Ok, guys.. jump onto this...
this is what my friend got to me yesterday... got it installed at some local dealer... did'nt bother to take any advice..which i would have given for free and done the install at a no profit no loss basis... but he decided to let someone else earn and got a mess... anyways.. now he comes to me for free advice and trouble shooting...
the low freq starts cutting at 70% volume.. cuts and starts automatically for a while.. then completely goes off.. then when the volume knob is turned down a tad bit, it starts automatically..
these are the details i collected
2 years old suzuki esteem 70 amps alt - 700cca battery
Pioneer DEH- 6050 from his previous car, not in too good a shape..
Kenwood 5023 - 50x2 @ 4 ohms, powering rear speakers
JBL CS - 300.1 300 x 1 @ 2ohms, refurb
pioneer 6 x 9's 6972 in the rear, retained from old car
kenwood 4" KFC 1051s powered by HU
Soundstream sub XW-12 - 4ohm dvc 300wrms in 1.5 cuft sealed enclosure
all amp wiring 8 gauge - speaker wires 16gauge, sub wires 12 gauge
I re-set the gains proper, using a digital multimeter..
ground check - ok
bass boost 0 - lpf 80Hz on sub amp
HU lpf - 100Hz .... hpf - 50 Hz .... eq - flat ... sub-lvl -0 .... bass 0, treble 0 .....
wire integrity - ok
yet bass cuts at the same levels....
1- HU
2- Amp
3- improper connections in the sub vc .may be they get disconnected with over excursion and then with lower volumes come in signal contact again....
either or all of the 3 are culprits...
also the quality of bass is yuck... and no real thump too, just muddy sloppy bass....
i am not gonna entertain this guy anymore... if he gets convinced on an entire new package, then i'd do it.. orelse dont wanna get my hands dirty..
whats your take on this ???
Victor...
Replies (9)
swez on 10/15/2008 22:39:59
Is there a good reason why this "friend" chose to go elsewhere for the install?
I'd check the voltage at the amp's input side as he cranks up the bass and see how much of a drop in voltage is present. As voltage drops, the amp will act as mentioned.
Also, have a quick peek at the internal sub wiring inside the box to make sure all wiring is secure.
Dave
PS Even though this amp is a refurb, if it was not tested completely after the repairs, it may still have lingering problems.
Victor on 10/16/2008 00:20:31
Of what I can think of.. this friend thinks that if he had approached me he would have been obligated to buy from me and also would not have been able to bargain as much as he wished, and also would not have been able to do entirely as he wishes with the system...
i forgot to mention, wiring inside the sub is ok.. parallel .. 4 ohm dvc .. a net load of 2 ohms to the jbl amp
did not check the voltage drop.. would do that if/when he coems in next....
lingering problems.. yes could be.. but what kind of lingering problems..??
ttocs on 10/16/2008 03:17:35
I thought the JBL amps liked a 4 awg when running at < 4ohms?
Victor on 10/16/2008 06:39:37
As fas as i know.. an 8 gauge wire would suffice for an amp rated at 300wrms@ 2ohms.... with maximum current draw = 40 amperes
http://www.bcae1.com/wire.htm
http://www.bcae1.com/images/swfs/systemdesignassistant.swf
used following values
length of main power wire : 15 ft
class AB efficiency 50%, class D efficiency 70%
amp1 class AB - maximum unclipped rms power output 100wrms
amp2 class D - maximum unclipped rms power output 300wrms
after entering the above data...
it suggest that a 12gauge would suffice for the 2 ch and 10 gauge would suffice for the monoblock...
already both the amps are wired with 8awg wires....
i do not see that as an issue...
MrBrownstone on 10/16/2008 08:36:27
8 guage is fine for that limited output if each amp has 8 separate 8guage wire. Might be a little thin for the whole system, but I believe the HU is the case here.
It appears that either the head unit is having some issues or if he's using deck power to power some speakers, the little head unit is getting easily maxed out...circuit protection is underway
Define, "...HU not in good condition..."
Victor on 10/16/2008 09:14:53
The guys does'nt disclose it.. but i guess the HU has been repaired as the warranty seal stickers were messed up with...
swez on 10/18/2008 10:05:00
The #8 gage is OK as mentioned for this dual amp setup. It depends on the overall length of power cable and amperage drawn. (#8 gage can handle 50-60A's in short runs, w/o excessive voltage drops)
As for the sub amp dropping a beat, if you/he scales back the gain a few clicks, this should cure the problem for now. (Is there an SPL difference between 250-300 watts RMS of bass?) Not from the ears perspective.
Think about it... a 150 watt RMS sub amp will be -3dB less that a 300 RMS system. Can the average listener tell the differance? (Not w/o a calibrated mike.
Swez
Victor on 10/18/2008 18:49:23
the jbl sub amp...blew its fuses twice in these 3 days.... THINK
swez on 10/19/2008 01:38:04
Internal amp guts problems here. It's drawing too much current and there's probably some overlooked issues from the rebuilder.
Swez
this is what my friend got to me yesterday... got it installed at some local dealer... did'nt bother to take any advice..which i would have given for free and done the install at a no profit no loss basis... but he decided to let someone else earn and got a mess... anyways.. now he comes to me for free advice and trouble shooting...
the low freq starts cutting at 70% volume.. cuts and starts automatically for a while.. then completely goes off.. then when the volume knob is turned down a tad bit, it starts automatically..
these are the details i collected
2 years old suzuki esteem 70 amps alt - 700cca battery
Pioneer DEH- 6050 from his previous car, not in too good a shape..
Kenwood 5023 - 50x2 @ 4 ohms, powering rear speakers
JBL CS - 300.1 300 x 1 @ 2ohms, refurb
pioneer 6 x 9's 6972 in the rear, retained from old car
kenwood 4" KFC 1051s powered by HU
Soundstream sub XW-12 - 4ohm dvc 300wrms in 1.5 cuft sealed enclosure
all amp wiring 8 gauge - speaker wires 16gauge, sub wires 12 gauge
I re-set the gains proper, using a digital multimeter..
ground check - ok
bass boost 0 - lpf 80Hz on sub amp
HU lpf - 100Hz .... hpf - 50 Hz .... eq - flat ... sub-lvl -0 .... bass 0, treble 0 .....
wire integrity - ok
yet bass cuts at the same levels....
1- HU
2- Amp
3- improper connections in the sub vc .may be they get disconnected with over excursion and then with lower volumes come in signal contact again....
either or all of the 3 are culprits...
also the quality of bass is yuck... and no real thump too, just muddy sloppy bass....
i am not gonna entertain this guy anymore... if he gets convinced on an entire new package, then i'd do it.. orelse dont wanna get my hands dirty..
whats your take on this ???
Victor...
Replies (9)
swez on 10/15/2008 22:39:59
Is there a good reason why this "friend" chose to go elsewhere for the install?
I'd check the voltage at the amp's input side as he cranks up the bass and see how much of a drop in voltage is present. As voltage drops, the amp will act as mentioned.
Also, have a quick peek at the internal sub wiring inside the box to make sure all wiring is secure.
Dave
PS Even though this amp is a refurb, if it was not tested completely after the repairs, it may still have lingering problems.
Victor on 10/16/2008 00:20:31
Of what I can think of.. this friend thinks that if he had approached me he would have been obligated to buy from me and also would not have been able to bargain as much as he wished, and also would not have been able to do entirely as he wishes with the system...
i forgot to mention, wiring inside the sub is ok.. parallel .. 4 ohm dvc .. a net load of 2 ohms to the jbl amp
did not check the voltage drop.. would do that if/when he coems in next....
lingering problems.. yes could be.. but what kind of lingering problems..??
ttocs on 10/16/2008 03:17:35
I thought the JBL amps liked a 4 awg when running at < 4ohms?
Victor on 10/16/2008 06:39:37
As fas as i know.. an 8 gauge wire would suffice for an amp rated at 300wrms@ 2ohms.... with maximum current draw = 40 amperes
http://www.bcae1.com/wire.htm
http://www.bcae1.com/images/swfs/systemdesignassistant.swf
used following values
length of main power wire : 15 ft
class AB efficiency 50%, class D efficiency 70%
amp1 class AB - maximum unclipped rms power output 100wrms
amp2 class D - maximum unclipped rms power output 300wrms
after entering the above data...
it suggest that a 12gauge would suffice for the 2 ch and 10 gauge would suffice for the monoblock...
already both the amps are wired with 8awg wires....
i do not see that as an issue...
MrBrownstone on 10/16/2008 08:36:27
8 guage is fine for that limited output if each amp has 8 separate 8guage wire. Might be a little thin for the whole system, but I believe the HU is the case here.
It appears that either the head unit is having some issues or if he's using deck power to power some speakers, the little head unit is getting easily maxed out...circuit protection is underway
Define, "...HU not in good condition..."
Victor on 10/16/2008 09:14:53
The guys does'nt disclose it.. but i guess the HU has been repaired as the warranty seal stickers were messed up with...
swez on 10/18/2008 10:05:00
The #8 gage is OK as mentioned for this dual amp setup. It depends on the overall length of power cable and amperage drawn. (#8 gage can handle 50-60A's in short runs, w/o excessive voltage drops)
As for the sub amp dropping a beat, if you/he scales back the gain a few clicks, this should cure the problem for now. (Is there an SPL difference between 250-300 watts RMS of bass?) Not from the ears perspective.
Think about it... a 150 watt RMS sub amp will be -3dB less that a 300 RMS system. Can the average listener tell the differance? (Not w/o a calibrated mike.
Swez
Victor on 10/18/2008 18:49:23
the jbl sub amp...blew its fuses twice in these 3 days.... THINK
swez on 10/19/2008 01:38:04
Internal amp guts problems here. It's drawing too much current and there's probably some overlooked issues from the rebuilder.
Swez
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