vref? Echobase?

[brokenstarguitar]

Ok, im building an Echobase and looking at the schematic im a little confused on where a few things go, mainly the 2nd resistor comimg in (1m). It says to connect the one end to the "IN" and the other end to "vref". What exactly is "vref"? Where does that resistor (and a few other components) go? Please help me. Thanks!

[cloudscapes]

vref is voltage reference, which in the stompbox world usually means half the circuit voltage. designs usually create this with a voltage divider (two serial resistors across ground and voltage) and a large-ish cap between where they join up and ground. the "center" of this, where they join up, is vref, and is connected to anywhere else in the circuit that needs vref.

I don't have the echobase schem on hand. there should be such a voltage divider circuit somewhere on the page?

[mth5044]

For future posts, always post the schematic, layout, etc you are referencing. We don't have them all memorized.

In this schematic, Vb "comes from" the two resistors and 100u cap that are in the lower left side of the schematic. There are also a lot of other Vb's around the schematic that you could tap off of.

http://s68.photobucket.com/user/Morocotuco/media/echobase-schem-MODS.jpg.html

[slacker]

You just connect all the points marked vref together, using a label like vref is just to make the schematic look neater/easier to read than drawing lines between all those points. Same goes for the other labels.
Vref is actually right at the top centre on the schematic here http://www.musicpcb.com/s/Echo-Base-build-PDF-updated-051810.pdf it's 5 volts from the 7805 filtered by the 47R resistor and 47uF cap.

[cloudscapes]

always better to make your own dedicated voltage divider + cap than using a voltage regulator shared by a digital part, even if filtered.

[slacker]

Completely agree, it's nearly seven years old now, if I was designing it now there's quite a few things I'd do differently.

[brokenstarguitar]

Oh ok. Thanks guys. I appreciate it. If i have any issues ill post back.