Power Transformer On Kern IP-777

Discussion in 'Amps and Cabs [BG]' started by rypped, Jul 8, 2013.

  1. rypped


    Jul 8, 2013
    Hey all,

    I've been having intermittent ground noise on my beloved IP-777 preamp... At first I thought a tube had gone microphonic on me but I tracked it down to an intermittent connection on the primary of the internal power supply transformer (not the wall wart). The numbers stamped on the frame are 177-8308 and 225641. For the life of me I can't track this part down on Google or any of the electronic distributors I commonly use. Anyone got any insight? A schematic/BOM would be great but from the threads I've seen it seems like any documentation on this gem has gone the way of the Dead Sea Scrolls.... Any help or ideas would be much appreciated.

  2. JGR

    JGR The "G" is for Gustav Commercial User

    Jun 29, 2006
    President, CEO, CFO, CIO, Chief Engineer, Technician, Janitor - Reiner Amplification
    Can you post pictures and measure the secondary voltage?
  3. WingKL


    May 12, 2007
    You can always reverse engineer the transformer by measuring the voltage output and the current usage and get an equivalent transformer of about the same size. Hammond makes plenty of transformers, one of which might work as a substitute.
  4. gregbackstrom

    gregbackstrom Supporting Member

    Feb 3, 2005
    Tacoma, Washington
    Or you can just call or email Les Plopa directly. He'll either fix it for free or extremely affordably. His email address is [email protected]. I probably have his phone number somewhere too.

    It may take him a week or two to get back to you, but he's great to work with!

    cromag31 likes this.
  5. BassmanPaul

    BassmanPaul Inactive

    When I bought one used, some one had "improved" it. I tried to get the schematic from Les which he agreed to supply. It was never forthcoming despite numerous contacts and I soured on the subject. I recycled the damn thing. Now I wish I hadn't as it would have helped you out.

    Hindsight is always 20/20.
  6. rypped


    Jul 8, 2013
    Hey guys, thanks very much....

    JGR, here's a couple images:


    The secondary is driven by the input wallwart (12VAC) generating 208VAC on the primary, which drives the preamp.

    A local amp technician thought the 177 may be an EIA code for Tri-Cities Manufacturing in Alabama... I'll looked them up and they are a contract manufacturer.... not sure I'll get what I need but I contacted them via their website.

    Greg, thanks much for Les's email... I'll give it a shot and see if he'll respond... that's the best hope yet! :hyper:
  7. rypped


    Jul 8, 2013
    Wow, Greg, Les responded within 6 hours and offered to ship me a new transformer FOC..... thanks again for the email address!:)
  8. majortoby


    Jul 2, 2009
    Tampa, Fl USA
    THAT'S customer service! Hats off to Les Plopa! :cool:
    cromag31 likes this.
  9. BassmanPaul

    BassmanPaul Inactive

    Only if it arrives! :bag:
  10. rypped


    Jul 8, 2013
    ah! ha ha Paul, I knew you'd say that :smug: I'll think positively.

    Sorry you didn't get your schematic.... I'm glad Les offered to send me a transformer, but ultimately I going to still feel insecure if I don't end up with a schematic.

    BTW, guys, Les did tell me that he's working toward restarting the business...has a chassis ready for build as we speak....
  11. gregbackstrom

    gregbackstrom Supporting Member

    Feb 3, 2005
    Tacoma, Washington
    That's consistent with my experience too. Les was--and continues to be--very generous with his time, knowledge and skill.
  12. rypped


    Jul 8, 2013
    Paul, for a while I was afraid you were going to be right. Took a while to tie off with Les after his first response due to some personal stuff going on in his life. But he did end up shipping me a free transformer and the preamp is back up and running....with no annoying noise!


    Thanks again for your help with Les's email address. You saved the day!
  13. gregbackstrom

    gregbackstrom Supporting Member

    Feb 3, 2005
    Tacoma, Washington
    Glad to hear it! Les took great care of me as well.
  14. BassmanPaul

    BassmanPaul Inactive

    Sorry I missed this on first posting and I'm glad he came through for you. To be fair to the man, he did offer to repair my unit for me. However the thing was my problem and up to me to put right.

    I have been building/servicing tube electronics since my early teens. I was more than capable of repairing my Kern. As I could not get the schematic, and I wasn't about to pass a known faultily device on to someone else, it went into the electronics recycling at our local transfer station. It's a great pity, I would have dearly loved to hear what an unmodified Kern would have sounded like.

    The positive side is that this "adventure" caused be to set about designing my own tube pre-amp. The result was delightful and is part of my main rig. You can see it, if you are interested, in the amp guts thread.

    Enjoy your Kern, I hope it's as good as it's cracked up to be. :D