Somebody help! Adding amplifier to receiver problem.

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-GZ-

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I'm trying to hook up an external ampiflier (actually 2 mono amps) to my Kenwood KR 9600 receiver by using the pre outs. The kicker is...that I want to still use the amplifier from the 9600 to power these two new speakers I got. Problem is...i get sound from the two mono amps but no power going to the speakers hooked up to the speaker outs on the 9600.
The pre out is actually a "pre out" and "power in" setup that has to be connected by a metal jumper when not in use. This is Greek to me as this receiver is older than I am.
So in short.
How do I add a power amplifier to a receiver that has "pre out/ power in " and still be able to utilize the receiver's amplifier????
I've searched the web and can't find anything.
Someone please help!!!
 

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Superduper

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The system has true separate preamp and power amplifier sections. They are tied together with the jumpers as you saw. Removing the jumpers will divorce the system and allow the parts to operate separately. While you can technically use splitters like you say, it will affect the impedance to a degree. Whether or not this becomes a problem will depend on how tolerable the amp or preamps are. Still even if it works, I don't suggest you connect the system in this manner unless the amplifiers have closely matched outputs (power), or separate input level controls, the louder (more powerful) amplifier will drown out the less powerful one. So even though the lower SPL setup might be emitting sound, if they are significantly attenuated from the more powerful setup, they will be all but acoustically invisible. I'm talking about in a typical home sized setup and not in a large hall where given sufficient space separation, even highly attenuated speakers (compared to the strong ones) will still be beneficial to ears in closer proximity to them.
 

goodman

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If you wanna use use receiver like before, you don't need to remove this bridges (pre out- power in)
LINE OUT signal you can find on TAPE A or B REC cinch - In yellow on this picture:




.......
 

-GZ-

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goodman said:
If you wanna use use receiver like before, you don't need to remove this bridges (pre out- power in)
LINE OUT signal you can find on TAPE A or B REC cinch - In yellow on this picture:




.......
That thought crossed my mind Goodman. Just couldn't remember how that worked. Plus I'm not sure if I can use my aux input and tape at the same time.
 

-GZ-

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Superduper said:
The system has true separate preamp and power amplifier sections. They are tied together with the jumpers as you saw. Removing the jumpers will divorce the system and allow the parts to operate separately. While you can technically use splitters like you say, it will affect the impedance to a degree. Whether or not this becomes a problem will depend on how tolerable the amp or preamps are. Still even if it works, I don't suggest you connect the system in this manner unless the amplifiers have closely matched outputs (power), or separate input level controls, the louder (more powerful) amplifier will drown out the less powerful one. So even though the lower SPL setup might be emitting sound, if they are significantly attenuated from the more powerful setup, they will be all but acoustically invisible. I'm talking about in a typical home sized setup and not in a large hall where given sufficient space separation, even highly attenuated speakers (compared to the strong ones) will still be beneficial to ears in closer proximity to them.
As far as the output power goes. The power amplifiers put out somewhere over 300 WPC into my 4 ohm Vegas (spec says 270 into 8 ohm) that have a silk dome tweeter 6.5" mid and 15" woofer. The Kenwood would be sending out 160wpc into 8 ohm speakers BUT it only needs to power two 4" mids and a 1" tweeter per channel as each speaker contains a powered 10" sub and 12" radiator. So my thinking is that there won't be a huge difference since that 15" Vega draws a lot of that 300 some watts.
As far as the pre out vs the tape rec. I'm going to try both ways but I'm hoping the rec out works as there would be less issues with resistance than if I continued the loop with a splitter on the pre out/power in. That way I'm only sending a signal out to the amp and not sending any signal back to the Kenwood. Or something like that. Sorry Norm if my uneducated theories are making your head hurt. Haha.
Either way, I won't know how its gonna work until I try it. Maybe the Kenwood won't be able to keep up with the power amps but I gotta try it.
These new speakers I got were the deal of the century and I want to incorporate them somehow.
I currently have 3 of the same power amps...just waiting to find that 4th one...then I can find two more Vegas like the ones I have. Then I'll have my ultimate 1200+ watt system with 4 15" woofers. Because I'm nuts!
 

goodman

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-GZ- said:
That thought crossed my mind Goodman. Just couldn't remember how that worked. Plus I'm not sure if I can use my aux input and tape at the same time.
If you connect TAPE DECK to TAPE A, you can use TAPE B for LINE OUT.
On front side you have switch dubbing TAPE A - TAPE B.
 

-GZ-

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goodman said:
If you connect TAPE DECK to TAPE A, you can use TAPE B for LINE OUT.
On front side you have switch dubbing TAPE A - TAPE B.
So plug my aux cord (for phone/iPod) into tape play A instead of aux input then run my power amps out of tape rec A or B?
 

Superduper

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OMG, STOP! You guys are heading for a disaster.

First, the separate but divorced setup I'm talking about are PRE-AMP out, and POWER-AMP in. Those other outputs are un-throttled line level connections. IF you hooked up your amplifier directly to those other outputs, you will likely blow up your speakers as soon as you turn on the audio.

Remember, Pre-Amp out is an attenuated (controlled) output. This output is controlled by the volume pot of the kenwood receiver. IF you hooked up the line level outputs to directly to your external amplifier, that is like turning the volume control to max and pinning it there.

===========
Greg, remember that both amplifers (the kenwood internal amp, and your external mono-blocks) are getting the exact same control signal. So if one outputs 160 max, and the other at 300+ max, then the monoblocks will always output more power to the speakers than the kenwood. Unless the speakers connected to the kenwood are HIGHER efficiency than the larger Cerwin Vegas, then they will be drowned out. There isn't really enough space separation in the average sized room. In my experience, most larger speakers are more efficient than small speakers. But the only way to know for sure is to try it and see how it goes. If you split them and can barely hear (or not at all) the smaller speakers, then they are only going along for the ride and probably just wasting energy (and keeping the amp warm) for no great benefit. And I'm not talking about placing your ears directly over the speakers. I'm talking about while seated in your listening chair. So hook them up like you planned and then alternately have someone else push the speaker buttons and see if you can hear the other speakers. Then you'll know if it's worth connecting them like you planned or not.

However, there is still some usefulness to connect them like you planned even if you can't hear them. The reason is that in those cases where you don't need 300wpc blasting away, you can simply leave the monoblocks powered off and listen to the kenwood connected speakers. The rest of the time, just leave the speaker switch off if they are otherwise audibly invisible.
 

-GZ-

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Well guys its hooked up....and it sounds fantastic.
Thankfully the guy at Radio Shack (i know right) warned me about the same thing Norm just said about the tape line levels inputs. Just saw your post now Norman. Hooked the mono blocks to the pre-out and power-in using the two splitters I bought.

Sooo some how the new speakers hooked up to the Kenwood are bright enough or getting enough power to where I can distinctly hear them at low and high volumes as well as the Vegas. Even though those are getting 160 WPC and have a 91db sensitivity. The Vegas are getting 270+ WPC and are rated at 102db sensitivity. My only explanation is my guess from earlier that the Kenwood only has to power 2 4" mids and a tweeter where the mono blocks have to power the tweeter the 6.5" AND the 15". I have no idea.

When I turn the loudness switch from off to 1 to 2....it seems like the towers from the Kenwood get a biggger bump in volume than the Vegas connected to the mono blocks. Not sure if the mono blocks are even related to the loudness switch on the Kenwood???
The powered subs in the new towers seems to be responding to the bass level knob on the Kenwood so the sub level dial on the speakers has to be adjusted as necessary...didn't expect that. Basically I adjust the Vegas to where I want them...then adjust the towers' sub levels to where they need to be in conjunction with the Kenwood bass level.
I'm still going to have to play with it a little more...obviously. I just can't believe how this setup just fills the room. It sounds absolutely amazing.
Norman feel free to chime in a little more about the bass level, loudness, power output or whatever...love hearin from you. There's just some things I have no explanation for.
 

-GZ-

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I just re-read your post Norman an kind of answered my own questions.
Just didn't realize that the bass control on the Kenwood would affect the bass level on the powered subs in the towers. I thought the powered subs acted independently of the dual 4" mids and the tweeter and were ONLY controlled by the sub level knob located on each speaker.

By the way. The new speakers are Boston Acoustics VR975's. $1600 brand new in 2002. Got em for $50!
 

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Superduper

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Greg, that is a great price. Can you go back and buy some for me? I'll take 10 pairs of those speakers.

BTW, glad you came to your senses and ignored those previous suggestions on wiring up your system. I was 1/2 expecting to see you follow up on your thread and say that your speakers are blown, your ear drums are blown, and there's smoke in the house. Was trying to find a tactful way of offering my condolences, but glad it didn't come to that. Speakers look great btw.

As to your questions, the SPL of a speaker "system" is exactly that, as a complete "system". If you took the SPL of each and every driver, you will come up with different results depending upon which driver you were measuring. In your case, it appears that your drivers complement each other enough and there were enough "holes" in the audio spectrum by your CV's that you are filling those holes. That is an excellent result. Interesting thing though on my Polks is that the sound is very well balanced and capable of good highs and lows, and midrange too.

There is also another reason why the difference isn't as pronounced as you thought. 160wpc and 270wpc isn't as much difference as it sounds to be. In terms of perceived "loudness" 270wpc is probably ony 15-20% louder than 160wpc as you would need 4x's the power (640wpc) to double the loudness (6db). In fact, in order to triple the loudness, you will need 10x's the power or 1,600wpc. This is why speaker sensitivity is so very important. If you have speakers that have +6db improvement over another, that's like quadrupling your amplfier power output. For Free!

Now, as to Pre-Amp out, think about everything you do on your Kenwood 9600, volume position, bass/treble, balance, high filter, dolby, whatever..... the signal outputted at the pre-out is 100% controlled by the unit. The only thing missing if you divorce the amplifier is, dare I say it, the amplifier!

Now as to your other question about the subwoofers in your towers.... unless they are controlled by a subwoofer-out connection (and I know they aren't), then I'm guessing that your speakers are hooked up like any other speaker except that it's plugged in to provide power to the internal subs. In this case, the speakers have internal circuitry to filter the lows and pass them to the internal sub amp to power the subs. Adjusting the bass control on your kenwood should have some affect on the subwoofer level.
 

-GZ-

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Theses things are amazing but I don't know if they can touch your Polks!
Thanks for the clarification on the powered subs Norman.
And I see what youre saying about the difference between the 160 WPC and 270 WPC not being a big difference. I think we've discussed that once before.
And I think you hit the nail on the head when you say the Boston's are filling in the "holes" in the Vegas' spectrum that were missing. I think theses speakers compliment each other absolutely perfectly....and the balance of power is right where it needs to be. Its funny how I can actually hear the voids appearing and reappearing by turning each set on and off.
I can't believe how full the sound is in my large rec room with this setup. It is absolutely amazing. Can't believe I'm running between 1100-1300 watts! I got really lucky with this and I couldn't be happier.
Thanks for your wisdom!
 
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