Thanks for all the replies. I wonder if the inconsistency between amps is an impedance issue. I've found the Underwood to be way more in need of an impedance matching preamp than either the lifeline or the realist.
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Double Bass Underwood vs Full Circle vs Realist
- Thread starter Endlesssolo
- Start date
I think I read somewhere the Full-Circle is intended to be used with a preamp, but I could be mistaken. Last night I was plugged straight into the amp.
Depends on the amp, of course, but the FC likes at least 1Mohm input impedance. In my experience, 5 Mohm is optimal. But you have to experiment. If you find a preamp that makes it feel right, then Bob’s yer uncle. I ended up with a Noble, but was happy with several others before that.
I have a Fishman Platinum Pro which will probably be my next gig experiment. I used it with the Realist numerous times and it seemed to help.
I've been using a full circle for about 15 years now. I've never once used a preamp. I've used it amplified through different combos, straight into the FOH, and recorded with it. I have never had any issues getting a great sound from it. On most gigs, I'd play upright one set, and an electric bass another set. I've always been able to dial in my sound in less than a minute. I have no desire to ever try another pickup.
The Realist copperhead tends to exaggerate low mid rumble with pizz. I believe this comes from the body of the bass. I used it because it worked fairly well with arco. I thought it was less dependent on corrective EQ and impedance buffering than other piezos I have used. Worked well on several basses I have used. Did not work well on the last bass I played. That particular bass was designed to be an acoustic cannon and was extremely resonant with extra low mid rumble. I suspect a bridge wing pickup that would focus more on string vibrations and less on the body would have worked better on that bass.
The Underwood has what I would describe as a honky sound. A high impedance buffer will help, but it still needs quite a bit corrective EQ. I liked the Underwood slightly better than the Fishman BP100 which has a similar problem with a bit different tonality.
For me, the closest to MBOL through and amp I have heard is the Ehrlund EAP. I did not play this bass professionally, but I did noodle around on it to explore how the pickup worked. I has been the best I have heard. I also ran sound for a couple of tours where the bass was used. The Ehrlund requires experimentation to find the best placement. Also, it's not considered a good choice for a mediocre sounding bass. Since the sound is fairly faithful to the original, you get mediocre amplified.
I have not tried the Ischell. From what I have read, is has similar problems and results to the Ehrlund AFAIK. Players seem to prefer one or the other. How the pickup interacts with a given bass may be significant. Recommendations for optimum placement seems to vary between these two.
The Underwood has what I would describe as a honky sound. A high impedance buffer will help, but it still needs quite a bit corrective EQ. I liked the Underwood slightly better than the Fishman BP100 which has a similar problem with a bit different tonality.
For me, the closest to MBOL through and amp I have heard is the Ehrlund EAP. I did not play this bass professionally, but I did noodle around on it to explore how the pickup worked. I has been the best I have heard. I also ran sound for a couple of tours where the bass was used. The Ehrlund requires experimentation to find the best placement. Also, it's not considered a good choice for a mediocre sounding bass. Since the sound is fairly faithful to the original, you get mediocre amplified.
I have not tried the Ischell. From what I have read, is has similar problems and results to the Ehrlund AFAIK. Players seem to prefer one or the other. How the pickup interacts with a given bass may be significant. Recommendations for optimum placement seems to vary between these two.
I built it so many years ago and I can't find the circuit. The website I got it from has also disappeared. Sorry. The closest I can find is
Piezo Preamps
The important point is that it is a simple impedence matcher. I probably spent much more time on the bass' action, soundpost, bridge and Underwood placement. It took years of fiddling to find the right sound.
The preamp was discretely velcroed to the back of the tailpiece. I also built an optional footswitch for a predetermined tone cut, for solos and arco. It plugged into the preamp and used the same principle as a BG tone control.
Have a look at Francis Deck’s Quick’n’dirty preamp. It’s basically a stripped down HPFpre without the high pass filter.
There are tons of designs. (One that stuck in my head is the mint box.)
The problem nowadays is to get get the right JFET in a hole-through version. You find interesting hints at Francis Deck’s site.
The problem gets even larger if you want a phase switch, since that needs a certain JFET.
BTW, the resistor values at the JFET depend on the JFET type and sometimes even on the part used. Francis wrote a lot of interesting stuff about that.
There are tons of designs. (One that stuck in my head is the mint box.)
The problem nowadays is to get get the right JFET in a hole-through version. You find interesting hints at Francis Deck’s site.
The problem gets even larger if you want a phase switch, since that needs a certain JFET.
BTW, the resistor values at the JFET depend on the JFET type and sometimes even on the part used. Francis wrote a lot of interesting stuff about that.
I’ve used all three, I'm happiest with the Full Circle. I've always been fighting with the upper mids of pickups and the Realist was better than Underwood in that regard and FC was better than the Realist. Underwood wins on ease of installation and replacement compared to the others.
I’m friends with a rockabilly slapper who uses only half of the Underwood (common in that genre) and he gets a great punchy tone with gut strings and GK heads (his 400RB finally died, he’s using an MB500 now) and an old school 1-15 cab that he’s been using for over 35 years. I was always envious of the volume levels he could get without using an HPF and never hearing a hint of feedback.
I’m friends with a rockabilly slapper who uses only half of the Underwood (common in that genre) and he gets a great punchy tone with gut strings and GK heads (his 400RB finally died, he’s using an MB500 now) and an old school 1-15 cab that he’s been using for over 35 years. I was always envious of the volume levels he could get without using an HPF and never hearing a hint of feedback.
That’s what I use: GK head, a 15” cab and the Underwood last transducer on the E side. I don’t use guts. I love my sounds but it’s not for everyone.
I know using only half of the Underwood is pretty common, what is the sonic difference between only the E side, only the G side and both sides?
Results will vary from bass to bass. My understanding is phase interference between the two elements degrades the tone. However, using one element did not work well for me. Using one element under the E side made the E and A more clear, but the D and G were weak. Using one element under the G side made the D and G sound better more clear, but the E and A were weak. Using both elements reduced clarity and focus, but the sound was more even.
I won’t recommend to cut off one sensor if you have a working two element bridge wing pickup, but only one sensor on the wire sounds better than two on the wire and only one used.
I did it on a two element Shadow SH-950, making a SH-951 out of it as the end element was broken.
Piezo elements are sensors and actors at the same time. Pressure or bending the sensor generates a voltage at the piezo (with very low current) but feeding a voltage to the sensor also changes thickness (minimally) or bending. So one element drives the other which is not good for the output impedance for piezo elements in parallel.
You get a cleaner sound from individually buffered piezo elements than buffering passive piezos connected in parallel.
BTW, I needed a two element pickup when I got my 5-string and thought that would be needed.
After a soundpost repositioning (away from the bridge foot) all strings were equally represented with a single element pickup.
I did it on a two element Shadow SH-950, making a SH-951 out of it as the end element was broken.
Piezo elements are sensors and actors at the same time. Pressure or bending the sensor generates a voltage at the piezo (with very low current) but feeding a voltage to the sensor also changes thickness (minimally) or bending. So one element drives the other which is not good for the output impedance for piezo elements in parallel.
You get a cleaner sound from individually buffered piezo elements than buffering passive piezos connected in parallel.
BTW, I needed a two element pickup when I got my 5-string and thought that would be needed.
After a soundpost repositioning (away from the bridge foot) all strings were equally represented with a single element pickup.
I did a little experiment today with my old underwood. I tried recording a little using the direct out post eq from my AI straight into my interface. I also put a nice mic (old 414) in front of my bass, recording each onto a mono track. I tried the underwood with both elements and with only the e string side element, which is the 'end' element, so the 'middle' element was basically hanging in space. This time I really did hear a difference between both elements and the single element. The single one is better, it's as if there is a phase battle with both elements in place. Problem is, there's noise and some weird output fluctuation with that middle element hanging there. I also tried using that middle element alone on the E string side and it barely worked. So maybe I have a problem with the middle element. My underwood is 25 years old at least, although it hasn't been used much. I might be convinced to cut the middle element out and splice the wire to the end element. Any suggestions about doing that?
I tried the same thing with my realist, very very different. So dark. Once I get this stuff sorted out, and get either a FC or Yamahiko single element, maybe I can make some better recordings and share the samples.
Thanks again for all the input and comments, I'm learning a lot.
I tried the same thing with my realist, very very different. So dark. Once I get this stuff sorted out, and get either a FC or Yamahiko single element, maybe I can make some better recordings and share the samples.
Thanks again for all the input and comments, I'm learning a lot.
I’m head to hear you’re making progress. Everyone I know that uses Underwood with just the end element lets the other hang loose but maybe there’s room for improvement.
For all your single element Underwood needs…
https://www.talkbass.com/threads/onederwood-pickup-update.1385237/
https://www.talkbass.com/threads/onederwood-pickup-update.1385237/
With the Full-Circle, I have to set my amp at the strangest EQ curve I’ve ever used. The sound is good though. It just might make gigs where I have to jump from upright to electric a little tricky.
