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Dougt69

Audiophyte
#1
Anyone on here have experience with amp selectors?

I am currently using one on my Hafler P500 power amp and Denon AVR-x1400h. It is a break before make type with two switches. I have it set up this way so I can listen to different sources in just two speaker stereo.I know this is suppose to basically just be a switch with no hardware in between how ever I seem to notice audible distortion in the upper end of the frequency spectrum. Is it possible that the amp selector could introduce distortion.

Also when listening to music at what volume would clipping start to happen on the output of the avr or power amp. Just looking for ballpark since I dont have an oscilloscope to test it.

Equipment List
AVR : Denon AVR-X1400h
Power Amp: Hafler P500
Amp Selector: SPECIALTY-AV SP-71
My main speakers are Klipsch R-820-F
Surrounds are Klipsch R620F
Center channel Polk Audio T30
Sub stage two Polk Audio PSW10
Atmos speakers are PIONEER SP-BS22A

Thank you
 
ski2xblack

ski2xblack

Audioholic General
Ratings
779 6 4
#2
I'm really confused as to exactly what you're trying to achieve with this convoluted approach.

That switcher may alter the load presented to the amps. They'll still hit their specified power into a given load, whatever that total load ends up being. The Hafler is capable of delivering several hundred watts of unclipped power into almost any load north of a dead short, so if you ever go there the switch box will likely let out the magic smoke (and potentially take the Hafler with it).
 
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Dougt69

Audiophyte
#3
The Hafler is rated at 255 watts per channel into an 8 ohm load and that is the load I am giving it.
The Denon AVR-X1400h is only rated at 80 watts per channel into an 8 ohm load.

The Klipsch R-820-F are rated at 150 watts RMS continus and 600 Watt peak. The amp switch is on these speakers.

as a note I had the receiver and amp before I purchased the Klipsch speakers.

I was reading that you really want an amp that is about two times the RMS of the speaker so you can drive the speakers without clipping the amp that is why I an using the Hafler with a switch. I am good with the Denon when it comes to just watching movies in Dolby Atmos surround, but when listening to music I like to have it a little louder. I did not want to use the denon that is only rated for half the power output of the Klipsch speakers and risk clipping therefore I put the switch in and using the Hafler amp for music.

I guess I could use banana plugs and switch them out at the speaker or make my own connection plate that is more accessible for changing them out.
 
everettT

everettT

Audioholic Ninja
Ratings
1,232 9 16
#4
The Hafler is rated at 255 watts per channel into an 8 ohm load and that is the load I am giving it.
The Denon AVR-X1400h is only rated at 80 watts per channel into an 8 ohm load.

The Klipsch R-820-F are rated at 150 watts RMS continus and 600 Watt peak. The amp switch is on these speakers.

as a note I had the receiver and amp before I purchased the Klipsch speakers.

I was reading that you really want an amp that is about two times the RMS of the speaker so you can drive the speakers without clipping the amp that is why I an using the Hafler with a switch. I am good with the Denon when it comes to just watching movies in Dolby Atmos surround, but when listening to music I like to have it a little louder. I did not want to use the denon that is only rated for half the power output of the Klipsch speakers and risk clipping therefore I put the switch in and using the Hafler amp for music.

I guess I could use banana plugs and switch them out at the speaker or make my own connection plate that is more accessible for changing them out.
RMS is meaningless. You just use the main preout to the amp. FWIW your denon can drive those to ear bleeding levels with a few watts.
 
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Dougt69

Audiophyte
#6
Thanks for the link. will be useful

So when using that calculator is states 112db with my set up with the Denon AVR-X1400h, and 117.4 with the Hafler P500.

here is my back ground. I was into competition level car audio system and have really lost interest in it but I am transitioning into Home audio. I have been subject to SPL levels in excess of 160 db My daily driver at the time was capable of 150 db. it is now just a show vehicle that has not been to a show in a few years. I have had a hard time deciding on weather to sell the car audio equipment or not. If I do it will be put into home audio

never the less loud levels for most people will be normal for me.

So in the short term for home audio my set up is what is in the first post. This is just getting my feet in the water.I will be constantly upgrading and testing. I am sure it is not different then a lot of people here your build is never done.
 
Swerd

Swerd

Audioholic Spartan
Ratings
4,682 11 6
#7
I agree with ski2black and everettT about questioning your need for the amp switcher.
  1. Your speakers are among the more sensitive speakers available. Klipsch rates them as producing 97 dB when given 2.83 volts (1 watt at 8 ohms) measured at 1 meter distance. Even if Klipsch exaggerates, 97 dB is probably much louder than you listen. And you probably listen at about 9-10 feet away, not 1 meter. Just as a guess, those speakers are more likely in the 90-92 dB range for sensitivity – still very sensitive. To compare, many quite good loudspeakers have rated sensitivities of 84-88 dB. So, I don't think you really need that Hafler amp to avoid clipping.

    That power handling rating of 150W continuous/600W peak only tells you how much power they can take without thermal failure. It does not mean you really need that much power for normal or even loud listening levels. It is possible that using that powerful Hafler amp at high volume could blow the tweeters in your speakers. Not guaranteed, but possible.

  2. Second, your Denon receiver may offer a way to use that external amp without any amp switcher. See the owners manual where talks about using Zone B preamp outputs.

  3. If that doesn't work as you want, look for another Denon AVR, such as an AVR-X3400H, that offers preamp out puts for at least the front left & right channels. I know for certain that will allow you to use your Hafler amp for the front left & right speakers while using the AVRs amp channels for your other HT speakers, at the same time or while listening in 2-channel mode.

  4. Please forget everything you learned from competition level car audio. Listening at those levels absolutely will cause you to loose your hearing prematurely.
 
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Dougt69

Audiophyte
#8
To be honest when I bought the Denon receiver I was only concerned about it having Dolby Atmos and 4k UHD with HDR support. Was not until after the fact that I realized I needed something with pre-outs. The Zone 2 on the Denon I have tried and it will output only analog signals from sources plugged into the receiver which is fine for some of my media. I do have an older Marantz SR7001 receiver coming that has a full set of pre-outs that I can make use of. I will be moving a lot of things around I am sure.
 
Swerd

Swerd

Audioholic Spartan
Ratings
4,682 11 6
#9
I do have an older Marantz SR7001 receiver coming that has a full set of pre-outs that I can make use of.
Good. Give that a try.

I do something similar. My AVR is connected by preamp outputs to an external B&K 2-channel amp that drives my front left & right speakers. At the same time, the AVR's internal amps drive the center and rear speakers. The AVR and it's remote control handle everything easily.
 
ryanosaur

ryanosaur

Audioholic Field Marshall
Ratings
891
#10
I agree with @everettT on that point. With 80w into 2 channels, you are well over what would be considered reference level dynamic peaks. And even as Klipsch is known to fudge their sensitivity, even at 90db sensitivity, your 2-channel listening would still clear those dynamic peaks.
Personally, I like having my amps, even though I might not ever really use them: but my speakers are in the 85 and 86dB range, so for me, I need ~128w to clear that same dynamic range, which is probably more than my marantz can do, even considering that real-world power is way different than the RMS ratings.
 
lovinthehd

lovinthehd

Audioholic Overlord
Ratings
4,935 18 47
#11
I'm in agreement with the comments so far. Am curious though how you have your sources arranged; are they set up so that you can use either amp or you have your music source plugged directly into the power amp or via the avr or ? I looked up that switcher, it doesn't even suggest use beyond 100wpc continuous.
 
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Dougt69

Audiophyte
#12
I think I will have to take the Amp selector apart and physically look at it. I know it is rated at 100 wpc but there is no parts in it that could fail that I am aware of. If it has a solid connection in it I would think wattage would not be a problem. They may specify 100 watts to cover themselves.

Currently both amps Right and Left outputs are connected to the amp selector then Right and left output on the amp selector go to the Front Right and Left speakers. my Denon receiver uses Arc from hdmi to output to all the speakers. At one time I was using Zone 2 out to XLR for the Hafler amp but could only use analog inputs that were plugged into the Denon unit.

What I have found out in the short term is to just use a 3.3mm Din to XLR cable that I plug into the TV headphone jack to the Hafler amp and it works fine I have volume control from TV. Still get Arc audio to the Denon and audio out of the headphone jack. Since the AVR controls the TV volume through ARC connection it all kind of works seamlessly. However it is not ideal

The TV is a Sony X900f 55
 
lovinthehd

lovinthehd

Audioholic Overlord
Ratings
4,935 18 47
#13
I think I will have to take the Amp selector apart and physically look at it. I know it is rated at 100 wpc but there is no parts in it that could fail that I am aware of. If it has a solid connection in it I would think wattage would not be a problem. They may specify 100 watts to cover themselves.

Currently both amps Right and Left outputs are connected to the amp selector then Right and left output on the amp selector go to the Front Right and Left speakers. my Denon receiver uses Arc from hdmi to output to all the speakers. At one time I was using Zone 2 out to XLR for the Hafler amp but could only use analog inputs that were plugged into the Denon unit.

What I have found out in the short term is to just use a 3.3mm Din to XLR cable that I plug into the TV headphone jack to the Hafler amp and it works fine I have volume control from TV. Still get Arc audio to the Denon and audio out of the headphone jack. Since the AVR controls the TV volume through ARC connection it all kind of works seamlessly. However it is not ideal

The TV is a Sony X900f 55
So no music sources that don't route thru the tv? TVs don't make for very good pre-amps. Your tv uses a 3.3mm DIN for a headphone jack?

Post up some pics when you take that selector apart!
 
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Dougt69

Audiophyte
#16
So after opening it up and seeing the 5 watt 100 ohm resistors I took the selector out of the equation. Much better now, cleaned it right up.
 

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