Benjolin/Zeitgeist questions

oscilloclast · Joined: Sep 29, 2005 Posts: 49 Location: VA

Hello fellow Benjolin and Zeitgeist builders,

First off I want to say I had a great time talking with Rob and Joker at EM 2009 and I really appreciate them putting together some interesting projects. I'm going to put both kits (I have the Benjolin working and I still have to put together the Zeitgeist) and a power supply in one box but I have some questions I'm hoping someone can answer:

Zeitgeist:
1. There are two jumpers. One is for the power connection but what is the other one for?
2. There are two headers. I'm assuming that one allows switching between CV control and LDR control of the delay time but what does the other header control?
3. What does each knob control? I'm assuming one knob controls the delay time and one knob controls feedback, but what about the other two?
4. Is there an opamp issue and if so how can it be resolved?

Benjolin:
1. What does the filter CV in control?

Thanks
David Rickert

jnuaury · Posted: Fri Nov 06, 2009 10:53 am Post subject:

could you post links to the schematics?

oscilloclast · Joined: Sep 29, 2005 Posts: 49 Location: VA

These two devices were offered at a couple DIY workshops that Rob and Joker were giving at the EM-2009 (and elsewhere). They are Rob's designs so I would not feel comfortable posting the schematics (not trying to be difficult but I'm sure he put a lot of time into them). Did you get to build them?

David

reidbingham · Joined: Nov 07, 2009 Posts: 3 Location: Brooklyn

hey I will try to answer you questions and maybe you can help me with mine.

For the zeitgeist:
1 - the jumper by the LED is for the battery and the jumper by the switch is for using a photo cell. The switch turns it on and off.

2 - what do you mean by 2 headers, I only see one 2x5 header.

3 - from left to right with the knobs at the top: Input, Feedback, Delay Control, Delay Control. I dont know the real name for the delay controls but thats the basic functionality of each pot.

4 - are you getting a hum/buzz/distortion? If so you might need to replace your TL074 (Or as it looks on my board: TLC27M41N).

For the Benjolin:
1 - I dont know which parameter of the filter it controls, havent had a chance to try it out yet.

Now for my question: Where did you get your bipolar 12V power supply? All I can find are kits or incredibly expensive bench monsters.

Danno Gee Ray · Joined: Sep 25, 2005 Posts: 1351 Location: Telford, PA USA

The Power Supply I'm using for my Benjolin is a surplus switching supply I picked up. It has +24VDC, +5VDC, +12VDC, and -12VDC outputs at various load capacities. The + - 12 VDC outputs are rated at 350 ma, and seem to be quite ample.

You can see my case build in this thread...

http://electro-music.com/forum/viewtopic.php?highlight=benjolin&t=37790

Sine · Joined: Sep 10, 2007 Posts: 111 Location: Netherlands

MFOS has a very simple kit that would be perfect for this.

http://musicfromouterspace.com/analogsynth/WALLWARTSUPPLY/WALLWARTSUPPLY.php

oscilloclast · Joined: Sep 29, 2005 Posts: 49 Location: VA

Thanks for the info! On the paperwork the term "header" refers to the two 3 prong headers (one of which is to turn the Light sensor on and off). It's confusing because I've always used the term header for power connectors etc. Thanks for the tip on the opamp I knew Rob was having issues with it. I got my power supply in an old medical equipment enclosure that was provided at the Baltimore workshop (with Peter Blasser). Ken stone offers a board for a power supply (you'll have to order the parts from Mouser etc.). You can go to his web site "www.cgs.synth.net" and look for the "+/- 15 Volt Power Supply" which you can adapt to +/- 12 v (by changing the regulators).

David

electri-fire · Last edited by electri-fire on Thu Nov 12, 2009 5:02 am; edited 1 time in total

http://electro-music.com/forum/forum-185.html

May I suggest the moderators to relocate this thread?

Edit: it's been relocated to here as I proposed, but I can't delete this post. Strange...

bartlebooth · Joined: Nov 11, 2009 Posts: 5 Location: Maryland

Hi, I am new to this forum and to DIY in general. I attended the Benjolin workshop in Baltimore but the kits didn't arrive in time for us to build them while Rob and Joker were there. I was able to build almost all of the Zeitgeist today but in order to finish it I have a few (probably stupid) questions:

1. I have all major components soldered on to the board. However, my kit does not have anything that appears to be a 3-pin header. Are these necessary (or more specifically what are they for)?

2. How do I connect 1/4 inch jacks to the input and output. The kit didn't come with jacks but I bought a few neutrik 1/4" slim jacks..it looks like I need to solder two wires to the jack and then I'll need some kind of connecter to attach to the header pins on the board? Is closest to the jack the ground? Also, if I connect the output jack ground to the ground header pin what does the input jack ground connect to?

3. The kit came with 2 metal toggle switches, where do these go? I don't see any mention on them on the instructions or diagram.

4. Once I get it working I'd like to connect it to the CV outs of the Benjolin. Any ideas how I would do that? is that what the other 5 pins on the 5x2 header are for?

Again, sorry if these are very basic questions but I'm a bit lost and would really like to get this kit up and running.

Thanks alot,
Steve

Rob · Posted: Thu Nov 12, 2009 4:41 am Post subject:

electri-fire · Posted: Thu Nov 12, 2009 4:59 am Post subject:

Rob · Posted: Thu Nov 12, 2009 6:23 am Post subject:

The Benjolin can run on a dual supply of +/-12V to +/18V, as it has its own +9V and -9V regulators on board. Optionally, 9V batteries can be connected after the regulators, which the regulators don't mind as long as there is ónly batteries or ónly a power supply connected! (Don't connect both batteries and a power supply at the same time to prevent possible explosion of the batteries!)
The Benjolin uses roughly 60mA of current.

The Zeitgeist has a +5V regulator that accepts a power supply voltage of +6V to +20V. It can easily share the +12V to +15V that also powers the Benjolin. The Zeitgeist uses roughly between 20mA and 40mA of current, depending on the delaytime.

oscilloclast · Joined: Sep 29, 2005 Posts: 49 Location: VA

Rob,

I got everything working and I am currently mounting everything in a case (the Peter B case which fits the boards perfectly). I noticed a few things about the kits and I just wanted to check and make sure that everything was working properly.

Benjolin:

1. Osc 2 pulse out is weaker/thinner sounding then Osc Pulse out. Is this the way it was designed?

2. The filtered out is a lower volume then the other outs. If this is the way it was designed is there any way to increase the filtered output to the level of the others? I’m going to be running these kits with my modular so the more signal I can get out the better. If there is nothing on the PCB I can do I’ll just increase the signal with an opamp.

Zeitgeist:

The output switch selects between “delayed signal” and “delayed signal + input signal”. Is that correct?

For the LDR it looks like there are two places on the board where it can be connected: one on the “sensor” input on the 10 pin header and one on the two prong header by the switch to select CV or LDR (for control of the delay time). Is that correct?

Thanks for putting together these kits, I’m having a great time exploring them! (the range of different sounds is incredible).

David
P.S. Hope you are feeling better.

Rob · Posted: Thu Nov 12, 2009 3:21 pm Post subject:

Wout Blommers · Posted: Thu Nov 12, 2009 4:18 pm Post subject:

back, Rob!

Very Happy

Wout

modulator_esp · Posted: Thu Nov 12, 2009 4:21 pm Post subject:

Hi Rob, was nice to meet you at em09 Smile

The benjolin sounds cool, let us know when you do some more workshops

Inventor · Posted: Thu Nov 12, 2009 4:27 pm Post subject:

Hey Rob, it was great to chat with you at EM09! You are quite the talent, I must say. Welcome back.

Les

Danno Gee Ray · Joined: Sep 25, 2005 Posts: 1351 Location: Telford, PA USA

Yes, welcome back. Cool projects.

A suggestion for the Benjolin kit. A drilling template for the pots and mount holes on the PCB would add to the coolness of the kit. I'm sure your PCB artwork has the domensions for the centers of the pots...Would make panel drilling easier. Something with the centers marked ( with a plus symbol) that a person could put on a panel and then center punch to locate drilling holes?

oscilloclast · Joined: Sep 29, 2005 Posts: 49 Location: VA

Thanks Rob,

I"ll go double check the output on the 2nd Osc Pulse.

David

electri-fire · Posted: Fri Nov 13, 2009 6:52 am Post subject: Zeitgeist knob labels

electri-fire · Posted: Fri Nov 13, 2009 7:00 am Post subject:

OmbientMike · Joined: Nov 20, 2005 Posts: 20 Location: NJ

OmbientMike · Joined: Nov 20, 2005 Posts: 20 Location: NJ

Hi All,

Mike Hunter here. I was the guy with the really long hair at the workshop at EM2009.

Here's a picture of my Benjlin and ZeitGeist built, together, into a wooden box...and not quite finished yet.

I've added a small amp and speaker behind the reproduction antique grille cloth. I'm going for that retro early 20th century look...

The blue patch cord allows the user to patch the Benjolin to the ZeitGeist (or to patch other effects inbetween.) the empy jack is to patch the output of the ZeitGeist to an external amp. If left unplugged, the audio goes to the build in amp and speaker.

I'll be posting some video to YouTbe soon.

(taken with my iPhone, sorry about the quality)

Posted Image, might have been reduced in size. Click Image to view fullscreen.

Posted Image, might have been reduced in size. Click Image to view fullscreen.

electri-fire · Posted: Fri Nov 13, 2009 11:53 am Post subject:

That's beautiful, Mike.

I'm sort of disorganised, so to not get lost I like to seperate topics. I opened a new one here to present your builds.

http://electro-music.com/forum/topic-38063.html

.

Danno Gee Ray · Joined: Sep 25, 2005 Posts: 1351 Location: Telford, PA USA

Very cool case Mike.