Bi-amping with Quickie

kkcinc · 1727

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Offline kkcinc

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on: February 04, 2012, 02:36:31 PM
I thought it might be nice if I could using my quickie for this, if possible. I would like to run two extra output jacks and a stereo pot for each set to match tweeter and woofer spl. Then use the original volume pot for total volume. Question is, is it that simple? I mean split the output signals, add two additional pots(?what value?), and one more set of jacks? High and low filters are already in the speakers. My 'glass is half empty' side is telling me there has got to be more to it.



Offline porcupunctis

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Reply #1 on: February 04, 2012, 03:50:06 PM
You cannot simply stack output jacks in parallel, however it can be done.  On the Foreplay, the second set is connected to the first via a 1K resistor from tip to tip.  The third set will need another resistor but I'm not sure if it should be another 1K or not.  I'm sure someone can verify this and I'd like to know myself.

Another option is to use a distribution amp,  I have used this one with good results in a few setups:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=180-006



Randall Massey
Teacher of Mathematics
Lifetime audio-electronics junkie


Offline Paul Joppa

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Reply #2 on: February 04, 2012, 04:32:56 PM
Usually, that isolation resistor in Foreplay III is not necessary - it's just there in case the situation is UNusual.

The pot feeding the treble amp should have a low value. The minimum load is 8K, so a 10K pot would be a good choice. For the bass you can use a higher value - 50K or 100K. The high value might lose some treble, but you don't care if it's feeding the bass amp.

For those who don't already have a crossover, here's a simple circuit for first order at 1590Hz. Change the capacitor to change the frequency; bigger cap = lower frequency.

Paul Joppa


Offline kkcinc

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Reply #3 on: February 05, 2012, 05:11:08 PM
Very nice. I can try that crossover as well. I'd love to see what it would look like at 600Hz(original factory point of spkrs) crossover and another one at 2k Hz(looks like a good point on paper). If you get a chance PJ, then I'll test all three on my Maggie 1.6qr's and report back. Always wanted to try line level cross. Seems like it would be best to not even show the amp the frequencies you are trying to cross out.