Testing .5ohm

[hispls 5,000+ posts]

[quote name='los33']3 D3100's from XS could hold up for a while on a daily, but that alternator would be stressing big time.
@hispls If he could afford 100 batteries he would have just purchased the largest alt or 2 and add 2 large batteries.
Running .5 ohm is not rocket science, the fact that he doesnt have the electrical is another thing. Most who ruin amps due to .5 ohm are either testing a new amp or an amp that has not been test at that ohm rating.

OR they run them below voltage limit.[/QUOTE]

Batteries and alternators aside, if his amp was safe to run at .5 ohm the manufacture would rate it for that. All the batteries in the world won't make driving 1/2 ohm less than 4X as strenuous on an amp as driving 1 ohm. Low voltage will make it worse, but let's not imply that adding more alternators and batteries makes loads under 1 ohm safe.

 

[los33]

Batteries and alternators aside, if his amp was safe to run at .5 ohm the manufacture would rate it for that. All the batteries in the world won't make driving 1/2 ohm less than 4X as strenuous on an amp as driving 1 ohm. Low voltage will make it worse, but let's not imply that adding more alternators and batteries makes loads under 1 ohm safe.

True and i do not want to imply its safe, but with multiple test anyone can know if it is safe enough.

With box rise you will be at 1 ohm anyway unless you got a perfect box.

 

[bgowdy 5,000+ posts]

I have sounstream Ta1.3k ran at .5 daily with a stock 80amp(i think) alt, 2 agms in back that total around 175ah i believe. 1 run of 1/0(bullz audio lmao i know). I have a volmeter wired into the amp so i can see it at all times while playing. I dont do a bunch of demoing and usually while playing at 1/2 power or more im not at idle, ill press the rpms up to 2k.

Voltage wise at demo vol i can usually hold stable about 12.5v(say 30 secs) depending on the song, heavier songs ill turn it down a tad to stable the voltage.

While im only giving an example, im not saying its the right thing to do. Mine does fine but im smart with my system, normal daily listening levels my voltage is 13v plus. the only time i get on it is at a comp or demoing at a comp, i dont give demos around town as security lol.

With all said my is rated to run .5 ohm and know some who do .25 with this amp.

 

---------- Post added at 06:40 PM ---------- Previous post was at 06:39 PM ----------

 

But i thought crescendo amps where .5 ohm stable

 

[los33]

I have sounstream Ta1.3k ran at .5 daily with a stock 80amp(i think) alt, 2 agms in back that total around 175ah i believe. 1 run of 1/0(bullz audio lmao i know). I have a volmeter wired into the amp so i can see it at all times while playing. I dont do a bunch of demoing and usually while playing at 1/2 power or more im not at idle, ill press the rpms up to 2k.
Voltage wise at demo vol i can usually hold stable about 12.5v(say 30 secs) depending on the song, heavier songs ill turn it down a tad to stable the voltage.

While im only giving an example, im not saying its the right thing to do. Mine does fine but im smart with my system, normal daily listening levels my voltage is 13v plus. the only time i get on it is at a comp or demoing at a comp, i dont give demos around town as security lol.

With all said my is rated to run .5 ohm and know some who do .25 with this amp.

 

---------- Post added at 06:40 PM ---------- Previous post was at 06:39 PM ----------

 

But i thought crescendo amps where .5 ohm stable

BC3500D and BC5500D are .5 ohm stable by manufacture.

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[bgowdy 5,000+ posts]

BC3500D and BC5500D are .5 ohm stable by manufacture.
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i see... so the 2k is not then?

 

[hispls 5,000+ posts]

True and i do not want to imply its safe, but with multiple test anyone can know if it is safe enough.With box rise you will be at 1 ohm anyway unless you got a perfect box.

Care to define "box rise"? How is it measured and quantified? If you don't understand IMPEDANCE or have seen some impedance curves of raw drivers and drivers installed you definitely should NOT be giving advice telling people to run their amp to half or quarter ohm.

I have sounstream Ta1.3k ran at .5 daily with a stock 80amp(i think) alt, 2 agms in back that total around 175ah i believe. 1 run of 1/0(bullz audio lmao i know). I have a volmeter wired into the amp so i can see it at all times while playing. I dont do a bunch of demoing and usually while playing at 1/2 power or more im not at idle, ill press the rpms up to 2k.
Voltage wise at demo vol i can usually hold stable about 12.5v(say 30 secs) depending on the song, heavier songs ill turn it down a tad to stable the voltage.

While im only giving an example, im not saying its the right thing to do. Mine does fine but im smart with my system, normal daily listening levels my voltage is 13v plus. the only time i get on it is at a comp or demoing at a comp, i dont give demos around town as security lol.

With all said my is rated to run .5 ohm and know some who do .25 with this amp.

 

---------- Post added at 06:40 PM ---------- Previous post was at 06:39 PM ----------

 

But i thought crescendo amps where .5 ohm stable

Because you are doing what you are doing in no way implies that your amp ever sees .5 ohm, nor that it is a safe condition that isn't risking breaking your equipment. Nor should it be construed to mean that somebody else running different equipment in a different box and different vehicle could wire to a .5 ohm nominal load and not actually have his amp see that and blow up very quickly. It simply isn't good for amps and isn't safe and is a bad idea unless you have a really good reason to do it and can afford the gamble.

BC3500D and BC5500D are .5 ohm stable by manufacture.
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i see... so the 2k is not then?

From Crescendo website: "1 Year/1ohm comprehensive warranty with 2 year/.5ohm optional extended warranty available."

IIRC they originally warrantied at .5 ohm and must have ran into trouble because they very quickly reneged on straight out no-questions-asked .5 ohm warranty.

 

[wew lad 5,000+ posts]

From Crescendo website: "1 Year/1ohm comprehensive warranty with 2 year/.5ohm optional extended warranty available."

IIRC they originally warrantied at .5 ohm and must have ran into trouble because they very quickly reneged on straight out no-questions-asked .5 ohm warranty.

That's definitely correct, I remember looking at the BC2200 from a while ago and they said that the entire Bass Clef line was .5 ohm stable starting with the BC2200.

Problem is they probably have people running it at .5 ohm without understanding the huge efficiency loss and the detriment it causes any electronics when they're starved for power.

add to that the people who push it further and run it at .25 ohm because .5 was "fine" and there's even more dead amps

 

[hispls 5,000+ posts]

That's definitely correct, I remember looking at the BC2200 from a while ago and they said that the entire Bass Clef line was .5 ohm stable starting with the BC2200.
Problem is they probably have people running it at .5 ohm without understanding the huge efficiency loss and the detriment it causes any electronics when they're starved for power.

add to that the people who push it further and run it at .25 ohm because .5 was "fine" and there's even more dead amps

I think they largely will blow up because driving .5 ohm is absolutely torturous on semiconductors. And yes, you really have no way of knowing what people are doing with them when they fail.

 

[los33]

Care to define "box rise"? How is it measured and quantified? If you don't understand IMPEDANCE or have seen some impedance curves of raw drivers and drivers installed you definitely should NOT be giving advice telling people to run their amp to half or quarter ohm.

You been in the game to long for me to say i know more then you so im not gonna argue that, but throwing that same remark of if you dont understand impedance rise then you should be advising shiit.

I know enough to be able to able to do it. As far as my remark of it jumping to 1 ohm that was a general statement not meant for all setups.

But the fact that because you are wired to .5 ohm does not mean you stay at .5 ohm in every bass note.

This is the reason all amps wired down to .5 ohm do not blow. Its all user dependent.

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[bgowdy 5,000+ posts]

Care to define "box rise"? How is it measured and quantified? If you don't understand IMPEDANCE or have seen some impedance curves of raw drivers and drivers installed you definitely should NOT be giving advice telling people to run their amp to half or quarter ohm.


Because you are doing what you are doing in no way implies that your amp ever sees .5 ohm, nor that it is a safe condition that isn't risking breaking your equipment. Nor should it be construed to mean that somebody else running different equipment in a different box and different vehicle could wire to a .5 ohm nominal load and not actually have his amp see that and blow up very quickly. It simply isn't good for amps and isn't safe and is a bad idea unless you have a really good reason to do it and can afford the gamble.

From Crescendo website: "1 Year/1ohm comprehensive warranty with 2 year/.5ohm optional extended warranty available."

IIRC they originally warrantied at .5 ohm and must have ran into trouble because they very quickly reneged on straight out no-questions-asked .5 ohm warranty.

understood, and you are correct.....

But what if a amp is factory "rated" to run .5 ohm daily?

 

[LosIsATool 5,000+ posts]

understood, and you are correct.....
But what if a amp is factory "rated" to run .5 ohm daily?

Some MMATs

 

[hispls 5,000+ posts]

You been in the game to long for me to say i know more then you so im not gonna argue that, but throwing that same remark of if you dont understand impedance rise then you should be advising shiit.
I know enough to be able to able to do it. As far as my remark of it jumping to 1 ohm that was a general statement not meant for all setups.

But the fact that because you are wired to .5 ohm does not mean you stay at .5 ohm in every bass note.

This is the reason all amps wired down to .5 ohm do not blow. Its all user dependent.

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A loudspeaker in a box acts like a rather complex circuit.

"Box rise" is a really ignorant sounding way to explain the impedance of this circuit changing with frequency. Without the relevant data for someone's particular application you cannot say what impedance an amp will see at any given frequency.

I repeat .5 ohm is very strenuous on semiconductors regardless of how many batteries you have and trying to do this with amps is a gamble. We still see amps for sale that are 25 years old and that was in the day they were built well. How many of these Chinese/Korean amps that people are running at

understood, and you are correct.....
But what if a amp is factory "rated" to run .5 ohm daily?

Very few are since most manufacturers know that is very abusive. Even if it's "rated" half ohm is BRUTAL for semiconductors. It's most probable that side by side the 2 ohm version of the same amp run at 2 ohms would far outlast the .5 ohm version. Many companies test their amps there and competitors will do it, but those with any sense won't warranty, or like Crescendo will charge more for the warranty..... Figure they know how many are likely to fail prematurely in that application and charge enough to give away some freebies.

Some MMATs

That's the only one I can think of off the top of my head that rates this and would stand behind a warranty. Bear in mind Mmats does their own engineering and R&D. This is NOT just a cookie cutter copy of the same circuit that the Chinese Koreans have been using for every amp for the last 10 years or so and might be a little more reliable. Again, they make 1 or 2 ohm versions of the same size amp so why on Earth would you chose to run .5 ohm which will sound audibly worse and be more stressful on the amp?

The days of "cheater" amps that are rated at 4 ohms being run at 1/4 ohm are long gone.