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NAD: GK 2001RB (and some issues...)

Discussion in 'Amps and Cabs [BG]' started by mouthmw, Feb 4, 2016.


  1. mouthmw

    mouthmw

    Jul 19, 2009
    Croatia
    My 2001RB finally arrived yesterday in a nice SKB 4U rack case. I quickly tested it through my 15" cab that I use for band practices and quieter needs.

    I connect the thing, set it to bridged mode, set the "right level" knob to full (I read the manual several times while waiting for it to arrive to familiarize myself with everything, plus I've been using 700RB II for years prior to that, so I'm not new to GK), plug my speakon cable to my cab, plug it in, and power it up.

    I noticed as soon as the amp is plugged in, the led power light is green. I turn it on, it blinks red a couple of times and it turns blue. Ok, here we go. I set my eq noonish (more like 11 o clock for starters), set my A channel gain, the boost and start turning the woofer. Nothing, nothing's coming out. I check my connections, all seems to be right. I start cranking the input knob slightly above noon and I start getting a low output distorted tone. So something is coming out. I turn it off, put it in "dual mono mode", and same thing again. Low farty distorted tone only after I crank up the input somewhere above noon. Both A and B (distortion channel) do the same thing. I'm pulling my hair out of course, this simply cannot be happening, just my luck.. Luckily I have an Ashdown head there too, so I test it to see if it's the cab acting out - works fine. I switch back to 2001RB again.

    I try out all the speakon outputs, and again, same thing. All of this happened in a period of like 5-10 minutes. I let the seller know it's not working. I put the amp in the "bridged" mode again, set it up again, turn it on again and bam. It works. Glorious power and tone. What just happened? Did it have to warm up a bit? I test it for about 10 minutes with 2 of my basses, all good, distortion channel good. I turn it off, try the "dual mono" mode, all good, all speakon outputs good. It works.

    Ok, I turn if off, pack it up, let the seller know about the weird behavior and luckily, I have band practice later that day, so I'll test it through my GK NEO 412.

    Band practice arrives, I hook the amp up in a "bridged mode" with my GK speakon cable. Again, nothing... Jeez! Low farty output for about 6-10 minutes (I really should have timed it..). And then it comes to life again. We're all floored by this thing's tone through my 412 and the incredible warmth that it actually produces, seriously haven't expected such a full warm tone, it just shined with my P with flats. Heft, power, low end, everything was there. The distortion channel sounded great too from what I've tried a bit too. Our practice went for about 40 minutes, and it worked without a hitch. Just to test it, I tried turning it off and on again. No problem, tried it 3 times, worked fine.

    Looks like the "cold start" produces an issue, and I'm not sure what to do. I contacted GK about it, and they asked me if it's problematic after the "cold start" or after every time I turn it on. I let them know about all that happened and they want the serial number too. I left my amp at my drummers to pick it this Saturday for a gig (should have taken it home I know..), along with a backup amp.

    Any ideas what could cause this thing to act weird for the first 10ish minutes? Relay problems? Capacitors? I didn't smell any burnt smell, and who knows if the seller knew about this or maybe the shipping caused the problem..

    I'm not in the USA unfortunately, and I don't know if there are any official GK services in Europe at all, so that's another huge bummer. My guitarist is an excellent amp tech though, and he could check it out. Any help would be appreciated because this thing, when it works, works like a champ!
     
  2. There are official Gk servicing people in Europe.

    @B-string ¿
     
    mouthmw likes this.
  3. There is a output mute to eliminate turn on/off pops. There could be a cap bad in the timer circuit (cap). Best info will be from G-K I have not had my hands in one. jason@gallien.com can provide you with schematics and info as he was/is also service head. As far as I know daniel@gallien.com is also still a valid email. Both are great and helpful folks.
     
    mouthmw likes this.
  4. mouthmw

    mouthmw

    Jul 19, 2009
    Croatia
    Thanks B-string! That's an interesting idea about the output mute! I already found and sent the schematics to my guitarist, unfortunately he won't be able to check the amp until after Saturday. I contacted Jason as well, he told me to check the output connectors and even the switch for the dual mono/bridge selector, and to try plugging into effects return (can't believe I didn't think of this), perhaps those have oxidized over time which I know can cause volume and cutting out issues (perhaps a bit different than this though).
    My guitarist said similar thing like you, about that mute eliminating the pop during turning it on and off, something about switching relay possibly messing it up (if I'm paraphrasing it right). I sure hope it's something simple :)
     
  5. Effects return jack is always a good first goto. The list of maladies is long and varied and has even been the source of squeals on occasion.
     
    mouthmw likes this.
  6. orangejulius3

    orangejulius3 Supporting Member

    May 6, 2013
    La Habra CA
    Don't bridge it next time around and see if it acts up. Leave it in dual mode.
     
  7. mouthmw

    mouthmw

    Jul 19, 2009
    Croatia
    I tried both man, didn't make a difference. Once it starts working, both work, when it doesn't, both don't. When it arrived to me, it was already set in bridged mode so that's what I tried first. Besides, I plan on playing it in bridged mode 99% of the time anyways.
     
  8. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA
    That's what I was thinking...s*** that's truly broken doesn't repair itself. Spray a bit of De-oxit in the FX send & return jacks and run a 1/4" plug in and out a few times. For that fact, you can place an instrument / signal cable between the two and leave it. It's kinda like chicken soup: even if it doesn't help, it can't hurt. In any regard, the fact the situation self-corrects within 10" may indicate a thermally-dependent fault.

    Riis
     
    mouthmw likes this.
  9. I don't know how close it is to the 400RB
    but I found an intermittant ribbon cable connection
    from the pre amp board to the main board on
    my 400RB.
    If yours uses that, a cleaning can't hurt.
     
    Zooberwerx likes this.
  10. mouthmw

    mouthmw

    Jul 19, 2009
    Croatia
    Jason mentioned that too, connection from preamp to poweramp. Will check, thanks!
    Today's the gig night so, fingers crossed that it makes it through! :)
     
    B-string likes this.
  11. mouthmw

    mouthmw

    Jul 19, 2009
    Croatia
    image.

    The gig went great, and it kicked some serious booty! Again, problems when I turned it on, left it on for 10 minutes, still nothing. Then my drummer went to check it out, tried the woofer knob and said "it's the knob man, look how loose and easy it is to turn it compared to other knobs". As soon as we "played" the knob to around 14 o'clock position, the signal started to come somewhat, until we got it. Worked without a hitch for the whole night and the woofer knob regained its function. Weird. From what little my singer (also electrician and builds his own pedals, luckily I have two talented techs in my band) saw through the grill, it might be a bad solder of the woofer knob, but it's weird that it worked fine after that. We will open her up and see, hoping it's just a small quirk like that. Btw, the distortion channel on this thing rips! I'm extremely happy with my rig now and glad to be back to GK entirely, even with this issue that needs to be fixed. Wow, what a tone, for real. I pushed my input gain, boost and woofer all around 11 o clock and it had tone and power in spades. Amazing. P with flats through GK rig? Oh yes, oh hell yes! Smooth fat warm vintage tone city with that punchy GK growl. Oh how I missed that growl! :D
     
  12. Just think........you could drive four of those 412 cabs with the 2001RB! (2 ohms stable per side in dual mono.)
     
    orangejulius3 likes this.
  13. mouthmw

    mouthmw

    Jul 19, 2009
    Croatia
    That is absolutely insane lol. Of course, I'd never get away with it :D I'm more than good with that I have now. This gets LOUD. The sound guy told me to turn it down a bit yesterday. But it's not just that it's loud, it's the tone man! That kickass tone!
     
    orangejulius3 and B-string like this.
  14. mouthmw

    mouthmw

    Jul 19, 2009
    Croatia
    Well, we've opened her up today. Of course, as it is with electronics, I was unable to make the amp not work yesterday and today, because yea, things always work fine when they have to get fixed.

    As we've opened the amp, we immediately saw that it was previously repaired on the preamp section, couple of solders on some pots and a replaced input jack. Some of the soldering was a bit lackluster so my guitarist fixed that up. What was also interesting, 2 of the molex cables weren't properly seated, so that was an easy fix. We plugged her into the osciloscope and began to monitor the behavior.

    All knobs seemed to respond fine, there were no signal cuts of any kind. We did a stress test then - blowing dry ice to simulate cold environment - no problemo. Blowing hot hair dryer to simulate how summer weather - all good. Checked the relay, stress tested it too, all good. No blown capacitors, fans worked jus fine too, all in all, in a good shape apart from some slightly shabby fixes on the preamp.

    So far, so good. If it acts up again, back to the drawing board :D
     
    B-string likes this.
  15. MB200 makes a cheap backup. Probably also capable of too loud through 4x12.
     
  16. mouthmw

    mouthmw

    Jul 19, 2009
    Croatia
    I have a backup already, but meh, I've had GK 700RB II that was completely reliable, so I'm confident in the RB line enough that I don't plan to keep a backup. Although, if I would, I'd go for a 700RB II rather than the MB line (I'm not into micro heads).
     

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