Okay. I promised Jamie last night that I wouldn't bring this up on the thread because I don't want a ruckus. But my curiosity is getting the better of me, so I'm gonna do it. Sorry Jamie. This is on me.
I had a long talk with my tech the other day about 9v vs 18v powering on board preamps on basses. This guy is a pro, owns his own shop, 25+ years of experience, certified by Gibson, Fender, EMG, you name it, he can do warranty work on it. I was debating the bqc in my faux forte and asked him if there was any real advantage to me going to 18v instead of 9. So we plugged it up, tried it out and I couldn't tell the difference except that I was more likely to get clipping (ie undesirable and potentially damaging distortion) in the preamp section of the head. He said that ideally, you want headroom to exist in the power section of your amplification, essentially the last stage before the signal hits a speaker. You don't want it at the input stage. Now this discussion was just about EMGs and other active pickups paired with any kind of preamp. He said that the concept of getting more headroom from running an 18v preamp on board your bass is actually a false perception because In the end, it's the power section of your rig where the headroom should come from, not the front end. Thusly, he doesn't encourage 18v operation with active pickups and not often with passive either unless the manufacturer of the preamp specifically calls for 18v in order to effectively process the signal that the preamp is shaping. Boosting on board headroom increases volume, but doesn't change the tone, unless the preamp was designed for 18v purposefully, and runs a higher risk of clipping the input stage of your amp which is unhealthy for it whether it's solid state or tube or hybrid. Having the preamp section overdrive itself to create overdrive is fine, but you don't want to clip your input, literally at the jack, under any circumstance.
So, in the interest of healthy, non insult throwing debate, I want to put it out there that 18v preamp mods aren't necessarily necessary. I went ahead and said just put a 9v in it because I couldn't tell a tonal difference because the circuit isn't designed to shape the tone based on being powered with 18 volts, so to add an extra battery is not redundant, but actually wasteful unless the pre was designed especially for two batteries.
So, what do you guys think? I told Jamie (brotherbassj) that I didn't want to put it out here for discussion for fear of incurring wrath or starting some sh!t, but we're family here, and we should be able to talk about this kind of stuff without making it personal. And so with that plead for sane, rational and intelligent debate, let's talk about this. I'll start it off with an example:
Why modify the trim pot Tone Pump to 18v? Have you a/B'd it in the same bass to compare? Did you really get a difference in tone or did you just make your signal hotter and give the illusion of a change in tone simply because the signal was louder, but hadn't actually changed the nature of how the preamp processes and shapes the signal, because adding a battery doesn't change how the preamp shapes the signal. It doesn't change the preamp's structural electronic design. It's just getting more power thrown at it. Louder doesn't mean tone change. That is unless you consider a greater volume push at the start of your signal chain to fall under the definition of a change in tone.
So let's hear about it. I think Sam does the most wiring work out of everyone here, but a lot of us do stuff for friends on the side. Personally I subscribe to the sandwich theory of setups and installs: a sandwich that someone else makes for me always tastes better than the same sandwich I make for myself. Similarly, I like having my basses set up and upgraded by another tech because of the same psychological perception that it makes the sandwich better. I could do it myself, but I feel like its better when my tech does it.
And yes, I realize I just threw in a sub-topic for debate: the sandwich theory of setups and installs.
Ready. Set. Go. And remember we're family here so let's not make it mean or nasty, but actually talk about the facts and the personal perceptions, please.
. Where did that one come from? That is my favorite color and maple quilting! If you EVER decide to sell it, PLEASE give me first dibs on it!!!! 
) for well over 25 years. I've never had one get louder from it....as they shouldn't.
