OPA's and the MiCA's (for the extr couple of dollars i think theyre worth it - 4 euro each)
FetidEye
koshi wrote:
@FetidEye

Here is quick feedback patch for you. It makes really nice voice. I think I need two of them now Dead Banana
Tracks really well. Works great in resonance mode. I've put the switches up for all the filters and sequenced with SH MK2 modulated with Maths and Modcan Quad LFO, no extra sources or processing. It gets brutal like ResEQ
thumbs up

[soundcloud url="https://api.soundcloud.com/tracks/281406005" params="auto_play=false&hide_related=false&show_comments=true&show_use r=true&show_reposts=false&visual=true" width="100%" height="450" iframe="true" /]


wow awesome!! thanks for the demo Koshi!!!
ok i'm ordering this one
mmeixner
could this be easily modified for +15V/-15V supply?
L-1
mmeixner wrote:
could this be easily modified for +15V/-15V supply?


easier is to make 15-12V converter.
mmeixner
L-1 wrote:
mmeixner wrote:
could this be easily modified for +15V/-15V supply?


easier is to make 15-12V converter.


ok - understood. thanks!
Daisuk
koshi wrote:
@FetidEye

Here is quick feedback patch for you. It makes really nice voice. I think I need two of them now Dead Banana
Tracks really well. Works great in resonance mode. I've put the switches up for all the filters and sequenced with SH MK2 modulated with Maths and Modcan Quad LFO, no extra sources or processing. It gets brutal like ResEQ
thumbs up

[soundcloud url="https://api.soundcloud.com/tracks/281406005" params="auto_play=false&hide_related=false&show_comments=true&show_use r=true&show_reposts=false&visual=true" width="100%" height="450" iframe="true" /]


Hey man, thanks for the demos! I didn't see this until now. Sounds interesting, this thing. I wonder if it could work as a sort of subtitute for the Cwejman Res-4, which I just can't seem to score anywhere. sad banana
koshi
Daisuk don't have Res4 to compare. You can't go wrong with both tho twisted
I would be tempted with second EQ tbh one for voice one for eq or for stereo 4 band.
Potentially this one might have more uses as great as mastering EQ.
Mind you I didn't use Res4 yet...
FetidEye
I finally ordered one. EQ madness coming up!
Emalot
I would like to know how it is for pinging percussive patch?
If somebody have an example..
koshi
Emalot No exactly pinging but I did this self oscillating patch using EQ in resonance mode as poly voice for Modular Podcast #3modulechallenge. Should give you an idea.

https://www.instagram.com/p/BMCoZr-D65B/
Daisuk
FetidEye wrote:
I finally ordered one. EQ madness coming up!


How do you like it? Still very much on the fence about this. Would love to hear it some more in action (preferably on less harsh stuff). smile
Addam
Daisuk wrote:

How do you like it? Still very much on the fence about this. Would love to hear it some more in action (preferably on less harsh stuff). smile


I'm about 90% sure this is next to enter my backlog so maybe for my sake... no more demos!!

Juuuuust kidding, I'm also interested in this thing's capabilities for more melodic stuff and have loved the demos so far. Maybe some vocal formant type stuff?? smile
Emalot
koshi wrote:
Emalot No exactly pinging but I did this self oscillating patch using EQ in resonance mode as poly voice for Modular Podcast #3modulechallenge. Should give you an idea.

https://www.instagram.com/p/BMCoZr-D65B/


Thank you!
NIce patch, but i would like to listen Ping in this VC EQ, sorts of percussion.
I 'm hesitating between RES-4 and this....I know Res 4 is perfect for pinging stuff.
L-1
RES-4 has thinner BW 0.02 - 0.5 octave, and bigger gain - up to 80 dB.

L-1 has 0.8 - 24 semitones BW, and +- 16dB gain. So it not oscillates in that ranges (some oscillation may be only with thinnest BW, max gain, and highest freq)

Also L-1 has:

individual ins-outs for each band

selfoscillation switches which turn on second reso loop

BP/shelf switches for 1 and 4 bands.

level controls are bipolar !!!

temperature compensation using tempco resistors

presice voltage source for offset voltages

hi-quality capacitors (styrene or mica)

hi-fi opamps for sound chains. (OPA2604 or other dual possible)

v/oct and offset trimming is easy using selfoscillation mode.
Kan Kaban
Excelent! Congrats, I´m looking foward to make one of these...
rew_
Please count me among those who would love more audio demos!
Dogma
Alex with the self Osc bands, does that narrow the bandwidth at all?
L-1
Yes, in selfoscillation mode - BW narrow, LEVEL high.
Dogma
Expect an order very soon smile been meaning to for ages - got most of my THAT candy ready smile
oneiric.tomb
Anybody ping this yet?
Or more importantly, has anyone just run a simple sawtooth through it and tweaked the bands?
OlivierWah
I order mine today, I will make demos with pings and sawtooths in few days grin.
OlivierWah
Hello,

I make a playlist if you want demos grin

https://soundcloud.com/user-675548359/sets/l-1-quad-vc-resonant-demos

1) Only a Sawtooth from Verbos Harmonic Oscillator, no res, no CVs at all, just touch the pots of L-1 and use only out 4. Use the 4 bands of the L-1 (sawtooth go in input 1).

2) Add resonance one band by one band and play with pots.

3) Same that 2), but add CV on master frequency of L-1 and Verbos to make melody.

4) Same that 3), but add CVs on other inputs of L-1.

5) Same that 4), but use two ouputs of L-1 to make stereo effects.

6) Use Squarewave with no res to make pings.

No post-mix and effects.
Cheers
L-1
OlivierWah
Thank you for the demos!

Can I place it on my site???
OlivierWah
Yes, no problem grin.
FetidEye
finally finished mine. 1st impressions are good!

I need to set the trimpots. is there a guide?
L-1
Calibration is V/oct and offset.
Turn first channel in selfoscillation. LEVEL - max, BANDWITH - min, DIP switch to reso.
V/oct and offset trimming is the same as for other oscillators and filters.
Send a note, says C1. Trim offset to C1 exact. Then check C2 C3 C4 C5. If pitch goes higher, trim v/oct in direction where pitch goes more higher. Return to C1, trim offset again exact. Repeat until you will have exact tracking.

Turn LEVEL on zero (center), swith back. Go to next channel.
OlivierWah
I return on the RES-4 and L-1 Quad Vc Resonant versus...

I have both, and they are really different in fact.

RES-4 is organic as hell and clinical, but don't auto-oscillate. You can modulate parameters at very high speed, with FM effects. L-1 Quad have less organic pings but have bipolar level with gain boost, and so you can make it scream (be careful !) and have ultra agressive sounds with all bands in resonant mode... Another nice point on L-1 in the more flexible use with the 4 ins/outs.

I thing the two modules are really amazing and have two really differents tastes. Get both (if you can).
L-1
I planned resonant mode for v/oct calibration, not for playing really.
L-1
A little video where I make dynamic equalization. I fed v/oct from a melody to FREQ CV IN, negative out from ADSR to LEVEL CV IN. It cuts melody notes from bass sound.


resynthesize
anyone have a good source for axial 4.7n polystyrene caps in the U.S.? trying to avoid the overseas waiting game...
Revok
resynthesize wrote:
anyone have a good source for axial 4.7n polystyrene caps in the U.S.? trying to avoid the overseas waiting game...


smallbear
L-1
https://eu.mouser.com/ProductDetail/Xicon/23PW247?qs=LLoUvApQnRSgj8Kqc cfvGA%3d%3d
resynthesize
L-1 wrote:
https://eu.mouser.com/ProductDetail/Xicon/23PW247?qs=LLoUvApQnRSgj8Kqc cfvGA%3d%3d


I saw these before, but they have radial leads. can i squeeze them or should I continue the hunt for axial?
resynthesize
Revok wrote:
resynthesize wrote:
anyone have a good source for axial 4.7n polystyrene caps in the U.S.? trying to avoid the overseas waiting game...


smallbear


unfortunately no 4.7n at small bear d'oh!
Revok
The 0.0047uF are the same as 4.7nF.

Here's a site you can reference for switching from uF to nF or pF: http://www.justradios.com/uFnFpF.html

Or you can multiply or divide by 1000.
uF*1000=nF
nF*1000=pF

pF/1000=nF
nF/1000=uF

edit:had the math backwards
resynthesize
Revok wrote:
The 0.0047uF are the same as 4.7nF.

Here's a site you can reference for switching from uF to nF or pF: http://www.justradios.com/uFnFpF.html

Or you can multiply or divide by 1000.
uF*1000=nF
nF*1000=pF

pF/1000=nF
nF/1000=uF

edit:had the math backwards


ah, thanks! just ordered some from smallbear.
resynthesize
would appreciate some help with this build. channels 1 and 2 are not affecting the audio at all, e.g. what I patch to the input is what I hear on the output. channel 3 and channel 4 have a sort of resonancy effect, but they sound like they're oscillating at a barely audible high frequency.

things i have done so far:

* checked orientation of all polarized components and IC
* checked for shorts from +12/-12 to ground
* inspected and touched up a few suspicious solder joints
* took a bunch of high-res pics for inspection (attached)

I don't see any obvious issues, so I have a few questions:

1) I substituted 1n4001 diodes instead of 1n4004 since that's what I had around. Is this OK?
2) The partslist for PCB2[1] lists 2 more 1n4004 diodes, but I don't see any place for them on the PCB. Is this a documentation error or did I overlook placement?
3) I bought OPA2604s from this reverb store[2], any chance they are fake or bad? I have some TL072s lying around, I was thinking of swapping them out to test.

Any other ideas? Any/all help much appreciated! very frustrating


[1]: http://l-1.su/images/VCEQ/L-1_QUAD_VC_EQ_PCB2_Parts_list.pdf
[2]: https://reverb.com/item/2412187-10-x-burr-brown-opa2604ap-opa2604-free -shipping-new-authentic-usa-seller
L-1
resynthesize

At first - all installed OPA2604 are fake.

Solve this at first. You can try another dual opamps if don't have OPA2604.

These are original OPA2604 in new (bigger logo) and old designs. As you can see - the circle must be not flat but 3D, and the logo must be drawn dual lines.

resynthesize
L-1 wrote:
resynthesize

At first - all installed OPA2604 are fake.

Solve this at first. You can try another dual opamps if don't have OPA2604.


I just tried swapping the OPA2604s out for TL072s. Same problem Dead Banana

Here's a quick video showing what I'm hearing: https://youtu.be/5QgItxuOvlA . it's just cellphone audio so you may have to turn up the volume to hear the high-pitched oscillation at the beginning. What else could be wrong?

edit: also swapped out all the TL074s, same behavior.
L-1
resynthesize

You didn't installed standoffs. They are needed for ground connection between boards (no ground pins at the connectors).

Build looks very clean! Good job!
resynthesize
L-1 wrote:
resynthesize

You didn't installed standoffs. They are needed for ground connection between boards (no ground pins at the connectors).

Build looks very clean! Good job!


duh! I thought I was being smart by testing everything before final assembly.

With the standoffs installed, channels 3 and 4 are working great, but channels 1 and 2 are still dead. By "dead", I mean that with no input, setting the self-osc dipswitches produce no output, and if I patch something to the input, I hear it at the output but the sound isn't affected by the channels at all.

What can I check? Is it possible some of the ICs were destroyed by having no ground path?

thanks for your guidance as always Alex.
Addam
You can always try the ol' IC switcheroo (put the op amps for channel 3 into channel 1, for instance). If you're worried about things getting fried you can check the voltages at the IC sockets with the ICs removed (being careful not to short anything). Having 2 working channels makes troubleshooting "nice" (not really) because you can compare the working side vs the non-working (with a multimeter or by probing with an oscilloscope if you have one).

A bit of a longshot but you can try doing a simple continuity test between the connectors bridging PCBs 1 and 2 when they're connected (with power off, of course)
L-1
resynthesize

Common for cannels 1 and 2 are THAT300, DG412 on this side. Check them and everything around. Try to swap them with another side.

If no selfoscillation when switches are on, or oscillation too quiet, possiple to reduce resistors values in resonance loops. There are 24K99. Installing 24K usually helps. I marked them red.

NS4W
the opamps are out of stock at mouser, could you point to another source? help
resynthesize
L-1 wrote:
resynthesize

Common for cannels 1 and 2 are THAT300, DG412 on this side. Check them and everything around. Try to swap them with another side.



Swapped the THAT300 and DG412s and reflowed all IC pins, no difference :(

I got out the scope and started probing around. I see a sine at the bottom pin of every 4.7n cap, so I assume that the 24.99k resistors are fine and oscillation is starting somewhere.

Here's the difference I noticed between the two pairs of channels:

For the working pair of channels, the DG412 pins 2 and 15 are outputting a sine, while on the non-working channels there is no/minimal voltage.

For the middle and top row of OPAs, I have a sine out at pin 1 of all ICs. For the bottom row,
for the bottom row, sine out of pin 7 of channel 4, pin 1 of channel 3, and no sines out of any pin for channels 1/2.

Does this help narrow down what else I could check?
L-1
NS4W

Buy from Banzai https://www.banzaimusic.com/OPA2604.html

or use another dual opamps.

resynthesize

If you have a sine at 1-st pin of 2-nd channel middle row OPA. That means you have it at pins 11 and 14 of the DG412 switch because they connected direct. But you have no signal at switch output (15 or 10 pins for 2-nd channel). Something around the switch then.
resynthesize
L-1 wrote:


If you have a sine at 1-st pin of 2-nd channel middle row OPA. That means you have it at pins 11 and 14 of the DG412 switch because they connected direct. But you have no signal at switch output (15 or 10 pins for 2-nd channel). Something around the switch then.


Thanks. I spent about 30 minutes going over everything around the switch. Finally, I pulled out the switch IC and happened to notice this:



The eagle-eyed among you will observe that the pin 5 socket is missing the little gold ring that makes contact with the IC leg. I replaced the IC and soldered that leg in and now everything is working. This was a first for me, will check sockets in the future before installing!
L-1
resynthesize

Good you solved that all !
NS4W
Under the THAT300P socket there are two areas with pads that looks like spots for smd-chips, shall I ignore those?
hmmm.....

Just want to make sure before I solder the socket and cover the area.
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