I'm into my hi end car audio and I have a 14v agm battery - would I be able to use this in the 914?

I say you would have an amp issue though.

No thats the point, my McIntosh amps are designed to run 14v. I run them on teh bench from a 14.2v power supply and they are better at the higher voltage tbh!

Don't see why not. Charging system is ~13.8 when running, although it may not be able to charge that battery. If they are lithium, i wouldn't do it. those take a very special charge, and will overheat and burn your car to the ground.

No, not lithium - they are sealed lead acid batteries, basically a slightly different cell structure to reach 14v rather than 12v

I have been running dual kinetik batteries for some time, and I know the current is well over 12 volts. No problems Yet.

Here is a link that might help

http://www.kinetikaudio.com/2009/support.asp

Very interesting Joseph, Are you running two 12v batts in your 914? If so which models?

Ok just looked on your blog! So two 12v batts from a 120 amp alternator. Do you have a split charge relay in there too?

Many racers run 16 Volt dual tap batteries (12V/16V) They have a 12V tap for the car electronics and a 16V tap for spark control or amplifiers like yours. They do require a voltage booster for normal charging. The voltage booster mounts in line with the alternator output. You will need around 16V just to keep your 14V battery charged. You could also have a custom alternator wound for higher voltage. Then you would use a resistor network to drop voltage to the vehicle electronics or several diodes in series. A typical diode will drop 0.7 volts in the forward bias. Most amplifiers, yours included have a voltage range. Usually 10-14 volts and will work fine within that range. 14 volts will net higher output wattage than 12V.

The real question... Your amplifier may be more valuable that your 914. Do you really want to install it in a car that spends most of its life on jack stands?

How much more power are you getting at 14v? Is it even enough to bother with?

The batteries are tied togeather, no isolators or relays. The guys at Kinetik said it would be fine. So far so good. Here is the thread

http://www.914world.com/bbs2/index.php?sho...=102167&hl=

p.s. My next stereo project is already in the process I really like what you did with yours

Wattage formula: P=IxE
P=Power/wattage
I=Amperage/current
E=Voltage

So, 12V x 20 Amps = 240 Watts Peak

or, 14V x 20 Amps = 280 Watts Peak

It does not seem like much until you get to a larger amp. Mine for example...
12V x 80 Amps = 960 Watts peak
or
14V x 80 Amps = 1120 Watts peak

The peak numbers most then be multiplied by 0.707 to get RMS Wattage.

So my 1120 Watts peak = 791.84 Watts RMS (Root Mean Squared)

Maximum amperage can be determined (best guess) by the recommended fuse size. My Kenwood amp uses four 20 Amp fuses on the Amp itself. So It can draw a maximum of 80 Amps. This would be at clipping level, distorted right before a fuse blows.

Some companies put oversize fuses (off brands) and are not reliable. The Federal Trade Commission does not regulate Car Audio the same as Home Hi-Fi. The is no regulation on Car Audio. Any Manufacturer can claim any wattage they want. The just claim it based on 20 Volts. Only name brand companies comply and rate their equipment correctly. Stay away from off brands claiming 1000 Watts of power.

I sort of agree, but remember that your amps aren't 100 % efficient. They get hot.

It's been a while since I've had a -4, but if your voltage regulator is the
old mechanical type, you can tune it to 15.5~16V by bending a tab.

Really i'd like to know more...

To all those that don't believe - yes amps make heat, of course they do, but they are also far more efficient with a higher voltage input, so the effort involved in getting a couple more volts input is well worth it.. When the alt is running in a car the battery is basically not used and the voltage supplied is (from the standard alt) 13.6 volts - shut the engine down and the voltage drops instantly to 12.5/6/4 whatever your battery is capable of. If you are involved in sound competitions as I am, keeping the voltage up is really important as the system is judged without the engine running, so the better the voltage supply and more constant the better. Going off topic slightly, some people use caps to keep the voltage from dropping, but you can tell everyone yo know that these are a waste of time as the problem in a car audio system is always the wiring to and from the battery - If the lights dim then it is most probably the negative wire because it is of a smaller awg to the supply wire, therefore causing a bottleneck in the circuit. Put a cap in and yes, it will supply the power needed, but the old wiring circuit still needs to supply the cap with its power, and through the smaller negative wire it will still struggle to circuit properly. So anyone that has a cap that says it improves their sound system you can now inform them of their weaknesses!

Anyway back on topic - a very interesting discussion has evolved and I look forward to other opinions... Oh and to the other nutter with all the Phoenix Gold equipment in his car - I now have two McIntosh amps in the car, ID horns and EMIT tweeters - Sounding amazing!!! Better than my home hifi

Do you use "pi" filters to eliminate engine noise?

What the hell are they?


No I dont. If you have a system wired correctly first time round without any ground loops you will have zero noise!

You just motivated me to start my "NEW" Phoenix build thread.

Us nutters need to stick togeather

here ya go. just need to do same fab work to make it work,
http://www.jegs.com/p/Powermaster/Powermas...042142/10002/-1

here ya go. just need to do same fab work to make it work,
http://www.jegs.com/p/Powermaster/Powermas...042142/10002/-1

Are any of those bolt in??

prolly not.

go check over on the samba and see if any of them are using 16v on a t4.

The schematic looks like the Greek letter pi. Two caps & one choke.

I agree, ground loops are bad, but I disagree about zero noise. Teach me. I've always run into either alternator noise (direct coupled) or ignition noise (RFI perhaps) issues with my sound system installations. Maybe your McIntosh gear has built in power supply filters. Yes? No? Thanks.

OK I'm using a HU, a pro audio (Alto UCS Pro) processor, two amps and 7 speakers in my 914 and it's noiseless.. Alt noise is always because of ground loops. A ground loop can be caused by so many things - stargrounding is a good idea and also look at the quality of your grounding points - most people don't want to drill into the chassis so use a seatbelt mounting bolt as the amp grounding point, but was the paint removed prior to bolting up? is it against bare metal... etc and you can then easily see the problems.. I have all my equipment grounded to the battery - HU too - I have run both positive and negative circuits around the car to feed all the equipment ( I hate relying on chassis points as they can corrode, especially on a car as old as me!!) If you want to have a browse of a good car audio forum over in the UK, have a look at www.talkaudio.co.uk - a great site and lots of you Americans are coming over to it as it's got a superb European audience - not that I'm biased as a moderator!

Wow!!! Very cool!!! Got any pics? Thanks!!!

Sure http://www.talkaudio.co.uk/ipb/index.php/t...install-thread/

Or if you don't want to read thirty pages, look here at just the pics - http://gallery.me.com/rodericdavies#100050...mp;sel= (scroll to the end and work backwards for the most recent stuff...)

Rod,

"So anyone that has a cap that says it improves their sound system you can now inform them of their weaknesses!"

That is not entirely true....

There are new Ultra-capacitors that can store EXPLOSIVE amounts of energy.
If these are placed close to the amplifier, then they can provide extra power when the amp is pulling a lot of current, then re-charge when the amp is pulling less current.

They are more than a filter, they are an energy source for load leveling.

Stu

Sweet. Don't let that car out of your sight.

Sorry, but still a waste of money. SUPERB marketing but a waste of money. An amp has an array of capacitors that store the amount of voltage it needs to produce it's maximum output, adding another cap before these is just a waste of time, the battery that fills this cap either fills the additional caps reserve, or the amps reserve first, now I know which one I would rather have topped up instantaniously, and it's not the external cap. In fact because the battery is desperately trying to fill the external cap the amps' caps are being deprived of the power they need so in fact it is doing the complete opposite to it's purpose.. Some of my friends run 15kw systems doing 20hz at 155db and the only caps in their cars are on their heads

You dont need a cap, but an extra battery never hurt

p.s. you put so much time into morphs kicks to make them custom. Why did you not seal them??

The KEF drivers I was using need a large volume of air behind them, so going IB was the best way to get them to work. Having the sub in the footwell helps as this can play upto about 80k so a load of the midbass is now produced by it... The morph builds are now history and I have studio drivers in the doors

I use KEFs & Tannoys at home. I just don't have the time or energy anymore to put a system in the 914.

This is as far as I got.

Click to view attachment

The theory behind the "stiffening Cap" is not about added power or voltage. It works because the Capacitor can charge and discharge faster than the car battery. A car battery is made to discharge a massive amount of current to start a car. This massive current is actually slow compared to an amplifier power supply. The electron speed (coulombs) from a car battery is slower than an amplifier consumes current just before clipping. The Stiffening Capacitor can charge and discharge at the same rate as the amplifier power supply. Most people and systems will never see the benefit of the capacitor as most systems are not played contiouously at clipping levels. Although when alternators do not have enough capacity or when power cables are long distance from the battery, they can have some noticeable effect. If your amplifier has a superior power supply the Capacitor willl also have less noticeable effect.

I am a former IASCA judge (International Auto Sound Challenge Association). It has been my experience that most Americans are not true Audiophiles. Most of us want loud bass so that our neighbors a mile away can hear it. boom boom boom. The equipment Rod is running is far superior to what most people use (and more expensive)

I agree with Rod about noise. If it installed correctly the first time you will not have noise. You also need to use quality equipment from a major brand. However, most mid to high quality equipment can benefit from a stiffening cap since most do not have superior internal power supplies.

Your FI control unit doesn't like either low or high voltages. It likes 12 to a little over 13. Voltages other than those in that range can cause changes in mixture.

The Cap'n

Most interesting. You guys know your shit.