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Measuring Amplifiers - Page 6

post #151 of 1917
Quote:
Originally Posted by staffcurtis View Post

The Crown startup was actually pretty interesting...I thought all churches made money anyway

Would you recommend that Techron amp if I could get it cheap?

Thanks


You'd want to make sure that the amp was set up for audio, IIRC the Techron amps were intended for driving field coils in MRI machines and as such were setup for constant current operation, this is again IIRC something that can be altered to allow for operation in constant voltage mode that is common in 99.9% of soild state audio amps.

That is if i don't have it all backwards in my head



Good luck
Later
Dan
post #152 of 1917
Thread Starter 
Here are the results of preliminary testing of the 'infamous' Buttkicker amplifier. It would not even come close to rated specifications. On the other hand, the specifications are rather limited. Here they are directly from the website.

"ButtKicker Amplifier Specifications

Model #: BKA1000-4A

1000 Watts @ 4 ohms

1900 Watts @ 2 ohms - will power 2 ButtKicker LFEs wired in parallel , and 4 ButtKicker LFEs used in individual home theater seats.

Class D switching technology

Variable high cutoff, 40 to 160 Hz

Low cutoff, 25 Hz switchable

RCA and ΒΌ inputs with 160mVolt and 1.25 Volt sensitivities eliminates the need for a separate pre-amplifier
Five way binding post output

120v or 240v versions available

Convection cooling, i.e. no fan

12"W x 11"L x 4.375"H,

11 lbs / 11.36 kg"

No S/N, distortion, frequency response, etc. is given at all. Here are the preliminary results of testing at 4 ohms. It doesn't look good for 2 ohms. Power is down, distortion is up, and frequency response, well, you get the picture.



I will post more tomorrow.

Chuck
post #153 of 1917
Bleh, I would have thought the BK would have better LF response than the EP2500.
post #154 of 1917
That FR is just as expected (from the Secrets review), but that power output is absolutely not. Most unfortunate.
post #155 of 1917
Looks like the Buttkicker took a butt whoopin', LOL

Thanks for testing it. I look foreward to the rest of the results.



Later
Dan
post #156 of 1917
Quote:
Originally Posted by Willd View Post

That FR is just as expected (from the Secrets review), but that power output is absolutely not. Most unfortunate.

yeah, I was going to say that too.... Those distortion levels are depressing...
post #157 of 1917
Quote:
Originally Posted by chasw98 View Post






Chuck

EP2500

post #158 of 1917
I gave those amps a try myself, and was totally depressed with the sound, but I was sure the buttkickers had more power than those ratings. Oh well....the amps were designed for transducers, and they still do good with that. for my shakers, I'd probably consider having a Behringer EP2500 over the buttkicker if I hadn't had one already. Anybody try a behringer with the buttkicker transducer?
post #159 of 1917
While we are on the subject of the EP2500, I just found out tonight that the parallel input mode on my unit does not function quite right. My left channel picks up the signal very strong but the "copied" version it sends to the right channel is decreased by 5dB or so

When I tested a 12Hz tone I actually got *zero* cone movement in the right channel subwoofer. Anyway, I switched it over to stereo mode and used a y-adapter and now all is well again.
post #160 of 1917
Thread Starter 
Here are some more numbers on the Buttkicker amplifier. I have included 2 pictures of the test rig so that you can see what I am doing and what the waveform looks like. This amp was designed for tactile transducers and performs that job very well. But if you will notice the Yellow Fluke voltmeter in the picture, it is reading the input voltage to try and get this amplifier to do what it says on the box. The front end of this amp is awful. If the input signal is too high, the waveform is distorted before you have even amplified it to send the signal to the speakers. When sending the signal to transducers, waveform does not matter!

This picture is showing the input voltage at over 7 volts and the distortion is at 14%.


This picture shows the frequency (49 Hz), distortion (13.7), waveform (top trace) and distortion (bottom trace), and input voltage (7.24 VAC).


And here is chart with readings as much as I could get from the amp at 4 & 2 ohms. I had to use 125 VAC to drive the amp just to get the maximum wattage.


Chuck
post #161 of 1917
Thread Starter 
Quote:
Originally Posted by jvgillow View Post

While we are on the subject of the EP2500, I just found out tonight that the parallel input mode on my unit does not function quite right. My left channel picks up the signal very strong but the "copied" version it sends to the right channel is decreased by 5dB or so

When I tested a 12Hz tone I actually got *zero* cone movement in the right channel subwoofer. Anyway, I switched it over to stereo mode and used a y-adapter and now all is well again.

Jeremy:
Interesting, all 4 of my Behringer amps do the same thing! I wired them individually to solve the problem also.
post #162 of 1917
Thank you very much for testing the BKA, Chuck. I am already looking at getting a much better amp now.

BTW, do you have any experience with the Crown XS-1200 or XS-900?

http://www.crownaudio.com/pdf/amps/137150.pdf
post #163 of 1917
Geez that test equipment looks impressive and it's doing the job you assembled it to do too.
As is often the case an unitended consequence of a tester trying a piece of equipment out for one purpose only serves to prove it was well designed for it's original purpose. The Buttkicker amp does 20 to 100 Hz well and for use with a tactile transducer that's all it had to do. I'm not sure the amount of distortion, 14%, is important in transducer reproduction, how much distortion can a "BUTT" discern anyway?
post #164 of 1917
Quote:
Originally Posted by LINEARX View Post

Geez that test equipment looks impressive and it's doing the job you assembled it to do too.
As is often the case an unitended consequence of a tester trying a piece of equipment out for one purpose only serves to prove it was well designed for it's original purpose. The Buttkicker amp does 20 to 100 Hz well and for use with a tactile transducer that's all it had to do. I'm not sure the amount of distortion, 14%, is important in transducer reproduction, how much distortion can a "BUTT" discern anyway?

True, but many have been using it to power DIY subs for a while.
post #165 of 1917
Wow, those Buttkicker ratings have me contemplating a different amp as well, particularly the distortion ratings. Guess I'll have to sell my Adire Audio Rava and Outlaw LFM-1 subs...
post #166 of 1917
Quote:
Originally Posted by deneb View Post

Wow, those Buttkicker ratings have me contemplating a different amp as well, particularly the distortion ratings. Guess I'll have to sell my Adire Audio Rava and Outlaw LFM-1 subs...

At least you haven't bought one yet. Don't just contemplate, DO get another amp instead of the BKA.
post #167 of 1917
Anybody have a link to that person with the burst-into-flames BKA? That was enough to discourage me from ever getting one.
post #168 of 1917
I'm actually now thinking about selling the buttkicker amp I have for my transducer, and getting the EP2500 for that. I can also compare the sound quality, and see if their equal, or if the Behringer is a much better buy. From what I've read here....especially thanks to the awesome efforts of CHASW98, I would bet the Berhinger would be even better for the buttkicker transducers than the buttkicker amp.... let alone for subs.
post #169 of 1917
Quote:
Originally Posted by jvgillow View Post

Anybody have a link to that person with the burst-into-flames BKA? That was enough to discourage me from ever getting one.

Wow...the buttkicker amp seems less appealing by the minute.
post #170 of 1917
Quote:
Originally Posted by Willd View Post

At least you haven't bought one yet. Don't just contemplate, DO get another amp instead of the BKA.

Unfortunately, I already have two of them I'm sure someone out there will need them for what they were designed for, at least I hope so!

Staffcurtis, looks like you're on to something...

Do we need to start a group therapy thread for Buttkicker letdown? Or maybe an 'ex-BKA owner needs a real sub amp' thread.
post #171 of 1917
Quote:
Originally Posted by deneb View Post

Do we need to start a group therapy thread for Buttkicker letdown? Or maybe an 'ex-BKA owner needs a real sub amp' thread.


I see I'm not alone here. There are a lot of folks that praise the buttkicker amp, and hail it as the best deal around. The only thing I could think of is that they haven't heard better from what's better out there. Compared to the Adcoms it was like night and day. I'll probably order a Behringer, so I at least know the powers there. I'm also contemplating a QSC PLX amp or a CE4000 for better sound quality. Either of those two should do my job nicely. I just would rather steer people away from my mistakes instead of letting others go down the wrong path.

Good luck!
post #172 of 1917
deneb,

I did post this one up a few days ago:

http://www.avsforum.com/avs-vb/showt...2#post11038142

I am always up for more input.
post #173 of 1917
Yeah, I saw that thread but didn't say much, I was monitoring the amp testing thread to see if your observations had any factual basis behind them, which it appears they did.

I did start an 'amp recommendations' thread.
post #174 of 1917
Link for the lazy?
post #175 of 1917
Quote:
Originally Posted by jvgillow View Post

Anybody have a link to that person with the burst-into-flames BKA? That was enough to discourage me from ever getting one.


http://www.avsforum.com/avs-vb/showthread.php?t=852780
post #176 of 1917
Quote:

Say what you want, it sure is a nifty way to make grilled cheese sandwiches.
post #177 of 1917
So now, I have to take my buttkicker out back and shoot it??

I was happy until now!!!

The trick for me would be to find an amp that hast the same form factor.
Is it possible that it was not feeling well? :^]
post #178 of 1917
Thread Starter 
Quote:
Originally Posted by digital desire View Post

Is it possible that it was not feeling well? :^]

It was brand new out of the box!
post #179 of 1917
Quote:
Originally Posted by chasw98 View Post

It was brand new out of the box!

Ooooh, that burns.

BTW what are the specs given by the BK company for the amplifier?
post #180 of 1917
Quote:
Originally Posted by crackyflipside View Post

Ooooh, that burns.

BTW what are the specs given by the BK company for the amplifier?

They were in Chuck's post further up.

http://www.avsforum.com/avs-vb/showt...&#post11032546

And believe me, whether it was new out of the box or a year old, it burns just as much.
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