Speaker Upgrade Includes Our Own Special Enhancement
This Lehighton client came to us with a 2008 Chevy Suburban speaker issue. The sound was…well it was REALLY bad. After a little diagnostic work we found that the front and rear factory mid-range speakers were blown and the tweeters had seen better days. To get this system up and running again we replaced the factory front component speakers with a new Hertz Energy component set. The rears were replaced with a pair of coaxials from Memphis Audio. While the doors were apart we installed Hushmat around the new speakers and foam wave guides to improve their performance. This speaker enhancement package makes a huge difference in the overall performance of the system.
Tiny Amplifier Packs a Powerful Punch!
We discussed with the client the type of music they would be listening to and decided that adding an amplifier would be a wise move. We wanted to be able to crank the system up without a repeat performance of the smoked factory speakers. The only condition was that the amp had to be out of sight. We used the new Memphis Audio 16-SA4.50. This amp is SMALL. How small? Small enough to install between the crossovers for the front speakers and concealed completely in the center console. Once we had the system set up and tuned in, it sounded awesome our client was thrilled!
If you are looking for a Chevy Suburban speaker or amp upgrade, or just some great car audio advice for any vehicle, stop in with your vehicle and let us show you what we have to offer. You will be happy you did!
Have you had any problem with the Memphis SA4.50 amplifier at low volume? I originally installed two of these in a Honda Civic but had to remove them due to a design flaw. At low volume the amplifier shuts down. This is a problem for both low volume listening and especially for using GPS Navigation with no music playing.
This amplifier uses the IRS2093M chipset with the 6645 MOSFET’s, it is a great sounding little amp. It’s unfortunate it has this fatal flaw. Apparently the 12 volt trigger turns on the supply rails but the chip does not initially start. I suspect they are holding it in an over current state via the CSD until reset by music signal threshold detector on any of the four inputs. I have forwarded the chipset data sheet and application notes to Memphis regarding this so hopefully a later Rev of this amplifier will resolve the problem.
Mitchell Schaffer says
No problems here. They work great for us.
You will only notice if you listen at lower listening levels. Also using it with GPS Navigation and no music, the amplifier turns off and isn’t ready when the GPS speaks an instruction. You end up missing the first few words of the GPS directions.
It’s too bad, it’s a great sounding little amplifier, I sure hated having to pull them out of the Civic.
Mitchell Schaffer says
Again, we have sold plenty of these amplifiers. It has been very popular since it was introduced and has been a solid performer. We have not experienced any abnormal function at all. Low volume, high volume… No issues.
That’s good but it will turn off at low volume, it’s built into the design. This has been stated by Memphis, ask them. Fortunately there isn’t much “low volume” in car audio, most in this market just want it loud and boomy so it should seldom be a problem. Where it becomes most obvious again is with GPS navigation and no music playing. In this case it definitely shuts off, try it!
For your market I think it will rarely be a problem but at least now you are aware in the event any customer reports an issue. As I have time, I will investigate further and determine if there are any easy resolutions. Due to the tiny size of the 48 pin chip however it’s not likely going to be a user changeable correction to disable the threshold detector. The CSD pin is normally used for over current, over/under voltage protection so the threshold detector must be disabled without impacting the performance of these protections. It’s going to take some serious solder surgery under a microscope! It would almost be easier to just do a new PCB layout for the chip and have some built up. In that case it could also be upgraded to the 6665 MOSFET as opposed to the 6645 that Memphis uses.
Oh btw, Memphis states they have not had, “many” complaints about the issue but enough that they do have their work around… “…you could use a line driver much like our LLD2A to increase the signal level from the source”. Basically they change the gain structure, crank up the signal coming in to keep the amp from turning off and then turn down the gain on the amp. Should solve all but the GPS issue but not a good approach at all from an engineering stand point.
Mitchell Schaffer says
Thanks for your input. If we ever run into this circumstance with the product we will get in touch with the manufacturer.
Yes, the fix turned out to be easier than expected, simply remove R27C from the board and decouple the threshold detector from the CSD (pin 48) on the chip. I’ve just sent Memphis the details so they will be able to provide you with pics indicating the location of the surface mount resistor. This would have been a lot easier if Memphis could have provided schematics but, oh well, it’s done and the test amplifier now works perfectly!
I just wish all this could have been known before pulling the two SA4.50’s out of the Civic. On the brighter side this incident did lead to my discovery of the 2093M chipset and it may just be the perfect solution for a DSP controlled CBT home theater speaker I’m developing.
Have a happy New Year!