SUNN Beta Lead solid state amp no sound
- oceanblood
- audio school graduate
- Posts: 21
- Joined: Fri Feb 08, 2008 2:04 am
- Location: Portland, Oregon
SUNN Beta Lead solid state amp no sound
Hi everyone.
I've got a Sunn Beta Lead, I've had for almost a decade with no problems. I was playing a show and it just stopped producing sound. Dude in the audience said the volume was decreasing gradually and finally the amp went silent. I checked the fuse and the fuse is good. It powers up, lights come on, but it produces no sound whatsoever, not even a hiss or buzz. Don't have any idea how to diagnose or fix the problem, but I LOVE this amp and don't want to loose it!!! Any ideas?? Thanks!
I've got a Sunn Beta Lead, I've had for almost a decade with no problems. I was playing a show and it just stopped producing sound. Dude in the audience said the volume was decreasing gradually and finally the amp went silent. I checked the fuse and the fuse is good. It powers up, lights come on, but it produces no sound whatsoever, not even a hiss or buzz. Don't have any idea how to diagnose or fix the problem, but I LOVE this amp and don't want to loose it!!! Any ideas?? Thanks!
i7-5930k
32GB ripjaws DDR4 @2133
Windows 7 Ultimate
Sonar X3
firepod
32GB ripjaws DDR4 @2133
Windows 7 Ultimate
Sonar X3
firepod
- oceanblood
- audio school graduate
- Posts: 21
- Joined: Fri Feb 08, 2008 2:04 am
- Location: Portland, Oregon
So weird. I just did some trouble shooting and figured out it was the CAB!! I have two mini cabs loaded with 8 inch Jensens. The two cabs together make 100w @ 4ohms which is the amps rating, but the cabs are completely DEAD now. I plugged in a 15w 8ohm amp into each one. Utter silence.
i7-5930k
32GB ripjaws DDR4 @2133
Windows 7 Ultimate
Sonar X3
firepod
32GB ripjaws DDR4 @2133
Windows 7 Ultimate
Sonar X3
firepod
- Nick Sevilla
- on a wing and a prayer
- Posts: 5572
- Joined: Mon Mar 03, 2008 1:34 pm
- Location: Lake Arrowhead California USA
- Contact:
They might have fuses in between the speakers and the inputs. Check there.oceanblood wrote:So weird. I just did some trouble shooting and figured out it was the CAB!! I have two mini cabs loaded with 8 inch Jensens. The two cabs together make 100w @ 4ohms which is the amps rating, but the cabs are completely DEAD now. I plugged in a 15w 8ohm amp into each one. Utter silence.
Howling at the neighbors. Hoping they have more mic cables.
- oceanblood
- audio school graduate
- Posts: 21
- Joined: Fri Feb 08, 2008 2:04 am
- Location: Portland, Oregon
CRAZY UPDATE!!!
So inside my mini cabs I had 4 25w 4ohm 8inch speakers wired in series/parallell, 2 jensens and 2 quantums. I tested them and the Jensens were dead. Since the quantums survived I figured I just got some weak ass jensens, so I just slapped in the old quantums I still had. Anyway, cabs seemed to be working fine and we had band practice, after about 20 minutes cabs died again!!! The thing is, I've been using these cabs with this amp and the same quantum speakers for over a year. What's going on? Did something change in my amp it's now killing off speakers??? Anybody know what's going on here?? The amp is rated at 100W and the 4 speakers @ 25W each total 100W. Amp was on 4 the night it killed the Jensens, was on 2 just now at band practice. Both cabs died again.
So inside my mini cabs I had 4 25w 4ohm 8inch speakers wired in series/parallell, 2 jensens and 2 quantums. I tested them and the Jensens were dead. Since the quantums survived I figured I just got some weak ass jensens, so I just slapped in the old quantums I still had. Anyway, cabs seemed to be working fine and we had band practice, after about 20 minutes cabs died again!!! The thing is, I've been using these cabs with this amp and the same quantum speakers for over a year. What's going on? Did something change in my amp it's now killing off speakers??? Anybody know what's going on here?? The amp is rated at 100W and the 4 speakers @ 25W each total 100W. Amp was on 4 the night it killed the Jensens, was on 2 just now at band practice. Both cabs died again.
i7-5930k
32GB ripjaws DDR4 @2133
Windows 7 Ultimate
Sonar X3
firepod
32GB ripjaws DDR4 @2133
Windows 7 Ultimate
Sonar X3
firepod
- oceanblood
- audio school graduate
- Posts: 21
- Joined: Fri Feb 08, 2008 2:04 am
- Location: Portland, Oregon
Just tested the cabs. So, the quantums that were in the cab the night the jensens died, those died today durring band practice. The old ones I had sitting in a box survived band practice. Did the speakers just die a natural death? Or is there some known problem with solid state amps that makes them fry speakers? Someone please respond.
i7-5930k
32GB ripjaws DDR4 @2133
Windows 7 Ultimate
Sonar X3
firepod
32GB ripjaws DDR4 @2133
Windows 7 Ultimate
Sonar X3
firepod
- Snarl 12/8
- cryogenically thawing
- Posts: 3511
- Joined: Sat Dec 20, 2008 5:01 pm
- Location: Right Cheer
- Contact:
An underpowered amp is going to blow speakers faster than an overpowered one. Is your amp clipping? When you present a low frequency square wave, the amp is pushing out the speaker and holding it there for a bit, and then sucking it in and holding it. Speakers need to be constantly vibrating when electric current is present in order to not overheat. They, essentially act as their own cooling fan for the voice coil. Are the voice coils fried? What do the blown speakers measure on an Ohm meter? I suspect that something has happened to your amp to cut its power and that is causing the speakers to blow. Get your head checked out. It's probably a cheaper issue to fix now than when it dies completely.
BTW - I am not a pro tech (or a pro audio anything), but I learned this underpowered amp thing in college. The hard, stupid way. (Many, many moons ago.)
Maybe something else is going on, but that's my theory.
BTW - I am not a pro tech (or a pro audio anything), but I learned this underpowered amp thing in college. The hard, stupid way. (Many, many moons ago.)
Maybe something else is going on, but that's my theory.
- oceanblood
- audio school graduate
- Posts: 21
- Joined: Fri Feb 08, 2008 2:04 am
- Location: Portland, Oregon
Hey Snarl!!
Thanks for the reply!!
All 4 speakers are rated at 4 ohms. Amp is 4 ohms. They're wired in series/parallel, which makes the total load 4 ohms. What do you mean by underpowered? I'm reading in other forums people are saying the cab should be at least double the wattage. Perhaps that's the problem?
Thanks for the reply!!
All 4 speakers are rated at 4 ohms. Amp is 4 ohms. They're wired in series/parallel, which makes the total load 4 ohms. What do you mean by underpowered? I'm reading in other forums people are saying the cab should be at least double the wattage. Perhaps that's the problem?
i7-5930k
32GB ripjaws DDR4 @2133
Windows 7 Ultimate
Sonar X3
firepod
32GB ripjaws DDR4 @2133
Windows 7 Ultimate
Sonar X3
firepod
-
- tinnitus
- Posts: 1135
- Joined: Sat Jun 03, 2006 8:19 am
- Location: beautiful Carlsbad, CA
- Contact:
SS amps produce hard edged waveforms when clipping. Tube amps have more soft clipping.
A clipped wave form to a speaker is like smashing it in and out very fast. No speaker can tolerate that abuse for long. It's like throwing your body back and forth against a hard brick wall. You wouldn't last long either.
A 100 watt SS amp will produce about 270 watts of peak to peak power. 25 watt speakers won't like that either. No need for math here.
The last speaker I fried was a crappy used Mitchell from the UK. A little Fender Deluxe Reverb fried it back in 1993.
All Eminence now. No more speaker issues. My 4x12 is rated at 480 watts, can't blow that no matter how hard I try. Plus, they sound better than those crappy Chi-com Celestians and are 1/2 the price too. BTW, made in the USA, if that matters.
A clipped wave form to a speaker is like smashing it in and out very fast. No speaker can tolerate that abuse for long. It's like throwing your body back and forth against a hard brick wall. You wouldn't last long either.
A 100 watt SS amp will produce about 270 watts of peak to peak power. 25 watt speakers won't like that either. No need for math here.
The last speaker I fried was a crappy used Mitchell from the UK. A little Fender Deluxe Reverb fried it back in 1993.
All Eminence now. No more speaker issues. My 4x12 is rated at 480 watts, can't blow that no matter how hard I try. Plus, they sound better than those crappy Chi-com Celestians and are 1/2 the price too. BTW, made in the USA, if that matters.
Jim Williams
Audio Upgrades
Audio Upgrades
Or is it more like trying to push the speaker in one direction further than it wants to go? Or is it that the DC current (the flat "tops" of the clipped waves) end up arcing across the voice coil?
You can destroy a speaker with a solid state amp two ways:
1) If the amp is overpowered, but not clipping, it will slam the speaker back and forth too far and too fast for it's physical limits. Cone can rip, can start to tear free of the basket, in extreme cases the voice coil can "jump the gap", but unless it's way the fuck overpowered, you will normally be warned by noticeable and nasty distortion which is pretty easily recognizable.
2) If the amp is underpowered, and you try to get that little bit more volume out of the thing, you end up clipping the power amp section, the "tops" of which look like DC, which kills speakers nearly instantly. You might not have time to hear the distortion before it's all over.
That second one kind of freaks me out because in the early days of my "career" an old soundguy told me that you could check to see if speakers were blown, or check polarity, by connecting a 9V battery to them and watching them jump. I guess maybe the battery is unable to source enough current to destroy the speaker?
You can destroy a speaker with a solid state amp two ways:
1) If the amp is overpowered, but not clipping, it will slam the speaker back and forth too far and too fast for it's physical limits. Cone can rip, can start to tear free of the basket, in extreme cases the voice coil can "jump the gap", but unless it's way the fuck overpowered, you will normally be warned by noticeable and nasty distortion which is pretty easily recognizable.
2) If the amp is underpowered, and you try to get that little bit more volume out of the thing, you end up clipping the power amp section, the "tops" of which look like DC, which kills speakers nearly instantly. You might not have time to hear the distortion before it's all over.
That second one kind of freaks me out because in the early days of my "career" an old soundguy told me that you could check to see if speakers were blown, or check polarity, by connecting a 9V battery to them and watching them jump. I guess maybe the battery is unable to source enough current to destroy the speaker?
- Scodiddly
- genitals didn't survive the freeze
- Posts: 3979
- Joined: Wed Dec 10, 2003 6:38 am
- Location: Mundelein, IL, USA
- Contact:
Just as a quick check for something unlikely but possible - measure the amp output with a DC voltmeter. Ideally have a speaker hooked up to sink any parasitic current. You're looking for problems with the amp producing constant DC, which is *not* something speakers will enjoy. If your speakers are all dead, maybe just a light bulb or a big resistor. Make this measurement with no signal present.
- oceanblood
- audio school graduate
- Posts: 21
- Joined: Fri Feb 08, 2008 2:04 am
- Location: Portland, Oregon
-
- tinnitus
- Posts: 1135
- Joined: Sat Jun 03, 2006 8:19 am
- Location: beautiful Carlsbad, CA
- Contact:
- Snarl 12/8
- cryogenically thawing
- Posts: 3511
- Joined: Sat Dec 20, 2008 5:01 pm
- Location: Right Cheer
- Contact:
It means DC electricity is getting straight from the power supply into the speaker outputs without passing "Go" and collecting $200. I like to think of amplifiers as modulated power supplies. You have a really solid, reliable, big source of constant electricity (DC) available. And then you let it go to the speaker in proportion to the input signal. So, if the input is wigglying very fast, but not very far (up and down, positive to negative, i.e. a quiet, high frequency) then you let through just a bit of electricity but in very fast little bursts, or whatever. One of the things that can go wrong is that the supply isn't modulated by the input, so you're just letting the constant electricity through to fry the speaker.oceanblood wrote:woah. You're saying to hook up a light bulb to my amp? What does it mean if it lights up?
Who is online
Users browsing this forum: No registered users and 61 guests