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Mr Stephen speaks wisdom.   8)
it really should have its own webcam/channel/site thing. on the www. instead of pron.
Building your own stompbox / Re: Understanding the EHX Y-Triggered Filter
« Last post by rankot on Today at 08:24:14 AM »

Thanks a lot! Then, what about R14/R15? 10k too?
It's a whole lotta...


from the datasheet:

The voltage at V- (pin 5) is four diode drops below
ground, which, for the 2181, is approximately -2.85 V.
Since this pin connects to a (high impedance) current
supply, not a voltage supply, bypassing at pin 5 is not
normally necessary.

what's your voltage at that pin? [way out of my paygrade.] as far as transistor type/number/prefix, it just sits there and provides a static current determined by the diodes referencing the base, which probably any transistor will do the same. way different types might show variations, but a 2222 is a 2222 by any name smelling as sweet.
Building your own stompbox / Re: Understanding the EHX Y-Triggered Filter
« Last post by rankot on Today at 08:02:12 AM »
I'm still waiting for my PCB to arrive, our post is at strike for two weeks :(

However, you may check resistor values which I was not sure about, as I wrote few posts above:
Could you, please, confirm resistor values asked before (see schematic at, resistors R2, R4, R5 and R6. They seem as 1k to me (if photograph colors are right), not as 10k as shown on original schematic.

I did use 1k on my layout, maybe they should be 10k?

Also, what you used is not the last version of my layout, there could be some mistakes there as well. I did finish a layout with some "bells and whistles", however, didn't want to publish it until I build it and make sure it's working. However, here it is, for reference, together with appropriate schematic:

Building your own stompbox / Re: Tone control calculator anybody??
« Last post by italianguy63 on Today at 07:42:21 AM »
> I've drawn the tone stack already, but with your values it does nothing

You must model the tube output impedance. Else C9 has nothing to work against. The simulated power source would pull Hoover Dam out of the river, and laughs at a mere 10nFd.


I also think C9 could be much bigger to give a strong effect (100nF may be too much).

Because of scaling (which I can't figure out) it looks like a small slump, but is >20dB above 2kHz.

Almost all the action of Tone happens at the right end of slider.

I tried these values too.. still nothin'.

Digital & DSP / Yahoo Groups and LT Spice
« Last post by Sooner Boomer on Today at 07:20:51 AM »
It's my understanding the the LT Spice group on Yahoo Groups was one of the best resources for learning LT Spice.  Now that they've shut down all the Yahoo Groups, what's a good alternative?
Building your own stompbox / Re: The Sidescroller MKII
« Last post by Freppo on Today at 06:27:47 AM »
your site helped me get an octave down effect using cmos chips salvaged out of old organs working. thanks!

Cool. Glad to hear that someone is actually reading those articles.  :)
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