Topic: Pro-Audio Amps for HT/Home Stereo Use

[psychodreamer]

Do you use pro-audio amps such as this in your home set-ups?

http://www.bluearan.co.uk/menu/index.php?id=ALTMAC22

[av_phile1]

I think there has been a thread on professional gears for home use way back.  Anyway, I see no problem with professional gears for home use, especially if raw brute power is required for your listening levels.  They have a more heat resilient design incorporating individual cooling fans per channel.  Downside: fans can become noisy overtime.  But that is really not a problem when you listen at high volume levels for which such cooling fans serve their purpose well especially in open space or huge auditoriums requiring enormous amplification power.

Because they were designed for high volumes, they often employ the more efficient class B amplifier topology but can suffer severe crossover distortions that can be objetionably audible at low volumes.   But that is really not a problem in large concert hall spaces at high volumes.   

Most professional amps have high current capability that allows you to do bridging and using low impedance load down to 2 ohms.

There are professional gears with water-resistant enclosures meant for outdoors.  In general, they do have very robust and heavy built.  Often using rack-mountable front panels using thick heavy gauge alloys.  Many home systems like those from Bryston, Aragon and Dreadnaught inherited such tank-like builds from these professional amps. 

And for the most part, they're more affordably priced than many Hi-Fi gears for the home.  Often much lower than a similar Hi-Fi amp of the same power level or lower.

[mixx]

the pros : all the headroom you want
the cons : a humongous electric bill

tried using 2 QSC RMX 1850HD amps powering 3 JBL Soundfactor dual 15" cab(L,C,R), and powered JBL eons for the surrounds and another QSC RMX in bridged mode powering a JBL 18" sub, signals coming out of a marantz sr6300, all i can say is never try this at home

[psychodreamer]

haha... pang-auditorium na yang set-up mo Mixx.. 

So,  you used the 6300 only as a pre-amp?   

Sir Av, thanks for the detailed reply.. it made me do some reading as well.. I guess I'd have to stick to the more refined HT / indoor amps since I'd be using it often at low levels as well.

[mixx]

yup the marantz served as my preamp only

[joey]

before, i used my carvin dcm-1500 driving my front speaker that each speaker cabinet have a two 15' full range celestion speaker match with a jbl 4216 horn tweeter (not sure for the jbl driver). i find it very powerfull and it rocks my house. for now im using my carvin to power up my 24' 2000watts subwoofer for my living room ht. for me i find it no problem at all, in fact i kinda like my sub.

[psychodreamer]

I would guess that this crossover / phase distortion isn't much of an issue for subs?  I could be wrong.

[joey]

the pros : all the headroom you want
the cons : a humongous electric bill

tried using 2 QSC RMX 1850HD amps powering 3 JBL Soundfactor dual 15" cab(L,C,R), and powered JBL eons for the surrounds and another QSC RMX in bridged mode powering a JBL 18" sub, signals coming out of a marantz sr6300, all i can say is never try this at home

this is what ive been dreaming of for my future HT setup.

[av_phile1]

I would guess that this crossover / phase distortion isn't much of an issue for subs?  I could be wrong.

It's always nice to have the least distortion of any type when reproducting audio signals.  But yes, it's not as objectionable as with the higher freqeuncies.  Once you go down into bass frequencies, there are other factors to consider that eclipse crossover distortion.  In fact, harmonic distortions have a way of bloating the bass signals to make them sound more powerful than what the amp can deliver.   Some of the finest subs use class D amps for better crossover distrotion management.  And they can go into the 1500watts RMS with less heat and better power management than similar class A/B amps. 

[av_phile1]

the pros : all the headroom you want
the cons : a humongous electric bill

tried using 2 QSC RMX 1850HD amps powering 3 JBL Soundfactor dual 15" cab(L,C,R), and powered JBL eons for the surrounds and another QSC RMX in bridged mode powering a JBL 18" sub, signals coming out of a marantz sr6300, all i can say is never try this at home

You must have a very large HT room.     What SPLs are we looking at for your typical HT experience?

[hattori_hanzo]

I used a pro-audio ones for my HT and stereo....

my gears composed of:




2 units QSC MX700 120Wx2 8ohms (phased out already) to power my 4 units of BOSE 402
1 unit BOSE 402c system controller
Yamaha 995 used as preamp
Pioneer LD player (I forgot the model though)

One thing I noticed when im playing a particular program at certain high SPL, my LD players starts to skip, I query audiophile shop (where I bought the QSC MX amps) about this, they told me to install a dedicated power outlet for the pro-amp. the reason why the LD skips is the high current from the pro-amp is drawing so much power that it is giving that negative effects on the player. so to make the story short, if you dont want to see your electric bills soar high medyo think first before using this kind of gears to your home. besides, the fan noise really annoys me... 

 

[psychodreamer]

Not quite a sound choice economically, especially these times..

How about sonically,  is it up to par with the usual HT stuff?

[hattori_hanzo]

with power yes, but with fidelity not so much...

[mixx]

You must have a very large HT room.     What SPLs are we looking at for your typical HT experience?

the room is about 30sqm, regarding spl im not sure how far i got 


"One thing I noticed when im playing a particular program at certain high SPL, my LD players starts to skip"

basically there are 2 factors:
1. power as first noted by hattori_hanzo and .....
2. the lens skips because of the high spl caused by speakers mostly 1st gen cd/ld players doesnt have the memory buffer yet so they are more prone to skips, the high spl tends to jar the lens out of tracking, i remember the 1st gen of dj cd players by denon DN2000f they skip so much when we played at high volumes


BTW heres a pic of one of my amps

[dagul27]

Is there a thread already regarding pro amps? Kung meron na,paki delete na lang ito sir mods.here are some of the pro amps that i've read from other forums that are being used for HT and music.I don't have extensive knowledge with regards to technical data but i would like to post these specs so our amp gurus can shed some light whether they're really good for home use.They're cheaper kasi,hehehe.

1. Crown(XLS series XLS-202, XLS-402, XLS-602, and XLS-802)

Power Output (1 kHz*)
                    Stereo            Bridge-Mono
                8 Ohm  4 Ohm       8 Ohm
XLS 802 - 500W   800W        1600W
XLS 602 -380W    600W        1200W
XLS 402 - 300W   450W        900W
XLS 202 - 200W   300W        600W
*1 kHz Power: refers to maximum average power in watts at 1 kHz with 0.5% THD.

Performance
Sensitivity (volts RMS) for full rated power at 4 ohms: 1.25 V.

Frequency Response (at 1 watt) 22 Hz to 20 kHz: +0 dB, –0.8 dB.

Signal-to-Noise Ratio (20 Hz to 20 kHz)
A-weighted, below rated power:
>98 dB.
No weighting, below rated power:
>93 dB.

Total Harmonic Distortion (THD): <0.5%.

Intermodulation Distortion (IMD):
(60 Hz and 7 kHz at 4:1) from full rated output to –40 dB: < 0.3%.

Damping Factor (8 ohm) 10 Hz to 400 Hz: >200.

Crosstalk (below rated power)
at 1 kHz: –76 dB. at 20 kHz: –58 dB.

Input Impedance (nominal): 20 kilohms balanced, 10 kilohms unbalanced.

Load Impedance: Rated for 2 to 8 ohms per channel in Stereo, 4 to 8 ohms in Bridge Mono.

AC Line Voltage and Frequency Configurations Available (±10%): 120 VAC 60 Hz, 100 VAC 50/60 Hz, 220 VAC 50 Hz, and 230-240 VAC

Controls
Level: Two front-panel rotary level controls, one for each channel.

Power: Front-panel switch; on when in the IN position.

Circuit Breaker: Back-panel breaker provides overload protection.

Mode Switch: Back-panel switch selects Dual or Bridge-Mono mode.

Indicators
Signal Presence Indicators: Two green LEDs, one for each channel, illuminate when the channel’s input signal exceeds –40 dBu.

Clip Indicators: Two red LEDs, one for each channel, illuminate when the channel’s output is being overdriven.

Power Indicator: Blue LED indicates amplifier has been turned on and AC power is available.

Fault Indicator: Two red LEDs illuminate when amplifier is in protect mode. Also illuminates briefly during normal power-up when amplifier is first switched on.
                               
*Taken from Crown Audio website


2.QSC

RMX Power Amplifiers
                    Watts per channel
Model                8Ω               4Ω             2Ω               Bridged 4Ω*
RMX850             200             300            430                    830
RMX1450           280             450            700                   1400
RMX1850HD      360             600             900                   1800
RMX2450           500            750            1200                  2400
RMX4050HD       850         1400            2000                  4000
RMX5050          1100        1800            2500                  5000

1 kHz, 0.1% THD *1 kHz, 1% THD
Professional Power Amplifiers
RMX850 | RMX1450 | RMX1850HD | RMX2450 | RMX4050HD | RMX5050
Speakon is a trademark of Neutrik

Features
• Professional quality performance—incorporates road-proven QSC designs
• The 4000 watt RMX4050HD operates on a standard 15 amp plug (120V)
• Both the RMX4050HD and RMX5050 feature a dual mono, high current
power supply for increased reliability and performance
• The RMX1850HD and RMX4050HD provide improved thermal performance
yielding higher continuous power in 2 ohm stereo or 4 ohm bridged
applications (a RMX HD exclusive!)
• Compact size—up to 2400 watts in 2 rack spaces or 5000 watts in
3 rack spaces
• High-current toroidal transformers for greater 2 ohm power and low noise
• Independent user-defeatable clip limiters reduce distortion
• Selectable low frequency filters (30 Hz or 50 Hz) protect speakers and
increase headroom
• Balanced 1/4" (6.3 mm) TRS, XLR, and barrier strip inputs
• Touch-proof binding post and Neutrik Speakon® outputs
• Front mounted gain controls for easy access
• Signal and Clip LED indicators to monitor performance
• Independent DC and thermal overload protection on each channel
automatically protects amplifier and speakers
• 3 year warranty plus optional 3 year extended service contract

*Taken from QSC Website

...to be continued

[mixx]

so far sir ive experimented with  the qsc rmx 1850hds for home theater and they are great, the only downside is you would need an external processor and it requires a huge amount of electricity, if you would try to search their websites they have amps that is really meant for movie theaters but i think they are a bit pricey compared to the models you specified

[av_phile1]

The specs on the Crown amp are not the best I know I can find for professionals amps.  And because both brands specify their power at 1khz, expect the conmtinuous power to be about 30% less when measured at full bandwidth of 20hz to 20khz.   Also the THD level at which the power is measured is relatively high, so expect the power to do down at a more high-fidelity grade THD levels. 

The specs on the QSC are less detailed, but the features are exellent.  I might just go with the QSC if the specs are the same or better compared to the Crown.  Either way, get the most powerful you can afford.  IF configured as class AB, they shouldn't consume a lot if driven at comfortable home listening levels.  With more power, you have a lot more headroom at low volumes to start worrying about THDs. 

[ProtegeManiac]

They're cheaper kasi,hehehe.

just how cheap are these? last time I was in audiophile buying cables the cheapest Crowns that they have were just under 60K, and that's already at a discounted price.

[ATJr.]

The specs on the Crown amp are not the best I know I can find for professionals amps.  And because both brands specify their power at 1khz, expect the conmtinuous power to be about 30% less when measured at full bandwidth of 20hz to 20khz.   Also the THD level at which the power is measured is relatively high, so expect the power to do down at a more high-fidelity grade THD levels. 

this doesn't mean that you can not get a 20-20khz bandwidth, you can although not at full power.

The specs on the QSC are less detailed, but the features are exellent.  I might just go with the QSC if the specs are the same or better compared to the Crown.  Either way, get the most powerful you can afford.  IF configured as class AB, they shouldn't consume a lot if driven at comfortable home listening levels.  With more power, you have a lot more headroom at low volumes to start worrying about THDs. 

amps meant for pa can be used for the home setting, but expect a higher voltage gain, gains of x40 are typical, whereas hi-fi amps are generally in the order of x20.

[av_phile1]

this doesn't mean that you can not get a 20-20khz bandwidth, you can although not at full power.

Ofcourse, nothng in my statement implied such

[av_phile1]

Totally forgot about that SPEAKON speaker terminals in many professional gears.  If the amps don't have your usual speaker binding posts or terminal, make sure you get the right SpeakOn terminals for your cables (female or male).

[dagul27]

just how cheap are these? last time I was in audiophile buying cables the cheapest Crowns that they have were just under 60K, and that's already at a discounted price.

I went to a local guitar store here in our place(Chicago po),Guitar center and they have the Crown XLS 202 for $250.I then called another pro audio shop(Sam Ash) and they have the XLS 402 for $250.

[dagul27]

has anyone tried this with their pro amp?

 


CleanBOX: 2-way stereo convertor box
ARTcessories - a full line of clever, affordable processing tools for live sound, stage, and studio. The ARTcessories line is designed to deliver solutions for a number of audio needs - like having phantom power, having one or two more mixing channels, testing cables, headphone processing, preamplification for microphones and turntables, and many more real-world applications. With their affordable prices and simple design, the new line of ARTcessories will satisfy the needs of working musicians and sound engineers everywhere.

Problem: You have a stereo output from a CD player (tape deck, VCR, computer sound card or other consumer electronics gear) and you need to connect it to the balanced line inputs of your mixer (EQ or other piece of professional audio equipment). Actually, there are three problems: 1.) Your source has RCA connectors and you need to connect to an XLR input. 2.) Your source signal is unbalanced, but you require a balanced signal where you're plugging into. 3.) The signal levels have to be matched properly.

Solution: Use a CleanBOX! It's RCA-to-XLR channel 1 takes RCA signal, matches the signal levels and then provides a balanced (XLR) output.

Problem: You have the balanced stereo output of a mixer (an EQ or other piece
of pro audio gear) and need to connect it to the inputs of a cassette deck, computer sound card , VCR or another type of consumer electronics unit. The three problems above apply here as well (except your source is balanced, and you require an unbalanced audio signal).

Solution: Use a CleanBOX! Its XLR-to-RCA channel 2 takes a XLR balanced signal, matches the signal levels and then provides an unbalanced (RCA) output.

Problem: You want to mix your voice (and/or instrument) with a CD and record the mix on a cassette deck or computer. Now you need to interconnect three pieces of equipment; two consumer level and one balanced pro audio level (the mixer). You have to go from unbalanced RCA to balanced XLR and from balanced XLR back to unbalanced RCA.

Solution: Simply use both channels on your CleanBOX .

• Dual channels - RCA unbalanced-to-XLR balanced and XLR balanced-to-RCA unbalanced
• Dual female RCA inputs and outputs plus dual XLR female Ins & male Outs
• Dual level controls, one for each channel
• Maximum Output Level: +18dB BAL, +12dB unbalanced
• Maximum Input Level: +22dB balanced and unbalanced
• S/N Ratio: > 9 0 d B
• Input Gain: -8dB balanced/ +20dB unbalanced
• Power: 12V DC (Adapter Included)
• Dimensions: 4.625 x 5.625 x 1.75 inches (92mm x 142mm x 45mm)
• Weight: 1lb (450g)

[mixx]

mura talaga yung xls series ng crown, here in the philippines they sell for 15K for the lowest model @ audiophile, if you would go for the crown brand try getting the CE series medyo mas matibay sya compared sa xls, but personally i go for the qsc brand 

[ATJr.]

Ofcourse, nothng in my statement implied such

yup, sure just want to emphasize this point as you forgot to mention it.

[ATJr.]

The specs on the Crown amp are not the best I know I can find for professionals amps.  And because both brands specify their power at 1khz,

and this is because amps used for PA duties are not subject to FTC ruling of 1974 if i am not mistaken, therefore the 1Khz power spec, if these amps were required to quote 20-20khz specs, i am sure the power would have been lesser.

[dagul27]

mura talaga yung xls series ng crown, here in the philippines they sell for 15K for the lowest model @ audiophile, if you would go for the crown brand try getting the CE series medyo mas matibay sya compared sa xls, but personally i go for the qsc brand 

Yup,mura XLS kasi lumang model na ata.ang pinalit nila ay the XTi Series(1000,2000 and 4000).Sabi din sa akin nung isang salesman dito QSC daw ang kunin ko.Subukan ko lang together with the Cleanbox,pwede ko naman isauli w/in 30 days.

[ATJr.]

if you want QSC but not its price, you can try Kinetics amps sold by Phasetron, i understand that they are QSC clones judging from examination of its innards..

[av_phile1]

If you just want more power for your HT for a large room, professional amps are a great option.  Relatively inexpensive and often with excellent build quality and reliability for its price, many entry level pro amps no doubt can go the distance.  We can bicker about the finer qualities of consumer grade amps.  But when you come to think of it, when watching a movie, I really doubt S/N ratios, damping factor, interchannel separation and flat frequency response, to name some, matter as much as when listening to pure music.  Ofcourse the better figures should yield better qualities.  But the differences are not that great to matter at all.  HT has never really embraced audiophile grade sonics.  Only now with High Definition using lossless DolbyTrueHD and DTS-HD.  So unless you're planning to go HD within the next 6 months, most entry level pro amps should be adequate for power hungry HT installation.  Even then, there are pro amp models  that rival consumer grade amps spec for spec.  At a price no doubt. 

[dagul27]

Okidoks i'm off this weekend.My Canare 4S11 cables and banana plugs just arrived.I Will try out one of those pro amps that i've mentioned.Will post results of my weekend project.