Hey hows it going,
I am looking to power a single 12" Alpine Type R 4ohmDVC. I want to used a Class D amp, so I was wondering what you guys would reccomend to use? Anything other than the JBL BP300.1 because that is what I am using now and not really that happy with it. My price cap is about $400-450 CND. Would like to hear any suggestions though.
My other question is, how do you feel about purchasing stuff off ebay? I have found some amps I like there buy have never bought online before and kinda weary. Any tips/suggestions?
Thanks in advance,
JRM
Replies (9)
Munchiesyumm on 06/19/2004 21:11:20
If you're not happy with the JBL amp than you're not going to be anymore "happier" with another amp besides "looks wise" possibly..brbrYou didn't explain exsactly the problem you have with the JBL amp or what features you are looking for an amp. So I don't really know what to show you. Maybe you could give some more details. brbrPlease make sure to list all of the components you have used for you're system so we can help you better. Even the what car/year.brbrbrEbay is a good source to look for products but it can be risky being that not everyone is out there to hook you up with a deal more people or rather companies are more in it for the money than the service. You must watch out for these things. Never buy from anyone with a bad reputation. I have bought and sold many things through ebay and have not run into any big delimmas yet. Even found some deals that I could get no where else. Shopping on ebay takes research, time, and effort, it all depends on weather you have the patients or not to deal with it. brbrbr
/////ALPINE on 06/19/2004 21:36:45
What I meant by not being happy with my current amp is that when I have the gain settings etc all dialed in with no distortion my sub does not have the thump that I know it can produce. With it set for minimal distortion it doesnt sound much better than my last amp and sub configuration which was the old model 12" Alpine TypeS and Rockford Fosgate 201s amp.
Current set up I have:
HU - Kenwood KDC-2019 (I think)
Amp - JBL BP300.1
Sub - 12" Alpine SWR-1241D
1.15cuft sealed box
Also using an 8ga wiring kit
I have the sub wired in paralled (+ to +, - to - then to amp). I know that this sub can sound much better because a friend of mine has the same one hooked up to a PPI amp, not sure which model. It just seems like when it does give a decent amout of bass its all distorted and not very clean sounding so I have to turn the gain down. Also I am not using any bass boost off amp or my HU.
So thats why I am thinking of upgrading to a higher quality amp, one with higher RMS output. I've heard from people that this sub can take alot more than the rated 300w RMS.
/////ALPINE on 06/19/2004 21:43:47
Also features on the amp I want are things like a subsonic filter, may use a ported box in the future, and remote bass control.
swez on 06/19/2004 22:55:23
The sub can take short bursts of higher power as will most better sub brands.
The JBL BP-300.1 will also put out more than 300 RMS at 1 & 2 ohm loads. It is rated for 300 RMS @ 2 ohms with a 12.9 volt voltage supply. If the amp gets a higher voltage supply... (say...13.5 -14.0 volts) the output will be higher than 300 RMS. (more like 350 + watts RMS) This is commonly referred to as an "underrated amp". (better than specs indicate)
===================================================
That HU is a correct product #. Just an older model, not carried anymore by many e-tailers. Crutchfield used to carry them.
http://www.crutchfield.com/S-HJpT9gBByvX/cgi-bin/ProdView.asp?i=113KDC2019&s=0
Specs: Kenwood KDC-2019
General Information:
Chassis Size Code IEJ
RMS Power Output 22 watts x 4 @ 4 ohms
Peak Output 50 watts
RMS Power Bandwidth 30-20kHz
Preamp Voltage 1.8 volts (See notes)
Video Control No
Preamp Outputs 2 pair (See notes)
Sub Preamp Outputs No
AUX Input No
Display Color White/Blue
Key Button Color Green/Blue
EQ Bands 3
Sound Shaping Type System Q
Wireless Remote Yes
Wired Remote No
Changer Control Yes
Security Detachable face
Tuner:
Tuner Type CR-2
FM Sensitivity 9.3 dBf
FM Presets 18
AM Presets 6
European Tuning Yes
Seek/Scan Seek
Radio Data System No
Satellite Radio Ready No
CD Specs:
CD Frequency Response 10-20kHz
CD Signal-to-Noise 96 dB
Anti-shock Memory None
CD Text No
CD-R Playback Yes
CD-RW Playback Yes
MP3 Playback No
WMA Playback ---
DVD Playback No
NOTES:
This HU has 4 RCA ouputs. Front L&R; Rear L&R, no sub outs
The voltage rating is 1.8 volts (at ~70% HU volume settings)
===================================================
To get the most clean output from your JBL, try using all 4 RCA outs from HU to input side of the amp. You'll get more input signal this way and the amp will deliver more clean power. Set your gain between 1.5 - 2.0 volts initially and see how that all works out.
Finally, not sure why this series performs better with all 4 inputs getting signals... but most everyone I have talked with that had a BP series amp, all said the same thing... "This amp is great when all 4 input RCA's are used". Try it and see what your finding are.
Comments: I believe this amp series takes the sum of all 4 RCA inputs, then integrates them into a single AC voltage (mono) which is much higher than just using 1 or 2 RCA inputs can usually deliver. In this case, 1.8 volts (x 4) out of each RCA preout, is integrated to a signal closer to 4.0 volts. (perhaps higher) Hense, more output from amp with less distortion and the gain number is variable to best output audio level and low distortion levels.
Worst case, can use rear speaker signals, connected to high signal (speaker input harness) and see if that improves your performance. The speaker level voltage is much higher than 1.8 preamp volts. (More like 9.38 volts AC x 4 channels at 4 ohms)
===================================================
The math:
P (watts) = I (current) x E (voltage)
P = 22 watts x 4 @ 4 ohms
I = Sq root (P/R) ... Sqrt (22/4) = sqrt of 5.5 = 2.35 amperes
E = Sq root (PxR) ... Sqrt (22 x 4) = sqrt of 88 = 9.38 volts
Using Ohm's Law, we have now determined the output voltage of the HU to each speaker. That Voltage is 9.38 volts @ a full 22 watts RMS. That translates to ~37.42 volts/4, coming out of the HU @ ~70% power. This is at a 4 ohm load.
The Amplifier input impedance may be much higher than 4 ohms however. So the actual voltage that gets past the preamp inputs will be somewhat lower. Sorry for the long post... but I really wanted to disect this one so we all can make sense of why the amp is not working as well as it can.
Does that help or confuse the issue?
Swez
PS "Don't throw the baby out with the dirty bath water". The baby is still fine... just get rid of the old bath water. The HU is the weaker link in this scenario. However, using all 4 RCA preouts to feed the JBL amp inputs... should make a big difference in overall performance. Why??? More RCA level input voltage to drive amp to full potential.
All depends on how we wire things up. This amp should be very able to drive that sub to full output with minimal distortion. It's all on how we hook things up.
http://www.crutchfield.com/S-HJpT9gBByvX/cgi-bin/ProdView.asp?a=&s=0&cc=01&g=300&id=features_and_specs&i=113KDC2019
/////ALPINE on 06/20/2004 00:23:52
Swez,
Just a question about using all 4 RCA inputs or outputs. Right now I only have my RCA cables connected from my rear outputs on my HU to the amp. On the amp there is inputs for front and rear and the place where I bought this amp told me that I would need to use "y-connectors" to use both inputs. So I have my "Right rear" output going into both the right input for the front and rear on the amp, and vice versa for the left.
So my question is do you mean running two sets of RCA cables from my HU to the amp or connect just the rear outputs from my HU to both the front and rear inputs on the amp using "y-connectors" like I am now.
I hope my explaination on the y-connectors makes sence. If not I can try and explain it better for you.
Thanks for the help, I want to keep using this amp but I just want to get the most out of this sub that I can.
Munchiesyumm on 06/20/2004 03:40:10
wow. swez !
Great explaination.
To anwser your question YES you want to run as many RCA sets as it is possible!
Good luck I hope u get it working like it should be! It takes time to get you're system tuned perfectly but keep ur head up you have a very nice system!
/////ALPINE on 06/20/2004 13:58:57
So what you are saying is that the guy who sold me those y-connectors was just trying to make an extra $25 bucks off me then?
Tomorrow I'll pick some RCA's up, then I'll let you know how it turns out.
Thanks for the help,
Munchiesyumm on 06/20/2004 15:07:55
It depends..
What store.. If it's a chain audio store than yes.
Especially places like Good guys, Circut city, Best buy
It could been that he just didn't know.
/////ALPINE on 06/20/2004 17:29:09
No this was a privately owned store. All he sold was JBL, Infinity and Crossfire equipment. He seems very knowledgeable about JBL I went in there a few times before I bought anything and we always ending up talking about his stuff he sold for a long time.
Meh a well, it was only 25 dollars.
I am looking to power a single 12" Alpine Type R 4ohmDVC. I want to used a Class D amp, so I was wondering what you guys would reccomend to use? Anything other than the JBL BP300.1 because that is what I am using now and not really that happy with it. My price cap is about $400-450 CND. Would like to hear any suggestions though.
My other question is, how do you feel about purchasing stuff off ebay? I have found some amps I like there buy have never bought online before and kinda weary. Any tips/suggestions?
Thanks in advance,
JRM
Replies (9)
Munchiesyumm on 06/19/2004 21:11:20
If you're not happy with the JBL amp than you're not going to be anymore "happier" with another amp besides "looks wise" possibly..brbrYou didn't explain exsactly the problem you have with the JBL amp or what features you are looking for an amp. So I don't really know what to show you. Maybe you could give some more details. brbrPlease make sure to list all of the components you have used for you're system so we can help you better. Even the what car/year.brbrbrEbay is a good source to look for products but it can be risky being that not everyone is out there to hook you up with a deal more people or rather companies are more in it for the money than the service. You must watch out for these things. Never buy from anyone with a bad reputation. I have bought and sold many things through ebay and have not run into any big delimmas yet. Even found some deals that I could get no where else. Shopping on ebay takes research, time, and effort, it all depends on weather you have the patients or not to deal with it. brbrbr
/////ALPINE on 06/19/2004 21:36:45
What I meant by not being happy with my current amp is that when I have the gain settings etc all dialed in with no distortion my sub does not have the thump that I know it can produce. With it set for minimal distortion it doesnt sound much better than my last amp and sub configuration which was the old model 12" Alpine TypeS and Rockford Fosgate 201s amp.
Current set up I have:
HU - Kenwood KDC-2019 (I think)
Amp - JBL BP300.1
Sub - 12" Alpine SWR-1241D
1.15cuft sealed box
Also using an 8ga wiring kit
I have the sub wired in paralled (+ to +, - to - then to amp). I know that this sub can sound much better because a friend of mine has the same one hooked up to a PPI amp, not sure which model. It just seems like when it does give a decent amout of bass its all distorted and not very clean sounding so I have to turn the gain down. Also I am not using any bass boost off amp or my HU.
So thats why I am thinking of upgrading to a higher quality amp, one with higher RMS output. I've heard from people that this sub can take alot more than the rated 300w RMS.
/////ALPINE on 06/19/2004 21:43:47
Also features on the amp I want are things like a subsonic filter, may use a ported box in the future, and remote bass control.
swez on 06/19/2004 22:55:23
The sub can take short bursts of higher power as will most better sub brands.
The JBL BP-300.1 will also put out more than 300 RMS at 1 & 2 ohm loads. It is rated for 300 RMS @ 2 ohms with a 12.9 volt voltage supply. If the amp gets a higher voltage supply... (say...13.5 -14.0 volts) the output will be higher than 300 RMS. (more like 350 + watts RMS) This is commonly referred to as an "underrated amp". (better than specs indicate)
===================================================
That HU is a correct product #. Just an older model, not carried anymore by many e-tailers. Crutchfield used to carry them.
http://www.crutchfield.com/S-HJpT9gBByvX/cgi-bin/ProdView.asp?i=113KDC2019&s=0
Specs: Kenwood KDC-2019
General Information:
Chassis Size Code IEJ
RMS Power Output 22 watts x 4 @ 4 ohms
Peak Output 50 watts
RMS Power Bandwidth 30-20kHz
Preamp Voltage 1.8 volts (See notes)
Video Control No
Preamp Outputs 2 pair (See notes)
Sub Preamp Outputs No
AUX Input No
Display Color White/Blue
Key Button Color Green/Blue
EQ Bands 3
Sound Shaping Type System Q
Wireless Remote Yes
Wired Remote No
Changer Control Yes
Security Detachable face
Tuner:
Tuner Type CR-2
FM Sensitivity 9.3 dBf
FM Presets 18
AM Presets 6
European Tuning Yes
Seek/Scan Seek
Radio Data System No
Satellite Radio Ready No
CD Specs:
CD Frequency Response 10-20kHz
CD Signal-to-Noise 96 dB
Anti-shock Memory None
CD Text No
CD-R Playback Yes
CD-RW Playback Yes
MP3 Playback No
WMA Playback ---
DVD Playback No
NOTES:
This HU has 4 RCA ouputs. Front L&R; Rear L&R, no sub outs
The voltage rating is 1.8 volts (at ~70% HU volume settings)
===================================================
To get the most clean output from your JBL, try using all 4 RCA outs from HU to input side of the amp. You'll get more input signal this way and the amp will deliver more clean power. Set your gain between 1.5 - 2.0 volts initially and see how that all works out.
Finally, not sure why this series performs better with all 4 inputs getting signals... but most everyone I have talked with that had a BP series amp, all said the same thing... "This amp is great when all 4 input RCA's are used". Try it and see what your finding are.
Comments: I believe this amp series takes the sum of all 4 RCA inputs, then integrates them into a single AC voltage (mono) which is much higher than just using 1 or 2 RCA inputs can usually deliver. In this case, 1.8 volts (x 4) out of each RCA preout, is integrated to a signal closer to 4.0 volts. (perhaps higher) Hense, more output from amp with less distortion and the gain number is variable to best output audio level and low distortion levels.
Worst case, can use rear speaker signals, connected to high signal (speaker input harness) and see if that improves your performance. The speaker level voltage is much higher than 1.8 preamp volts. (More like 9.38 volts AC x 4 channels at 4 ohms)
===================================================
The math:
P (watts) = I (current) x E (voltage)
P = 22 watts x 4 @ 4 ohms
I = Sq root (P/R) ... Sqrt (22/4) = sqrt of 5.5 = 2.35 amperes
E = Sq root (PxR) ... Sqrt (22 x 4) = sqrt of 88 = 9.38 volts
Using Ohm's Law, we have now determined the output voltage of the HU to each speaker. That Voltage is 9.38 volts @ a full 22 watts RMS. That translates to ~37.42 volts/4, coming out of the HU @ ~70% power. This is at a 4 ohm load.
The Amplifier input impedance may be much higher than 4 ohms however. So the actual voltage that gets past the preamp inputs will be somewhat lower. Sorry for the long post... but I really wanted to disect this one so we all can make sense of why the amp is not working as well as it can.
Does that help or confuse the issue?
Swez
PS "Don't throw the baby out with the dirty bath water". The baby is still fine... just get rid of the old bath water. The HU is the weaker link in this scenario. However, using all 4 RCA preouts to feed the JBL amp inputs... should make a big difference in overall performance. Why??? More RCA level input voltage to drive amp to full potential.
All depends on how we wire things up. This amp should be very able to drive that sub to full output with minimal distortion. It's all on how we hook things up.
http://www.crutchfield.com/S-HJpT9gBByvX/cgi-bin/ProdView.asp?a=&s=0&cc=01&g=300&id=features_and_specs&i=113KDC2019
/////ALPINE on 06/20/2004 00:23:52
Swez,
Just a question about using all 4 RCA inputs or outputs. Right now I only have my RCA cables connected from my rear outputs on my HU to the amp. On the amp there is inputs for front and rear and the place where I bought this amp told me that I would need to use "y-connectors" to use both inputs. So I have my "Right rear" output going into both the right input for the front and rear on the amp, and vice versa for the left.
So my question is do you mean running two sets of RCA cables from my HU to the amp or connect just the rear outputs from my HU to both the front and rear inputs on the amp using "y-connectors" like I am now.
I hope my explaination on the y-connectors makes sence. If not I can try and explain it better for you.
Thanks for the help, I want to keep using this amp but I just want to get the most out of this sub that I can.
Munchiesyumm on 06/20/2004 03:40:10
wow. swez !
Great explaination.
To anwser your question YES you want to run as many RCA sets as it is possible!
Good luck I hope u get it working like it should be! It takes time to get you're system tuned perfectly but keep ur head up you have a very nice system!
/////ALPINE on 06/20/2004 13:58:57
So what you are saying is that the guy who sold me those y-connectors was just trying to make an extra $25 bucks off me then?
Tomorrow I'll pick some RCA's up, then I'll let you know how it turns out.
Thanks for the help,
Munchiesyumm on 06/20/2004 15:07:55
It depends..
What store.. If it's a chain audio store than yes.
Especially places like Good guys, Circut city, Best buy
It could been that he just didn't know.
/////ALPINE on 06/20/2004 17:29:09
No this was a privately owned store. All he sold was JBL, Infinity and Crossfire equipment. He seems very knowledgeable about JBL I went in there a few times before I bought anything and we always ending up talking about his stuff he sold for a long time.
Meh a well, it was only 25 dollars.
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