Resonant Lopass Gate PCB's (New Batch 4/29/12)

[parasitk]

I hate to say it, but that diagonal look never did it for me. Just seems like a lot of wasted space.

[urbanscallywag]

Another Buchla question (I have many more...).

I wanted to clarify, are the knobs on the LPG offset control? There aren't any CV attenuators?

[Luka]

yup
there is no attenuators on the buchla panel at all
there was another buchla module for that

[bugfight]

[phdinfunk]

[BananaPlug]

Anybody have a sample of what two of the LPGs in series sounds like? How useful is that?

[phdinfunk]

Here in Taiwan I haven't got a computer at my house yet, so I'm drawing my designs by hand (no internet at home, did I mention I'm getting a lot done lately, LOL). Unfortunately that means I cannot post a pic yet.

I like the traditional Buchla Diagonal look and have discovered that, on a somewhat larger than standard panel, it is aesthetically pleasing to add the resonance knobs under the mode switch knobs. Also, for my CV inputs, I think having two inputs per Gate and having a dual-pot attentuation knob pan between them will be most useful for live performance.

--Jonathan, who will soon try to communicate with the Chinese at the internet cafe enough to get a drawing scanned...

[cyclotron]

2 here...

sent email w info per request

[LektroiD]

Just bought all the parts for these, as per parts list here:
http://electro-music.com/forum/download.php?id=14435
I got one set of slow vactrols and one set of fast, just so both my boards are different. Any idea when the boards are likely to be shipped (if they haven't already)? I know there's a postage lag across the pond, but my soldering iron is quivering in anticipation.

[numbertalk]

Do you mind clarifying for the numbskulls (which admittedly might just be me ) which switch position corresponds to which mode for the 3PDT toggle? For example, when the top 2 sets of poles ("top" referring to how the switch lugs are shown and oriented in the blown-up switch diagram on the schematic), which mode is this, then the middle "off" (or "open") setting then finally when the bottom 2 sets of poles are connected.

[djthomaswhite]

Boards are being ordered on Monday October 20th from the Fab House. They will take 10 business days to be made and 2 after to ship to me. All orders will be shipped within a few days to a week of the boards arrival at my house.

The switch action may be best reported by Matthias Fonik. He has built this with 3PDT and I have only used Rotary. But, It would appear to be like the original:

Up - Filter
Middle - Both
Down - Amplifier (Gate)

Can someone verify this who has built Matthias' board layout?

Thanks guys!

Getting REAL close to order date!!!

[panele]

i`ll take 2 pcbs
thank you

[numbernone]

OK this is a question from an outsider, as I am doing my own boards to suit my own purposes. I am also using the second Fonik layout incorporating the 3/2 vactrol. This allows me to make a very very small board which is a top priority for me...

Why was the decision made to use the first layout with the pair of vactrols? Mainly to give the opportunity to use different types?

That is all. Peace be to all LPG thwappers and thwackers.

[djthomaswhite]

I used the dual design like the prototype I had built in the final design. It does allow for one of each type of Vactrol to be used in the two slots, but I don't know how useful this is in all honesty. You can likely modify my board to use the single Vactrol but I am not sure how. Any ideas out there?

Thomas

[Luka]

i really wanted some of these boards but looks like it wont happen since out dollar bombed out my budget for this stuff had diminished by almost a half. shame.

so thomas, did you tweak many values and signal flow from matthias' design. i have a bunch of them on pnp ready to go, so just wondeing if adding a deep switch and resonace will bring it in line with yours

[djthomaswhite]

Hi Luka,

If you read back through this forum topic you will find a listing of all changes that have come about. You could also print my modified schematic to compare to the one on Matthias' website. The main differences are:

1. Addition of resonance circuit (1 pot, 1 resistor and some routing changes)
2. Addition of the "Deep" Switch (simple offset switch with value set by resistor)
3. Additional Mixer section for multiple audio ins
4. Additional Mixer section for multiple CV ins
5. Capacitor between pins 13 and 14 of the TL084 IC when using the resonance mod
6. PCB mounted resonance and offset pots

That is about it. All of these could be added to the PCB layout on the Fonik site fairly easily. This has proven to be a great group and any feedback you request will likely be answered. Soon there will be a great many more people "in the know" about how lopass gates work and what mods can be done to this circuit that I couldn't dream up in my limited knowledge. Thanks!

T

[Luka]

thanks thomas

you have done great with this project
i wish international financial situation hadn't got so sticky and i could have joined in on your group buy

i have a quad panel design now ready to go too

[neandrewthal]

[Luka]

well my layouts are a bit different from the norm so it probably isnt much use to most poeple. it took me some time to get it to this stage with the options i wanted to include.

ive come up with a sort of euro layout for MOTM sized panels
this is a 3U wide, 5U high panel (where U is 1.75inch)
uses low profile panel components (davis clone knobs and banana jacks)

i havent tested it on cardboard yet but will
i think there should be just enough room to get your fingers around the knobs
still need to work on my labels and line work a bit, they are all just snapped to grid instead of lining up with objects

but yeah, this is fitting in with my form, it you want to get some context of how it fits in check my blog link below as ive made a quite a few posts of late showing the designs for my case

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[neandrewthal]

[machine.cuisine]

djthomaswhite, your videos on youtube are awesome demos. I can't wait to use build and use the LPG.

[phdinfunk]

Is anyone/Has anyone organized parts kits availability?

Or maybe made a BOM that has Mouser Parts Numbers.

I have enough time that I could make a BOM Mouser Compliant IF I won't be duplicating someone else's work.

Then you all could just ship the BOM off to mouser, pay them and wait... oh yea, then you'll need to solder together your modules .

Thanks,

Jonathan

[djthomaswhite]

Here is my Mouser parts list in Excel format. It worked for me, but may need to be adjusted for your particular builds. I will likely be adding bypass caps to the IC's on the final PCB, which is the only change needed so far from the beta testing. Actually it is not needed, but it is good design practice.

Beta testing has been good! There are a couple of quirks we are making sure are not problems but things are looking good for the order to be placed Monday for the boards. Please order now if you want to get in on this one-time-run of boards.

Thanks!

Thomas

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Lopass Gate Rev3.0 Mouser Parts List.xls
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[djthomaswhite]

Hi all,

Reminders have been sent out one last time for those who have expressed interest but have not paid for the PCB's. I am not trying to be a pest, just making sure in the swirl of DIY-madness that you do not forget about this "one time run" of these PCBs.

There are less than 2 days left to get an order in! If you are thinking about this but on the fence you need to decide by Midnight tomorrow (Sunday, USA Pacific time) if you want to place an order.

I will accept order requests all the way until when I wake up for work Monday morning. So, if at the last minute you decide you want to get in on this send me an email. I will invoice you via PayPal on Monday and consider you will in fact pay for your PCB request. If not I may end up with extras but I will take that risk to make sure all who want to can be involved in this community build.

Status of testing: The PCB is solid. I am going to use a flamethrower and sledgehammer later today for the final round of stress testing... HA! I will add bypass caps maybe. (EDIT: I will not be adding bypass caps. My power filtering has them in there less with between 1 and 2 inches maximum trace to each of the two IC's. If you find them necessary adding them will not be hard with a little extra solder and the bonus ground pads on the bottom of the PCB). In a little less than a month from now you should have your PCBs and maybe even have them built already. Thanks for your continued support of this project!

Thomas

[numbertalk]