PTB versus Q-Filter

Mon Sep 25, 2017 6:11 pm

It's been a long time since I've posted, but I actually have something to share and ask:

Recently I put a set of Bill Lawrence (Wilde) Microcoils into my Legacy, and also added their Q-Filter this time, too.

I was expecting the Q-Filter to add mid-range, but actually this sounds more like a more subtle version of the guitar's original bass cut control from the PTB circuit.

Can anyone explain the difference quantitatively between the Q-Filter and the bass cut? Is there any good reason to add an extra component (an inductor) to cut frequencies?

Re: PTB versus Q-Filter

Tue Sep 26, 2017 6:33 am

Greenblues wrote:It's been a long time since I've posted, but I actually have something to share and ask:

Recently I put a set of Bill Lawrence (Wilde) Microcoils into my Legacy, and also added their Q-Filter this time, too.

I was expecting the Q-Filter to add mid-range, but actually this sounds more like a more subtle version of the guitar's original bass cut control from the PTB circuit.

Can anyone explain the difference quantitatively between the Q-Filter and the bass cut? Is there any good reason to add an extra component (an inductor) to cut frequencies?


I recall some discussion on the Q-Filter, so I searched our forums and found this thread: http://www.guitarsbyleo.com/FORUM/viewtopic.php?p=95220#p95220.

Hope this helps.

:ugeek:

Re: PTB versus Q-Filter

Tue Sep 26, 2017 4:46 pm

Thanks, Craig. I did come across that. It seems like the Q-filter cuts more midrange than the PTB. I might have to do some math...

Re: PTB versus Q-Filter

Wed Oct 04, 2017 12:29 am

Q-Filter gone. PTB fully restored. I really missed it.

At least with the Microcoils, I found the effect of the Q-Filter was rather subtle, but the PTB's bass-cut is just as effective for thinning out the sound on the neck pickup with overdrive. I read somewhere that the Q-Filter starts to cut bass between 1-4 on the dial. With fuzz and overdrive, G&L's stock bass cut seems to work better reducing gain. This makes sense because the Bass cut works almost exactly the same as a volume control with a treble-bleed cap across it. (Which begs the question of whether the bass-cut is redundant with a treble-bleed. I spent a lot of time with alligator clips sticking out of the guitar auditioning different caps and resistors to find the perfect treble-bleed circuit, and noticed that the volume control can cut a lot of bass with larger values.)

Originally I started experimenting with the Legacy's circuit after my first set of Bill Lawrence's Keystones. Perfect bridge lead sound with the tone rolled off a bit. Those are one of the best sets of pickups (along with a few types of VVG pickups I've tried) I've ever had and converted me to a fan of the brand, but the PTB wasn't so effective with the Keystones...I was less much impressed with their L-280s and much more impressed with the L-45s but both killed the twang of the low-E string's attack so I went back to true-single coils (and these are probably the quietest true-singles ever). Bill and Becky's website encourages users to experiment with tone control values, so I started with the traditional two-tone control circuit I found on their website. I've spent the past few years experimenting but I'm tired of taking apart my strat and just want to spend more time to playing it! That's definitely happening now with the Microcoils and PTB.

The description I found of the Microcoils as having a strong fundamental sounded like the original Duncan SSL-2 pickups in the '93 Legacy, and they are actually pretty close: a typical strat tone but bigger and warmer. Fortuanately, the Microcoils do work very well with the PTB, unlike the Keystones. These new pickups are not hot (at least compared to my Vox's Co-Axe pickups), and do dip in the midrange even without the Q-Filter. So I finally ordered a Villex Passive Booster following Louis Cyfer's recommendation. I'm hoping this will make these pickups more effective with some old-style fuzz boxes I have.