700B and speaker impedance

yeliab1

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#1
Hello,
I just joined your forum and this is my first post. I've been reading about the mods being done to PL amps. I figure this is the best place to get my information.
I have a 700B that I've owned for years. It is due back from being refurbished. I always ran a pair of Klipsch CF-3's with it. I acquired another pair of CF-3s and I want to run them in parallel , 2 on each channel. It this acceptable / possible, without hurting my amp?
 

Elite-ist

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#2
Welcome to our forum. Although the Klipsch CF-3 are rated at 8 ohms, that's only an average rating. I bet that in the low frequency range the draw on the amp would be 3 ohms, if you hooked them up in parallel. I would also recommend speaker protection for those speakers while running the PL 700B. Those speakers are fairly efficient from the specs I've read at 100dB 1watt/1meter.



Nando.
 

hayabusa

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#3
Hello,
I just joined your forum and this is my first post. I've been reading about the mods being done to PL amps. I figure this is the best place to get my information.
I have a 700B that I've owned for years. It is due back from being refurbished. I always ran a pair of Klipsch CF-3's with it. I acquired another pair of CF-3s and I want to run them in parallel , 2 on each channel. It this acceptable / possible, without hurting my amp?
Welcome to the Phoenix audio forum. I would second what Elite-ist said along with my opinion. I would at the very least, install Watts Abundant dc board. I think it's a more reliable way then fuses, to protect those speakers. I would also run a cooling fan as it certainly won't hurt anything.

I have run into a problem with my PL 400 when driving loads that go under 4 ohms. The limiter circuitry would kick in on bass notes when driving the speakers to higher spl. The problem did not appear, at lower volume.
 

yeliab1

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#4
PL700B and CF-3's

I am having speaker protection installed during the refurbish. Thanks for the quick replies.
I read that these speakers are 8 ohm nominal. I also saw an impedance curve on another 8 ohm klipsch speaker, and it dipped to 2 ohms.
I don't want to burn my "new" amp down.
Thanks again
 

Elite-ist

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#5
You should be in for a real treat once your Phase Linear 700B has been upgraded. So, we have amp, speakers - what else rounds out your stereo system?

Nando.
 

yeliab1

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#7
700B

You should be in for a real treat once your Phase Linear 700B has been upgraded. So, we have amp, speakers - what else rounds out your stereo system?


CT-27 preamp,
TFM-15 that I was bi-amping with. It won't turn on anymore.
PM-900 that I'm running a pair of CF-3's with, while the PL is out being repaired.
I plan to use the PM-900 with some sonosubs, ASA my PL gets back.
Thanks for askin'...
 

marcok

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#8
First of all ,
welcome aboard .
Suggestion : speakers connected in series as described in PL owner's manual.
Simple , considering the efficiency of your speakers .
Ciao
Marco
 

Fishoz

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#9
CT-27 preamp,
TFM-15 that I was bi-amping with. It won't turn on anymore.
PM-900 that I'm running a pair of CF-3's with, while the PL is out being repaired.
I plan to use the PM-900 with some sonosubs, ASA my PL gets back.
Thanks for askin'...[/QUOTE]


Don't thank him...we need fodder to pick on you.....naw, not really, we're just nosy.

Actually, welcome here! You're going to find some very helpful info and people on this site.
 

yeliab1

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#11
I think you're right

I'd think a second 700B would be the ticket for that second set of speakers! Would look way cool too!
Just sayin...... :toothy5:

I took your advice. Well, kind of. I bought a 700 II,with fresh re-cap. I was going to run the Klipsch on the PM-900 and use the 700 B on the subs. And...I thought what a waste that would be.
So I bought a second 700. It's a Series II, I know, but it should work out well.
I wish I would have found this site sooner and had some WO upgrades on my B, but, live and learn.
Are there any Carver repair experts @ here?? I have a TFM-15 that just stopped working one day. It needs pampered.
 

WOPL Sniffer

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#12
How do you guys get away with running 2 WOPL's at a time. My electrician will laugh all the way to the bank. With 15 amp breakers in the house, it won't take the initial turn on let alone the constant current draw during Jam sessions. Can you say SAG????
 

yeliab1

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#13
Wire Fire

How do you guys get away with running 2 WOPL's at a time. My electrician will laugh all the way to the bank. With 15 amp breakers in the house, it won't take the initial turn on let alone the constant current draw during Jam sessions. Can you say SAG????
Hello,
I'm not an electrician, but...
Pull some 10/3 romex and use a 220 volt 30 amp plug.
Skip a breaker in the box so you have 2, 110 volt, 30 amp circuits at the receptacle / AV cabinet.
 

Gepetto

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#14
How do you guys get away with running 2 WOPL's at a time. My electrician will laugh all the way to the bank. With 15 amp breakers in the house, it won't take the initial turn on let alone the constant current draw during Jam sessions. Can you say SAG????
2 separate 20A circuit breaker runs using 12/2 w/Ground. One for each amp. Each 5-15R outlet is nominally rated for 15A by UL, you can pull 80% of that according to NEC or 12A per outlet. This gives you 1440VA at the plug which is enough for a PL700 maxed out.
 

stuwee

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#15
Thread crap, so these WOPL's don't like anything below 4ohms? or they do what? Blow up and take the speakers with them?

I'll rephrase, if they dip into 2ohms and lower...Danger Will Robinson...Danger.

I can't imagine 2 pairs of Klipsch speaks straining any amp in impedance, I could be wrong tho...
 

Gepetto

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#16
Thread crap, so these WOPL's don't like anything below 4ohms? or they do what? Blow up and take the speakers with them?

I'll rephrase, if they dip into 2ohms and lower...Danger Will Robinson...Danger.

I can't imagine 2 pairs of Klipsch speaks straining any amp in impedance, I could be wrong tho...
They handle tough loads fine Craig...
 

FredR

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#18
WOPLs can handle Infinity 9Kappas, which have two super low dips in impedance. See attached. A single WOPL 700 can drive them with some caveats. Waveform protection needed to be disabled. Easy mod on control board. This still leaves average current protection by the fuses. To avoid nuisance blown fuses I run 12 amp line fuses and 8 amp B+ and B- fuses. Super low impedance seems to just suck power out of the amp. Not a short but pretty close. To run at even moderate volume you need a lot of air flow over the heat sinks. I also build the amps with thicker gauge hookup wire, particularly on the high current paths.

I decided to bi-amp so as to split the dips between two amps. This puts much less strain on the amps and allows me to use low noise fans to cool them.

Disclaimer: Proceed at your own risk as driving near shorts may be hazardous to your amps health.
 

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Northwinds

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#20
To avoid nuisance blown fuses I run 12 amp line fuses and 8 amp B+ and B- fuses

Disclaimer: Proceed at your own risk as driving near shorts may be hazardous to your amps health.
I like your style Fred, ballz to the wall
 
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