| Author | Message | ||
| lbpesq
Senior Member Username: lbpesq Post Number: 3125 Registered: 7-2004 |
When I adjust the low pass filters on my Alembic and Alembic equipped guitars, I find that I'm usually making a VERY fine adjustment at a sweet spot that encompasses maybe only 10-20% of the total travel of the filter knob. Since I'm in this 10-20% area all the time, I'm wondering if the filter could be set up to just cover this area, but spread it out over the entire range of travel of the filter knob? In other words, let's say the standard filter spread is "1-10" and I'm always setting somewhere in the "5-6" range. Can the filter be adjusted so that the "1" position gives me the equivalent of the "5" and the "10" position gives me the equivalent of the "6". I would think this would result in my having more control in the "5-6" range. Does this make sense? Do other guitarists have similar experiences? Can this be done? Thoughts? Bill, tgo | ||
| grateful
Advanced Member Username: grateful Post Number: 279 Registered: 12-2004 |
I have similar experiences Bill; my battered old ears can hear no difference from approx 10 down to 7. However, I do like the combination of two pickups with the filters at opposite extremes (sounds like no electric guitar I've heard before), though I wouldn't turn a filter that far down when using only one pickup. Mark | ||
| lbpesq
Senior Member Username: lbpesq Post Number: 3131 Registered: 7-2004 |
Mark: I'm going to run this idea up the flagpole the next time I'm in Santa Rosa (probably this week or next). Everyone Else (guitar players): I'm surprised no one else has posted on this thread. Heck, if a bass player posts something about some esoteric cab that no one's heard of, they'll get half a dozen responses by lunch time. Are Mark and I the only ones who notice this phenomena when it comes to filters on guitars? Does it happen to you too? Bill, tgo | ||
| elwoodblue
Advanced Member Username: elwoodblue Post Number: 379 Registered: 6-2002 |
you mean those basses with the really thin strings?  I like your idea bill...a meta-filter. | ||
| dfung60
Advanced Member Username: dfung60 Post Number: 340 Registered: 5-2002 |
The mod that does what you want isn't too hard, but it may be challenging to find the parts you need. The filter knob is a pot that presents a certain range of resistances across it's rotation from 0 ohms to the rated value of the pot (25K, 250K, etc.). So you need to determine the high and low values of resistance for your useful range, then replace the pot with a circuit that creates that more limited range. Determining the range is pretty easy if you have some electronics experience and equipment. Using an ohmmeter, you want to read the resistance values off the pot in the high and low positions of your favored range. Set the knob to the lower position, turn off your amp, then read the resistance between the middle lug and the outer leg that has a wire on it. Now, turn your amp back on and set the knob to the high position, turn your amp off and measure the resistance across the pot in this position. The reason you're turning your amp off between tests is to prevent a speaker- blowing transient if you brush the wrong wire while testing. Now, you need to go find a regular resistor that approximates the value of the lower range reading. It doesn't need to be exact, but in the general range. This is a low-power application, so a small 1/2-watt resistor will be more than enough. Ideally, you would want to find one with tighter tolerance (5% would be better than 20%) just so the value is reasonably close to your desired value. Next, you need to find the difference between your high and low value and try to find an audio taper pot that has roughly this range. Unlike plain resistors, pots don't come in every arbitrary value, so you may have to improvise here a bit. Finding a pot that the right value, taper, and physical size may not be possible. Resistances in serial are cumulative, so what you want to do is remove the existing pot, then install the new one. The little resistor goes inline on either leg of the new pot. Now, when the pot is turned all the way up, the new pot doesn't present any resistance, so the total resistance that onboard preamp "sees" is the resistor value, which should be like the high-end of your favored range. When you turn the pot down, the preamp "sees" the sum of the little resistor and the new pot which should be the low-end of your favored range. The mod itself is very simple, but finding exactly the parts you need will probably be a fairly big challenge unless you're lucky. David Fung | ||
| lbpesq
Senior Member Username: lbpesq Post Number: 3133 Registered: 7-2004 |
David: Many thanks for your, as usual, sage advice. I just might do this, or at least approach Susan about a mod along these lines. Bill, tgo | ||
| davehouck
Moderator Username: davehouck Post Number: 6709 Registered: 5-2002 |
Great post David!! | ||
| grateful
Advanced Member Username: grateful Post Number: 280 Registered: 12-2004 |
David, I'm in awe of your electronics knowledge, and appreciate the way you generously share it. Thanks, Mark | ||
| fasteddy
Junior Username: fasteddy Post Number: 12 Registered: 7-2007 |
" ... I'm going to run this idea up the flagpole the next time I'm in Santa Rosa (probably this week or next). ..." It would be quite possible to make a "retro fit" kit to do this ... and an inline filter box is not that hard either, if the onboard filtering is removed altogether. Mmmmmm ... | ||
| lbpesq
Senior Member Username: lbpesq Post Number: 3141 Registered: 7-2004 |
I spoke with Susan & Ron about this today. They seemed to think it is very do-able and liked the idea. So the project has wings but has not yet taken flight. Ed: "and an inline filter box is not that hard either" They already have one. That's essentially what an SF-2 is. Bill, tgo |
