After replacing the display and backlight module, the OEM Pioneer audio system has a lot of life left in it and am contemplating ways towards improvement.

Sure, it would be easy to swap it out for an aftermarket system, but enjoy improving on OEM designs...and happily, Toyota has left room for design improvement throughout the vehicle....

Dampening the doorskins and speaker boxes present improvement to sound quality, but am investigating whether swapping out original 1990's amplifier and receiver capacitors with contemporary audio grade capacitors offers benefits...

Plenty of ClubLexus forum posts suggesting replacing aged capacitors on ECU..but hardly anywhere else.

Anyone with images of internals of amplifier for 1998-2000 LS400? (such as capacitors)

Thanks.

 

I simply added PP film capacitors 0.47uf/50V or 0.22uf/50V in parallel with most of electrolytic capacitors used for the coupling. I also added those to DC lines aiming for the better decoupling. This is a common technique to improve the frequency response. The small tanδ and better impedance curve give the amplifier good high frequency characteristics.

As the result, the sound quality was very much improved. For examples, violins sound quite vividly. It also improved the women's vocal as if they were just in front of me. It used to be they were singing behind the curtain. I took some photos but I can't find those at the moment.

Those electrolytic capacitors do not contain the infamous QAS and as far as I have checked, those were still mostly OK although the capacitances were a bit decreased. That was the reason why I only added PP film capacitors.

 

Hi Yamae; Thank you for your "sound" advice.

Am contemplating replacing the original.capacitors and, or, implementation of your recommendation.

I googled Audio grade capacitors and came up.with Elna Silmic and Cerafine series electrolytic capacitors that appear to offer increased sound quality.

Attached are relevant data sheets.

Appreciate receiving your comments on this approach or other capacitor brands as well.(provided necessary values are available)

Meanwhile, can anyone post images of the amplifier circuit board depicting said capacitors.

Thanks...

 

the factory system in the 90 is pretty decent if working right. the factory NAK system in a 90 is killer! they are rare tho and they hardly ever still work if you can find them sadly.

 

the cd player went in the nak system in my original 90, then the tape deck quit, and finally the amp blew up so i had no choice but to replace it with something modern (circa 2005) bought the absolute best of the best top dog pioneer premier head unit and speakers, and as crazy as it sounds, it never sounded as good or had the power of the factory nak system

 

Honestly, I don;t see why you would go through the effort of trying to improve the OEM amplifier when you can just replace the unit with something from the aftermarket realm. Currently, I am running a JL Audio VX800/8i in place of my stock amplifier. Fits nice and tidy under the front passenger seat in place of the OEM amplifier. It also has internal programmable DSP. Not only have i been able to successfully re-EQ the speaker system, but I was also able to time-align the speakers to the listening position also. Another thing, the amplifier has a Toslink SPDIF input which I have taken advantage of by utilizing USB-OTG connectivity on my Android phone to an external Peachtree Audio USB to Toslink bridge. Straight digital input, with minimal noise floor.

 

The short answer is I have already decided to swap-out, and, or add capacitors and present findings.

The only way I justify any expenditure is because I treat this car as a hobby...so imstalling a new sound system is not my goal here.

Taking replacement to it's logical conclusion would suggest replacing vehicle with a newer model.

Appreciate your feedback but am not pursuing installing a new amplifier, new speaker (OEM are 2 ohm-you replaced speakers too?) or control head in a 20 year old car.

Anyone with OEM amplifier circuit board images?

Thanks....