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who has burnt the DI on their Demeter hbp1?

Discussion in 'Amps [BG]' started by Steve, Mar 22, 2014.


  1. Steve

    Steve

    Joined:
    Aug 10, 2001
    you know. hit it with phantom power accidentally.

    I'm looking at one that sounds amazing on the unbalanced outs and distorted and NASTY on all the balanced outs.

    That sound like the culprit to you?
     
  2. Geri O

    Geri O

    Joined:
    Sep 6, 2013
    Location:
    Florence, MS
    That's the most likely culprit.

    I thought that nearly all amp makers had circuitry (usually blocking capacitors) that prevented phantom power from destroying the XLR output of a bass amp, but maybe not. I'd ask Demeter. Regardless of the cause, and unless you have really good electronic guys with up to date information (and amazingly enough in Jacakson, MS, we have two!), I'd ship to Demeter and have them do the repairs.

    If I were looking at the head, that would be my last concern. I personally never use the balanced output of a bass head, preferring a Countryman or Radial DI going straight to the console. When I was doing production, I'd use whatever the bass player of the band preferred, INSURING that the phantom power of our console was turned off. I'm of the opinion that I want as few electronics in the path of my bass on it's way to the PA or recording device. I certainly don't want to open that argument again, but I never weighed in at the time. Whatever everyone else's opinions rate, that's fine, I'll never tell anyone that they are wrong for whatever they prefer to do.
     
  3. Steve

    Steve

    Joined:
    Aug 10, 2001
    There actually IS a real tech about 20 miles north so, I could hassle it out if I had to which I don't. It was a near "too good to be true" snag off ebay and that is where it is going back.

    I prefer to drive the power amp balanced if the option is available. It is on the HBP1... 'swhy I bought it.
     
  4. Geri O

    Geri O

    Joined:
    Sep 6, 2013
    Location:
    Florence, MS
    Oh, my apologies, I didn't realize it was a preamp. Yes, it would be handy to have the balanced out for driving a power amp, no doubt. I'm gonna take a look at the unit.


    Good luck.
     
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  6. J.Wolf

    J.Wolf

    Joined:
    Apr 29, 2003
    Location:
    Asheville, NC
    Disclosures:
    Director of Advertising, Bass Gear Magazine
    This is definitely a thing with the Demeter preamps (HBP-1) anyways. You can buy them with an optional upgrade to a jensen transformer on the DI which prevents it from being susceptible to damage from
    48v phantom power. I had one for years and miraculously never had issues or damage, but was always worried and mildly annoyed that I always had to ask and re-ask a soundman "if this xlr line was getting phantom power" before plugging in the DI line. Eventually rather than spend the 2-300 (can't remember exactly) that Demeter charges for a retrofit, I just picked up a radial JDI to use as a DI either in front of the Demeter or coming out of the unbalanced out.

    I didn't realize the phantom zap could cause problems with the balanced 1/4" out as well though, that's new to me. I always ran balanced 1/4 from the preamp to the power amp, but i can't say for certain that it made any sonic difference, for a 1' cable run.

    Long story short, yes Demeter will fix the problem, but i don't think it will be super cheap.
     
  7. Geri O

    Geri O

    Joined:
    Sep 6, 2013
    Location:
    Florence, MS
    If you are running a TRS 1/4" balanced connection from your preamp to your amp, you are doing the same thing as an XLR would do, ASSuming that both the output and the input connections are balanced TRS, too.

    The phantom zap would cause problems for the 1/4" connectors as well, if they are simply paralleled with the XLR connectors. It's a wonder that in our shop, we've never fried a CD player or computer output used with a simple 1/8" mini-plug to XLR adapter. It would be very easy to do, especially with the smaller mixers that use global phantom power (only one switch, all channels are either on or off). I bought a stereo Radial JDI just for that purpose.

    If I were buying that unit, I'd spring for the Jensen option, no questions asked. I'd probably still use my Radial DI, but there's never anything wrong with a Jensen transformer in that situation.

    Again, this certainly isn't meant to be the Gospel, just my take on things. That Demeter preamp is very cool-looking! If I weren't into an EBS rig, I'd consider that and a power amp combination.
     
  8. Steve

    Steve

    Joined:
    Aug 10, 2001
    all I know is I had an amazing first date and now I can't get her out of my mind.

    Ugh! This is the first attack of GAS in about ten years and I have it bad.

    They should make a thing, you know, that you can stick in a DI...like a gender changer...that has a couple of blocking caps in there...

    Get right on that and let me know when it's done.
     
  9. J.Wolf

    J.Wolf

    Joined:
    Apr 29, 2003
    Location:
    Asheville, NC
    Disclosures:
    Director of Advertising, Bass Gear Magazine
    IMO it's the best 1u tube rack pre out there, for my tone goals anyways, and certainly the most flexible in terms of eq and efx loop control. There are 'tubier' 1u rack pres, like the old kern, read and Demeter 659, but the HBP-1 kills in the 'clean/hifi tube' dept
     
  10. Steve

    Steve

    Joined:
    Aug 10, 2001
    That thing has the perfect blend of SVPCL and Avalon U5.

    I about stole that thing for $430 or so, I could almost talk myself into just getting it fixed. I'd be into it $100 over market but, I'd have it....
     
  11. J.Wolf

    J.Wolf

    Joined:
    Apr 29, 2003
    Location:
    Asheville, NC
    Disclosures:
    Director of Advertising, Bass Gear Magazine
    I think I sold mine for 425 shipped. Seemed like market value at the time, but these days they seem to go for quite a bit more
     
  12. Steve

    Steve

    Joined:
    Aug 10, 2001
    HA!!!!

    Dirt in the mic / line and ground lift push buttons.

    This day just got better.
     
  13. Geri O

    Geri O

    Joined:
    Sep 6, 2013
    Location:
    Florence, MS
    LOL, I don't know of a DC blocker made specifically for that purpose, but you could use an inline 1:1 isolation transformer to do the same thing.

    I would get something with a Jensen or Lundahl transformer to keep the bass tone from being affected by its use.

    Check out the IL9, made by Sescom.
     
  14. Dave Curran

    Dave Curran Lilduke

    Joined:
    Jul 27, 2013
    Location:
    NEPA
    You could just get a mic splitter box with a transformer isolated output. Has a xlr input, and 2 xlr outputs. One is isolated, use this to go FOH, as the transformer won't pass phantom power. The direct out will, so if you go that route, make sure to label accordingly (cover the direct out with duct tape or similar).

    Here's radials take on it.

    http://radialeng.com/js2.php
     
  15. Steve

    Steve

    Joined:
    Aug 10, 2001
    one of the brains here had the work around of just using the unbalanced out to feed a venue direct box and never plugging the pre into an xlr direct.

    That seemed right up my alley. I have a 2' patch cord already.

    In any case, I sat it on top of an Acme B4 and vibrated the dook out of it for 5 sets last night and it worked like a champ.
    James Demeter, where have you been all my life? Holey mackerel that thing is impressive
     
  16. J.Wolf

    J.Wolf

    Joined:
    Apr 29, 2003
    Location:
    Asheville, NC
    Disclosures:
    Director of Advertising, Bass Gear Magazine
    Adding a passive radial JDI to the demeters unbalanced out seemed like the easiest, cheapest way to get the Demeter tone into the phantom safe DI.

    Plus, having a nice passive DI around is never a bad thing
     
  17. MSGNoff

    MSGNoff 1SG Supporting Member

    Joined:
    Nov 15, 2013
    Location:
    Oregon
    I just purchased a HBP-1 and had the same concern, so I emailed Demeter regarding a 48v phantom power hit. Here's what I received from Mr. Demeter himself;

    "Its safe with 48V but sometimes it will see 70V and that is bad. It will take out a $10 output chip (user replaceable), but the unbalanced out put will continue to work. If the phantom is on and running other things it is safe to plug it in. We have found that sometimes the turn on surge will do damage. We seldom see this problem, so our newer protection circuit seems to be working."

    There is a protection circuit which can be replaced by the user. FWIW; I will run out of the unbalanced 1/4 when we play a venue without our own FOH system and sound dude. This way I'm protected.
     
  18. BassmanPaul

    BassmanPaul Gold Supporting Member

    Joined:
    Aug 25, 2007
    Location:
    Toronto Ontario Canada
    IMO, any amplifier that sports a DI should have been designed with Phantom Power in mind. In my own build, I used a reverse connected Altec mic input transformer. It isolates the circuitry from the 48V Phantom Power. These days, most mixers have a global switch that turns all of the channel's 48V supplies on. I mostly use condenser microphones, AKG and EV, when I play so I need the 48V supply on.
     

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