Speaker hookup question

laatsch55

laatsch55

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#102
jhsellers said:
Judicious, but not such that I want to dampen the music. Series connection will dramatically limit the audible power developed. The fact that most of us here love power amps - making half-vast assumptions - means that we love to crank it once in a while. :)

JHS
Click to expand...

Series connection will also put one set out of phase with the other and blow your damping factor plumb to shit...bad deal, get another amp for the other speaks....( says the man with too many amps)
And welcome to Phoenix!! If you've lurked then you know...
 
laatsch55

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jhsellers said:
Hello, all.

I'm a recent newbie to this forum - lurked for some time, and finally registered since I have an original Phase Linear 400 that I bought new in 1974.

Because I've not been a regular visitor, I had not seen this thread regarding speaker loading until today - seeing that it's almost three years old until vbnks resurrected it with his post about "tube preferences".

Coincidentally, I did see an earlier reference about "tubes" from WOPL Sniffer in this thread that linked to the amplifiedparts.com website - copied here:

"Read this: https://www.amplifiedparts.com/tech-corner/speaker-impedance-power-handling-and-wiring "

This copied link addresses speaker impedance relative to tube amplifiers - and driver impedance is very important for tube output circuits; so much so that tube amplifiers need output transformers for proper operation.

However, I did not know the Phase Linear amps were sensitive to lower speaker loads. Can they not handle 4-ohm loading? I actually have never driven my PL400 with two pair of speakers, but I have done this with several other power amplifiers. I presently have two pair of 8-ohm speakers in parallel on an older Carver amp, and I regularly use 8-ohm drivers in parallel on power amps with vehicle audio systems. In fact, I've heard of some amplifiers that can handle 2-ohm speaker loads. I consider parallel speaker loading to be normal for solid-state amplifiers, and most should handle it without problem.

Why the caution against wiring parallel speakers with the PL amps? Certainly it might require additional cooling, but with judicious listening levels I would think this is a normal setup for home audio. Are the PL amps that weak for current carrying capacity on the output devices?

Thanks,
John
Click to expand...

No, not weak, but in dire need of cooling,m that's what kills a PL...
 
Gibsonian

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#104
jhsellers said:
Hello, all.

I'm a recent newbie to this forum - lurked for some time, and finally registered since I have an original Phase Linear 400 that I bought new in 1974.

Because I've not been a regular visitor, I had not seen this thread regarding speaker loading until today - seeing that it's almost three years old until vbnks resurrected it with his post about "tube preferences".

Coincidentally, I did see an earlier reference about "tubes" from WOPL Sniffer in this thread that linked to the amplifiedparts.com website - copied here:

"Read this: https://www.amplifiedparts.com/tech-corner/speaker-impedance-power-handling-and-wiring "

This copied link addresses speaker impedance relative to tube amplifiers - and driver impedance is very important for tube output circuits; so much so that tube amplifiers need output transformers for proper operation.

However, I did not know the Phase Linear amps were sensitive to lower speaker loads. Can they not handle 4-ohm loading? I actually have never driven my PL400 with two pair of speakers, but I have done this with several other power amplifiers. I presently have two pair of 8-ohm speakers in parallel on an older Carver amp, and I regularly use 8-ohm drivers in parallel on power amps with vehicle audio systems. In fact, I've heard of some amplifiers that can handle 2-ohm speaker loads. I consider parallel speaker loading to be normal for solid-state amplifiers, and most should handle it without problem.

Why the caution against wiring parallel speakers with the PL amps? Certainly it might require additional cooling, but with judicious listening levels I would think this is a normal setup for home audio. Are the PL amps that weak for current carrying capacity on the output devices?

Thanks,
John
Click to expand...

Have listened to 4 ohms thru 400 and 700's, works fine, sounds good, just need fans. If you listen like normal folk, might get by fine no fan. If you can get these amps about as hot as you think you should ever get them and play them there, they sound as good as they'll ever sound. I like to run them hot for best SQ.
 
WOPL Sniffer

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Speaking of...... I need another 700B/II....................... ANybody got one for sale??? I've been holding out for a Pro 700 but it doesn't appear to be helping. The last guy wanted $1000 for a bombed out unit............... I passed
 
mlucitt

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#112
jhsellers said:
Judicious, but not such that I want to dampen the music. Series connection will dramatically limit the audible power developed. The fact that most of us here love power amps - making half-vast assumptions - means that we love to crank it once in a while. :)

JHS
Click to expand...
Not as dramatically as you may think, the PL700 will develop about 960 watts RMS after WOA treatments (depending on the input level). This is into 8 Ohms. The same power into 16 ohms is 480 Watts RMS. This is a 50% reduction in electrical power but you will probably not be able to hear the difference of the audible power; at 100 Watts RMS continuous, most efficient speakers will cause pain thresholds if you are in the same room. So, just turn it up a little bit more to get 200 Watts RMS continuous and let me know what you think. But the amp will run cooler...
 
mlucitt

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laatsch55 said:
Series connection will also put one set out of phase with the other and blow your damping factor plumb to shit...bad deal, get another amp for the other speaks....( says the man with too many amps)
And welcome to Phoenix!! If you've lurked then you know...
Click to expand...
I meant to say drivers, not speakers (as in speaker boxes). We were discussing how to hookup speakers and I was thinking multiple drivers in one cabinet. For example, wiring two 8 Ohm woofers in the same cabinet from the appropriate crossover tap in series to double the impedance to 16 Ohms rather than parallel to cut it in half to 4 Ohms.
Phase stays the same and damping should not suffer too much.
 
J!m

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Going (way) back to tubes:

Go on McMaster-Carr and buy a bag of silicone o-rings that fit snugly on your power tubes. It cuts the mictophonics and it’s cheap.

I use them in my Counterpoints even though they are not power tubes (mosfet output).
 
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