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Ampeg V-4B Back Panel

Discussion in 'Amps and Cabs [BG]' started by Jeff O'Connor, Feb 19, 2005.


  1. Jeff O'Connor

    Jeff O'Connor Supporting Member

    Feb 16, 2004
    Stratford, CT
    Can anyone give a little insight on the exact use of all the jacks on the back panel of the "older" ones? "speaker jacks, ins and outs and so on..." Thanks folks! :meh:
     
  2. Rockbobmel

    Rockbobmel Supporting Member

    Yot gotta be more pacific.
     
  3. Jeff O'Connor

    Jeff O'Connor Supporting Member

    Feb 16, 2004
    Stratford, CT
    Like I know the main speaker jack, but like what the other speaker jack is used for and the ....is it power amp in? Just what the uses are of the other jacks.
     
  4. Rockbobmel

    Rockbobmel Supporting Member

    Mine is a V-4 and it has 2 extention amp jacks. (Preamp Out). Do NOT run the power amp without a load on it. A footswitch jack (prolly not on the V4B), and a Speaker, and Ext Speaker. You add your total speaker impedence and switch to that impedence.
     
  5. Jeff O'Connor

    Jeff O'Connor Supporting Member

    Feb 16, 2004
    Stratford, CT
    Is yours a older model? Thanks much so far!
     
  6. Rockbobmel

    Rockbobmel Supporting Member

    Mine is a VT-22 (V-4) head. It is a 1972 or 73.
     
  7. Mine's a '73 V4B.

    From left to right:

    2-prong AC convenience outlet (uses: Hairdryer?)

    2ea. Ext. Amp jacks that also read "Ext. Amp Impedance 10K ohm" (I do not believe these are intended for Preamp or Power Amp In/Out although they might can be used in that way. I believe they are to daisy-chain to the front-panel instrument ins on other V4Bs.

    1 speaker jack (for your primary cabinet)

    1 Ext. Speaker jack (for a second cabinet)

    8-4-2 ohm selector switch.
     
  8. Jeff O'Connor

    Jeff O'Connor Supporting Member

    Feb 16, 2004
    Stratford, CT
    Thanks so much! So those ext. amp jacks do send a preamp signal out?
     
  9. 4Mal

    4Mal Supporting Member

    Jun 2, 2002
    Columbia River Gorge
    The V4B has a line out for driving an external power amp according to a schematic I found on line. Passin' wind is just about through recapping mine and one of my first tests will be to take that line out to my recorder. I have high hops there... we'll see
     
  10. Mines kinda hummy. Does he know you are gonna try that? He might be able to add something to quiet it down if it needs it.

    Also, the volume knob on mine effects the signal level on that jack. As such, gotta have it up loud to get a good level out.
     
  11. Yes. But do not forget that not all preamp signals are created equal.
     
  12. Passinwind

    Passinwind I Know Nothing Supporting Member

    Heh, I'm working on that right now. I'm glad I saw this thread, I was maybe just gonna disconnect that output and call it good. :cool: BTW, disconnecting that output wire cuts a bit of noise in the V4's power section, at least it does on the one I'm working on.
     
  13. 4Mal

    4Mal Supporting Member

    Jun 2, 2002
    Columbia River Gorge

    High hops ? Jeeze, This typing thing is going to kill me one day ...
     
  14. Passinwind

    Passinwind I Know Nothing Supporting Member

    Man, I thought you meant you were buying a few rounds of Walking Man IPA when I got done... :bassist:
     
  15. Jeff O'Connor

    Jeff O'Connor Supporting Member

    Feb 16, 2004
    Stratford, CT
    how would I plug up a 4 ohm and a 8 ohm cabinet to this baby?
    ;)
     
  16. 4Mal

    4Mal Supporting Member

    Jun 2, 2002
    Columbia River Gorge
    Oh - I think that can be arranged ... Maybe we should pay Bob a visit and examine his fancy concrete counter top. See just how well it avoids those ugly rings ...
     
  17. 66pbass

    66pbass

    Dec 25, 2002
    Pittsburgh, PA
    Just plug 'em in and set your impedance (ohms) switch to 2 ohms.

    A rule of thumb: your total load will be lower than the lowest cab impedance.

    (Actual load will be 2.67 ohms)
     
  18. 4Mal

    4Mal Supporting Member

    Jun 2, 2002
    Columbia River Gorge
    OK I've had a chance to fire up the V4B. Charlie's work completely quieted down the amp. He'll have to speak to what was actually done, I know the gist but not really the gory details. The pre-out on the back is interesting. First - going straight to a channel of my recorder - it's dead quiet. With the bass boosted, mids cut and treble up a scootch - great slap tone. Natural compression built in - vey nice (now If I could only slap worth a damn!) I played with a couple of other tone settings but what I really wanted to do was to lay another track side by side using a Demeter VTBP-201. I didn't get the gains leveled and the Demeter track came out hotter but just comparing at a basic level. The Demeter is much more clear and transparent the mids are much more detailed. I think the Demeter is also much punchier. Frankly I would expect all that and with the differing levels, it's not a fair comparison, but ... The Ampeg has an undeniable warmth and from just a 10 minute exercise I can tell you that the signal coming off the pre-out will sit very nicely in a lot of tracks. The sweet spot is just going to be huge on this thing! I could get someting similar out of the Demeter but I'd be using a parametric EQ and an external compressor and a couple of hours of setup time to get there. I am extremely impressed. Charlie (Passin'wind) has worked a minor miracle on my Ampeg! The pre out is very useful. Charlie did tell me that the signal coming of the pre-out is not very hot and it may be that I'll have to add some gain to drive an external power amp like my Crown. The other thing is that the power amp is on and must be driving a load, so you make niose recording this way. I'm OK with that as for me it's a headphone break. It also seems like the pre-out drains a little of the volume from the amp as well. Odd but for my uses (100 watts in a studio setting) it's overkill anyway. I may take Charlie up on his suggestion of adding a power amp kill switch though.

    King - I would highly recommend that you consider the recap and maybe talk with Charlie about some of the other things he had to do. I know that he disconnected the lower pre-out as it is very close to one of the filter caps and that is a source of noise. I think the moved some grounding points around, did some lead dressing, spread monkey dust about and held a voodoo session complete with chicken foot ...

    Now if only he couild come up with a way to lose my wife's cat - the dog's and I would be that much happier!