Review: Underhill Dual Filter Onboard Preamp

[Zazie Moondust]

Really curious about an Underhill preamp since they are modular and let me combine different knobs I'll actually use. Pretty much what I seen to actually find useful is a bright switch, mids knob and low pass filter and this might let me combine them all?

Any one use the FT Treble boost filter (the push pull treble boost in some of the preamps)? Does it kind of work like a bright switch on its own with the filters fully open or would I need a separate treble control for that?

 

[Memnochthebass]

Really curious about an Underhill preamp since they are modular and let me combine different knobs I'll actually use. Pretty much what I seen to actually find useful is a bright switch, mids knob and low pass filter and this might let me combine them all?

Any one use the FT Treble boost filter (the push pull treble boost in some of the preamps)? Does it kind of work like a bright switch on its own with the filters fully open or would I need a separate treble control for that?

It adds treble that you can set on the board for the filter itself, so kind of like a bright switch. I have an oddball combination of a Cali Dub with the treble filter and Paradactyl 2 band running as one preamp; if I roll the frequency for both pickups all the way off with the Cali section, the treble control on the Paradactyl section has nothing to work with until I use the treble filter. Then I can use the treble control to find tune it if I want. Not really designed for that purpose, but it works...

 

[Zazie Moondust]

It adds treble that you can set on the board for the filter itself, so kind of like a bright switch. I have an oddball combination of a Cali Dub with the treble filter and Paradactyl 2 band running as one preamp; if I roll the frequency for both pickups all the way off with the Cali section, the treble control on the Paradactyl section has nothing to work with until I use the treble filter. Then I can use the treble control to find tune it if I want. Not really designed for that purpose, but it works...

That layout is kind of one of the ideas I have floating around.

I only have 5 knobs though so it's either 2 bands of EQ or 2 filters one got each pickup, but not both. So I guess it's really a question if I need a treble EQ to boost ultra highs above unity or if the push pull already does that.

 

[millahh]

That layout is kind of one of the ideas I have floating around.

I only have 5 knobs though so it's either 2 bands of EQ or 2 filters one got each pickup, but not both. So I guess it's really a question if I need a treble EQ to boost ultra highs above unity or if the push pull already does that.

Just a note, the treble boost is blending in raw treble signal rather than EQing treble up (Tim walked me through this via email a couple of days ago when I was considering a hybrid arrangement).

 

[millahh]

Alright, dropped the L-2000 off at the shop:
-Calistan install, and drilling an extra hole for the fourth knob
-inner/parallel/outer switch
-routing & install for new battery box, since the 4th knob eats that space in the control cavity
-setup

Should get it back in a month!

 

[millahh]

Yes I was definitely tinkering heavy on my G&Ls back then. I was big on the “single coil with bass boost” mode (series with capacitor or “OMG) and added that to all my modern G&Ls. I always preferred the outer coils for single-coil mode

Ok, while I'm waiting for the bass with the filter to get back from the shop, I'm curious about that L2K you wired for volume/volume. Specifically, did you run volumes maxed out, or dialed back to about 75% (as is more typical)? If the latter, how tricky was it to keep volumes matched between pickups? Did you have marked knobs, or do it by feel/ear?

 

[sunbeast]

Ok, while I'm waiting for the bass with the filter to get back from the shop, I'm curious about that L2K you wired for volume/volume. Specifically, did you run volumes maxed out, or dialed back to about 75% (as is more typical)? If the latter, how tricky was it to keep volumes matched between pickups? Did you have marked knobs, or do it by feel/ear?

I’ve rarely dialed both volumes back on a passive bass like that, too much treble loss in a passive circuit (I prefer to use the tone control for that)- the exception was my SB-2 before I added a tone control, since a stock SB-2 only has volume controls to affect the tone. One pickup was always dimed and the other usually off all the way or rolled down just a hair to favor the main pickup (depending on the tones I was going for).

 

[lalo_garcia-maynez]

Here’s a USA Spector bolt on bass with Rautia multi coil pickups and a lusithand double special preamp (specifically designed to be used with multi coil pickups). The bass came out sounding great !! It was but expensive but it sounds really close to my Wal bass .
I love the end result ! I hope you like it
Lalo García

I will post a video later on showcasing the bass tone and great flexibility!