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Question On Power Supply & TS-667v

CM-4441

Member
Dec 10, 2010
73
0
16
NE Florida
I have a TS-667v and a 45amp output Iota power supply. The 667v would be used in my base setup. I think the PS is a little low for the 667v. Right? Should I hook up the Iota to a battery and run the 667v off the battery? For a battery I was thinking an AGM for safety reason as it would be in the house. What are your thoughts on this?

Terry
 

I was going to say 75-80 amp peaks pretty easily.

EDIT_______
The battery will add capacitance and smooth peaks, but it won't make power where you don't have power.
 
For those interested in the 'math(s)' (the Europeans and some Canadians pluralize it????), it kinda goes along like this.

(for biased amplifiers)

TOTAL CURRENT DRAW
(power out X 1.4 = power in ) / voltage at COLLECTORS!!!!!

That goes for a STRAIGHT amplifier, not one with driver(s) in it.

IOW, a 2879 will do about 150 watts PEP. 150 X 1.4 = 210 watts input. Divide that by 12 (typically that's the voltage you'll find on the collector of a 667, when run from a typical power supply or in your 'AVERAGE' installation in the mobile) and you get....... 17.5 amps of input. Keep in mind, those shitty fuseholders in a 667 are ONLY UL RATED for 15 amps!!!!! Not the 30+++ that go through there (incidentally, UL ONLY rates the auto glass fuseHOLDERS to 20 amps.... Even though they MAKE a 25-80 amp fuses (I have them all), the HOLDERS are only rated to 20 amps, if they grip the fuse. If it's a SPRING LOADED holder, it's 15 amps).

4X17.5 = 70 amps. That's the 2879s draw.

The DRIVER is another 15 or so amps. It (IN THE TEXAS STAR CIRCUITRY) does 70-75 watts PEP.

75 * 1.4 = 105 watts input

105/12 = 8.75 (round it to 9).

THESE NUMBERS ARE FOR A PRETTY MUCH STOCK RADIO DRIVING YOUR 667. If you have a dual final radio, hotrodded finals radio, 148 or other chassis with NPC, Negative Peak Limiting or other assymetrical modulation or overdriven condition, then the current draws above INCREASE, especially on the DRIVER side.

So, with a stock radio driving a 667 at normal levels, you can expect a 78.75 amp draw. This assumes a typical electric system, typical install, typical smaller gauge than necessary wire, etc. If you run oversized wire, have a big alternator, etc... You're not going to increase the efficiency MUCH (maybe a couple percent), BUT, you INCREASE the collector voltage, and that's what REALLY matters.... If you can get 50 percent more voltage, you get double the watts! The fuseholders on ANY Texas Star 4 transistor or larger amplifier HAVE GOT TO BE RIPPED OUT. Then replace the power wire with a MINIMUM of 8 gauge for EACH bank of transistors (with the fuseholders out, magically, there are 4 holes in the back for the pair of grounds and pair of positives! Tie both positives and negatives in the amp together to prevent ground loops, etc. Put a LARGE AGU fuse AT THE POWER SOURCE if your in the car, or use the power supplies internal, if you feel lucky :) This usually garners an ADDITIONAL 100 WATTS OR MORE OF OUTPUT, and you didn't increase distortion or overdrive much at all.... (the driver gets a bit more output, but hey.... :).

If you use a class C box, battle box, etc., then instead of 1.4 above, you should use 1.25 to 1.35... They are more efficient, usually in the neighborhood of 65 to 75 percent.

Another thing to keep in mind is this: The amplifiers are MOST efficient at FULL PEP OUTPUT. Just because you're running your 4 pill at 45 watts of carrier doesn't mean it's pulling 4 amps!!!!!The efficiency suffers as you lower the power... SO, it does NOT always follow that a lot of 'swing' will keep the amp cool.... The amplifier creates the LEAST amount of heat at full power, IF the amp is installed and working correctly!

Hope this helps you, and anyone else that might ask the same questions. The numbers are pretty tried and true, and if you doubt them, I'd suggest a perusal of the Toshiba, Motorola or Thompson spec sheets, they pretty much agree with what I stated, with exception of power levels: The mfg's rate the transistors at a lot less than we typically see out of them.


--Toll_Free
 
I don't quite agree with the statement that a battery doesn't add peak power.... That's pretty much ALL a battery is, unless you run a marine type.... And even those have a huge peak discharge capability.

Don't believe me, fully charge one. Then gently place a 1" x 1.175 box end wrench across the two terminals.

See what's causing that steel to turn to liquid? That's called PEAK ENERGY, or joules.

Capacitors are ALSO a peak storage device.

Batteries just have more AVG storage capacity. Especially when you get to the "ESD" high peak discharge caps! Man, ever seen one explode? I have, in a sweep tube amp.. The cap was an OEM OLD unit surplus, and it wouldn't handle the surge current put upon the weak power supply.. Man, it was spectacular to watch something THAT small release THAT much power!

When sizing mobile installs, you usually want enough deep cycle to support carrier level, and enough 'car battery' to supply peaks... Or, add capacitors above that.

The biggest problem he is going to have is feeding his power supply as a battery charger! More often than not, you end up buying pass transistors or fets. You need to throw a steering diode in line (that will pass the peak and avg currents you expect to have... Yeah, it has to be stud mounted and heat sunk) so that their is no current fed back into the pass transistors thereby increasing Pdiss. Been there, done that, had a pile of carcasses to show for it :(


--Toll_Free
 
I don't quite agree with the statement that a battery doesn't add peak power....
I know what you are saying is right, but I didn't say that a battery wouldn't add to peak power availability, I said that it wouldn't make power where there was none.

My line of thinking when I said that was even though a battery will store and release power on demand, ultimately the power supply is the limiting factor as a power supply does make power.

I could be wrong though, if the supply is = or > the "overall average" usage of the amplifier, it may well be sustainable :unsure:
 
A good lead acid battery will give you reserve power, this will supply the needed amperage at 12V when transmitting and will recharge during your rigs receiving from your lower amperage power supply. So if your transmit duty cycle is shorter than the recharge cycle, you'll be OK. IE If your transmit draws 100A and your power supply is current limited at 50 A, when transmitting your regulated power supply will supply 50A and the battery 50A, during receive the power supply will supply 50A to recharge the battery minus the receiver power draw, usually less than 2 A. So if in this case you are long winded, you will need a larger power supply, if you supply less then 50% of the conversation you'll be OK. (assuming high duty cycle modes, FM etc.)
 
Last edited:
I am a little disturbed that people would consider a battery before a properly sized power supply.
These are lead-acid batteries. lead and sulfuric acid. Although when over-charged, they out-gas hydrogen and oxygen, there are small amounts of the chemicals gassing unless its a valve regulated type like the AGM or gel type. Do you want to breath that stuff in your house?

IOTA has the 75Amp version of the power supply. Why not just do it right?

Even though, i must wonder about the wisdom of operating a 12v amplifier in a place where harmonics could cause trouble with the neighbors. This is why people use tube amps at home. Or 50v pills, to eliminate power supply troubles.
 
dudmuck,
Amazing, isn't it? As if there's some 'secret' benefit to being 'barely adequate' (IF that) when it isn't difficult at all to 'doing it right' to start with.
When that being 'frugal' starts affecting health, the 'cost' of doing it 'frugally' just jumped by several orders of magnitude. Unfortunately, there's -no- exaggeration in that.
- 'Doc
 
Kinda like tryin to modify a 4V for HF use.

Open mouth, insert something......


Also, a proper sized power supply WAS recommended. When that was rebuked, duty cycle, battery and load over time was brought into the equation.

I've used lead / acid storage batteries for > 15 years in residential and commercial backup options..... I've never had a problem. Then again, I vent them, put them on real top charge type chargers and maintain them... That kind of goes without saying.

--Toll_Free
 
Just to clear things up a little: I am using an AGM battery. This is a temporary setup until after the Christmas expense is over. I really can't justify getting a 90 amp power supply either. I might go for another 45 amp and hook them both together. The cost of an Iota 90amp is sky high.

Terry
 

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