Grateful Dead Music Forum

A place to talk about the music of the Grateful Dead 

 #138244  by James-T
 Sat Apr 12, 2014 9:30 am
I recently built a rack for my pedals and a newly acquired GCX system (had in a trade! finally no $ spent on gear!). I did a little last minute research on signal chains and effects and one guy on one of the forums said it perfectly (paraphrased):
Think of it this way; would you want to add a clean boost to an OD pedal pushing it harder, or would you want a clean boost not to alter the OD's effect and simply push your amp a bit harder, similarly do you want an OD effect also driving (distorting) a delay or reverb signal or do you want to add reverb or delay to an overdriven signal? That basic concept really helped me understand why I was committing my effects in a specific order in my signal chain.
So I'm looking for another ah ha moment where I could understand and explain the basic principals of guitar volume.

To some these questions may seem pretty dumb and have obvious answers, but I'm not really an electronics guy and I think having a better understanding of the electronics principles behind these simple questions can help one manage their signal chain, myself included! If anyone has watched the Trey youtube of him going over his rack, his one really poignant tip to the viewers is know your own equipment. I couldn't agree more. So if anyone's game here are my student questions:

1. What is the difference between a volume pedal and the volume control on your guitar and the volume control on your amp?

2. What is the difference between a stratobalster in your guitar and one in a box at the start of your signal chain. Is a stratobaster a clean boost?

3. What is the difference between a clean boost and a volume pedal. Are they acting the same way, only a volume pedal reduces db's seen by the amp and a clean boost increases the dbs seen by your amp.

4. Finally how is clean boost different than simply turning up the volume up on your amp?

5. Why is my vintage Gibson PAF low output neck pick-up on my LP louder than the high output Super 11 on my PRS? Likewise why is the super high SD SSL-5 middle pick-up (+/-14K) at the same volume as the ultra low output neck pick-up (4K) on my Aria pro? When you raise a pick-up up closer to the strings does it just get louder or does it shape the tone differently as well?

If any one was to tackle any of these questions I'd be very appreciative! :smile:


 #138250  by PurpleTrails
 Sat Apr 12, 2014 4:03 pm
1. The volume knob on your guitar and a passive volume pedal are basically the same, given that your volume pedal has the same impedance. They basically enable you to reduce the signal strength coming from your guitar entering the preamp part of your amp. A volume pedal may also act as a buffer depending on design. Theoretically you could approximate an obel setup by leaving your guitar volume maxed at all times and putting a volume pedal at the end of your effects chain so you could drive your effects with a consistent signal level, but be able to vary the strength of signal hitting the preamp section, hence distortion. Yeah, you lose the lowered capacitance you get with an obel and onboard buffer, and tone will suffer some as a result, especially if you have a longish instrument cord.

The volume knob on your amp controls the output of the power section of your amp. So the hotter the signal hitting the preamp, and the more gain you use in your preamp, the more the amp distorts. The amp volume knob in most cases controls the loudness of the sound coming out of the speakers. So if you have your amp set up to be at the edge of breakup, rolling off your guitar volume or gain will make the sound cleaner, and reduce volume, while rolling off your amp volume will decrease the volume but not change the basic tone.

2. Not sure. I think a stratoblaster is a clean-ish boost, but I'm not exactly sure how it compares to having a boost pedal up front of your chain.

3. Clean boost is active. It increases the signal strength and may have some tone shaping going on. Think of it being a pre-preamp. Passive volume pedal decreases the signal strength like the volume knob on your guitar. I think an active volume pedal is like a clean boost with an easily controllable output setting, but I'm not totally sure of this.

4. Clean boost is boosting the signal before it hits the preamp on your amp, and also before it hits pedals downstream from it. So you can put a boost or preamp pedal basically anywhere in your effects chain and drive the effects downstream of it harder as a result. FWIW I have an FET preamp in the middle of my chain, and it can really drive my analog delay at the end of my chain to do some really interesting stuff. Regardless, if you are boosting the signal hitting the preamp section of the amp it will tend to distort more, while turning the amp volume knob does little to effect distortion.

5. No idea. My guess is that it has something to do with how close your pickups are to your strings, as you elude to. Alternatively, you may have different values on things like capacitors in the guitars in question that may be affecting output, or possibly how much of the signal spectrum is coming through, which may affect perceived volume.