aftermarket radio volume vs oem

Could anyone chime in on whether my proposed radio upgrade would have similar volume capability to my existing OEM setup?

2004 Lexus RX330

Factory "Lexus Premium Audio System" without navigation and without Mark Levinson -- this uses a remote OEM amplifier that appears to have a 240 watt (total,max) rating according to some internet posts.

Proposed nav head unit - Clarion NX602 -- claims 18W rms X 4 at <1% THD+N

I want to wire the Clarion speaker outputs to the speaker leads at the OEM amplifier harness (disconnected) so that I can retain fader control.

I just don't want to go nearly $1000 into this upgrade and find out that the OEM system, which is fine for us, is actually capable of much louder and/or cleaner sound output than the onboard Clarion amp.  I have no interest in adding an aftermarket multichannel amp and/or upgraded speakers.  Looking forward to experienced replies!

Why not purchase a Metra TYTO-01 and use the factory amp?

i am an idiot wrote: Why not purchase a Metra TYTO-01 and use the factory amp?

Well, two reasons.

1) The TOYT-01 application list calls out Toyota JBL systems, giving specific year ranges of Toyotas, no Lexus is mentioned.

2) No mention of maintaining fader control is mentioned.  If this device can accomplish fading then it must be via the TX+/TX- serial data pair also found on the 20 pin connector at the OEM radio, because the OEM amp only has 2 channels of analog audio data in.

Does the TOYT-01 work on my 2004 Lexus RX330, and will it allow the Clarion radio's fader function to properly control front/rear volume differential?

FWIW I emailed someone at BeatSonic about the SLA-82A and was informed their product will definitely not do fader control; I then asked if he knew of any workaround and he said no.  That doesn't mean he was being truthful or all-knowing of the aftermarket accessories market, but I took him at his word.

Thanks a bunch.  I never found that data sheet on my own, just sales sites that showed only Toyota applications and limited info.  I didn't know Axxess was Metra, or vice versa, either.

Everything is installed and the TYTO-01 does not control fading properly.  It seems to be commanding the factory amp based on the sum output of front + rear rather than directing sound to the front or rear as "instructed" by the Clarion headunit's RCA outputs.  I am absolutely sure that all wiring and connections are complete and proper.  I haven't tested the RCA outputs of the Clarion to be certain they are truly working as intended so that is the one unknown factor, though I feel pretty confident that they work properly.  For example, the balance function works perfectly and that is an "analog" signal to the amp's line level inputs.

Example: I go to the balance-fader submenu, set sound all the way to the left, then move the fader control through its range front to rear... if it is in the center then both speakers are at their loudest.  As the control is moved either F or R, both speakers get equally quieter progressively, so that when the control is either max F or max R both speakers on the left side are at their softest level, but equal to each other (given minor differences due to different speaker designs).  IOW the fader control makes both F and R speakers produce an equal output at any given position; they're just loudest in the center fader position and quietest in either extreme fader position.  You can't make either speaker turn off or even be slightly quieter than the other.

Apparently the Metra's serial data amplifier control logic is either faulty or incompatible with this particular non-Mark Levinson amplifier.

The Metra/Axxess interface claims to be updateable but I would think they would have hammered out any faults in its ability to control an eight year old system by now, unless they have a custom program reflash that addresses this particular system.

Any thoughts?  THank you for your time.

Make sure that there is ground on the shield of the RCA jacks of the Clarion unit. If you have no meter, ground one end a small wire, then touch and hold the other end of that wire to the outer connection of any one of the RCA cables of the tyto-01.

I could do that, but I don't understand the concept.  The RCA's easily accessible outer conductor "sleeve" is not ground, per se.  It is the floating negative lead for one channel.  AFAIK the four sleeve circuits aren't connected together nor should they be at true ground potential.   If you mean the actual shielding that is one layer beneath the jacket, I do not want to cut or pierce the jacket(s) to check this.  I don't know if that braided shielding actually carries the (-) voltage or if there are two conductors AND grounded shielding on thse audio outputs.  Clarification, please?

The outer conductor of every car CD player rests at ground unless there is a problem with the deck. Sometimes there is an open trace which lets them float.   When they are not grounded, they act exactly as you are describing. Probably should have said most and not every. I am sure Macintosh probably made a unit that had balanced outputs.

i am an idiot wrote: The outer conductor of every car CD player rests at ground unless there is a problem with the deck. Sometimes there is an open trace which lets them float.   When they are not grounded, they act exactly as you are describing. Probably should have said most and not every. I am sure Macintosh probably made a unit that had balanced outputs.

OK, I'm really surprised.  I'll check that out and report back.  As long as the radio is out I will probably also verify that the 4 outputs respond properly to fader control.  Might be a while before I can get to this.  Thanks for the help.