I'm currently thinking about changing my amplifier setup and want some opinions on some amps.brbrI'm looking at the JBL Powervalve 300.1 or maybe the US acoustics USX 600 D.brbrI'm running US acoustics 4065 for highs and would like to use it's outboard sub x-over since neither of the above have a 24db slope.brbrThe JBL is 1 ohm stable but, does it gain any power at that load?brbrIs either mono amp's x-over defeatable?brbrThe 600 D has only a 20 amp fuse, but claims more power output @ 2ohms than the JBL (rating at US.... website). However, in the past all I ever heard about on the site is JBL. Which one has true power specs? Which is cleaner?brbrPlease don't try and talk me into all that big power amp stuff. I'm way past those days. Just good SQ for me now, so give me the real deal on these amps.
Replies (12)
asplundher on 03/5/2004 18:35:03
Sorry! I separated all the questions but, when I edited something later, it all jumbled up.
swez on 03/5/2004 19:40:04
I see your point and have taken the same approach. I now have a USX-4065 and a JBL 2 channel that develops 300 RMS when bridged MONO to a 4 ohm load. (2 x 20A., fuses here) My goal is above average SQ and some degree of SPL. My target is a clean, pure, realistic mix of SQ and ~120dB of clean SPL. Plenty for me.
The JBL MONOVALVE series is 1 or 2 ohm stable. There is no power output differential between 1 or 2 ohms... just capability. Its Class D mode operation nets very efficient use of power VS power to drive the subs. Last time I calculated that, was very close top 90% efficient. Ie: 100 watts consumed, nets almost 90 watts output. The only drawback, class D will not do well above 500 Hz. Not bad huh?
Compare that to a classic 2/4 channel Class A/B amp. These are cleaner and more suited for high frequency reproduction. The are not as efficient as Class D models, but do the mid/highs well. The efficiency rating of most typical Class A/B amps is/are between 50-60%. That's not a big problem in modest 2/4 channel amps as far as power consumption goes... only when using larger 2 channel amps for subs, does the power efficiency come into the game. (500 RMS and higher)
NOTE: Amp efficiencies vary from one maker to another. Different designs and component choices play a part in this. Some amps just loaf along very nicely at rated power and stay cool. Some amps really puff hard at rated output and may generate a fair amount of heat. Indication of how close to the limits the amp design is to internal components. A cooler running amp is working less hard and will usually last longer than a hot running amp. ELECTRONIC DEVICE HATE HEAT !!!
The last major aspect to the system are the speakers. This is the soul of any good system. Here, the old addage... ya get what ya paid for is generally most notable. Efficiency ratings on drivers can be very deceptive by design. Some speakers tout a 92% efficiency rating, while others may be in the low 80's. Which is better? Without a frequency plot at 1 watt/1 meter over a wide range of usable frequencies, the numbers are meaningless, if not outright deceptive.
Better speaker makers have these LEAP plots on their web sites. The ones who don't want you to know them, do not. There's usually a good reason not as well.
Swez
asplundher on 03/5/2004 20:52:02
So is the 600D any good? Both of them seem to have similar ratings into 2ohms but, the 600 D consumes less, right?
I'd rather have less power consumption.
Another option I have is an older Punch 150/Cadence 245 I have laying around, but if I ever want to add 2 subs , they gotta be 8ohms. And you know hard it is to find budget 8ohm subs. For now I'm running a 4ohm 200rms sub with a twin spare.
swez on 03/5/2004 22:28:21
Both amps are rated at 300 RMS @ 2 ohms. The USX-600D has 200 RMS @ 4 ohms while the JBL BP300.1 is 150 RMS @ 4 ohms.
I like the USB phase feature and other goodies included as well. It is rated at 12.9 volts as is the JBL, so a tad more power is available at 13.5 volts input or higher.
The JBL has a few less features, but is well built and very rugged too. It has 2 x 20A. fuses and max current draw is 29A. It too is rated at 12.9 volts input power.
Looks like the USB uses a higher level power supply for efficiency design as it only draws under 20A. at full power. If you are concerned about current draw, this is a good choice. It may run a bit hotter than the JBL at high output levels... but in most cases, that would probably be marginal.
Flip a coin!
Swez
asplundher on 03/6/2004 09:03:38
After some research, I have come to the conclusion that some engineers often lack common sense.
If you run a 4 channel US acoustics amp, then it is almost impossible to run their class D amp with it. The sub x-over on the 600 D is non defeatable. If you try to feed it a full range signal from the 4 channel, then one of the highs will have to be crossed over too low to apply full power. If the low pass crossovers on both amps are used then you will have to play around with settings to match each other and you will end up with a 36db slope! Overly Steep!
Doesn't that make having the x-over on the pass thru rca's redundant unless you use another sub amp with a defeatable x-over or no x-over at all?
So what did they intend the 600 D to be used with; only their 2 channel amps or some other brand's? You would figure they would make their whole line be able to work with each other.
Now I'm dissapointed! I guess I will have to work with some of the older amps I already have.
swez on 03/6/2004 10:24:25
From what I see on the pre-outs, they can be set to employ HP, LP, Flat or full range to the next amp in the chain.
QUOTE:
"Preamp Outputs: The preamp output jacks provide a convenient source for daisy-chaining an additional amplifier without running an extra set of RCA cables from the front of the vehicle to the amplifier location. The position of the selector switch determines the type of signals sent through the RCA line outputs. It may be set to "low", "1+2" or "3+4". When set to "low", the low-pass frequency control sets the low-pass crossover frequency for the line outputs. Setting the switch to "1+2" allows you to set the line output high-pass frequency with the channel 1+2 high-pass frequency control. Selecting "3+4" allows you to set the line output high-pass frequency with the channel 3+4 high-pass frequency control. Either high-pass selector may be set to "flat" for full-range output. "
Setting the rear channel to HP, full range may be the most usable feature here. Using the LP feature will just be a redundant filter that only sends designated bands of signal (LP) to the next amp input.
I am sure the engineering teams thought about this part of integration between full range and sub amp models. A quick e-mail or call to Tech Service at US-Acoustics will give you the recommended configurations.
Swez
asplundher on 03/6/2004 10:41:29
The only problem with that though is that I'm running 5 1/4's off the rear as well. If you set the rear or front to send a full range signal then that is what the speakers running off that channel will see as well.
Plus I wanted to use the 24db slope instead of the 12 on the 600D.
I just can't see any other way around it, unless a different sub amp is used. The JBL is the same (nondefeatable). How do you beat that situation? I really wouldn't mind trying one these amps.
asplundher on 03/6/2004 10:47:21
The only other scenario that it could be used as a subsonic filter if the rears could handle down to 30hz or so. LOL! That would work though but, not in my application. I did however purchase a 2080 with it which will fit the application but, it was intended for my girl's car. I'd hate to have to take it from her. Might not have a choice. It might get ugly!br
swez on 03/6/2004 13:46:14
You can always add bass blockers to the 5/4" right off the amp outputs. These are -6dB slopes, but more than adequate for most car installs.
Also, why do you think you need a -24dB slope LP filter slope to subs? A -12dB is generally a smoother transition between mids and subs. However, if you really want that slope, an inline xover will give you that at additional costs.
If you really desire active filtering of a high level 3rd, 4th order active filtering, can run an active crossover with built in sub filtering as well between HU and amps. This crossover may also have SS filtering and a line level preamp booster to improve S/N ratios. This way, you get all the filtering contro desireed in one package.
This one makes sense:
http://www.audiocontrol.com/MobileAudio/Products/
Crossovers/3XS.html
Similar devices out there, will do the same functions at a lower cost. The brand name is not the issue... fuction and performance are.
Swez
asplundher on 03/6/2004 20:00:27
Not that I really need the 24db slope but, I do like having better control and it sounds cleaner to me too.
Besides that, I also wanted to simplify my total setup with the pass-thru's. I have dual rca's on my HU and don't want to run a separate x-over. I think I'll just settle for one of the amps I already have. The Punch 150 is powerful enough with a low current draw. Just will have to find some 8 or 2 ohm subs later.
Thanks anyway!
swez on 03/6/2004 21:02:40
DVC 4+4 will get you a net 4 ohm load when using a pair. Simply wire sub A VC's on series (8 ohms)... same for sub B, then wire both subs in parallel for a 4 ohm net load.
Hard to find 8 or 2 ohm subs, SVC style. MTX has some 8 ohms and many home stereo subs are 8 ohms too... but T/S parameters usually call for larger enclosures.
Have a look at: www.partsexpress.com for raw 8 ohm drivers. They have a wide selection in power, performance and price.
Good luck,
Swez
asplundher on 03/21/2004 08:48:20
I have e-mailed the company and are waiting to see what their suggestions are for running both 4065 and class D amps.
I'll keep you posted.
Replies (12)
asplundher on 03/5/2004 18:35:03
Sorry! I separated all the questions but, when I edited something later, it all jumbled up.
swez on 03/5/2004 19:40:04
I see your point and have taken the same approach. I now have a USX-4065 and a JBL 2 channel that develops 300 RMS when bridged MONO to a 4 ohm load. (2 x 20A., fuses here) My goal is above average SQ and some degree of SPL. My target is a clean, pure, realistic mix of SQ and ~120dB of clean SPL. Plenty for me.
The JBL MONOVALVE series is 1 or 2 ohm stable. There is no power output differential between 1 or 2 ohms... just capability. Its Class D mode operation nets very efficient use of power VS power to drive the subs. Last time I calculated that, was very close top 90% efficient. Ie: 100 watts consumed, nets almost 90 watts output. The only drawback, class D will not do well above 500 Hz. Not bad huh?
Compare that to a classic 2/4 channel Class A/B amp. These are cleaner and more suited for high frequency reproduction. The are not as efficient as Class D models, but do the mid/highs well. The efficiency rating of most typical Class A/B amps is/are between 50-60%. That's not a big problem in modest 2/4 channel amps as far as power consumption goes... only when using larger 2 channel amps for subs, does the power efficiency come into the game. (500 RMS and higher)
NOTE: Amp efficiencies vary from one maker to another. Different designs and component choices play a part in this. Some amps just loaf along very nicely at rated power and stay cool. Some amps really puff hard at rated output and may generate a fair amount of heat. Indication of how close to the limits the amp design is to internal components. A cooler running amp is working less hard and will usually last longer than a hot running amp. ELECTRONIC DEVICE HATE HEAT !!!
The last major aspect to the system are the speakers. This is the soul of any good system. Here, the old addage... ya get what ya paid for is generally most notable. Efficiency ratings on drivers can be very deceptive by design. Some speakers tout a 92% efficiency rating, while others may be in the low 80's. Which is better? Without a frequency plot at 1 watt/1 meter over a wide range of usable frequencies, the numbers are meaningless, if not outright deceptive.
Better speaker makers have these LEAP plots on their web sites. The ones who don't want you to know them, do not. There's usually a good reason not as well.
Swez
asplundher on 03/5/2004 20:52:02
So is the 600D any good? Both of them seem to have similar ratings into 2ohms but, the 600 D consumes less, right?
I'd rather have less power consumption.
Another option I have is an older Punch 150/Cadence 245 I have laying around, but if I ever want to add 2 subs , they gotta be 8ohms. And you know hard it is to find budget 8ohm subs. For now I'm running a 4ohm 200rms sub with a twin spare.
swez on 03/5/2004 22:28:21
Both amps are rated at 300 RMS @ 2 ohms. The USX-600D has 200 RMS @ 4 ohms while the JBL BP300.1 is 150 RMS @ 4 ohms.
I like the USB phase feature and other goodies included as well. It is rated at 12.9 volts as is the JBL, so a tad more power is available at 13.5 volts input or higher.
The JBL has a few less features, but is well built and very rugged too. It has 2 x 20A. fuses and max current draw is 29A. It too is rated at 12.9 volts input power.
Looks like the USB uses a higher level power supply for efficiency design as it only draws under 20A. at full power. If you are concerned about current draw, this is a good choice. It may run a bit hotter than the JBL at high output levels... but in most cases, that would probably be marginal.
Flip a coin!
Swez
asplundher on 03/6/2004 09:03:38
After some research, I have come to the conclusion that some engineers often lack common sense.
If you run a 4 channel US acoustics amp, then it is almost impossible to run their class D amp with it. The sub x-over on the 600 D is non defeatable. If you try to feed it a full range signal from the 4 channel, then one of the highs will have to be crossed over too low to apply full power. If the low pass crossovers on both amps are used then you will have to play around with settings to match each other and you will end up with a 36db slope! Overly Steep!
Doesn't that make having the x-over on the pass thru rca's redundant unless you use another sub amp with a defeatable x-over or no x-over at all?
So what did they intend the 600 D to be used with; only their 2 channel amps or some other brand's? You would figure they would make their whole line be able to work with each other.
Now I'm dissapointed! I guess I will have to work with some of the older amps I already have.
swez on 03/6/2004 10:24:25
From what I see on the pre-outs, they can be set to employ HP, LP, Flat or full range to the next amp in the chain.
QUOTE:
"Preamp Outputs: The preamp output jacks provide a convenient source for daisy-chaining an additional amplifier without running an extra set of RCA cables from the front of the vehicle to the amplifier location. The position of the selector switch determines the type of signals sent through the RCA line outputs. It may be set to "low", "1+2" or "3+4". When set to "low", the low-pass frequency control sets the low-pass crossover frequency for the line outputs. Setting the switch to "1+2" allows you to set the line output high-pass frequency with the channel 1+2 high-pass frequency control. Selecting "3+4" allows you to set the line output high-pass frequency with the channel 3+4 high-pass frequency control. Either high-pass selector may be set to "flat" for full-range output. "
Setting the rear channel to HP, full range may be the most usable feature here. Using the LP feature will just be a redundant filter that only sends designated bands of signal (LP) to the next amp input.
I am sure the engineering teams thought about this part of integration between full range and sub amp models. A quick e-mail or call to Tech Service at US-Acoustics will give you the recommended configurations.
Swez
asplundher on 03/6/2004 10:41:29
The only problem with that though is that I'm running 5 1/4's off the rear as well. If you set the rear or front to send a full range signal then that is what the speakers running off that channel will see as well.
Plus I wanted to use the 24db slope instead of the 12 on the 600D.
I just can't see any other way around it, unless a different sub amp is used. The JBL is the same (nondefeatable). How do you beat that situation? I really wouldn't mind trying one these amps.
asplundher on 03/6/2004 10:47:21
The only other scenario that it could be used as a subsonic filter if the rears could handle down to 30hz or so. LOL! That would work though but, not in my application. I did however purchase a 2080 with it which will fit the application but, it was intended for my girl's car. I'd hate to have to take it from her. Might not have a choice. It might get ugly!br
swez on 03/6/2004 13:46:14
You can always add bass blockers to the 5/4" right off the amp outputs. These are -6dB slopes, but more than adequate for most car installs.
Also, why do you think you need a -24dB slope LP filter slope to subs? A -12dB is generally a smoother transition between mids and subs. However, if you really want that slope, an inline xover will give you that at additional costs.
If you really desire active filtering of a high level 3rd, 4th order active filtering, can run an active crossover with built in sub filtering as well between HU and amps. This crossover may also have SS filtering and a line level preamp booster to improve S/N ratios. This way, you get all the filtering contro desireed in one package.
This one makes sense:
http://www.audiocontrol.com/MobileAudio/Products/
Crossovers/3XS.html
Similar devices out there, will do the same functions at a lower cost. The brand name is not the issue... fuction and performance are.
Swez
asplundher on 03/6/2004 20:00:27
Not that I really need the 24db slope but, I do like having better control and it sounds cleaner to me too.
Besides that, I also wanted to simplify my total setup with the pass-thru's. I have dual rca's on my HU and don't want to run a separate x-over. I think I'll just settle for one of the amps I already have. The Punch 150 is powerful enough with a low current draw. Just will have to find some 8 or 2 ohm subs later.
Thanks anyway!
swez on 03/6/2004 21:02:40
DVC 4+4 will get you a net 4 ohm load when using a pair. Simply wire sub A VC's on series (8 ohms)... same for sub B, then wire both subs in parallel for a 4 ohm net load.
Hard to find 8 or 2 ohm subs, SVC style. MTX has some 8 ohms and many home stereo subs are 8 ohms too... but T/S parameters usually call for larger enclosures.
Have a look at: www.partsexpress.com for raw 8 ohm drivers. They have a wide selection in power, performance and price.
Good luck,
Swez
asplundher on 03/21/2004 08:48:20
I have e-mailed the company and are waiting to see what their suggestions are for running both 4065 and class D amps.
I'll keep you posted.
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