ROG Fetzer Valve in front of ROG Ruby

[vanhansen]

Ok, I did some initial research on putting the Fetzer Valve in front of the Ruby and am going to tackle it.  I came across this thread, http://www.diystompboxes.com/sboxforum/viewtopic.php?t=21375&highlight=fetzer+valve

Brian says, "Simply connect the Fetzer Valve output cap to lug 3 of the Ruby volume pot."

Now here's my question. I see lug 3 goes to the 47n cap, but what would go to the input of the Ruby?  Once they are chained, I'll be going in to the Fetzer and out of the Ruby.  Doesn't something need to go to the "in" of the Ruby at the transistor gate?

I thought I had it all planned out until I ran across this.  Originally I was thinking in to the Fetzer, then off the Fetzer volume wiper to the "in" of the Ruby.  Grounds would be connected together and they'll also share the same power supply (easy enough there).

Now I'm a little confused on getting the signal from the Fetzer to the Ruby.    I like the idea of both being hooked up to the same volume pot but need help getting this straight and understanding why to go to lug 3.

Also, on the Fetzer, can I use a 1K resistor in place of the 1.5K off the source?  Would this just require rebiasing?  And could I also just .02uF instead of .022uF off the drain for the output cap? Again, a possible rebias? All I could find in my bag-o-resistors are two .01uF caps. I could use them in series. I don't have a .022uF cap.

[B Tremblay]

From the runoffgroove.com FAQ:



As for your other questions:

Yes, subbing a 1k for the 1k5 is fine.  This will increase the gain a bit.  Just use the trimmer to set the drain voltage at 4.5v and you're good to go.

To create a .02uF cap from two .01uF caps, they need to be in parallel - not in series.  That's an OK substitution as well.

Also, re-biasing is only needed when swapping FETs.  Changing the output cap value or using a different source resistor when you build the circuit won't affect the bias.

[vanhansen]

Thanks, Brian.  I thought putting caps and resistors in series added the values.  Is it different for caps then it is for resistors?  I've read the DIY Faq over and over.  I guess I missed that part if it's in there.

EDIT: I found it in the Faq.  Had to look a little closer.  

I appreciate the help.  This makes sense now.

[vanhansen]

Brian, one more question.

While driving home tonight a thought came to me.  I'd like to switch between the Fetzer and just the Ruby.  What I'm think would work, and please help me correct this, is use a SPDT On-On toggle switch to accomplish this.  I would run the lead off the input jack to the center lug.  Then, from the two outer lugs, one would go to the Ruby input, the other to the Fetzer input.

Now, what I'm concerned about is signal bleed or issues when one of the two circuit inputs are bypassed.  Would there be an issue with the Fetzer out being connected to lug 3 on the Ruby volume with this setup?

[B Tremblay]

Now, what I'm concerned about is signal bleed or issues when one of the two circuit inputs are bypassed.  Would there be an issue with the Fetzer out being connected to lug 3 on the Ruby volume with this setup?

Possibly.  Keep in mind that when the Fetzer is bypassed, your Ruby has lost its output buffer and the low input impedance of the 386 will affect your tone.

My suggestion is that you build a completely stock Fetzer and a completely stock Ruby.  Use a DPDT switch to bypass the Fetzer.  You'll have two volume controls, but having a pre-set boost that easily activated may be more convenient.

[vanhansen]

Thanks.  I may try that too.

I forgot to mention that I would be keeping the Ruby Input buffer in place with my idea, just switching between it's buffer and the Fetzer Valve.  They would be two complete circuits.

I appreciate the input and advice.