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Official Ampeg Portaflex Club

Discussion in 'Amps and Cabs [BG]' started by JimmyM, May 25, 2008.


  1. ShaunNecro

    ShaunNecro

    Aug 1, 2007
    Houston, TX
    So, yeah. Pretty nice cosmetic condition blueline B15N. Spent about an hour playing it at the guy's house, lol.

    20190718_213834.
     
    bobyoung53, blastoff, PillO and 5 others like this.
  2. flatwound251

    flatwound251 Supporting Member

    Apr 22, 2019
    Los Angeles, Ca.
    Finally got the damping material for my SB-12 and attached it, re-installed the speaker and - it's done! Put the amp head on and fired it up - it sounds really good! I played it for about an hour, and it seems to work fine. The standby switch works, and there isn't any crackling from the pots. The only thing I noticed was that the tube cage directly above the two 6L6GCs gets very hot. Is that normal?

    P1020114_new damping attached. P1020114.1_Speaker reinstalled. P1020115_complete & back in action.
     
  3. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Sure. The power transformer and tubes can get pretty hot. But that's how tubes work.
     
  4. Orfeus Hebros

    Orfeus Hebros

    Jul 15, 2019
    Thank you so much! That's all I needed! I'll keep you guys updated about the project :)
     
  5. chupacerveza

    chupacerveza

    Jan 3, 2011
    Austin, TX
    Tubes are literally heaters.
     
  6. farace

    farace

    Jul 9, 2016
    Connecticut USA
    I won't need to measure mine, then. :) It's a '72, so should be identical.
     
    jumbodbassman likes this.
  7. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    If you want it to run cooler, you need to remove the heat. I use a small desk fan blowing onto the amp. With this quiet fan, my B-15 tubes and transformers remain cool. Any quiet fan will work.

    Caframo chinook

    EC29717A-7E9D-45B6-8730-97C7DDB34EE0.


    https://www.amazon.com/dp/B0010UPOEQ/ref=twister_B00OBU7VJI?_encoding=UTF8&psc=1

    Prices vary, shop around.
     
  8. shadven

    shadven Twang-tastic Bass Player and Song Writer Supporting Member

    Dec 30, 2009
    Tampa, FL
    I rock, therefore I am.
    Yeah, it’s normal.
     
  9. flatwound251

    flatwound251 Supporting Member

    Apr 22, 2019
    Los Angeles, Ca.
    Great idea! Makes total sense. Also, thanks to you, JimmyM, and the other forum members for all of your advice, links, and guidance on my SB-12 refurb project. You all were a big of help, and I really appreciate it!
    Now, about those B-15Ns... I think I another project.
     
  10. OT, Ok, I posted a few weeks ago about buying a Mullard M8080 (6C4) for my SVT head, I put it in today and besides having absolutely no microphonics, I was able to almost completely get rid of the hum with the hum control, with the old tube minimum hum was all the way to the left and it still had some, with this new tube it adjusts somewhere in the middle of it's travel like it's supposed to and I can't hear any hum at all. Wonderful discovery. Oh and I also discovered this head is probably a 75, it says 7530 on top of the output transformer. Were the white rocker switch SVT's made as early as the middle of 1975?
     
  11. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Can't answer the white rocker switch question, but even though it's $40, I might give the Mullard a try because every single 6C4 I've ever tried has been microphonic.
     
    chupacerveza likes this.
  12. Same here, this thing is now so quiet I'm sitting my bedroom with a B-15T 15" cab right next to me I hear no hum at all, amazing:laugh:. I got it on sale at the Tube Depot, 35.00 but shipping out here was about 15 bucks so 50.00 in all but well worth it. Thanks to Beans for suggesting Mullard preamp tubes.
     
    Last edited: Jul 30, 2019
  13. Audioeng03

    Audioeng03

    Jun 19, 2019
    Clermont, Fl
    I've been searching for an Altec 421A that was properly date coded for my '70 B15N, for a while. I finally found one with a '69 date code, and decided that was close enough for me. I recently installed it, and this thing sounds sweet!

    I've had a Black Widow in it for the last 5 years or so. It sounded fine, but I always felt like there was better tone hiding in that amp. The Altec just sounds so much clearer and smoother. Also, the tone seems much more well rounded, and full.

    I am absolutely in love with the current tone I'm getting. I can't wait to take this thing into the studio with me for my next session.
     
  14. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Oh no! Not in the studio! The engineer's going to reject it because your speaker's date code isn't pure!

    :D
     
  15. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    You could have caught the initial edge of the conversion to white switches. Your amp might be a '76 if the transformer sat around for months before the amp was assembled.. Check the pot codes, starting with 137, they are always a good indicator....
     
    chupacerveza likes this.
  16. Someone once asked me to post a picture of my Ampeg Bassamp 835, it's supposed to be a 1959, I for got where I found that out. It originally came with EL-37 power tubes, 6L6's work and I think they're better actually. It's got a very nice tone, control panel left to right three inputs, string bass, bottom, electric bass or guitar middle and top, Magnetic/crystal pickup knob(which doesn't seem to do anything) Volume, Treble, Bass, then panel light, fuse and off, standby, and on control on top. It says Ampeg Bassamp 35 watts on top of knobs. I've never gigged with it but it makes a nice sounding practice amp and is plenty loud for the house. The original Jensen is long gone, it had a Utah 15" coaxial speaker in it when I got it but since I had the tech go through it it won't handle the power anymore even though I had it reconed, so I put a Leslie speaker in it which sounds pretty good except it doesn't have much top end.

    bassamp 835 front. bassamp 835 whole back. bassamp 835 back.
     
    Last edited: Aug 4, 2019
  17. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Looks like a job for the Delta 15a!
     
  18. Yes, I, going to have to get a new one eventually, I'm only going to be in the States another month though so we'll see.
     
    JimmyM and chupacerveza like this.
  19. What do you recommend, the Pro Delta 15a? Edit, actually the cheaper one looks like the specs are almost as good and it goes a little lower but what do you think?
     
    chupacerveza likes this.
  20. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    I've got the regular old Delta 15a in my B-15 double baffle repro cabs. It's terrific and sound pretty much identical to the 66 Ampeg labeled CTS in my 64 double baffle cab. The Beta 15a is also a good one...a little cheaper and just a shade darker and lower.
     
    lowplaces and chupacerveza like this.

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