APTflexType: electret film
Mode: passive
Preamp: –

This new pickup for double bass comes from Russia, and is placed under the foot of the bridge. No piezo is used, but an new electret film. This film allows a thickness of only 0.5 mm. In addition, the sheet is flexible and totally even, and fits the curvature of top and bridge feet perfectly.
Due to the placement on the bass’ top, the sound of the APT-flex is round and powerful for both pizzicato and arco.
The electret film sensor is shielded with copper foil, and has a rigid cable joint. The jack is attached to the tailpiece by means of a cable fastener or a plastic clip.

(out of production)


14 thoughts on “APTflex-electret

  1. Jonas Post author

    I have this pickup on all of my basses. Very easy to install, and due to it’s small thickness, no adjustments are needed. The output is not as high as from most other (piezo) pickups, but my amp has no problem to compensate this. The sound is well balanced, very round and full.

  2. Peter

    As we all know the sound of a doublebass is a system. The single components like instrument, strings, pickup, bow etc. have to fit. Regarding the pickup I’ve first tried the APT Flex on my 4/4 Doublebass. Cause this instrument has a big sound with a lot of body, the APT Flex was too “boomy”. Second I’ve mounted the pickup on my other doublebass which is something like a 5/8 size. The sound of this instrument is more clear. And now it works great. A warm sound is in the air and best of all – it’s dynamically. The pickup follows the movement of playing. Like strings should do also. I’m using gut strings of Gerold Genßler which are following my intentions. And the APT Flex “translates” exactly. In arco and pizz playing. No problem if you change from pizz to arco. As sometimes from other pickups wellknown no sudden raising of the volume, no scratchy sound. It keeps warm sounding. The easy mounting is great. If you don’t want to change anything on your instrument you should try.
    I’m sharing Jonas’ opinion: the output of the pickup isn’t very high. With my mixing console for computer recording I have to compensate with plugins like `gain volume´.
    With my amp on stage the lower output is no problem.
    The next step is to check out the pickup with my Electric Upright. I’m pry.

  3. Geert

    The bridge on my Eminence needed to be replaced. One of the adjusters was broken and I found the action too low. Because I found the Realist to sound a bit mid/piezo-like on many occasions I decided try the APTflex with the new bridge. I was inspired by the CD Arkeology with bassist Stefano Dall’Ora, who uses an eminence with this pickup on this recording with a very good result. The eminence on this recording doesn’t sound like an amplified URB but has a different sound with a unique acoustic character (which also differs from a mic-ed URB!).

    So far my experiences with this pickup on the eminence are very positive:

    The pickup is much thinner than the Realist and has a flat/even surface, which make it fit better under the bridge-foot. The pickup sits evenly on the top and is not bumpy like the Realist.

    The APTflex sounds much more even across all frequencies and requires less EQ to sound good than the Realist. To me the APTflex does not sound bright. With the Realist I had to cut a bit more treble and a lot more mids. No need to boost bass. The APTflex sounds OK direct into an AI Coda with all EQ flat. Further EQ-ing according to personal taste (or room/situation) instead of trying to make the pickup sound acceptable. I still cut mids but not to get rid of piezo-mids but to get the tone I like.

    On a rehearsal with loud drummer I played via a Fishman pre-amp into a PA system. Excellent sound with very little EQ-ing (some cutting of mids).

    The eminence with an APTflex sounds more acoustic to me but with its own character. More like an acoustic eminence bass instead of like an amplified “normal” URB.

    It has a more volume than my old Realist. Less gain required to get the same volume.

    Like the Realist, good for arco.

    Nice even sound from low E to thumb-position.

    For scientists amongst you: I did not do the control experiments, which would be trying the APTflex in combination with my old bridge and the Realist with the new bridge. The new bridge has more wood left on the string side (higher action), is overall thicker and has two functional bridge adjusters.

  4. Manuel Malvar

    Please i need information about the APTflex-electric pick up and your price.
    I am a musician in Buenos Aires from many years, acoustic upright player.

    Manuel Malvar Marengo

  5. Al James

    Thanks Jonas for the very prompt delivery of the APTflex i fitted it within 5 minutes of opening the box.I was immediately impressed with the very full rounded sound compared to the RSII i had fitted before there was non of the scratchy highs associated with piezo pickups i could actually leave the treble on my EBS drome untouched !I also found the output good enough even without my fishman preamp also comparing it to the realist which i have also owned there was non of the low mid rumble and artificial highs which had me forever tinkering with the eq as soon as i plugged in i had a good workable sound only needing slight tweek to get about as good a sound as you can without a mic
    thanks again


  6. Rainer

    Thank you Jonas for the extraordinary support!
    + very easy and quick installation
    + the ATPflex sounds very naturally and well balanced
    + no preamp and no battery necessary
    + the best pickup I ever had – and I had some!

  7. Maxim

    I’m about to buy a double bass from a friend of mine. I’m playing electric bass for a few years now and now i’m looking to electrify his double bass. I don’t want to adjust a lot of thing because i don’t really know a lot about it.

    I’m interested to buy the APT-FlexElectret for it’s easy installation but I want to have that rockabilly slap kind of sound. Is this possible with this pick-up?

    Thank you

  8. Jonas Post author

    in general: yes. But to emphesize the “slap” sound, you may consider an additional piezo pickup for under the fingerboard.
    And the APTflex works best on high impedance inputs, which most e-bass amps don’t have.

  9. Roberto Seitz

    Hello Jonas. I’m interested in getting an APT-flex pickup. Is out of production??. How do I get one? Is there a way to get at least one used? Greetings and many thanks.
    Robert Seitz


Leave a Reply

Your email address will not be published. Required fields are marked *