lexlyf

Percy, if i sent a rockwood (just kidding), I meant a rockford Fosgate 4 channel amp to you.......what is the ballpark cost invloved in getting the internals swapped out for better components? How long is the process?

Percy

Tom,

[QUOTE]Originally posted by tmilne
[B]I spoke with a Diamond tech this time. His take:

He said the power on the stock amp was not enough to drive their speakers. He said coax's may work, but the improvement would be modest. Most importantly, he said the stock premium system does have preamp outs, but they are difficult to find and require a knowledgeable installer. He said use them and not the line level outs with a converter. He said they are on a plug on the the input side of factory amp which is behind glove box above right kick panel. He said something about pink, purple and brown colored wires.



My take....(Master SQ)
Wire locations are DIFFERENT between a GS4, SC, LX, etc. Non Nak systems for the IS3, GS4/GS3 as well as ML systems for the GS4/GS3 won't have the same preout wires as the NAK systems or the older SC non Nak systems. Can't go by wire colors either since they might also vary. The hack by 933005spd proved useful for the SC models in that there are 4 pre out sets of wires. You have to cut the plug and splice them into RCA female jacks, but the trick works well. For the other ones that only have 2 pre out sets of wires, you'll need some sort of fader control.

I read in another post about coax vs seperates. IME and IMO, stick with seperates. Most coaxials will have a hole for the midwoofer, plus the tweeter that is covering the midwoofer can possibly affect the sound, especially when the midwoofer has to move some good amounts of air. Plus, with the Lexus lineup, most of the arrangement of speakers are with the tweeters up high and the midwoofers down low. Midwoofers are responsible for the width of soundstage while the tweets are responsible for the height of the soundstage. Ideally, you don't want the height of the soundstage to be down at your knees. The demo McIntosh vehicle (a mere BMW 325) had kickpods with the tweeters pointing up. This resulted in a "Frowning" stage effect. Midwoofers were fine...the tweets had to be relocated badly. Now if a kickpanel arrangement is done correctly, and tuned correctly, then you can get away with it. And possibly with coaxials in a kickpanel installation will do well, but for the most part, stick with seperates. More flexibility in installations.

Percy

Percy

Most RF amps are utilizing surface mount components. They're a Bit#h to work on! Process itself would take a few hours since I have to completely strip down the amp to it's bare board. Plus, a schematic is needed so I know which op amps are for pre amp, and so that I can find the signal chain and beef/clean it up. But a schematic is necessary!

Percy

RealMarty

We seem to have widely divergent opinions here (and this is the first time I've heard of pre-outs on the stock amp on the GS).

And I'm having trouble following which questions are being answered where.

Percy,

Would you please net the - you need additional amps with the Dyns/you don't need them - out for me. Will the std amp deliver enough power to drive the Dyns at reasonable volumes? Do I really need additional amplification to take advantage of them? If so, I'm going to stick with stock. I'm not looking for major wiring, just good sound. Thanks.

lexlyf

Percy, what amp would be easier for you to work on? Ummmmm....let me rephrase that...what amp would be easier for you to work on BESIDES a McIntosh?

M.

Mean Gene

Guys - I didn't mean to imply that the factory amps WOULDN'T drive the Dyns or Diamonds. I'm old school, though & firmly believe in the clarity that additional power brings to the table. I did play around with the factory amplification on my first system of Diamonds & it didn't take much to drive the amps into clipping & the speakers into distortion! I understand the budget concerns of most of ya'll because I've been there myself. But I don't understand the logic of stepping up in speaker quality with Dyns, Diamonds or Focals & then holding them back with inadequate power? It's like a recent post in the GS section about running premium gas. Sure, the ECU will retard the timing so that middle grade gasoline will work & not harm the engine but what's the point in buying a high performance car & then choking it down? Even a minimal increase in power ( a good 4 channel amp ) would help but the final decision lies with each & everyone of ya'll, not me or Percy. Good luck to all of U & your systems!

RealMarty

Touche' Gene,

My issue with the amps is one of turning a simple speaker swap into a more involved and expensive installation. At a certain point I've got to decide if I'm getting into more $ and complexity than I want and just stick with the stock system.

I'm also of the belief of using enough amp power so that it is functioning well below mid power when generating more than sufficient volume in an SQ-focused system. (Keep that puppy humming into its power band but still well below the elbow of the distortion "hockey stick". -- My home system uses a high line amp with 200 W rms/channel in when my speakers are rated at only 30W min to drive them.) So I get the premise of not underpowering the speakers.

Suppose I go for additional power. Where could the amp be located? What does a decent amp cost that would have the kind of power needed to do the job properly? I just want an off-the-shelf amp that will do the speakers justice and doesn't require multiple batteries and capacitors the size of Rhode Island.

Percy

[QUOTE]Originally posted by RealMarty
[B]We seem to have widely divergent opinions here (and this is the first time I've heard of pre-outs on the stock amp on the GS).

Marty, the only pre outs are in WIRE form. There is still a low level signal but there is no real aftermarket interface. That is, they exist in the form of the stock Toyota/Denso connector. But, NO REAL AFTERMARKET/RCA pre outs.



Percy,

Would you please net the - you need additional amps with the Dyns/you don't need them - out for me. Will the std amp deliver enough power to drive the Dyns at reasonable volumes?

The stock amp is still more than adequate to drive them to loud levels.


Do I really need additional amplification to take advantage of them?
If you stick with the stock amp, then you should be fine for a simple speaker upgrade. If you decide later in time to go with an aftermarket amp, then more power to you! With an aftermarket, there's more current, better signal to noise ratio and better channel seperation as well as clarity.

If so, I'm going to stick with stock. I'm not looking for major wiring, just good sound.
Then a speaker swap will do the trick nicely.

Percy

Mean Gene

Marty - The easiest place would be to build a small amp rack which U can locate across the back of the rear seat ( in the trunk ). Here U can mount the amp & any crossovers that come with the speakers. That's the way I had my original system - if I can find the pics, I'll repost them. It'll fit right behind the sub & take up virtually NO room in the trunk. Baring that ( & going for the stealth install ), remove the rear seat & mount things in the void between the seat & the X-brace. U'll need to fabricate the same rack but it'll be outta sight & unless U really stand on the system, overheating won't be a problem. As far amps, while I admit that they're somewhat relying on their reputation, Rockford Fosgate has never let me down but any name brand multi-channel amp should do. Didn't someone else mention that the Diamond tech suggested some others - personally, I don't like Xtant or Soundstream since Brad & others told me about their horror stories with them. Also, my basshead sons have used Soundstream with alot of problems but even they haven't hurt my old hand-me-down RF's ( the old waffle-iron ones )!! Since this is such a subjective topic, simply try a speaker swap & then if you're not happy, add the amp.

RealMarty

Percy, Gene,

Thanks for all the info.

Gene, I'd love to see those pictures if you can find them.

I think I'll stick with my original plan to do just the speaker upgrade. Then, if I'm not hearing the sound quality I'm looking for from the upgraded Dyns I'll go for the amp. Gene, I like your idea of putting it under the seat or up under the package shelf where it will be out of the way and won't take away storage space.

Ok, so this brings on the next question (sorry to be such a pain, but this is really my first venture into car systems).

If the head unit is in the dash and the amp is either in the trunk or under the back seat I'm going to have to get the pre-out level inputs to the trunk. How is that done? I assume I'm going to have to tap the signal at the source and run the low-level inputs to the back of the car and risk introducing a substantial amount of noise...and re-route the speaker output wire to the doors from the amp in the rear of the car.

With an outboard amp will I still have full use of my in-dash fader and balance controls?

Stealth

How about the Levinson amp for running the dyn's ?

Percy

Even better!

Percy