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Thread: 5-channel HT with higher power amplification levels for only front channels

  1. #1
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    5-channel HT with higher power amplification levels for only front channels

    I've owned many many receivers over the years and, in general, I'm not impressed with their sound quality. Yeah, that would be the whole bunch...

    Currently, I have a 5.1-channel Oynko with 140 WPC and a few Denon 5.1 receivers, 1 Denon receiver has 105 WPC. The sound quality of the Oynko just plane stinks and really loud levels can't be achieved - ever. I think the published Oynko receiver power ratings are very suspect or their maybe the pre-amp is not designed to drive the power amps very loud. The sound quality of the Denon receivers is OK, but, in general, the power levels are not sufficient for my installations.

    With a couple of minor acceptions, my speakers in all installations in the house and garage are typically JBL 2225, 2425, 2405. I love the sound quality at both low and high levels and they are reasonably efficient and, generally, they can take some abuse with ease. I also have several sub-powered 18" JBL speakers, which are really great.

    In one TV room experiment about 3 years ago, I connected only two JBL speakers to the Oynko and because the sound was so disappointing, I connected the Oynko pre-amp outputs to an Adcom 555 power amplifier with 200WPC. As time went on, I added two rear speakers and a center speaker, a couple of powered sub-woofers and these newer additions for the rear and center channels were driven only off the Oynko receiver. Several years ago, the Adcom power amp was moved to perform different service in another system and currently, all the that systems 5 speakers are driven from the Oynko receiver only.

    My experience with 5 channel systems is that they are annoying to balance the volume levels, especially when non-music sources sound better on stereo only and having to switch to multi-channel system and to re-balance for music material over and over again. I assume this is another disadvantage for using only one external power amplifier.

    I'm currently weighing the idea of buying a few used Adcom 555 power amplifiers for the rear channels of two systems.

    Questions
    1. Is it common to connect only the two front channels of a 5.1 system receiver to an external power amplifier? My recollection is that the sound is not too bad???
    2. If I decided to go with all external power amps that are connected to the receiver pre-amp outputs, is it better to go with multi-channel power amps or two or three stereo power amplifiers?
    3. Are there any alternatives for receiver powered ONLY systems like the Denon 5700 receiver at 140WPS? These receivers are cheap as dirt on E-bay now.
    4. Are the HDMI outputs and the newer THX decoders that are on new 2016 receivers so useful when used with a satellite cable source (ATT Satelite)?

    SORRY FOR THE LONG POST...

  2. #2
    Senior Member Ed Zeppeli's Avatar
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    I can't answer all your questions but I use a Marantz SR7008 and utilize the pre-outs to drive a Crown and my 4430 mains. Their room eq system seems to do a pretty good job of balancing speaker levels but I always tend to bump up the centre channel output for movie dialogue. I always play music in two channel mode.

    To me, it seems unnecessary to have external amps for surround data as I've never heard any deficiencies there and the internal amps of the receiver seem adequate.

    I am curious as to why you feel you're always re-balancing your system. Is it a mixing issue or an output issue?


    Best Regards,

    Warren
    DIY Array, 2242 sub, 4408, 4208, Control 8SR, E120 Guitar cab, Control 1, LSR305.

  3. #3
    Senior Member Chris Brown's Avatar
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    There is nothing wrong with using an external amp just for your front speakers. How much this benefits you depends a lot on how your receiver is designed, and how you have your speakers configured.

    My home theater receiver for example, has a shared power supply. It will do over 200wpc (8ohms, 20hz-20khz, 1% THD) with only 2 channels driven, but falls to less than 100wpc (8ohms, 20hz-20khz, 1% THD) with all 7 channels driven simultaneously. So in my case, the more channels I can offload to external amplifiers, the more power the built-in amplifier can direct to the remaining channels.

    Speaker configuration matters also. Low-frequency content is what consumes the most power. Most have their surround speakers set to "small", and with a THX spec crossover that means anything under 80hz is being sent to the subwoofer (and any speakers that are set to "large"). My receiver for example, jumps up to ~150wpc with all 7 channels driven when measured at 1khz instead of 20hz-20khz. If you only have two speakers that are set to "large", then you probably don't need dedicated amplifiers for anything else. If you are running "large" speakers on all channels, then you might benefit from more than one external amplifier.

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    Cable box is used for news (2 channel stereo only) and for music (all channel stereo). I found I'm re-balancing the speakers often after I change modes.

    **********

    I moved to a home that is only 9 years old about 3 years ago. ALL THE CIRCUITS IN THE FUSE BOX ARE 10 AMP!

    I'm researching BIG milti-channel amplifiers and I think 10 amp circuits are not going to work. Is that correct?

  5. #5
    Senior Member Ed Zeppeli's Avatar
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    Quote Originally Posted by robertbartsch View Post
    Cable box is used for news (2 channel stereo only) and for music (all channel stereo). I found I'm re-balancing the speakers often after I change modes.

    **********

    I moved to a home that is only 9 years old about 3 years ago. ALL THE CIRCUITS IN THE FUSE BOX ARE 10 AMP!

    I'm researching BIG milti-channel amplifiers and I think 10 amp circuits are not going to work. Is that correct?
    Wow. 10 amp breakers seems....not to code. You can't even run a toaster or blowdryer with that!
    DIY Array, 2242 sub, 4408, 4208, Control 8SR, E120 Guitar cab, Control 1, LSR305.

  6. #6
    Senior Member 1audiohack's Avatar
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    Quote Originally Posted by robertbartsch View Post
    ....I moved to a home that is only 9 years old about 3 years ago. ALL THE CIRCUITS IN THE FUSE BOX ARE 10 AMP!
    Can't be.

    The breaker amp rating is on the toggle. Newer breakers have the kA rating in white or yellow on the body. This is usually 10kA and what many people see first. It used to be this was just in raised black fine print.

    Look again.

    Barry.
    If we knew what the hell we were doing, we wouldn't call it research would we.

  7. #7
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by robertbartsch View Post
    I've owned many many receivers over the years and, in general, I'm not impressed with their sound quality. Yeah, that would be the whole bunch...
    Agreed 100%

    I have personally used, sold, and installed Marantz, Denon, Onkyo, Integra, and most of the other AVRs at one point or another and have never felt any of them brought out the potential of the speakers... But unless you're going to spend ungodly sums of money I think using one of these AVR's with upgraded amplification on the front channels is the best way to go.


    Quote Originally Posted by Ed Zeppeli View Post
    I am curious as to why you feel you're always re-balancing your system. Is it a mixing issue or an output issue?
    +1

    Using external amps will not affect this... Once the system is initially balanced.


    Quote Originally Posted by Ed Zeppeli View Post
    To me, it seems unnecessary to have external amps for surround data as I've never heard any deficiencies there and the internal amps of the receiver seem adequate.
    Agreed. I've used the built in AVR's amps for surrounds in numerous systems as a cost savings measure. I'm sure using external higher-quality amplifiers for all channels will be superior… But perhaps not particularly audible in the surrounds.


    Widget

  8. #8
    Senior Member rdgrimes's Avatar
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    Even the biggest flagship AVRs are mediocre even for 2-ch power. For 5.1 music they are useless at volume.
    I'm recommending the Outlaw 2200 mono-block, you can buy as many as you want. Most bigger AVRs can handle running surround channels only, but L-R and Center really benefit from a real amp.

  9. #9
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by rdgrimes View Post
    Even the biggest flagship AVRs are mediocre even for 2-ch power. For 5.1 music they are useless at volume.
    In my earlier post I wasn't commenting on maximum SPL but rather sound quality in general, but it wouldn't surprise me if maximum SPL was also compromised.

    Other than the added features that most people do not need, I see no benefit in buying the more expensive AVRs. I always spec the least expensive model with line level outputs and whatever other features that are needed to satisfy the system design.



    Widget

  10. #10
    Senior Member Ed Zeppeli's Avatar
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    Quote Originally Posted by Mr. Widget View Post
    Other than the added features that most people do not need, I see no benefit in buying the more expensive AVRs. I always spec the least expensive model with line level outputs and whatever other features that are needed to satisfy the system design.



    Widget
    Good call. I always seek out the receivers with pre outs as well. Unfortunately that feature seems to only be common on the more expensive models. The main reason I bought the Marantz was for the pre outs as well as the decent room eq function of Audyssey XT. Also, they were clearing them out at over 50% off.

    Seeking out a really nice pre-amp that would serve those functions would likely have cost multiple times more $.
    DIY Array, 2242 sub, 4408, 4208, Control 8SR, E120 Guitar cab, Control 1, LSR305.

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    Our house, a 3,300SF ranch, was built new in 2006 and it sat empty for 7 years until we bought it. It has 33 circuits in the breaker box and ALL are marked 10KA on the circuit breakers - including the 2 circuits that are 240 volts (oven and A/C).

    We have an empty 380SF room upstairs that is unfinished. Since no empty circuits slots are left in the smallish breaker box, I called a licensed electrician out to look at putting an extra box in for the new bathroom we wish to add. The only time we have had issues with blown breakers is for the outdoor circuit which was running an 800 watt electric smoker.

    I'm reading on the Internet about people who are blowing 20 amp breakers using larger multi-channel power amplifiers.

  12. #12
    Administrator Robh3606's Avatar
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    I'm reading on the Internet about people who are blowing 20 amp breakers using larger multi-channel power amplifiers.
    Really what amps are they using?? I have 3 Crown PS200's a single PS400 an Emotive XPA-3 and a Crown XTI-2002 all on a single 20 amp and no issues at all even stupid loud with action movies so lots of LFE

    Rob
    "I could be arguing in my spare time"

  13. #13
    Senior Member 1audiohack's Avatar
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    Agreed. One can make an immense amount of noise on a 120V 20A circuit.

    Robert, the 10KA number you see is the instant short circuit trip rating. This is of no concern. It is the current rating on the actual toggle portion of the breaker that indicates it's size.

    The tripping of the smoker is interesting. If your house has arc fault breakers, those are another adventure all together but the patio will / should be on a GFI. If the smoker (and every other thing on the circuit) has more than 6mA of combined current leakage it will trip a GFI.

    Your oven is most likely on a two pole 50A breaker as an example. You would be hard pressed to run a hot plate on a 120V 10A breaker.

    Barry.
    If we knew what the hell we were doing, we wouldn't call it research would we.

  14. #14
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    Here's a Square D breaker, 20A. It has 10kA on it, too, but it's a 20 amp breaker



    I do the FR/FL pre out of the AVR into an input on my 2 channel preamp into separate 2 channel amp. So by selecting that input on the 2ch preamp, I get TV sound through the "stereo" and control the TV volume with the 2ch preamp. For surround, I set the 2 ch preamp on a setting that gives good balance front to back (usually 70 or so in my case) and then control the overall volume with the AVR volume control.

  15. #15
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    .....lots of posts on blown 20 amp circuits - Adcom 7807, 7805, big Parasounds, big Krell, etc.... apparently, the biggest power draw is when the amps are first turned on.

    I'm probably going to buy a few more Adcam 555s and call it a day....??

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