Pro amps officially better than consumer amps!

[v_squared123]

Any thoughts on my setup? Would the DVDO be a good idea?

[cembros]

FYI gutiar center has a coupon for $100 off anything over $499. I just got another xls 2500 for $499. You can get the coupon from their website.

[v_squared123]

Thanks for the heads up!

[DanteMarone]

Even if both your consumer pre and professional power-amp both have balanced XLR's, there will still be a level mismatch because the consumer reference is -4db, and the pro is +10 db (if I remember correctly).http://homerecording.com/bbs/general...-level-270644/ http://www.diyaudio.com/forums/diyau...structure.html You can live with it, but it will compromise your system somewhat; you may be cranking your pre up to where it is distorting more than if the levels were properly matched, and you may be getting both more noise, and less than rated power from the pro-amp. Now that I've got my HT up and running, I'm working on a tri-amp speaker system to make use of all those channels of amplification maximized for just the accurate reproduction of music in stereo, and since I cant get an affordable consumer level 3-way active crossover (ain't any), for now I'm going to be using a pro-DBX 234 which is going to be level-mismatched on the input of my power amps (I'm not going to crank it far enough to where the interface with my consumer amps will be an issue, but the impedance may be mismatched as well. Once I feel it out, I probably end up getting one of those level matching devices (it's an old DBX with unbalanced 1/4 so I only needed eight 1/4' to RCA adapters, the newer 234s and 234sx have balanced or maybe both, I don't remember-or once I have the crossover frequencies sussed I may just get some of these inexpensive consumer level crossovers that aren't easily adjustable, so I would need to order them for the frequencies I need. Now I agree that bi-wiring, or "passive biamping" of speakers that have internal crossovers is USUALLY not worth the effort, but with some speakers the latter can make a significant difference depending on the design of the crossovers. And while I used to think that active bi or tri-amping was only worthwhile for professional sound reinforcement systems, I have become firmly convinced, that passive crossovers, no matter how well made, even with the silver-oil capacitors and inductors hand-wound on the thighs of Danish virgins, are the weakest link in the vast majority of systems, and really a bad idea. This article from Down Under is a bit long, but addresses the issue pretty damn comprehensively. part 1 http://sound.westhost.com/bi-amp.htm part 2 http://sound.westhost.com/bi-amp2.htm Rod Elliot has a lot of other interesting and informative articles about various audio issues on that site.

Now a lot of Crown amps sound pretty good, but the majority of pro-amps would not sound good hooked up to truly hi-fidelity speakers, they would be harsh, lacking in detail (especially low-level detail) and have a serious lack of any realistic soundstage. Part of the issue is fidelity to what? If your point of reference is live rock and roll or EDM you have no point of reference for fidelity, because these music forms (of which I am a a fan of many of the former, and some of the latter) do not exist outside of electronics (well electromechanical in the case of speaker systems). What sounds "right" to you is the sound of a club, but this is a completely artificial source. You may not like jazz or classical, but they can provide a reference for fidelity-the sound of strings, reeds, skins, etc. producing live music in a particular space that is generally constructed to present these natural forms of music well. Where the vast majority of pro-amps would fail in comparison to high quality consumer amps is that when driving highly accurate speakers, when you closed your eyes the speakers would disappear, you could not point accurately to where they are if someone spun you around blindfolded first. Really good consumer gear can, with good recordings, reproduce live acoustic performances right down to the position of the instruments-not just in the left to right way that the pro-stuff can (and those often can't do that with out a noticable whole in the middle), but also front-to back, and even often height-and you get a real sense of the space they were recorded in, where the musicians and their instruments are in that space, and many low-level details. You can hear when the singer takes a breath, the guitarist is sliding his hand down the fingerboard or switches from using a pick to his fingers (Jeff Beck hasn't used a pick in decades), when the stand-up bass player doesn't move his location, but just swivels his axe on it's peg and is faxing 45 degrees different. Now I sometimes crank-up some old Ozzy-era Sabbath, Soundgarden, or Nine Inch Nails. In those cases the music never actually existed as an acoustic event, what I hear then is about as close to what the band and producers heard from the studio monitors* when they approved the mix. Reproducing loud rock only requires quantity, those sound reinforcement speakers at live gigs, in addition to high SPL's are also producing a lot of distortion. So if that is all you want to hear, go for what they use (CBGB always had great sound, no where near as distorted as at large venues). Now the Crown, and Bryston amps a lot of Brit studios use are accurate, and can do a lot of what I was describing about actual acoustic events with jazz and classical, but most pro-amps can't, they are not designed to reproduce that kind of detail or realistic soundstage. There are some similar issues with HT; get enough power and some big Sonotube based subs and the gunshots, car explosions and alien ship landings can blow you away, but check the scene where the couple is in bed. Do they sound like they are talking in a little well upholstered room with drapes and carpet? When she slides her leg up the sheet or he tussles her hair does that sound like the sounds you've heard in similar situations? Usually the primary considerations besides high-output is really solid construction for the road (an area where Behringer falls short as one of the professional posters above alluded to-if you can't bring a back-up unit, don't go there). Now there are a lot of high end systems that can reproduce a string quartet playing in a drawing room so convincingly that with your eyes closed you could almost picture them in their tuxes and gowns, and smell the champagne the help is distributing-but can't crank out loud rock and roll with any realism or balls. Then there are those high end systems that can do it all. You could throw on a Metallica live and feel like you can picture what color shirt Lars is wearing, or an old Alice in Chains and feel like you know whether Layne scored enough good dope that day. These systems do more than reproduce the music, they convey some (sometimes a lot) of the emotion of the music. You can get an idea of what I'm talking about without an appt. at a "high end salon" with a pair of headphones and a a binaural recording (at least decent specimens of both).

[Josh]

This is probably more a question for Big Daddy then anyone, but when it says that Input Sensitivity is 1.4V, and there is gain control (which affects sensitivity), what "level" is that input sensitivity rated? Zero gain? Full gain? And if you increase the gain, does that increase the Sensitivity (to say, 3V) or decrease it?

This all links back to my Passive Preamp thread

[Big Daddy]

Originally Posted by DanteMarone

Even if both your consumer pre and professional power-amp both have balanced XLR's, there will still be a level mismatch because the consumer reference is -4db, and the pro is +10 db (if I remember correctly).http://homerecording.com/bbs/general...-level-270644/ http://www.diyaudio.com/forums/diyau...structure.html You can live with it, but it will compromise your system somewhat; you may be cranking your pre up to where it is distorting more than if the levels were properly matched, and you may be getting both more noise, and less than rated power from the pro-amp. Now that I've got my HT up and running, I'm working on a tri-amp speaker system to make use of all those channels of amplification maximized for just the accurate reproduction of music in stereo, and since I cant get an affordable consumer level 3-way active crossover (ain't any), for now I'm going to be using a pro-DBX 234 which is going to be level-mismatched on the input of my power amps (I'm not going to crank it far enough to where the interface with my consumer amps will be an issue, but the impedance may be mismatched as well. Once I feel it out, I probably end up getting one of those level matching devices (it's an old DBX with unbalanced 1/4 so I only needed eight 1/4' to RCA adapters, the newer 234s and 234sx have balanced or maybe both, I don't remember-or once I have the crossover frequencies sussed I may just get some of these inexpensive consumer level crossovers that aren't easily adjustable, so I would need to order them for the frequencies I need. Now I agree that bi-wiring, or "passive biamping" of speakers that have internal crossovers is USUALLY not worth the effort, but with some speakers the latter can make a significant difference depending on the design of the crossovers. And while I used to think that active bi or tri-amping was only worthwhile for professional sound reinforcement systems, I have become firmly convinced, that passive crossovers, no matter how well made, even with the silver-oil capacitors and inductors hand-wound on the thighs of Danish virgins, are the weakest link in the vast majority of systems, and really a bad idea. This article from Down Under is a bit long, but addresses the issue pretty damn comprehensively. part 1 http://sound.westhost.com/bi-amp.htm part 2 http://sound.westhost.com/bi-amp2.htm Rod Elliot has a lot of other interesting and informative articles about various audio issues on that site.

Now a lot of Crown amps sound pretty good, but the majority of pro-amps would not sound good hooked up to truly hi-fidelity speakers, they would be harsh, lacking in detail (especially low-level detail) and have a serious lack of any realistic soundstage. Part of the issue is fidelity to what? If your point of reference is live rock and roll or EDM you have no point of reference for fidelity, because these music forms (of which I am a a fan of many of the former, and some of the latter) do not exist outside of electronics (well electromechanical in the case of speaker systems). What sounds "right" to you is the sound of a club, but this is a completely artificial source. You may not like jazz or classical, but they can provide a reference for fidelity-the sound of strings, reeds, skins, etc. producing live music in a particular space that is generally constructed to present these natural forms of music well. Where the vast majority of pro-amps would fail in comparison to high quality consumer amps is that when driving highly accurate speakers, when you closed your eyes the speakers would disappear, you could not point accurately to where they are if someone spun you around blindfolded first. Really good consumer gear can, with good recordings, reproduce live acoustic performances right down to the position of the instruments-not just in the left to right way that the pro-stuff can (and those often can't do that with out a noticable whole in the middle), but also front-to back, and even often height-and you get a real sense of the space they were recorded in, where the musicians and their instruments are in that space, and many low-level details. You can hear when the singer takes a breath, the guitarist is sliding his hand down the fingerboard or switches from using a pick to his fingers (Jeff Beck hasn't used a pick in decades), when the stand-up bass player doesn't move his location, but just swivels his axe on it's peg and is faxing 45 degrees different. Now I sometimes crank-up some old Ozzy-era Sabbath, Soundgarden, or Nine Inch Nails. In those cases the music never actually existed as an acoustic event, what I hear then is about as close to what the band and producers heard from the studio monitors* when they approved the mix. Reproducing loud rock only requires quantity, those sound reinforcement speakers at live gigs, in addition to high SPL's are also producing a lot of distortion. So if that is all you want to hear, go for what they use (CBGB always had great sound, no where near as distorted as at large venues). Now the Crown, and Bryston amps a lot of Brit studios use are accurate, and can do a lot of what I was describing about actual acoustic events with jazz and classical, but most pro-amps can't, they are not designed to reproduce that kind of detail or realistic soundstage. There are some similar issues with HT; get enough power and some big Sonotube based subs and the gunshots, car explosions and alien ship landings can blow you away, but check the scene where the couple is in bed. Do they sound like they are talking in a little well upholstered room with drapes and carpet? When she slides her leg up the sheet or he tussles her hair does that sound like the sounds you've heard in similar situations? Usually the primary considerations besides high-output is really solid construction for the road (an area where Behringer falls short as one of the professional posters above alluded to-if you can't bring a back-up unit, don't go there). Now there are a lot of high end systems that can reproduce a string quartet playing in a drawing room so convincingly that with your eyes closed you could almost picture them in their tuxes and gowns, and smell the champagne the help is distributing-but can't crank out loud rock and roll with any realism or balls. Then there are those high end systems that can do it all. You could throw on a Metallica live and feel like you can picture what color shirt Lars is wearing, or an old Alice in Chains and feel like you know whether Layne scored enough good dope that day. These systems do more than reproduce the music, they convey some (sometimes a lot) of the emotion of the music. You can get an idea of what I'm talking about without an appt. at a "high end salon" with a pair of headphones and a a binaural recording (at least decent specimens of both).

I believe you are confusing things a little. The +4dBu and -10dBV refer to the voltage reference levels between XLR and RCA. Please refer to the Balanced (XLR, TRS) Vs. Unbalanced (RCA, TS) Connection thread. You will find detailed explanation and calculations there.

I also have to disagree with the second paragraph of your post. I experimented with a pro amplifier and compared it to other home amplifiers. I was very impressed with the performance pro amp. I summarized the results in the bottom of Post #1 in The Official Behringer & Other Pro Amplifiers Thread.

For your information, I have spent a lifetime attending high-end audio shows and dealers and have listened to speakers that cost over a $100,000. There is no doubt in my mind that the majority of home audio amplifiers are extremely overpriced as compared to pro amplifiers. In home audio, Bob Carver proved this a long time ago and in recent years, Emotiva has done a wonderful job of building quality amplifiers and selling them significantly lower than other more established brands.

[Big Daddy]

Originally Posted by Josh

This is probably more a question for Big Daddy then anyone, but when it says that Input Sensitivity is 1.4V, and there is gain control (which affects sensitivity), what "level" is that input sensitivity rated? Zero gain? Full gain? And if you increase the gain, does that increase the Sensitivity (to say, 3V) or decrease it?

This all links back to my Passive Preamp thread

The simple answer to your question is yes with a big caveat. When you make the mistake of asking Big Daddy a simple question, he will give you a full page answer.

Input sensitivity is the voltage required by the amplifier to amplify a signal without clipping at its rated capacity. An amplifier takes input signals and makes them larger. How much larger depends on the input sensitivity and the maximum power output of the amplifier. You can turn the input sensitivity level all the way up, but that does not make the amplifier generate more power than its maximum. It just gets to that maximum level with a smaller input voltage.

Amplifier level/gain controls are input sensitivity controls. They are not power controls. They have absolutely nothing to do with output power. They do not change the available output power. They are sensitivity controls. They determine what input level will cause the amplifier to produce full power.

In pro audio the 1.2V (+4dBu) figure has a significance. Most professional audio equipment is designed around a nominal operating level of +4dBu. For example, most consoles will output about 1.2 volts when the meter reads 0dB.

VUMeter.jpg

Think of an amplifier's sensitivity the same way you think of a speaker's sensitivity. A speaker with high sensitivity doesn't need many watts to play loudly, whereas a speaker with low sensitivty needs more watts to play at the same level. Using the same analogy, a high-sensitivity amplifier does not need much of a signal from the preamp to play at full power, whereas a low-sensitivity amplifier needs more preamp drive to reach the same power.

Let's assume you want to play a song at a reasonable level. With a high-sensitivity amplifier, you might only need to set your preamp's volume control to 9 o'clock. With a low-sensitivity amplifier, you will need to set the volume control on the preamp to maybe 12 o'clock to get the same level of loudness.

Basically, you want to set the amplifier's gain so the preamp/processor is just below its limit when you are producing the maximum power you want to achieve. If the amplifier level is set higher, you need to turn the preamp/processor down, which increases the noise level. If the amplifier level is set too low, you will not be able to achieve the desired volume from the speakers without the preamp/processor running into distortion.

How to Set an Amplifier's Sensitivity Level

You want the maximum input signal to cause full power at the amplifier.

To set the amplifier controls to achieve full power with your maximum input signal use the following procedure. If your system uses active crossovers, for the moment, set all the crossover output level controls to maximum.

1. Disconnect the speakers. You do not want to accidentally damage them.
   
2. Set preamp output level to maximum. For practical reasons, it may be better to increase the volume to around 75%.
   
3. Turn the pro amplifier's input sensitivity controls all the way down to minimum level (least sensitivity or off).
   
   Note: Even at minimum sensitivity, it is possible that some amplifiers may produce some level of sound.
   
4. Slowly turn the sensitivity control on the amplifier up until clipping just begins. Stop.
   
5. This is the maximum possible power output with the maximum possible input signal. Because there is never a bigger input signal, this setting guarantees the amplifier cannot clip. You have indirectly set the dynamic range of your system. However, it is still possible that at this level, you may damage your speakers.
   
6. Do not adjust the sensitivity level on the amplifier anymore.
   
7. On the preamp, turn volume level control all the way down.
   
8. Connect all the speakers.
   
9. Play some music and slowly turn the volume up on the preamp.

Moral of the Story: Amplifier input sensitivity controls do not change the available output power. They only change the input level required to produce full output power.


It may be helpful to review the following section from A Guide to Amplifiers.

Input Sensitivity of an Amplifier:
A pre-amplifier has two basic functions:

1. Allow input switching.
2. To achieve synergy between the source(s) and the amplifier(s).

Input switching is well understood by most users and is rather elementary. The second function is not quite as easy for most users to understand. To select an appropriate preamp, you must know two things:

1. The output voltage of the source. Most CD players, for example, have an output voltage of 2 volts.
2. The input sensitivity of the amplifier. Most amplifiers have an input sensitivity of around 1 volt.

Output Voltage: The output voltage of the source is normally a constant level unless the source has a variable output knob. This output voltage (e.g., 2 volts of CD music) drives the input stage of the preamp which in turn drives the input stage of the amplifier.

Input Sensitivity: The input sensitivity of an amplifier is defined as how many volts are required to bring the amplifier to full power. Any amount of voltage beyond that number will force the amplifier to try to output more power than it is capable of and therefore results in clipping.

So we can conclude that an important job of the preamp is to control the voltage from the source to the amplifier. This is done by adjusting the volume control. When the preamp volume is all the way down, the output signal is attenuated completely to zero volts and no sound. As the volume knob is turned up, the voltage increases as does the sound generated from the amplifier. Assuming the output voltage of the source is more than the input sensitivity of the amplifier, the ideal working range on a volume control should be where the preamp would not add any voltage gain to its input signal beyond the amplifier’s input sensitivity.

When do we need gain in a preamp?

When the input sensitivity of the amplifier is above the output voltage of the source. It is possible for some amplifiers to need up to 5 volts to bring them to full power. On the other hand, it is possible for some to only need 1/2 volt to come to full power. It is also possible for some modified CD players or Digital/Analog Converters to have less then 2 volts.

As an example, assume an amplifier with an input sensitivity of 2 volts is connected to a source with an output voltage of 1 volts. We will definitely need a preamp with some gain. Otherwise, it will not be possible to play the amplifier as loud as it it is capable of. Even if the speakers are very efficient, the music will lack dynamics and weight at low listening levels. Turntables have very low output sensitivity. That is the main reason why you need a built-in or external phono stage with turntables,


Example: Let’s say we have an 8-ohm loudspeaker that has a sensitivity of 87dB for one watt at one meter. Assume we are trying to achieve a desired maximum peak sound pressure level of 105dB. If the signal source has an output voltage of 1 volt, how much amplifier gain is required?

Remember that in order to increase the level of sound by 3dB, we need to double the amplifier’s power.

SPL, Watts
87dB, 1
90dB, 2
93dB, 4
96dB, 8
99dB, 16
102dB, 32
105dB, 64

Therefore, we need 64 watts to achieve a peak SPL of 105dB. From Ohm’s law,

Power = V^2 / R

64 = V^2 / 8, and V = 23 volts

So the amplifier needs to provide a voltage gain of 23 times which is approximately 27dBv. Please note that 0 dBv is defined as Vo = 1 volt, and

dBv = 20 . LOG(V/Vo) = 20 x LOG(23/1) = 27 dBv.

Some amplifiers have knobs that control the amplifier’s input sensitivity. When the knob is turned clockwise, the sensitivity will increase. Turning the control counter-clockwise will decrease sensitivity. This control is not a volume control for the amplifier. The amplifier can be driven to full power with a wide range of signal levels. A low level signal will require increased sensitivity for full power. A high level signal will require decreased sensitivity.

[prerich]

Originally Posted by Big Daddy

I believe you are confusing things a little. The +4dBu and -10dBV refer to the voltage reference levels between XLR and RCA. Please refer to the Balanced (XLR, TRS) Vs. Unbalanced (RCA, TS) Connection thread. You will find detailed explanation and calculations there.

I also have to disagree with the second paragraph of your post. I experimented with a pro amplifier and compared it to other home amplifiers. I was very impressed with the performance pro amp. I summarized the results in the bottom of Post #1 in The Official Behringer & Other Pro Amplifiers Thread.

For your information, I have spent a lifetime attending high-end audio shows and dealers and have listened to speakers that cost over a $100,000. There is no doubt in my mind that the majority of home audio amplifiers are extremely overpriced as compared to pro amplifiers. In home audio, Bob Carver proved this a long time ago and in recent years, Emotiva has done a wonderful job of building quality amplifiers and selling them significantly lower than other more established brands.

Agreed. Andrew Robinson over at Hometheaterreview.com is doing a lot to dispell these myths also. He has an at length review of the Crown XLS 2000. He has also ventured into looking at speakers that don't cost a ton either (replaced his B&W 802's with Tekton Pendragons...now he has three Pendragons behind an acousticly transparent screen). For the original retail of my LCR power amp, I could have bought 5 crowns and had more power. I'm with you on this Big Daddy!

@Dante...if you ever take the red pill........

[SubSolar]

How come the Yamaha P-S series isn't that popular for HT use compared to say Crown? Can't seem to find a thread anywhere. Seems like a pretty good price for what you get, $750 for 750 watts x 2 for the P7000S. Looking for something to power a pair of Martin Logan Theos.

[prerich]

Originally Posted by SubSolar

How come the Yamaha P-S series isn't that popular for HT use compared to say Crown? Can't seem to find a thread anywhere. Seems like a pretty good price for what you get, $750 for 750 watts x 2 for the P7000S. Looking for something to power a pair of Martin Logan Theos.

First - welcome to the forum. I've used Yamaha pro amps before (the old P-series) and they served me well. The Crown has gotten a lot of press mainly because of Andrew Robinson over at HTR. He's taken the time to review these and had the guts to try a pro amp in his main theater. The Yamaha seems to fit the bill quite nicely however you do get more flexiblity with the Crown amps ability for multiple configurations.

[v_squared123]

Yamaha P-S series? Never heard of them. Anyone else own them and care to comment? $750 for 750 watts x 2 isn't too bad!

[saprano]

Do the crowns have 5 channel amps?

I'm happy with my SC37 but when i finally get new tower speakers i might need more power. Maby not though. 150-170 watts should be enough for anything.

I am curious about the crowns. They're so cheap.

[v_squared123]

Originally Posted by saprano

Do the crowns have 5 channel amps?

I'm happy with my SC37 but when i finally get new tower speakers i might need more power. Maby not though. 150-170 watts should be enough for anything.

I am curious about the crowns. They're so cheap.

Isnt 150-170 watts peak power? Or is that RMS? From what I've seen by looking around there isn't a five channel crown amp UNLESS you look into the Commercial "theater" amps...but I believe those cost upwards of thousands.

[saprano]

Originally Posted by v_squared123

Isnt 150-170 watts peak power? Or is that RMS? From what I've seen by looking around there isn't a five channel crown amp UNLESS you look into the Commercial "theater" amps...but I believe those cost upwards of thousands.

RMS it seems-

http://www.hometheater.com/content/p...-labs-measures

The pioneer elites with ICE amps were very good at delivering their rated power, and higher, into multiple channels.

So these crown amps weren't made for HT is the reason why there aren't any beyond 2 channels?

[v_squared123]

Originally Posted by saprano

RMS it seems-

http://www.hometheater.com/content/p...-labs-measures

The pioneer elites with ICE amps were very good at delivering their rated power, and higher, into multiple channels.

So these crown amps weren't made for HT is the reason why there aren't any beyond 2 channels?

I would think so

[cembros]

It's been a while since I've been here, I'm loving my amps. Of course, just like everyone else I'm looking to try and experiment with new things. That said, I'm wondering if there would be any benefit in getting a 3rd amp and running my Theos bi-amped with the crossover running 1 ch to the woofer (I think it crosses over at 425hz) and the other to the panel. I would then just use the 3rd amp for the center mono bridged. Any thoughts? Not even sure how to go about bi-amping. Any advice appreciated. Not sure if I would actually do this but it's fun to speculate.

[Nick The Slick]

Originally Posted by cembros

It's been a while since I've been here, I'm loving my amps. Of course, just like everyone else I'm looking to try and experiment with new things. That said, I'm wondering if there would be any benefit in getting a 3rd amp and running my Theos bi-amped with the crossover running 1 ch to the woofer (I think it crosses over at 425hz) and the other to the panel. I would then just use the 3rd amp for the center mono bridged. Any thoughts? Not even sure how to go about bi-amping. Any advice appreciated. Not sure if I would actually do this but it's fun to speculate.

These Crowns actually have a bi-amp crossover function in which one channel sends the high pass info and the other the low pass info, all you have to set is the crossover point and connect the right portion of the speaker to the right output (can't recall off the top of my head but I'm pretty sure channel 1 is high pass and channel 2 is low pass). Whether it's worth it or not is debatable and would be up to you to decide. Personally if it were me I wouldn't bother with the bi-amping and get the third just to have all 3 front stage channels on a bridged mono amp

[cembros]

Originally Posted by Nick The Slick

These Crowns actually have a bi-amp crossover function in which one channel sends the high pass info and the other the low pass info, all you have to set is the crossover point and connect the right portion of the speaker to the right output (can't recall off the top of my head but I'm pretty sure channel 1 is high pass and channel 2 is low pass). Whether it's worth it or not is debatable and would be up to you to decide. Personally if it were me I wouldn't bother with the bi-amping and get the third just to have all 3 front stage channels on a bridged mono amp

Well I'll have to buy a 3rd regardless because I'm looking to replace my SC-05 with a preamp so I'll need something to power the rears.

[Nick The Slick]

Originally Posted by cembros

Well I'll have to buy a 3rd regardless because I'm looking to replace my SC-05 with a preamp so I'll need something to power the rears.

True. Well the way you have it set up now you can actually test the bi-amp function to see if you like it or not and if it gives you any benefit. Like I said it's really easy to setup (well, depending on how hard it is to get behind your gear and switch wires up lol). Just run the L channel RCA to one amp and R channel RCA to the other amp (channel 1 input). Then run one set of wires to the top/high pass portion of your speaker and the other set to the woofer/low pass (I was wrong on the amp side as well. Channel 1 is low pass, channel 2 is high pass). Then hold mode/menu to bring up the menu, change amp mode to "Input Y", change the filter to xover, then of course set freq to whatever the appropriate crossover is for the Theos. Could help you decide if you need a 3rd and 4th or just a 3rd or whatever.

[cembros]

Originally Posted by Nick The Slick

True. Well the way you have it set up now you can actually test the bi-amp function to see if you like it or not and if it gives you any benefit. Like I said it's really easy to setup (well, depending on how hard it is to get behind your gear and switch wires up lol). Just run the L channel RCA to one amp and R channel RCA to the other amp (channel 1 input). Then run one set of wires to the top/high pass portion of your speaker and the other set to the woofer/low pass (I was wrong on the amp side as well. Channel 1 is low pass, channel 2 is high pass). Then hold mode/menu to bring up the menu, change amp mode to "Input Y", change the filter to xover, then of course set freq to whatever the appropriate crossover is for the Theos. Could help you decide if you need a 3rd and 4th or just a 3rd or whatever.

Sounds easy enough, I'll try it out when I get a third. I know bi-amping is usually dismissed as a waste but since I''ll be getting a third amp anyway it should be fun to try it out.