Help with Effects Loop on Aguilar DB659

Discussion in 'Amps and Cabs [BG]' started by shriekback, Dec 15, 2007.

  1. shriekback

    shriekback Supporting Member

    Nov 25, 2007
    Eugene, OR
    Hi everyone,

    So I recently picked up an Aguilar DB 659 preamp (thanks "fhodshon"!) and I am a bit perplexed by the effects loop and its various settings. I am hoping that I might get some guidance from those with more experience with this piece in particular and/or from those who are more aquainted with effects loops in general.

    First of all is the series/parallel option. I understand (I think) that the parallel option will combine the wet signal with the dry signal, but how do I control the relative levels with the send and return knobs? In Series mode (that's when the whole signal is passed through the loop, right?) what exactly do the send and return controls do?

    Further questions:

    If I am going to use a compressor in the loop, wouldn't it be best to run it in series?

    If I use pedals, should I use the regular setting or the -20db setting?

    Thanks for any help anyone might have to offer.
  2. When I get home, I will try to take a picture of my DB659 and DBX 166xl for you.
  3. I have been running mine with send at 2 'o clock and return at 5 'o clock... both pulled out.
  4. shriekback

    shriekback Supporting Member

    Nov 25, 2007
    Eugene, OR
    Thanks, that helps. I think I can construct the rest of the operation from those choices.

    I assume, for example, that this means that if I were to use effect pedals in the loop that I would not pull out the send knob (for -20db).

    Any elaboration would be welcome, of course.

  5. I just scored one of these; it arrived last night. I thought that I would play around with it today and try to answer shriekback's questions, but ended up with a question of my own.

    The only question that I can answer is regarding the use of a compressor - yes, it would be better to use the series setting. No sense blending a wet and dry signal if the effect is a compressor; that would defeat the purpose of the compressor.

    So here is my question - to shriekback, bothroysnvts, or anyone else that has a DB659. I expected that when I pull out the send knob, that the signal would be attenuated by 20 dB. However, on my unit, the sound is louder in the "pulled" position than in the "pushed" position. I tested this with a cable going straight from the send to the receive, so it is not a function of any effects box. Are your 659's the same as this, or is mine wired backwards?

  6. shriekback

    shriekback Supporting Member

    Nov 25, 2007
    Eugene, OR
    Hi Franco,

    My 659 works just as yours does, that is, the gain goes up when I pull out the send knob. I don't know what the -20db therefore means exactly, but yours suffers no apparent malfunction (unless mine shares it, of course).

    Since we're not getting exactly snowed over by help, here's what some naive experimentation (starting with bothroysnvts' tip) has yielded:

    I think the send, in either series or parallel, is just to get the optimal level going to an effects processor, (so it has sufficient signal but is not overdriven).

    The return, in the series mode, then is just used (combined with the volume) to level the output of the effect processor with the gain established by the volume knob if the effects loop were not in use (just as a level control is used on an effect pedal to equalize the gain with that when it is in bypass mode, so that switching it on and off does not make your volume go up and down). Assuming your effect does not add any gain, it should be all the way clockwise (as bothroysnvts has his set).

    The return, in parallel mode, seems to determine how much of the wet signal is included in the mix with the dry, determining the amount of the effect in the overall sound.

    If I have any of the above wrong, I hope someone will set me straight.

    I hope you are as pleased with your new pre as I am with mine, Franco. I am waiting on a pair of 1950s RCA 12ax7 tubes that I hope will make it sound even better. My audiophile pal is also going to replace the more pedestrian electrolytic capacitors used in it with some high-end Blackgate caps. Many used in the pre he thought were quite good, while others were, well, cheap. I will post as to the worthiness of that effort when it gets done. A similar effort did very good things for the sound of my Ashdown RPM-1 pre, so I expect it will do so with the Aguilar as well.
  7. Shriekback,

    Yeah I think your analysis of the send and receive controls is right on.

    The only effect I use (depending on the amp) is an Ashdown bass overdrive. However, I could not get it to sound good in the FX loop of the 659. In fact it sounded really bad, as if the front end of the Ashdown was being overloaded, even with the send level turned way down and the knob pushed in (or out). But in line between the bass and input to the preamp the Ashdown sounded good. I'm not going to worry about it, because the Aguilar can get a nice gritty sound by itself, so I probably wouldn't bother with the overdrive pedal anyway (although being able to footswitch between clean and crunchy is nice).

    Yeah I'm pretty happy with the sound. I was looking to put together a relatively lightweight rig (with a Crest CA-4) that would give me more or less the Aguilar sound, as my Aguilar DB680/DB728 rig is pretty heavy and only gets used on easy load-in gigs. I plan on using the DB659 on at least one of next weekend's gigs, so we'll see.

    BTW, I like your avatar. I used to have an early model L2.

  8. shriekback

    shriekback Supporting Member

    Nov 25, 2007
    Eugene, OR

    I have noticed that my EBS multicomp also seems to be easily overdriven in the effects loop, especially when the knob is pulled out, which I think is supposed to be instrument level. When I have the send turned down pretty far so there is no distortion, the effect of the compression is much more pronounced than when I have it between my bass and the pre. Does the effects loop in the DB680 have the same issues for you?

    It would be interesting to hear, when you have had more time and gigs with it, how you would compare the the sound of DB659 to that of the DB680. I suspect there aren't many players out there who have both at the same time.

    That DB680/DB728 combo has to be one of the more impressive bass amps ever, but I would bet it is a task to move about. I too grabbed a DB659 aiming to put together a lighter and more portable rig (my Ashdown RPM-1/APM1000 combo isn't exactly a featherweight either). My plan now is to pair the DB659 with an AI SA Focus III power amp to drive my two Acme LowB2s. I am not yet convinced it will sound quite as good as the Ashdown (awesome, that is) but I'm not getting any younger and my bandmates pitch in less and less to haul my stuff.

    You let an early L2 get away? I hope you'll be able to forgive yourself someday. There are some other basses out there that probably aren't completely terrible, even if still largely based upon crude 1950's design and engineering.

    Thanks for the response. (I was just kidding about the last crack about your presumed Steinberger-guilt.)
  9. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Yamaha, Ampeg, Line 6, EMG
    When I get confused about knobs and switches (and I often do), I just start turning them until I get a combination that sounds really good to my ears. Hasn't failed me in 30 years.
  10. Jimmy: that usually works, but in this case there was no combination that sounded good.

    Shriekback: Good idea. I will try the FX loop in the DB680 as a comparison. I have not yet used the Ashdown overdrive with that amp, because I get such a nice gritty sound with that rig by itself. Will also try the FX loop of my other amps (but none of them have the send/receive level controls).

    The DB680/DB728 indeed is a bitch to haul. With an 8-space Calzone rack case and a Furman glorified power strip, it weighs about 120 lbs.

    If I had unlimited funds, I would have kept the Steinberger, but needed to fund another acquisition. I did make a pretty good profit on it, however. Can't look back!
  11. lonotes

    lonotes A place for everything, & everything out of place

    Oct 15, 2003
    Port Richey,FL
    From the manual;

    Effects Loop:
    The Send pot is push/pull for line or instrument level. This allows you to use a studio effects unit (line level) or a stomp box (requires instrument level) in the FX loop. Adjust the amount of send so as to get maximum performance from your effects unit. Don’t give the FX so much level as to overdrive it.
    The parallel/series pot is push/pull for parallel or series operation. In the parallel mode affected signals are mixed to the dry sound. In series mode the entire sound of your bass is processed by the effects in the loop. The amount of effects can be adjusted with the return pot. If you pull the return pot out for series operation without any effects plugged in the loop, the loop will be open and no sound will result.
  12. tombowlus

    tombowlus If it sounds good, it is good Gold Supporting Member

    Apr 3, 2003
    North central Ohio
    Editor-in-Chief, Bass Gear Magazine
    Once you get used to this setup, I think you'll really love it. The effects loop setup on the 659 is both elegant, and super useful. It's probably my favorite 'effects loop' (wow, who would have thought that one could actually have a 'favorite effects loop'?), as it lets me use either rack gear or pedals, and I can dial in just how much I want from either. :cool:

    Great preamp, IMHO, and yes, it kills with the DB 728!!! :bassist: :bassist: :bassist:
  13. OK I did not try the Ashdown OD in the FX loop of the DB680, because I keep the DB680/DB728 rig upstairs close to the garage door rather than downstairs in my music room (that rig is just too heavy to carry up and down stairs). However, I did try it in the FX loop of two SWR amps, and it sounded just as crappy as it did in the DB659. In fact, even worse, since the DB659's send level control allowed some improvement in sound. Bottom line is that in all three amps, the Ashdown OD sounds much better before the amp input than in the FX loop. So whatever the problem is, it is clearly with the stompbox and not the DB659.

    When I use the Ashdown OD, I had been placing it in line between a Raven Labs MDB mixer (so I can plug in two basses and adjust the gain controls on the MDB for equal volume on the two basses) and whatever amp I am using. So I guess I will continue to do so.
  14. koobie


    Jul 11, 2007
    Portland OR
    Sorry for the off-track comments, but why not just rack the amp & preamp separately? And just lose the glorified power strip, or put a cheapie inside the case? A 120 lb. amp case is crazy heavy.

    BTW, to the OP, I saw Shriekback two or three times in their heyday, they rocked. I think it was upon seeing and hearing Shriekback and Talk Talk that I realized wanking guitarist's days were coming to an end (guilty as charged).
  15. shriekback

    shriekback Supporting Member

    Nov 25, 2007
    Eugene, OR
    Hey koobie,

    Did you see Shriekback in Portland? I saw them there when they openend for Simple Minds, 'round about '85, at the old Paramount Theater (now Schnitzer) and again, headlining this time, about '86 at the Starry Night Club.

    Those were good shows. I ran into them after the first show at a hotel restaurant. Seemed like genuinely nice people, and I'm obviously a big fan of their music.

    Back to the topic (sort of),

    Franco, I agree with koobie. As great looking as your big Aguilar rig must be as a single unit, it would be a whole lot easier to move if it were in a couple of stackable cases. I bet it would still look really cool too.

    It sure is interesting how much different an effect pedal will sound in an effects loop as opposed to in front of the preamp. My EBS multicomp, which is usually a very subtle compressor even turned up all the way, can squish the hell out of my sound if turned up even half way and run in the effects loop. I wonder why that is.
  16. Regarding the weight of my DB680/DB728 rig, yeah in retrospect it might have been better to rack 'em separately. But I didn't realize just how much of a bitch it is until I had already scored the 8U case. The Furman glorified power strip doesn't add that much weight, and the pull-out lights and voltage meter are useful.

    I could sell the 8U case and get separate cases for the 680 and 728, but I decided to keep them in a single case. I already have a3U shallow "auxiliary" case that I take to every gig that houses my tuner, wireless unit, and Raven Labs MDB (and a nice power strip mounted in the back), so if I split up the 680 and 728, I would be stacking three cases on top of the cabs.

    I have a cart that I always take to the gigs, so the only part I need help with is getting the case on top of the cabs (if I use two), and the other guys in the band always help. The basic criterion is lack of stairs. If I can wheel my equipment cart right up to the spot where I set up, I might use the big rig. If there are stairs or a high stage, I will likely use another amp. I have several amps that I use (and like), so keeping the Aguilar for easy load-ins isn't that big of a deal. In addition to the new Aguilar DB659/Crest-CA4 rig, I have an Alembic F1-X/SF-2/Crest CA-9 rig (about 75 lbs), a Mesa 400+, and an SWR 350. So I do have some choices.