Brazilian amp testing

[Sparkomatic 10+ year member]

So here i have found on a forum from there some testing done between Taramps Banda Stetsom SounDigital. Apparently a dealer of all 3 amps has done testing on the 2500 series amps with a 2 ohm resitive load and a batt bank of 300 Ah

Taramps 2500 wrms @ 2 ohms

60 hz = 52v, 1352wrms @ 2ohms

100hz = 54,1V, 1463wrms @ 2ohms

Banda Ice 2500 wrms @ 2 ohms

60hz = 60V, 1800wrms @ 2ohms

100hz = 60,9V, 1854wrms @ 2ohms

SounDigital 2500 wrms @ 2ohms

60hz = 70,9V, 2513wrms @ 2ohms

100hz = 69,8V, 2436wrms @ 2ohms

Stetsom 2500 wrms @ 2 ohms

60hz = 61,7V, 1903wrms @ 2ohms

100hz = 63,8V, 2035wrms @ 2ohms

I donot know how exactly the test were done and where is current output measurement but i thought this would be some info on the amps as people are always looking and questioning them. and now with questions regarding the Banda and taramps I too would like to see some larger version comparisons.

Click to read more...

 

[ninjawhiteboy12 10+ year member]

nice find, they could have done the test a little better but cool, it looks likes Soundigital came out on top

 

[roarzorz 10+ year member]

Resistive load tests provide useless information. They need to do reactive tests to show more real world usable power.

 

[mrogowski 5,000+ posts]

Sounds about right. Its tough to let the air out of company's specs, but you gotta call a spade a spade.

 

[mrogowski 5,000+ posts]

Resistive load tests provide useless information. They need to do reactive tests to show more real world usable power.

Huh???

 

[Sparkomatic 10+ year member]

http://www.4shared.com/file/144198828/829dbc89/3o_teste_taramps_sd.html

here is a vid of the testing on taramps and the SD

 

[soundstreamer 10+ year member]

http://www.4shared.com/file/144198828/829dbc89/3o_teste_taramps_sd.html

here is a vid of the testing on taramps and the SD

Are these guys are affiliated with SoundDigital in any way? If this is a honest comparison of the amps... good job SoundDigital!

 

[gunz4me2 10+ year member]

Resistive load tests provide useless information. They need to do reactive tests to show more real world usable power.

A reactive load simulates a subwoofer or is generally the subwoofer or other driver. Under most testing circumstances, I have observed the reactive load showing power numbers up to 25% higher than the resistive load. In other words, the reactive load erroneously skews the results by showing that the amplifier is under rated and is capable of producing more power when in reality it is NOT!

I do question your reasoning as to how a reactive load would show "real world usable power".

 

[roarzorz 10+ year member]

A reactive load simulates a subwoofer or is generally the subwoofer or other driver. Under most testing circumstances, I have observed the reactive load showing power numbers up to 25% higher than the resistive load. In other words, the reactive load erroneously skews the results by showing that the amplifier is under rated and is capable of producing more power when in reality it is NOT!
I do question your reasoning as to how a reactive load would show "real world usable power".

What the hell are you talking about? You will never see a higher power output using a reactive load (actually testing with a subwoofer) because of impedance rise unless you're doing the testing wrong.

 

[gunz4me2 10+ year member]

What the hell are you talking about? You will never see a higher power output using a reactive load (actually testing with a subwoofer) because of impedance rise unless you're doing the testing wrong.

I take it you don't know how to fight impedance rise on a reactive load test utilizing subwoofers to skew the results? I do!

Read this: http://www.bcae1.com/measpwr.htm and take special note of the Test Data section at the end where a reactive load is compared to a resistive load. After you are done with the aforementioned reading, come back and provide "real world" examples to prove why I am wrong (ETA: and more importantly, why Mr. Perry Babin is wrong), assuming you can.//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[roarzorz 10+ year member]

I take it you don't know how to fight impedance rise on a reactive load test utilizing subwoofers to skew the results? I do!

So you purposely do the test wrong to skew the results? Do the test right and you won't have that problem.

Read this: http://www.bcae1.com/measpwr.htm and take special note of the Test Data section at the end where a reactive load is compared to a resistive load. After you are done with the aforementioned reading, come back and provide "real world" examples to prove why I am wrong (ETA: and more importantly, why Mr. Perry Babin is wrong), assuming you can.//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

That entire write up is a joke. Talking about "Quickly disconnect the dummy load of one channel and measure its exact resistance while it is still hot." How silly is that? A totally useless step. Just clamp current output, calculate, and be done.

I also don't see where clamping current output on a reactive load was done at all. It only says "The power is the calculated power using the speaker's nominal impedance (4 ohms) and the voltage across the speaker's terminals at the various frequencies. " They're assuming a constant 4ohm impedance which is WRONG. It will not remain constant under a reactive load. You must clamp current output to calculate actual power output.

Every idiot online thinks they're a know it all. Have fun with that. :shakes head: :walks out:

 

[dtbrown 10+ year member]

A reactive load simulates a subwoofer or is generally the subwoofer or other driver. Under most testing circumstances, I have observed the reactive load showing power numbers up to 25% higher than the resistive load. In other words, the reactive load erroneously skews the results by showing that the amplifier is under rated and is capable of producing more power when in reality it is NOT!
I do question your reasoning as to how a reactive load would show "real world usable power".

LOL, well then who ever you where watching test an amp was either trying to purposely get higher numbers by messing with the load or didn't know how to power test with a reactive load. But if tested right with a reactive load you'll always see less power then a resistive load.

So with what you saw doesn't apply 99% of the time if a test is done right with a reactive load.

 

[gunz4me2 10+ year member]

So you purposely do the test wrong to skew the results? Do the test right and you won't have that problem.

Funny thing about statistics and how one can skew the results to make them say anything they want, isn't it?

I also don't see where clamping current output on a reactive load was done at all. It only says "The power is the calculated power using the speaker's nominal impedance (4 ohms) and the voltage across the speaker's terminals at the various frequencies. " They're assuming a constant 4ohm impedance which is WRONG. It will not remain constant under a reactive load. You must clamp current output to calculate actual power output.

With ohms law, one technically needs two the values to solve for the final (i.e. Watts = Voltage^2/ohms). Voltage at measured impedance would suffice and/or the use of an ammeter. Then again, technically you are correct because the higher voltage would generally be at a higher impedance, BUT that impedance is TOUGH to measure while a subwoofer is bouncing back and forth. I wish you luck in getting that exact voltage at a particular impedance level for a millisecond to perform your calculations outside of a scientific lab.

Sadly, even with an amp clamp it is quite possible to see the appropriate amperage pass through when multiplied with the voltage to simulate a higher power output level than is technically possible. I've performed the power measurement tests myself both ways utilizing an oscilloscope to determine clipping in addition to borrowed, properly calibrated Fluke instruments to determine voltage and amperage. In 80% of the cases, I've observed higher output levels just prior to clipping with subwoofers, i.e. your precious "real world" reactive load, than into Dale dummy resistive loads.

The bottom line is no matter how you slice it or dice it, a reactive load is NOT a true representation of how an amplifier will perform to provide "real world usable power". We are going to be in permanent disagreement on that one.

Every idiot online thinks they're a know it all. Have fun with that. :shakes head: :walks out:

Pot -> Kettle -> Black...//content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

 

[murilo 10+ year member]

Hello

Amplifier power should be no different considering a reactive load or resistive load (considering both at the same resistance/impedance). Our amps are designed to try to have a flat power output regardless of the load characteristic (if capacitive or inductive), as we know this is very difficult but we think this is very important, specially when we produce amplifiers used in PA speakers, huge very low frequency subs and massive SPL drivers.

Power measurement standards specify resistive loads so is what we and all other factories use when measuring power.

 

[2lo2flo 10+ year member]

Tests that we did..

Stetsom 2k5d and 7k2d

http://www.caraudioclassifieds.org/forum/showthread.php?t=21445