Monday, November 30, 2009

vibrato



vibrato I built for someone. design similar to the one I made months ago (down the blog) with some improvments/bugfixes.

and yes, still making Hollow Earths. it's just taking time to get through thel ist is all. and yes as of 2010 they will be $275 instead of $200. I underestimated the cost in time and materials when I initially started making them. sorry about that. people on the list have already been informed.

6 comments:

Nychthemeron said...

ilu cloudscapes omgggggg

With that said, I'm seriously looking forward to seeing this one completed.

Anonymous said...

Hi,

may I ask you how's your solution driving the pt2399 with an avr lfo? As a buddy and me have something similar (an avr pwm lfo) already completed - which was originaly intended for a phaser - but could be also (ab)used for a vibe. Have a look here: http://www.youtube.com/watch?v=4ab0OiB7shU
Thanks in advance!

Regards
Helge

cloudscapes said...

Hi Helge, basically it works like this.

The AVR has some stored wavetables (except for the random mode) for the triangle/sine/square/ramp shapes. It outputs a PWM which in turn drives an NPN (I used a BC547 i think). The NPN acts as a ground sink on the 2399's delay time pin (pin 6). The more "grounded" that pin is, the shorter the delay time, if memory serves. I think I added a filter cap in there somewhere between the PWM output and the NPN.
Obviously the NPN needs to be biased with some trims. I just did that by hear while feeding a test signal into the 2399's input.

Anonymous said...

Hi,

thank you so much! Some great info you shared here with me. Defintely gonna try that!

Regards
Helge

postgeek said...

Just curious if you're still putting these out or if they're scrapped for the time being... i'd really like to get a hold of one.

Max said...

i have a LFO with a output PWM... can i used the NPN transistors and the others things in the pin 6 like this schematic?...

http://www.valvewizard.co.uk/jennygreenteethschem.jpg

also I wanted to test the difference in response with a LDR but i dont know other things would lead... you awsome man!