Amp upgrade? Possible? Feasible?

[ekolpack]

I have an 08 with the JBL sound system. I'm looking at upgrading the speakers to some fancy stuff, and it occurs to me that the amp may not have enough power, or fidelity to do them justice.

Firstly, is this the case? Anybody have specs on the factory JBL amp? Specifically watts/channel into ??? ohms?

Secondly, IF the JBL amp is underpowered (key word IF), is it feasible to replace the amp? Will it mess up DSP or time correction? Am I better off sticking with the JBL even if it's a little wimpy? I don't need tons of volume, but plan on installing a single 500W sub, so I'd like the rest of the system to be able to keep up if possible.

Thanks fellas!

 

[Ratchey]

I have an 08 with the JBL sound system. I'm looking at upgrading the speakers to some fancy stuff, and it occurs to me that the amp may not have enough power, or fidelity to do them justice.

Firstly, is this the case? Anybody have specs on the factory JBL amp? Specifically watts/channel into ??? ohms?

Secondly, IF the JBL amp is underpowered (key word IF), is it feasible to replace the amp? Will it mess up DSP or time correction? Am I better off sticking with the JBL even if it's a little wimpy? I don't need tons of volume, but plan on installing a single 500W sub, so I'd like the rest of the system to be able to keep up if possible.

Thanks fellas!

I replaced the stock amp in my Lexus ES. It required a DSP to accomplish it as the signal input is through a digital cable. I just spliced into the harness coming out of the amp and used the high level input into the dsp then out to a couple of Alpine amps to create 9 channels. The DSP will give you the time correction capabilities. I found this was the easiest way to replace the amp while keeping the phone and navigations capabilities fully intact.


As to whether the stock amp is under powered will depend on the sensitivity of the new speakers. If the are in the 80dB range then it will likely not be powerful enough, if they are in the 90dB range, it may just work for you. Depends on what your expectations are.

 

[grinchy]

The tlc and jbl use MOST network, there are no low level signals available outside of the MOST bus. The LX and mark levinson is a more traditional signal + amp situation, and you can replace the stock 12 channel ml amp with a dsp + amp if you’re up to the cost and complexity.
it should be possible to do an aftermarket hu and aftermarket dsp and amp in a tlc. there would probably be significant complexity in it, not sure anyone on forum has tried yet. Theres an audio thread around somewhere Where the plugs and pin outs are posted up.

 

[ekolpack]

The tlc and jbl use MOST network, there are no low level signals available outside of the MOST bus. The LX and mark levinson is a more traditional signal + amp situation, and you can replace the stock 12 channel ml amp with a dsp + amp if you’re up to the cost and complexity.
it should be possible to do an aftermarket hu and aftermarket dsp and amp in a tlc. there would probably be significant complexity in it, not sure anyone on forum has tried yet. Theres an audio thread around somewhere Where the plugs and pin outs are posted up.

Gotcha. So if installing an aftermarket head unit with normal analog speaker outs (whether line level or speaker) there will be no way to interface with the JBL amp? Sounds like if I want an aftermarket head unit, barring finding something that supports MOST protocol, I'll have to get a replacement amp either way. Would the ML amp from an LX570 be a good choice, or am I better off getting a few 4 channel Alpines or Kenwoods or something? The ML will have the proper Land Cruiser DSP already integrated into the amp, correct? Or does the DSP come from the head unit? Thanks a ton!

 

[CharlieS]

I could be WAYYYY wrong, but I thought the main barrier to throwing a typical double DIN stereo in was the issue of integrated climate controls.

 

[grinchy]

Yes, that’s an issue too, (the climate integration). I think trying to match the overpriced ml amp to a tlc would be a mistake. Different drivers different speaker wiring, and cost is going to climb quickly. If you can solve the aftermarket HU and climate items, then yes you could amp up and rerun the speaker wires and add new drivers. It would be a big job to do it all correctly(rewiring will require pulling all the interior, for example). leaving the wiring and replacing drivers would be a more approachable option.

I’ve probably done the most as far as redoing an LX, replacing the Dsp and amps and sub. I left the stock wiring and the other stock drivers.

 

[ekolpack]

Yes, that’s an issue too, (the climate integration). I think trying to match the overpriced ml amp to a tlc would be a mistake. Different drivers different speaker wiring, and cost is going to climb quickly. If you can solve the aftermarket HU and climate items, then yes you could amp up and rerun the speaker wires and add new drivers. It would be a big job to do it all correctly(rewiring will require pulling all the interior, for example). leaving the wiring and replacing drivers would be a more approachable option.

I’ve probably done the most as far as redoing an LX, replacing the Dsp and amps and sub. I left the stock wiring and the other stock drivers.

The motivation for this is that I'll have much of the interior pulled apart anyway for a rebuild, so thinking I might as well install, or at least wire up for future install, a new sound system.

I'm thinking I should run

- 5 channels of high quality RCA cabling under passenger seat to feed line inputs on amp(s) (2 front, 2 rear, 1 sub)
- 14 channels of speaker outs from amp(s) to wherever stock amp resides to feed speakers (9 mids, 2 tweeters, 1 sub, 2 extra just in case)
- Obviously 12v, ignition and/or remote to amps, probably tapped from stock amp (which is supposedly under either driver or passenger seat on 08 TLC)

The head unit I'm looking at supposedly has working climate controls built-in ( Tesla Android Style Stereos Units for the 200- Combined - https://forum.ih8mud.com/threads/tesla-android-style-stereos-units-for-the-200-combined.1194718/ ) so that shouldn't be an issue. I really wish the JBL amp would accept normal analog audio input. That would make this whole thing WAY easier. I'm trying to confirm whether it does or not and having a tough time. Even the FSM doesn't seem to help (or I'm looking in the wrong place).

 

[ekolpack]

Well, I believe this will solve the MOST digital protocol amp input problem.

Amazon product ASIN B001OAA2X0
This unit converts analog outs from normal non-digital head units to the correct Toyota/JBL digital signal the amp wants to see. This should allow me to use an aftermarket head with the stock amp and wiring.

Now I just need to know the rough wattage output and impedance load this amp can handle. I'm guessing I could get a ballpark by looking at the wattage and impedance of the stock JBL speakers and assume (ASSume?) the amp is probably in the same ballpark.

What this would also allow one to do is add a speaker-to-line level converter to basically use the stock amp as a DSP translator/crossover network for the whole system, then feed external amps with more power handling to push more air. Hopefully this isn't necessary. If the JBL has at least 50W @ 2ohms/channel of mid-range and a little less for highs, I think I can get by with higher sensitivity speakers to keep up with my sub.

Either way, I can tap off the sub out from the stock amp, convert it to line and feed a much stronger sub amp (500W RMS @ 4ohms).

 

[grinchy]

The aftermarket head unit is already planning on using the jbl amp, so it will likely have a similar interface box.
I think you’ll find the stock amp insufficient if you’re used to a more advanced setup. I have a Lexus so the hands on could differ, but my memory of the stock ml system vs the current dsp + amp solution I think I’m far ahead. Just the sub alone makes a large difference.
Example - the ML amp is a miracle of miniaturization, driving 12 channels into 18 or so drivers in a pretty small space, including time delay and dsp. It advertised something like 480w, and 100 of that was the sub, so less than 40wpc, and I’m sure the dynamic peak across via pink noise is way less, maybe 20wpc. Impressive but they were designing on a small bom Cost and space budget.

 

[ekolpack]

Well, after being concerned I had run into a dead end because there are little-to-no 2 ohm speakers available for mids or tweeters (especially in 4" size) I think I have gone far enough down the rabbit hole to find a solution. I will enumerate it here for any future people with the same dilemma. If you're messing with "upgrading" the stereo in your Land Cruiser, this is stuff you should definitely take into account.

Problem:
The stock JBL drivers (ie. speakers) are supposedly very low impedance (around 2 ohms), even the midrange and tweeters.
Therefor the stock JBL amp is expecting to see a 2 ohm load.
If you replace the stock speakers with 4 ohm speakers, the amp will deliver half the wattage/voltage to these speakers, which will result in a noticeable 3dB drop in SPL (volume)
This will be especially lopsided if you beef up the sub or add a sub amp, which will result in much more bass, along with noticeably LESS mids and highs.

Solution:
If selecting 4 ohm speakers, choose those which have a 3dB higher sensitivity rating than the stock JBL's (whatever that is).

For example, if a stock 2 ohm JBL driver's sensitivity is 88dB and the stock amp delivers 30W of white noise to that driver, it will yield 103.5dB SPL @ 3 feet.
In order for a 4 ohm driver receiving half that wattage from the amp to yield the same 103.5dB SPL output, it would need to have a sensitivity rating of 91dB.

So in order to match the stock sound system (at least in terms of SPL) we'd really need to know the sensitivity of the stock JBL drivers. Anybody have any idea?

If I had to guess, I'd say it's around 88 or 89, so 4 ohm drivers with sensitivity around 91-92dB should be a great match (again, at least in terms of SPL....the extent to which there may be DSP/EQ/tuning inside the amp is a whole different ballgame).

 

[ekolpack]

The aftermarket head unit is already planning on using the jbl amp, so it will likely have a similar interface box.
I think you’ll find the stock amp insufficient if you’re used to a more advanced setup. I have a Lexus so the hands on could differ, but my memory of the stock ml system vs the current dsp + amp solution I think I’m far ahead. Just the sub alone makes a large difference.
Example - the ML amp is a miracle of miniaturization, driving 12 channels into 18 or so drivers in a pretty small space, including time delay and dsp. It advertised something like 480w, and 100 of that was the sub, so less than 40wpc, and I’m sure the dynamic peak across via pink noise is way less, maybe 20wpc. Impressive but they were designing on a small bom Cost and space budget.

That's a good point. The head unit in question is advertised as compatible with the TLC 200 series, so whatever signal it's sending to the amp, it ought to be correct.

I still have the issue of "upgrading" speakers. I'm really not in love with the stock sound, despite the "upgraded" JBL sound system. That said, I'm an audio engineer and kind of an audio snob.....okay, a lot of an audio snob.

I'll probably start by replacing the sub (just because I have a really nice one sitting around), tweeters in the A pillar, dash speakers and maaaaybe the front door speakers. I don't think I'm gunna worry too much about back doors, far back corners or tailgate. Even if I have to go 4 ohms, as long as I keep the sensitivity specs at 91dB or more, I think I'll be good.....and even if I'm off by 1dB or so, that can be fixed with EQ, especially with a fancy Android head unit.....just wouldn't want to dip below 90dB in a 4 ohm driver.

 

[grinchy]

Doesn’t hurt to try. You can absolutely go high level behind the jbl and just put a five channel in to drive the tweets, mid/bass, and the center. Then replace those drivers with whatever you like. Won’t fix the house sound but will fix the volume and allow for sub balance.
Is your current HU non functional?

 

[ekolpack]

Doesn’t hurt to try. You can absolutely go high level behind the jbl and just put a five channel in to drive the tweets, mid/bass, and the center. Then replace those drivers with whatever you like. Won’t fix the house sound but will fix the volume and allow for sub balance.
Is your current HU non functional?

That's a really good idea! I think I'll start by just adding a mono amp for the sub and upgrading aforementioned speakers (dash left, center, right, A pillar tweets and sub.....maybe front doors). If I need more volume from mids/highs down the road to keep up with the sub, I'll grab a 5ch amp for dash L C R and tweeters.

Although I love Focals (have used their studio monitors) I'll be going with an all Hertz system....they seem to be a bit more highly regarded than Focal. All drivers I've chosen so far are between 92-94dB sensitivity, so even at 4 ohms, I'm sure they'll keep up just fine with the stock drivers, unless they are super sensitive, which I highly doubt. I'm guessing these will even be louder than stock, and pull less wattage from the amp, reducing wear on it.

My stock head unit and nav and DVD and all features work just fine. I'm just not too impressed with the old tech (which was kind dated even when new) or the sound. I'd really love a big, responsive, bright touch screen, better cameras (the backup cam is almost useless) and 360 surround cams. Might add a cam to the undercarriage for off-roading as well, if I have another input on that head.

 

[Mjones]

That's a really good idea! I think I'll start by just adding a mono amp for the sub and upgrading aforementioned speakers (dash left, center, right, A pillar tweets and sub.....maybe front doors). If I need more volume from mids/highs down the road to keep up with the sub, I'll grab a 5ch amp for dash L C R and tweeters.

Although I love Focals (have used their studio monitors) I'll be going with an all Hertz system....they seem to be a bit more highly regarded than Focal. All drivers I've chosen so far are between 92-94dB sensitivity, so even at 4 ohms, I'm sure they'll keep up just fine with the stock drivers, unless they are super sensitive, which I highly doubt. I'm guessing these will even be louder than stock, and pull less wattage from the amp, reducing wear on it.

My stock head unit and nav and DVD and all features work just fine. I'm just not too impressed with the old tech (which was kind dated even when new) or the sound. I'd really love a big, responsive, bright touch screen, better cameras (the backup cam is almost useless) and 360 surround cams. Might add a cam to the undercarriage for off-roading as well, if I have another input on that head.

I remember reading on mud that Focal had direct replacement speakers for LC200. I've look around and can't find it quickly but may be worth checking if Focal direct replacements meet 2ohm load and fitting requirements.