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Advice on preamp signal chain for doubling

Discussion in 'Amps, Mics & Pickups [DB]' started by markroman, Apr 26, 2017.

  1. Dear TB community,

    I'd like to know if I can safely daisy-chain three preamps in my signal path.

    Recently, I've accumulated some new toys I'd like to experiment with in my live setup for UB, particularly on doubling gigs:

    Prodipe BL21 Lanen - electret condenser mic for UB (www.prodipe.co.uk/mics/2140-bl21-lanen-contrabasse.html)

    Vintage Revolution Acoustic Box Live - mic/p-up blender (www.vintage-revolution.com/acousticbox)

    A quick rundown of my existing signal chain for doubling gigs:

    - UB w/ Rev. Solo II Transducer > BBE Acoustimax preamp >
    - EB (passive P-Bass) >
    BOTH -> Radial Bassbone (V1; EB on the Ch. w/3-band EQ) > (DI to PA) ->
    -> Ampeg B-50R 50w solid state combo amp.

    Here's my question: Can I safely daisy-chain the three preamps (Vintage Revival > BBE > Bassbone) before the amp?

    Would I run into possible impedance, signal distortion, phase & clipping issues?

    The goal is blending the mic & pickup signals, then feeding the blended upright bass signal into my existing doubling setup - I'd like to continue to use the BBE in the mix to help tune the blended UB signal to the individual room / PA system, bearing down on resonant frequencies as necessary.

    Relevant advantages of the BBE Acoustimax:
    -reliably consistent tone shaping & feedback control from the stage
    -sweepable mid scoop/boost & notch filter
    -inexpensive & portable
    -mute footswitch (!)
    -3-band EQ

    (The hype around the technology behind the BBE's sonic maximizer is indeed a bit of a marketing gimick, but I have to say, in loud band situations, the signal processing allows for some dynamic variability on demand via footswitch)

    Many thanks!

    Mark Roman


    P.S. the Ampeg does not have an Effects Loop, but both the BBE & the Bassbone do (TRS Y-Cable needed as there is only one input/output plug available)


    You can find the specs on those three preamps here

    Vintage Revolution Acoustic Box Live: Acoustic Box Live Vintage Revolution buy online webshop

    BBE Acoustimax: http://www.bbesound.com/products/manuals/acoustimax_manual_rev3.pdf

    Radial Bassbone: http://www.tonebone.com/pdfs/manual-bassbone.pdf

    Last edited: May 6, 2017
  2. bump! IMG_1182.JPG
  3. Did you try it already?
    I don't think it's wise to use 3 pre-amps.. It could be safe, if you don't boost the signal level too much with each stage.. but then, that's what these boxes do, and the gain of your amp.
    I once blew up my amps powermodule (end stage) because i had set my preamp to high and the gain wide open..

    Why not only use the Acoustic Box? It has all the features you need..

    Interresting mic, that BL21. Please let us know what your experience with it is? Not to expensive either.
    markroman likes this.
  4. Thanks for your reply, GoofusInsanius - I appreciate the chance to nerd out on such a high level!

    The idea of using the Acoustic Box independently has become more and more tempting as I examine things more closely: On doubling gigs, I can still use it in conjunction with the "clean channel" of the Bassbone. I think it could really provide a lot of UB-friendly tone shaping on it's own with those two independent sweepable mid-controls, plus the Notch & the LoPass Filters on the mic channel. Also, the independent level controls for the PA & Amp output signals are a huge plus. And the size! I might miss stepping on all of those cool stomp boxes, but I won't miss dragging them around! Also, (for me as a German-American) the switchable voltage selector is absolutely great.

    I'll be receiving it shortly, so I'll be sure to share my impressions here once I have some playing experience with the Acoustic Box in the mix behind me. As to the BL21 Microphone - I've only owned it for a short time (used it twice so far, once in the studio, once over the PA on a small outdoor festival gig) and I have never used another clip-on mic before. However, I can say this about the mic: live, it really adds some body to the acoustic sound.

    In the studio, the engineer favored the U87 signal, as the BL21's signal was not very well-rounded, weighted more heavily towards the mids & highs. It makes sense, too, if you look at the Frequency Response Curves: (BL21 Lanen Contrabass instrument mic Prodipe). I think that a rolled-off low end is potetntially a good quality in an UB mic for live use, though - everyone seems to be talking about HiPass Filters on TB lately! Strong Sub-bass / Contra-Octave level lows in the mix tend to muddy up signal definition.

    To sum it up, I have a lot of happy experimentation ahead of me and I'll come back here with an update as the possibilities unfold. Thanks again for reading.
    GoofusInsanius likes this.
  5. Jay Corwin

    Jay Corwin Supporting Member

    Jan 29, 2008
    Sanborn, NY
    I have a B50R and a B100R. The B50R has never been very friendly to me on upright regardless of the preamp.
  6. jthisdell


    Jun 12, 2014
    Roanoke, VA
    Hmmm, interesting set up. What I do know is that the gain on the Tonebone is very low, designed to be very clean and not overdrive the pre amp of a bass amp. So if you have any problem it would probably not be there. But yeah, gain + gain + gain + gain could be too much gain.
  7. Cool music, and thanks for weighing in - I don't know what it is about it, but I love the B-50R sound for upright in particular - more than any other amp I've tried... from MarkBass to the SVT to The Flightcase. Granted, I'm going to have to play a lot more jobs before feeling justified in paying three times as much for an amplifier with all the bells and whistles on board (LPF, Parallel Inputs, 48v Phantom, etc.) seeing as how all this outboard stuff has been pretty easy to find used for less.

    Thanks as well for the advice, I'm new to the electronics side of things - What I'm thinking is that I could probably use the Acoustic Box and the Bassbone in conjunction for doubling in the future as I have been doing with the BBE (on a low gain setting) through the Bassbone's un-EQ'ed channel up until now. It's reassuring to know the Bassbone is not totally unsuited for the use I've put it to, if used with care.
  8. Just a little update:

    this post was the beginning of a long & protracted process of reflection on what gear I already had, what gear I really needed and what gear I could actually afford - The goal eventually became hunting down a portable, professional-level, doubling-ready amplification rig to replace the Ampeg Portabass 250 & PB112H cab I sold upon leaving the U.S. back in 2011.

    So far, heres a summary of the gear I'll be using (most of it already ordered, some of it still in the mail) along with the approximate costs in dollars:

    Prodipe BL21 Mic ($110, new)
    Acoustic Box Live ($219, used)
    Genz Benz STL 6.0 ($373, used)
    STL 6.0 Footswitch ($57, new)
    Eden EX112 ($250, new)

    *Total: $759

    The URB is already outfitted with a Revolution Solo II piezo. The BG is a frankenstein P-Bass (5-piece alder Squier body & pickups, no-name maple neck) with flats.

    The idea is to start with one 8-ohm, 12" cab and add a second one a bit later as funds become available.

    Once all the gear is in one place (will take a while - it's scattered about & partially in the mail at the moment) I'll post a longer summary of my first impressions!

    *Edit: tweaked prices, added total.
    Last edited: Sep 16, 2017
  9. Ric Vice

    Ric Vice Supporting Member

    Jul 2, 2005
    Olivette, Missouri
    Nice Rube Goldberg, mix and match setup. The Prodipe looks like a AMT clone, but at a better price point.

    markroman likes this.
  10. Thanks! The result of many hours of forum/ebay scouring...
    The mic has been great so far, sent as is to the FOH on a couple of smaller gigs.
    The idea is to use the Effects send of the Genz as the input for the blended URB signal.
    I'm looking forward to all the tonal flexibility, but a bit concerned about feedback through the amp.
    Last edited: Sep 16, 2017
  11. Hoyt


    Jun 29, 2006
    Saint Charles, IL.
    As someone who is also "Rube Goldberging" preamps, if I had to spend my $$ all over again I'd just save up enough for the Grace Designs FeliX. Perfect for doubling, running a mic (with a full 48v phantom power available), notch filtering, high pass filter, and a clean DI.

    For upright I'm experimenting with adding a Sennheiser E604 to my Underwood bridge pickup, then sending those into my Rane AP-13, then sending the final mix to a Grace Design BiX before feeding my Crest Prolite 2.0 with some positive results. Obviously for loud gigs (rockabilly, etc.) I'd only send the mic to the FOH.

    I think the problem with doubling is that we want the URB to have that "MBOL" sound whereas with the slab we want some coloration of the tone. Personally, I think that getting the URB to sound right is the more important of the two, and treat the slab tone as secondary to my needs. Just MHO.
    markroman likes this.
  12. Nice to read about your experiences, thanks for posting! Rube Goldberging is a good way to describe it ;-)

    Just to clarify, I'm abandoning the Tonebone and the BBE Acoustimax preamps in favor of the Acoustic Box for the upright (through the efx return) and the Genz Benz tube preamp stage for the electric. My priorities are light weight, low cost and ease of travel with some form of 'my sound' (or at least a familiar sound) in tow for backline gigs with the upright only.

    The Acoustic Box paired with mic & piezo is a great gig-bag alternative for that application, (as is the Genz 6.0 itself!) in my view. Also, the total cost of the equipment I'll be using (mic, a-box, genz, footswitch, eden) still remains below the Grace Design Felix's price point. It does look like a beautiful alternative with the variable hpf's, but it's something I'd have to save up for purchasing in the distant future...

    In terms of doubling, I think you're right about the bare bones approach - I'll be running the passive electric bass through the tube preamp on the Genz for a while before experimenting with anything else!
    Hoyt likes this.
  13. Update:
    as of last week, all of this used gear I've been chasing down is finally in one spot and ready to rumble - the cabinet I wound up with is a Genz Benz Shuttle 2 single 12" that I got a great deal on from Bass Direct in the UK. I will be playing my first (acoustic blues-songwriter) gig out with the upright through the new gear on Sunday and will report back on the results!
    Here's the signal chain now:

    URB >
    Prodipe BL21 Lanen condenser
    Revolution Solo II Pickup
    > Vintage Revolution Acoustic Box (1.0)
    > Genz Benz Shuttle 6.0
    > Genz Benz Shuttle 2 single 12" 8 ohm cab

    On doubling gigs, the upright signal would come into the power amp via the effects loop with the bass guitar routed through the shuttle's tube preamp.

    It's such a beautiful privelege to get to play on all of this high- level equipment!
    Total price tag including mic, blender, amp, cab and footswitch: $ 1,036.
    image.jpeg image.jpeg
    Hoyt and GoofusInsanius like this.
  14. Thanks for the update, let us know how the gig went?
    How did the Prodipe behave itself? Not to much feedback?
    Hoyt and markroman like this.
  15. Hey all,

    here's my first impression of the Prodipe BL21 Lanen Contrabass Condenser microphone in live application, powered by the Vintage Revolution (V1) Acoustic Box Live:

    - Scenario -

    Last night's gig (Guitar/vox, Bass/vox & Trumpet) was an acoustic trio concert with a piedmont fingerpicking-style, eclectic blues singer-songwriter. The room was a rectangular, high-ceilinged cafe with an attentive, seated audience and a couple of unabashedly dancing little kids - It's housed in a segment of the former Orangeries in a historic city park, so the wall stage-left features two tall, arched windows. Opposite those on the wall stage-right, they've affixed two large acoustic panels in the exact shape & size of the windows, a rather elegant touch that makes for a decent acoustic space despite the parallel surfaces, high ceilings and all that glass & plaster. There's a few pictures of our live setup on here: www.instagram.com/kbcsound

    - Gear & Settings -

    I left the amp at home, sending the bass to the house using the Vintage Revolution 'Acoustic Box' to blend the mic and the piezo signals. The BBE Acoustimax was also threaded into the signal chain between the piezo and the Acoustic Box (adding extra headroom for dynamic variation, or muting of the piezo for arco playing on demand via footswitch).

    There were no monitors, no sub, just two PA loudspeakers and a bit of natural reverb to go by in terms of our dynamics in the room. The speakers were practically on the stage, one of the two situated directly next to my scroll. The sound man was a very sweet local yokel who became extremely skeptical of running the preamp into the board as soon as he saw yet another microphone pointing at the top of the bass (trumpet player was already making him nervous with his own clip condenser), so he started in, cajoling me into going direct into the board with his trusty DI box and let him do the heavy lifting with tha on-board EQ. He turned out to be very nice, though - let's just say it took a little convincing to get things set up... Hence, my mic volume remained at the uttermost conservative limit, around 9 o'clock - the piezo wasn't much louder (about 12 o'clock) on account of the two preamps in series conveying the piezo signal to the house.

    - Impressions -

    I was feeling pretty good from the start - realized I still had quite a bit of headroom despite the space's very live acoustics during soundcheck, but decided to stay cool for the sound man and really play to the room with the band. I felt I could hear myself acoustically very well - like most (unplugged) living room rehearsals with this band and unlike the generally quacky, loud piezo sound I'm accustomed to from playing live into the PA with a preamp - Here I was, able to hear myself in a very nuanced way without driving the other musicians up the wall, or causing them to increase their volume! I drove the mic a little and realized that's what I was hearing - the little bit of mic support really made a huge difference in this room & playing situation: It didn't feel like playing with a trio, it had a bit of an acoustic property that I'm used to from orchestral and chamber music settings which really allowed us to play a couple of very dynamic, interactive sets of music. Feedback never reared it's ugly little head!

    Afterwards, I received a lot of spontaneous, positive feedback from the audience on the bass-sound, and even got a silent nod of acknowledgement from the soundman ;-)
    Last edited: Jan 22, 2018
    Groove Doctor and GoofusInsanius like this.
  16. To get things back on topic for a minute though....
    Here's a very similar diagram to what I've got up my sleeve from TB's @jvgreene:
    Doubling Diagram
    The only difference being that I'm using the "tuner out" output of the Bassbone to keep the tuner out of the signal chain.
  17. Good to hear that you had a nice experience. Smart to keep your setup in place, so that you can controll your signal chain.
    No monitors, that properly kept the feedback away :) FOH speakers that close to the mic might have influenced feedback, but glad that they didn't.
    So overall you're happy with the Prodipe BL21?
    markroman likes this.
  18. Yep - I would reccomend it.
    I guess it boils down to more of a philosophical question - Of course I'd rather support the hard work and R&D of some nice Scandinavian guys and get a DPA - the likely qualitative difference is not lost on me.

    However, I'd still say: better a specialized URB condenser mic that I can actually afford for the time being rather than no mic at all! There's always room for better gear as the work your improved sound brings in enables you to shop around the top shelf market segment.

    I'll continue to post my subjective impressions of the mic here as it applies to my doubling-setup odyssey, as the thread title suggests.

    There is some info on the BL21 out there:

    What about Prodipe BL21 Lanen?

    If I find anything else of interest that I located while researching the mic before my purchase, I'll send you a quick PM.
    Groove Doctor and GoofusInsanius like this.
  19. @agedhorse - as I've experimented at home with an efficient setup for doubling using my new (used) Genz Shuttle 6.0, I've noticed that patching my upright bass preamp into the Genz's power amp through the "effects receive" on the back of the amp unfortunately only seems to work as long as the amp's input (on the front of the Genz, before the tube preamp) is not in use... meaning the regular input and the effects receive apparently can not be used simultaneously -

    However, I once mistakenly plugged the upright preamp into the effects send while my electric bass was plugged into the input - and voila, both the upright and electric were audible.

    coupla questions:
    - Is this normal, according to the circuit design?

    - If not, do you recommend I try the reset (plugging and unplugging a cable in the effects receive a dozen times or so) of the effects loop - or any other troubleshooting tips for accessing the Genz's power amp and preamp simultaneously for doubling applications?

    - If all else fails: Can I safely run the amp as described in this post? (Upright mic & piezo > Vintage Revolution Acoustic Box > Effects send // Passive P-Bass > Amplifier input). If yes, is the upright bass bypassing the Genz's tube preamp in this scenario, as I suspected by the sound/function of the amplifier?

    Please forgive my novice-level knowledge of electronic circuitry, I hope my questions are relatively clearly formulated. Many thanks in advance.
    Last edited: Jan 25, 2018
  20. jthisdell


    Jun 12, 2014
    Roanoke, VA
    well that's unexpectedly interesting!
    markroman likes this.
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