Amps Tech 21 Power Engine

Discussion in 'Gear Talk' started by CapnDenny1, Oct 8, 2019.

  1. CapnDenny1

    CapnDenny1 Student Of The Blues

    Joined:
    Mar 2, 2012
    Messages:
    2,024
    Likes Received:
    1,504
    i have a Tech 21 Power Engine in the shop. It was reported to be buzzing really bad.

    It is apower amp intended to amplify one of those pedal board thingy’s which the player goes directly to the house sound. It has only a couple small knobs on the back. It's basically a powered speaker.

    I verified that with nothing plugged in it did hum when the levl control was turned up. I tried it with a guitar and it sounded really bad. I ordered some caps, but didn’t use them.

    I did some research, and others had the sme issuie. But Tech 21 explained that the input went thru an isolation transformer. They said it will be noisy, unless you have an active low impedance source driving the input.

    So I took. Phone plug and shorted out the wires. When I plugged that in, the amp was pretty much silent.

    I then took a cord and connected the output of an ipad to the Power Engine. It also did not buzz or hum.

    So I contacted the customer and told him there isn’t anything wrong with his amp. I will do the two demos for him and try to get him to understand.
     
    CaptainMoto, Jalapeno and PapaBear like this.
  2. zwantedone

    zwantedone Blues Newbie

    Joined:
    Aug 18, 2010
    Messages:
    113
    Likes Received:
    68
    I believe Tech 21 still makes a grounding plug for that issue. I had the same problem with the one I have. I talked to Tech 21, and they sent me a plug. No more issue. Silence is golden...
     
  3. CapnDenny1

    CapnDenny1 Student Of The Blues

    Joined:
    Mar 2, 2012
    Messages:
    2,024
    Likes Received:
    1,504
    Can you show me what it is, or does? I read about it, but I built one and it didn't help.
     
  4. zwantedone

    zwantedone Blues Newbie

    Joined:
    Aug 18, 2010
    Messages:
    113
    Likes Received:
    68
    Cap't, if you go to Tech 21 website, optional accessories, there is a picture of the grounding plug. What is does or how it does it, I have no clue. Might not be what you are looking for...Will
     
    #4 zwantedone, Oct 10, 2019
    Last edited: Oct 10, 2019
  5. jmin

    jmin San Francisco, CA

    Joined:
    Dec 17, 2013
    Messages:
    1,940
    Likes Received:
    1,516
    You guys got my curiosity going, so I looked it up (should have copied all the links... (n)). Anyway, it's an XLR shorting plug that loops pin 1 to pin 3 (that's what someone said...and said it worked). It's $8 on amazon.
    But if you already made one and it didn't work...back to square one.
     
  6. CapnDenny1

    CapnDenny1 Student Of The Blues

    Joined:
    Mar 2, 2012
    Messages:
    2,024
    Likes Received:
    1,504
    It didn't help when I had a guitar plugged in directly. You can't do that, with or without the shorting plug. It may help in some cases, like with a switch mode power supply on your pedal board.
     
  7. CapnDenny1

    CapnDenny1 Student Of The Blues

    Joined:
    Mar 2, 2012
    Messages:
    2,024
    Likes Received:
    1,504
    my email to Tech 21 support, from about an hour ago.

    Hello,
    I have a customer’s amp who reported noise from his Power Engine 60. I tested it and determined that if driven by a low impedance source it was OK. I also found out about the Grounding Plug. I was told to short pins 1 and 3 to build one myself. I tried this and it didn’t help with the high impedance sources. But I would still like to provide one to my customer. Can you tell me if that is correct, just connect pins 1 and 3 of the XLR plug? And also when he should use that?
    Thanks,
    Dennis Kelley
    Dba: Capn Denny’s Cabs

    Response back from Tech 21.

    Dear Dennis,

    Thanks for your inquiry. I don't know that the claim regarding a low impedance signal is totally accurate... If you run the high impedance signal directly from an instrument, even without the benefit of tone-shaping from a preamp, you'll get a decent sound. If there's hum, it's usually caused by interference (maybe the pickups are too close to the transformer in the chassis, or facing a computer monitor, etc.), and when you roll the instrument's volume knob all the way down the hum will usually go away, indicating that things are working properly.

    Any buzz from the Power Engine would often be caused by using a digital-switching power supply with the preamp (the 1Spot, for example, is notorious for adding noise). So when customers experienced noise when using the 1/4" unbalanced low impedance 1/4" Output from our first-generation FlyRigs, we came up with the idea of the Grounding Plug (which I prefer to call a "shunt").

    Soldering pins 1 & 3 together, and inserting that into the Power Engine's XLR Input while running the preamp signal to the 1/4" Input usually solves the problem.

    I had one guy ask, "But when you solder the pins together, how do you plug it in?" Adorable.

    Regards,
    Lloyd Schwartz, Solutions Architect
    Tech 21 USA, Inc.
    790 Bloomfield Ave., Bldg. B
    Clifton, NJ 07012
    973 777 6996
    973 777 9899 Fax
    www.tech21nyc.com

    Like us on Facebook!
     
    PapaBear, Grateful_Ed and paparaptor like this.
  8. dan5150

    dan5150 Shredding the Blues

    Joined:
    Apr 2, 2012
    Messages:
    265
    Likes Received:
    141
    Yup. I used to use a Power Engine. Made one of those shorted XLR plugs. Worked great.
     
  9. Iheartbacon

    Iheartbacon Blues Newbie

    Joined:
    Sep 29, 2016
    Messages:
    233
    Likes Received:
    224
    That is hilarious!
     
    PapaBear likes this.
  10. cowboy

    cowboy Blues, Booze & BBQ

    Joined:
    Jul 7, 2009
    Messages:
    1,796
    Likes Received:
    1,526
    I've had Tech 21 TM 60 (1-12) for years and had great support from Tech 21...still a great little amp...never tried the Power Engine but did get a loaded 4-10 blemished cab (fits the TM60) from Tech 21 for $200...never could find the blemish...

    I'm assuming the Power Engine is NOT a flat response speaker?...just wondering...later.

    cowboy