From:
         
         PaulC   (p.cochrane@worldnet.att.net)
   Date:
         10/20/2001 8:12 PM
 Subject:
         OEI 30 watter in!



Hey guys - just wanted to post my results with the new OEI 30 watt AC30 style OT. I put this in a homebrew that is sort of like a TB, but without the
1st stage. Or you can think of it as an AC30 output section with a fender style preamp without the 2nd stage! 
Anyway - this replaced a drake reissue, and replaced it for good. This tranny was exactly what the amp was looking for. A little bit more low end, but
with more definition. The mids are clearer, but with more "girth". Has a nice growl that lets the wood tones through. The hi end is smoother, and more
upfront - has that "bell" thing going on. When clipped it had less fizz, and more hair. On the scope when pushed hard the x-over was decreased while
the clipping was a little bit flatter. Also seemed to knock down the ghosting a bit.
It has a 4ohm tap included that lets me run the blues in parallel for a clearer mid sound with a punchier low end. Has a piano clean vibe now on the
bottom. Very cool piece of iron - will be getting many more! Try it out... Later - Paul 


   From:
         
         Steve A.   (steve_ahola@yahoo.com)
   Date:
         10/21/2001 6:35 AM
 Subject:
         Re: OEI 30 watter in!



Paul:

It has a 4ohm tap included that lets me run the blues in parallel for a clearer mid sound with a punchier low end. 

    Tell us more about that! I always assumed that a pair of speakers sounded the same whether hooked up in series or parallel, but that can't be
right— can it? In series, wouldn't the inductance of the other speaker act as a filter (sort of like with pickups)?

    I've been thinking of getting one of those OEI AC30 OT's for my rewired Peavey Classic 50. Joe mentioned that his tranny might be a little brighter
than the stock Peavey one, but adding an AC30-style cut control would allow you to trim the highs a bit if necessary.

--Thanks!

Steve Ahola 


   From:
         
         PaulC   (p.cochrane@worldnet.att.net)
   Date:
         10/21/2001 2:52 PM
 Subject:
         Re: OEI 30 watter in!



Well - you're asking me to back up something I can hear, but not give you the math for!! It's been explained to me (but not sticking in my brain) that
it's about a change in the backflow voltage produced by the speakers in the different hook-ups. The parallel setup increases damping. The change in
inductance also effects the responce. Ever taken a 4x12 and wired it in parallel for 4 ohms? Big change - mids clear up and the lows punch up some.
Ol' Jerry talks about changing the way you series/parallel the speakers in a 4x12 to get 16 ohms for different sounds. To be honest I'm not really
hearing that one, but the 4 ohms is obvious. With my amp it just seems to add some needed attack to the bottom end and cut back a little on some
speaker flubbing. I should get Ted to spell it all out... 


   From:
         
         jaysg   (jayfbv@yahoo.com)
   Date:
         10/21/2001 3:04 PM
 Subject:
         Re: OEI 30 watter in!



     I always assumed that a pair of speakers sounded the same whether hooked up in series or parallel, but that can't be right—
     can it?

The Rivera 2-12" Rake cabinet has two 8 ohm speakers in series. Aside from less damping, any inconsistencies between the two speakers are
accentuated. That might be desirable depending on the variables. 


   From:
         
         R.G.
   Date:
         10/21/2001 4:37 PM
 Subject:
         Re: OEI 30 watter in!



Paul's right about the damping. Each speaker in series acts like an impedance to spoil the damping you'd have from the output of the amp. Series
speakers do sound different from parallel. More to the point, since speakers have different impedances at different frequencies, the damping gets
really bad wherever the impedance(s) go high - like at the low end resonance and at the high end where the inductance of the voice coil takes over.
This has the effect of making the tone variances more pronounced.

The parallel connection is more tightly controlled by the amp.

R.G. 


   From:
         
         Ingo/Shinrock   (ingo@shinrock.de)
   Date:
         10/21/2001 6:41 PM
 Subject:
         Re: OEI 30 watter in!



Hi R.G.
you´ve got my e-mail?
Regards
Ingo 


   From:
         
         Heiko Frost   (heiko_frost@hotmail.com)
   Date:
         10/22/2001 12:08 AM
 Subject:
         Re: OEI 30 watter in!



Hey guys,

I ordered my OEI AC30 OT last week and cannot wait to get it. Just in time as I finished up construction my latest amp this afternoon.

-Heiko 


   From:
         
         Steve A.   (steve_ahola@yahoo.com)
   Date:
         10/22/2001 1:30 AM
 Subject:
         So what 4 speakers in series/parallel?



R.G.

    So in a 4 speaker cabinet wired in series/parallel do these effects cancel out to some extent?

    From what you were saying about two speaker connected in series, it might be a good experiment to try using two different speakers rather than
two of the same.

--Thanks!

Steve Ahola