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Ampeg BA 115 question

Discussion in 'Amps and Cabs [BG]' started by Eldermike, Sep 15, 2004.


  1. Eldermike

    Eldermike

    Jul 27, 2004
    NC
    I have a BA 115 that I use for pratice and some small gigs. I got it used in a trade deal with some other gear and didn't actually think I would ever use it but I use it often, everything from playing a CD to acoustic guitar and a really great bass amp for small rooms.

    Back when i got it I ran into a problem with the pad input jack. Every now and then the volume would drop about half and then just come back. Since I could not use it this way I took it to an ampeg repair guy I know and He could not make it do it so i took back and just never used that jack I only use the unpadded one and adjust the volume. I forgot about the problem until I joined this forum and found that ampeg actually watches this.

    So, here is my theory. I think that both jacks are also switches wired in series and the unpadded jack is the one that is at fault here. But it works fine as an input but makes an intermittent connection as a switch when not in use.

    How do i fix it? Or is it ok to use active inputs in the unpadded jack as long as you watch the volume?

    Thanks
    Mike
     
  2. Lyle Caldwell

    Lyle Caldwell

    Sep 7, 2004
    Memphis
    I don't know the particulars of that amp, but most padded inputs are just the same as the unpadded input but with a resistor wired to it. Odds are your problem is a bad resistor or a bad solder joint on the resistor.

    Either way, it won't hurt anything to use the unpadded input with your bass. If it sounds good, it is good.
     
  3. Eldermike

    Eldermike

    Jul 27, 2004
    NC
    Thanks, I have been using it this way for a year now so i agree, it will not hurt it. But I still think that both jacks are in series, I know one of them has a resistor but I think the way they keep you from using both is to put them in series using a switch jack.
     
  4. Lyle Caldwell

    Lyle Caldwell

    Sep 7, 2004
    Memphis
    They probably are in series, but that doesn't mean your problem is with the unpadded input.
     
  5. Eldermike

    Eldermike

    Jul 27, 2004
    NC
    Thanks. The amp works great with the one input.
     
  6. McHack

    McHack

    Jul 29, 2003
    Central Ohio!
    First off, I've got a BA115SP, not an BA115. It has an effect module included in the pre-amp section. Its ok, only a couple of the settings are really useful... I pretty much just set it to SVT mode, jack up the gain a bit, & blend it in just under half...

    I can tell you, the two input jacks are in no way switched. My son & I will both plug in & practice together when he wants me to teach him something... It works just fine, no problems at all...

    That said, both of my basses have active pre-amps,, w/ passive pups... I use the hot input jack,,, ALWAYS. No problems.
     
  7. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    The jacks are not in series, they have a switch setup in the contacts. The "-15" input is attenuated.

    The "-15" jack should be a LOT less sensitive. If it wasn't a lot less sensitive, and then *became* a lot less sensitive, that could have been some dirt on a contact being loosened so it works right.

    Or there could be dirt on the -15 jack contacts, or a loose solder connection, or...............

    I'd plug in and out of both a few times to clear off any crud, and then it may work fine. Unused contacts have a way of getting crud on them and not working right.

    You can use either one. The only reason for the -15 input is for hot active basses, so you can run the volume at a reasonable setting, instead of turned way down.

    If you don't have a problem with overloading the preamp, use whichever you want.


    Yes, you can use both inputs at once. The basses will be paralleled, same as with most amps.

    The -15 input may be a little lower in sensitivity when using two basses, by about 3 dB or so. Usually not noticeable. it depends somewhat on the volume setting on the other bass.
     
  8. McHack

    McHack

    Jul 29, 2003
    Central Ohio!
    GAH, my bad...

    The input jacks are switched!!! :p

    When we found we could use both jacks simultaneously, the usage of the product sure made it seems as tho they're unswitched.

    I do have a question regarding MY amp, Jerrold... As mentioned previously, its a BA115SP. My question has to do w/ the effects module. Specifically, settings 13, 14 & 15.
    Synth 1, Synth 2 & Square Wave (overdrive).

    When I try to use these 3 effects, (only these 3 mind you) it sounds as if the effect will only "engage" unless you really jack in the input into the amp... When playing a lower volumes, it sounds as if the effects are simply bypassed.

    This does NOT occur on any of the other effects in the module. What could I be setting wrong? Or, from this description, do you suspect a problem in the effects module?
     
  9. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    I don't know, I have asked the DSP folks about it. We'll see.

    Generally, though, if a DSP works on one setting, it works on any other setting also...the same things are done internally.

    So, I doubt there is an overall problem.

    We have changed the DSP code from time to time. Look on the serial number and tell me what it has in position 5 and 6 (date code).

    Would be something like "M7" or "O6", etc, with years starting at 1988 as "A" and months 1-9,0,A,B.
     
  10. McHack

    McHack

    Jul 29, 2003
    Central Ohio!
    Ok thx... Will do when I get home tonite...
     
  11. Eldermike

    Eldermike

    Jul 27, 2004
    NC
    Thanks, I will clean the contacts.

    BTW, this amp is a killer drum machine amp.
     
  12. McHack

    McHack

    Jul 29, 2003
    Central Ohio!
    Dagnabbit...

    I forgot to find my serial # last night... must email self to home account.
     
  13. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    It turns out that those effects have a relatively higher threshold level before they start working. Otherwise they would be somewhat noisy and uncontrollable.

    Two have "threshold" as their adjustable parameter. You can therefore do some adjustment there (similar to the octave generator).

    Aside from that, running the preamp gain higher will feed more level and help stay over the threshold.

    It sort of comes with the territory in that type of effect (synth bass, etc). A low threshold gives you "synth noise" instead of "synth bass".

    Incidentally, the BA115 preamp itself has a LOT of headroom. So for the original question of the input jack, there is room for use of the "normal" input even with hotter basses. But I still expect that is likely to be a dirty contact issue.