[grsimmon]

I currently run a single 2BSST with a pair of PMC FB1+'s.    However,   I have read a number of articles etc. including Bryston newletter, regarding the benefits of bi-amping,   and suffice it to say I am pretty sold on the idea of switching to using PowerPacs.  It just makes sense,  not to mention freeing up some of my rack space.   Before I make the leap I want to ask a few questions:

My understanding is that to truly get the full benefits of biamping,  I would need to go active with my crossover, for example a Bryston 10B unit.  Questions:
  a)   am I understanding this right? 
  b)  how, exactly, do I bypass the PMC passive crossovers? 
  c)  how do I know what values to set the Bryston electonic crossover at?
  d)  should I purchase a 10B standard or 10B  LR ?     
   


Regarding the PowerPacs themselves:

e)  Since my speakers are 2 way,  does that mean that I would need 2 PowerPacs per speaker - once for each driver, for example a 60 and a 120?  Or could I somehow get away with one PowerPac per speaker?  Is it possible / preferable  or silly to biwire a single PowerPac on each speaker to the speaker posts? 

f)  What is the correct way to bolt or screw the PowerPacs onto the back of my speakers?  Is it OK to pierce the cabinet wall, or is that to be avoided, etc. etc. ?


Regarding PowerPac power cords:

g)  I will want to run the power cords back to my Torus unit,  but that's going to by like a 10-15 foot run.   Does Bryston sell such a cord,  or could I use a 10 amp industrial extension cord from the local hardware store? 


If anyone has any info., answers, suggestions,  I'm all ears and thanks in advance.     Anyone else who might be curious to see what I'm getting at, check out this Bryston newsletter at:

   www.bryston.ca/newsletters/25_files/vol2is5.html


Thanks,   Greg

[James Tanner]

Hi Greg,

NO you should not use the Bryston 10B electronic crossover with your FB1's.

You can not bypass the Passive crosovers because passive crossovers provide level matching , rolloff slopes, flat frequency response etc. to the independent drivers in the speaker. This is true of most passive design speakers so simply replacing the passive crossover with an active one assumes the active unit will supply all the necessary 'tailoring' required.

The 10B assumes each driver is 'flat' across the frequency band that it will operate over which is not usually the case with passively designed speakers. In other words the designer of a passive speaker can manipulate the result he wants to achieve, using passive components.

If a speaker is designed as an 'ACTIVE' speaker and then uses a passive crossover to provide a less expensive alternative then removing the passive crossover becomes a viable alternative.

james

[jethro]

Greg:

e) To bi-amp you would need two powerpaks per speaker.

f) PMC speakers used to come with threaded inserts for mounting powerpaks.
I think they stopped this practice a couple years ago. You can always mount them on
the wall or lay them on a shelf.

If you haven't already done so, I would try to borrow a 4B-SST or two powerpak 300s
and single-amp your FB1s before going the bi-amp route.

--Steve 

[grsimmon]

OK,   thank you both for that information, that's very helpful.    My remaining questions for you or anyone else out that are:

1)   how can I run power cords from the PowerPacs,  back 15 feet to my Torus?  (suitable extension cord? Bryston stock cords?)   I really don't want to plug them directly into my wall outlets  ( I live in rural Alaska;  the electricity is so unstable from the town's diesel generator that our clocks are sometimes 10 minutes off by the end of the day)

2)   can I biwire PowerPacs to my PMC's the same way as a regular stereo amp?   I currently do that with my 2BSST, like the results, and would like to continue if possible.   


Thanks again,
Greg

[James Tanner]

Hi Greg,

We do not have any power cords 15 feet long.

Yes you can bi-wire the PowerPacs the same as you do your 2B SST.

What size Torus do you have and where is it currently located?

james

[grsimmon]

Hi James:

I currently run an ExactPower unit,   but will be purchasing a Torus "A024-HCB-A1AB" - (balanced, 10 outlet) next month.   I have my rack located between my speakers,  but also set back about 4-5 feet behind.    The long run of 15 feet per side is needed to, essentially, get my cables, cords, etc. out of the way so I'm not tripping on them.   If I shot the power cords directly to the rack it would be more like 8-10 feet.
Since it sounds like a no-go on Bryston cords,  would I be able to use 10 amp extension cords (or lower)  to make this work?   Personally I don't go for the exotic power cord stuff,  and it won't hurt my ego if I have to get these at the hardware store.   BUT  if you think this is a bad idea for other reasons,  then maybe I need to come up with something else - please let me know what you think. 

Thanks again,   Greg

[James Tanner]

Hi Greg,

The longest we have here is 9 foot power cords if you can make that work.

james