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Fawd
11-29-2009, 08:39 PM
Hello Everyone! My current set-up is as follows:

JBL L890CH x2 Tower Speakers
JBL LC2CH Center Channel
JBL L8400P Subwoofer
Onkyo TX-SR708 Reciever

I was looking to purchase two JBL L820CH speakers to use as my rear channels. I was wondering if it would be wise to buy an external amp to use in addition to my reciever... I use the system rather frequently and at high volume levels... any advice as to if I should buy an amp? If so, which is a good make/model?

Of coarse, price is a factor :( My price range for an amp is in the 250-750 dollar range... the less the better! But, if that isnt enough, post what you would advise :)

Thanks again!

jcrobso
11-30-2009, 09:47 AM
If it is a 7.1 just hook your new JBLs up the surround speaker outputs on the back of the receiver. Then you go through the setup on the receiver to configure it.

rdgrimes
11-30-2009, 11:18 AM
The L890s will greatly benefit from an amp that has plenty of power, particularly one that is fully rated at 4u. I'd be looking for 200WPC at 8u with a decent 4u rating too. One very good alternative would be to use a 2-ch (fronts) or a 3-ch (fronts and center) and let the Onkyo handle the other channels.

The L890 has a pretty big impedance dip in the mid-bass, and a better amp will be able to handle that.

The Emotiva 3-ch:
http://emotiva.com/xpa3.shtm

Has what you need and will put a smile on your face. ;)

robertbartsch
11-30-2009, 12:02 PM
Is this Onkyo rated at 130wpc into 7.1? If yes, I beleive I have this one.

...just wondering:

1. Is your amp difficult to balance the channels?
2. Does it suffer loud popping noises from a variety of sources including cable TV?

I read on the Net the popping noise can be fixed by downloading new software but I have not done this.

Anyway, for my Onkyo set-up, all speakers have similar sensativities but the surround and rear channels must be manually set to "+10" and the fronts and center channel to "-3" in order to balance the system.

I beleive the pre-amp output signal for this amp is very low so you need to be careful when attempting to match a suitable power amp with this receiver.

jcrobso
11-30-2009, 01:56 PM
Before you get another amp, I think you should give them a try on you Onkyo.
They are rated at 90bd 1 watt at 1 meter, this normal for most HT speakers.
How big is your room? Now if your room is 30'X40' you might need a bigger amp.:blink:

jblsound
11-30-2009, 02:51 PM
I don't think the Onkyo really has enough power for the L890's mid-bass. Best add a strong 200wpc power amp.

Fawd
12-01-2009, 08:43 AM
Is this Onkyo rated at 130wpc into 7.1? If yes, I beleive I have this one.

...just wondering:

1. Is your amp difficult to balance the channels?
2. Does it suffer loud popping noises from a variety of sources including cable TV?

I read on the Net the popping noise can be fixed by downloading new software but I have not done this.

Anyway, for my Onkyo set-up, all speakers have similar sensativities but the surround and rear channels must be manually set to "+10" and the fronts and center channel to "-3" in order to balance the system.

I beleive the pre-amp output signal for this amp is very low so you need to be careful when attempting to match a suitable power amp with this receiver.

I havent had any trouble with the Onkyo in regards to sound quality... But, when I turn the volume up to higher levels, the mid-ranged on the l890s do seem to have some trouble... (whether that is from the amp, or the physical speakers themselves I am unsure).

I have my speakers set up similarly to yours.

Fawd
12-01-2009, 08:44 AM
The L890s will greatly benefit from an amp that has plenty of power, particularly one that is fully rated at 4u. I'd be looking for 200WPC at 8u with a decent 4u rating too. One very good alternative would be to use a 2-ch (fronts) or a 3-ch (fronts and center) and let the Onkyo handle the other channels.

The L890 has a pretty big impedance dip in the mid-bass, and a better amp will be able to handle that.

The Emotiva 3-ch:
http://emotiva.com/xpa3.shtm

Has what you need and will put a smile on your face. ;)

Thank you very much! I will investigate this model further.

rdgrimes
12-01-2009, 09:38 AM
I havent had any trouble with the Onkyo in regards to sound quality... But, when I turn the volume up to higher levels, the mid-ranged on the l890s do seem to have some trouble... (whether that is from the amp, or the physical speakers themselves I am unsure).

I have my speakers set up similarly to yours.
To some extent, you may be hearing some of the limitations of the L-series drivers and XO. Also look at your placement and room treatments to eliminate early reflections that might add to the "muddiness" in the mids.

Audiobeer
12-01-2009, 06:26 PM
I have the same speaker setuo across the front as you do. I have the onkyo 806 model. The speakers really shined when I used a seperate amp for the 890s. It wasn't a subtle change, It was dramatic!

Fawd
12-02-2009, 08:18 AM
I have the same speaker setuo across the front as you do. I have the onkyo 806 model. The speakers really shined when I used a seperate amp for the 890s. It wasn't a subtle change, It was dramatic!

Really?? Could you elaborate on the differences you experienced with an external amp? Which seperate amp are you using?

Thanks for the help everyone :)

timc
12-05-2009, 01:02 AM
You should also check out the Marantz MM-8003. This is a 8x140wpc, wich enables you to biamp the entire frontrow in a 5.1 setup.



-Tim

JBL 4645
12-05-2009, 03:41 PM
Before you get another amp, I think you should give them a try on you Onkyo.
They are rated at 90bd 1 watt at 1 meter, this normal for most HT speakers.
How big is your room? Now if your room is 30'X40' you might need a bigger amp.:blink:

No its worse…:D you also need bigger speakers as well!

I’ve been looking at some AVR amps for myself and I’m keep a lookout for ones that support RCA phones for audio outputs as some AVR receivers today are skipping on external outputs, for customized user set-up.

I was looking at
ONKYO TX-NR807 DolbyTrue dtsHD THX RCA 7.1 phone outputs 799.00
http://www.us.onkyo.com/model.cfm?class=Receiver&m=TX-NR807
ONKYO TX-SR707 DolbyTrue dtsHD THX RCA 7.1 phone outputs 599.00
http://www.us.onkyo.com/model.cfm?m=TX-SR707&class=Receiver&p=i
The price might be a bit high because its roughly $1500.00 a bit out of your budget range. But why rush! Save up a bit more and get a bit more entertainment for your money.

The difference is mostly (wattage) that you’re paying for. I’ll be using my own amps and the AVR Dolby/dts decoding, etc.
:happyh::tree:

lgvenable
12-05-2009, 09:44 PM
I stumbled into a great deal and acquired all of the older stereo amps and JBL Pro drivers from the Chicago Museum of Science and Industry; when they went IMAX.

All the amps are balanced audio, and I'll put this new 80.1 pre-amp against anything. I hear folks throwing around big $$ figures for amps, but careful shopping has netted me this mix:

stereo amps for each channel:
BGW 750D x 5
AB Systems 821's x 5
BGW 250D's x 4
AB Systems 713 mono-tri-amps x 5

All for like you stole them prices.
However great deals are available on eBay for AB International and AB Systems amps. The last two went for 140 (with shipping) and the Precedent 600A I just got for 169 (w/shipping).

These amps are all balanced audio (except the 600A which I'll retrofit to balanced audio); so used when driven full (gain set to max) they're dead quiet with the balanced audio inputs of the 80.1.

I got the 80.1 for well off list price from a shop in Texas, if anyone is interested PM me, and I'll give you his name. That was GREAT price as well, allowing me to have 450.00 more in my budget than I'd thought I'd have.Point is you can get great prices and electronics if you shop carefully. These AB Systems (or AB International) amps are built like tanks, are easy to get fixed; and don't have wave soldered guts >> which once they are fried are done.

Here's an amp I acquired last night for 129 + shipping at 275 wpc 8 ohm or 725 wpc mono bridged. $$129!!!! and in use they are great. I can understand why the museum used them for nearly 20 years.

amp link:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=160382261418&ssPageName=STRK:MEWNX:IT

specs:
http://www.abamps.com/productarchive.html#600a

The amps I've had to have fixed?? I found a sound engineer in the Evansville area who charges $125 to take out clean, or electrically match new power transistors; and restore each of the 5 amps needing work to perfect condition for chump change (125 each). I found him by asking the folks at the local Guitar Center who they used to fix amps locally. What a find! Great work at reasonable prices!

JBL 4645
12-06-2009, 04:13 AM
^^^^Oh, that’s nice buy all you need is several more of the same amp and you’re sorted. That is more or less like 75.00 pounds UK.

Yes it pays to shop around.:applaud:

lgvenable
12-06-2009, 09:16 PM
4645

That's 19 amps, enough for tri-amping every channel, given that five of the amps are mon-triamplifier's.


I'll admit I bought an AB International 600A amp, and a set of JBL Control 5's for the front high (or wide) Auddessey DSX channels; but dude; that's enough amps to have every driver pair have a separate amp, w/each of the stereo amps bridged.

I'm getting ready to build front channels to replace my L100T's with 2445J/2385A horns, 2404 J Baby Cheeks, and 2206H 12 woofers, each speaker bank driven by an AB 713 amp (250-150-150 at 8 ohms).

I guess I'm one of the lucky ones, as my wife puts up with my audio addiction; but I'll admit she does think I've stepped over a line with 19...err 20 amps now.
FYI...I had to add a 25KVA isolation transformer and 5 20 amp circuits to the wall where these are all in the process of being built into.

lgvenable
12-06-2009, 09:17 PM
double post edited away


sorry

gsxronax
01-20-2011, 11:02 PM
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