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DB750 delay on power up?

Discussion in 'Amps and Cabs [BG]' started by eots, Apr 9, 2006.


  1. eots

    eots

    Dec 18, 2004
    Morris, IL.
    Just got my Aguilar DB750.
    I didn't realize it 'only' comes with speakon output jacks for the speakers so I wasn't prepared and didn't have a cord.
    The blue diagnostic led kept blinking when I powered it on for the 1st time and never stopped. I suspected it may need to have the speaker connected when powering up, but no where in the manual does it state this as if it were critical.
    Well, I took it to practice to try it out for the 1st time as there was a speakon cord there to use. It still kept flashing the blue led for several attempts (waiting 30-60- seconds) then one time after fiddling with the mute switch, it decided to pass.:confused:
    This is a concern since I'm used to lights coming on immediately when I flip a switch.
    None of my other amps have required preconnected speakers .
    I've had other tube amps before that need to warm up for a 'few' seconds before coming alive. This seems like an issue to me.
    I practiced for several hours tonite and it's everything I've read about on TB.:hyper: :bassist: but I'm concerned about reliability at this point.
    Does anyone elses DB750 work everytime after it's brief diagnostic check or has it gone on for longer than a minute while blinking?
    This is a brand new unit.
     
  2. jokerjkny

    jokerjkny

    Jan 19, 2002
    NY / NJ / PHL
    the 750's take a little bit to start up. no biggie. and YES, you should always have a speaker connnected to it.
     
  3. jablues

    jablues

    Oct 17, 2005
    Seville, Spain.
    +1
     
  4. PJR

    PJR

    Jun 20, 2001
    N.E. PA
    It does take about 30 seconds to fully power up. In that time the blue led will flash. If you turn it off mid flash it will start the diagnostic all over.

    This is normal.

    PJR
     
  5. Mine takes the 30-40 seconds as well. If yours is blinking for more than that, I believe there is a problem. If it's new, your warranty will cover it without a problem. The people at Aguilar are very nice to work with.

    If it is a problem, get it fixed and don't look back. Don't let this "glitch" deter you from keeping one of the best amps around.
     
  6. kjones

    kjones

    Dec 4, 2004
    Maryland
    Yep, 30-45 seconds for me as well. I would recommend that eots look at his watch, and if it is genuinely taking more than one minute, then there's probably something to talk to Dave B. about. I don't find it a problem, because it gets turned on once at the beginning of a gig, then I just mute in between sets.

    I have operated it without a speaker attached on several occasions, twice in the studio and once on stage. The tone is so "me" by this point, that even though it has fan noise, I took the DI out of it so I could get the sound of the tube(s) in the preamp. I had no problem doing so without a speaker attached, and haven't had a difficulty of any kind since. My reasoning was the same as Smash's-FET power side shouldn't require the attachment of a speaker.
     
  7. Lowtonejoe

    Lowtonejoe Supporting Member

    Jul 3, 2004
    Pasco, WA
    The DB750 has a solid state output????:eek:

    Dang! I thought that it was the ultimate tube amp. :meh:

    All of a sudden getting the DB750 over an AG500SC doesn't seem to be much of an issue.:(

    I'm just so surprised.

    :confused:

    Joe.
     
  8. kjones

    kjones

    Dec 4, 2004
    Maryland
    joe, it's still an issue, believe me. Although the tones of the 750 and 500 are related, they really can't substitute for each other. To me, the 750 is much more oldschool, with a very round bottom end. The 500 is more angular, more modern, more metal, especially if you use the drive channel.

    Perhaps the 750's tubes in the pre make the difference; more likely Aguilar just wanted them to have individual voices. My opinion and experience would be that if you actually listen to both, you will have a definite preference.
     
  9. Lowtonejoe

    Lowtonejoe Supporting Member

    Jul 3, 2004
    Pasco, WA
    You are probably right but it just seems like a ridiculously expensive price for a hybrid amp.

    But then I haven't even heard one.

    Still...I dunno.

    C'mon Powerball!!

    :D

    Joe.
     
  10. fretless Bob

    fretless Bob If you fail to prepare, you prepare to fail.

    Nov 27, 2005
    Harrow, London, U.K
    mine can take anything from 20 to 60 secs, what it is doing when it's blinking is engaging all of the different power up stages, this is the major part of the power up stage. If the amp did'nt have these power up stages and there was something wrong it would blow the whole amp, not just a certain section.



    and by the way NEVER turn that amp on without a speaker connected unless you have a...... urmm...... i can't remember what it's called, but what it does is stop all of that power making a current in the amp and blowing the tubes.

    i think you can use it for a while but it isnt advised as far as i have been told.

    Dave
     
  11. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    RTFM, K?

    Aguilar DB750 Hybrid Head

    Diagnostic and Protection

    The DB750 is equipped with a self-diagnostic and status/protection circuit. Upon power-up the unit’s blue status LED will blink for approximately 45 seconds. During this time several circuit parameters are verified, or allowed to become self calibrated.

    1. The high B+ voltage to the preamp tubes is slowly ramped up, allowing the tube heaters to warm up before full current us drawn by the valves.

    2. DC offset at the amp’s output is monitored. Only if none is present (normal condition), will the unit proceed with the self-check protocol.

    3. Temperature on the MOSFET heat sink is checked, and again only if normal temperature is detected, will the status check to continue.

    4. If all the voltages, offsets, and temperature are in accordance with factory specifications, then the amp’s input, and output relays will be energized. This will then cause the operate LED to illuminate and status LED to stop blinking, and the amp is now ready for normal operation.

    5. Continues monitoring of the above parameters, protect both the DB 750 and speakers connected to the amp, in the event of unit, of user error. This will be indicated by the status LED’s blinking.

    6. If the status LED continues blinking, or starts blinking during amplifier use, this indicates a system fault. The amplifier requires servicing in order for normal operation to resume.
     
  12. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    It ain't gonna hurt it none. It's solid state. It's tube amps you have to worry about.
     
  13. fretless Bob

    fretless Bob If you fail to prepare, you prepare to fail.

    Nov 27, 2005
    Harrow, London, U.K
    it has tubes in it,

    doesnt that make it a tube amp?
     
  14. KJung

    KJung Supporting Member

    Absolutely not.... the generally used definition of a 'tube amp' is both power tubes and preamp tubes. It's the power tubes, from my understanding, that can get you into trouble when running the amp without a load.

    Preamp tubes with a SS power section (like the Ag in question, the Eden and SWR 'proline stuff, etc.) are typically called hybrids, and since they have a SS power section, most can be run without a load with no problems.

    I know there are some issues running some switching power supplies without loads also... but I'm getting in way over my technical knowledge here!

    K
     
  15. fretless Bob

    fretless Bob If you fail to prepare, you prepare to fail.

    Nov 27, 2005
    Harrow, London, U.K
    ok then.

    When i bought mine from the gallery Alex said never to use it without a cab conncted. maybe it was his misunderstanding(?)

    Dave
     
  16. KJung

    KJung Supporting Member

    I was never sure or the exact rules about that 'running without a load' thing myself.... most SS amps can do it with no problem, but some can't. I guess there probably isn't a hard and fast rule. Not sure about true 100% tube amps... my memory says running a tube amp without a load is a very bad thing.

    It would be interesting to hear from the EE type folks regarding what the issues are in safely or 'not safely' running without a load.
     
  17. eots

    eots

    Dec 18, 2004
    Morris, IL.
    So should my amp pass diagnostics without a speaker connected?
     
  18. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    Yes.
     
  19. Folmeister

    Folmeister Knowledge is Good - Emile Faber Supporting Member

    May 7, 2003
    Tomball, Texas
    This is an issue that a good friend of mine has dealt with. He has two, yes two, DB750s. The first one he brought home would not get through the diagnostic cycle. He took it back and got another one. That one worked fine. When he bought his second one, he fired up more than one and made sure he got the one that cycled the fastest. Mine has never had any issue and cycles through every time. One of the things that I was focusing on with this whole issue is power conditioners. My friend was running his through a Furman unit, and I think they might be an issue with the 750s seemingly large draw upon powering up. He was freaking out when he got the exchange unit home and it was doing the same thing. I told him to try bypassing the Furman and that seemed to solve the problem. I use a power strip between my 750 and the wall, but it is a shop strip with a simple breaker. I know 750s draw a lot of power because I can see the lights dim in some of the venues we play when I fire it up. Oh, I have used my 750 as a DI in the studio without any "load" problems. I looooove the 750 as a DI!
     
  20. Lowtonejoe

    Lowtonejoe Supporting Member

    Jul 3, 2004
    Pasco, WA
    Unfortunately, yes, it was sincere.

    And just as unfortunately, the correlation between it's power and weight blew right over my head. (But there is a nagging familiarity about this, like maybe someone pointed this out to me before and I just forgot.)

    My only experience with Aguilar products is my two GS112's. Maybe after hearing the amps I would unhesitatingly agree about it being worth the money but for now I still think it seems a bit expensive.

    Well, o.k., too expensive, but then so are alot of other things I want!

    :D

    Joe.
     

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