Could you explain exactly how to test?
Kenwood Basic M2A Shuts Down at Higher Volume
- Thread starter OnThePike
- Start date
Could you explain exactly how to test?
Thank you. Some days are better than others. 10 days until surgery #3. But it's not life-threatening. I appreciate your response.
If I'm using the Ipod --
iTrax iPod Mixer (which includes L/M/H pots) --> Channel Mixer (which includes L/M/H pots) --> Preamp (which includes multiple sound enhancement switches) --> EQ (tape monitor loop) --> M2A (which includes L//H pots and vol) --> Speakers.
So there's a lot of additional amplification involved --but this doesn't seem to be the problem, though it probably doesn't help either.
What if I bypassed the protection circuit, if possible, and just let the speaker fuses blow
Hmm... maybe my meds are kicking in now...
dr*audio
Fish fingers and custard!
Next thing to try is to see if it's only one channel that causes the amp to shut down. Note where the volume knob is when the amp shuts down, then turn it off and turn the balance to the right, then repeat the test. Does it shut down at the same point? Then try it with the left channel. If it only shuts down with one channel and not the other, you need to check your speakers. Possibly a woofer is frozen or the voice coil is rubbing.
whoaru99
Epic Member
Since you've already substitued different wire to the speakers and the same thing happens, it's probably not the wire.
whoaru99
Epic Member
What if I bypassed the protection circuit, if possible, and just let the speaker fuses blow
Hmm... maybe my meds are kicking in now...
If it is the amp shutting down from overload/pushing too hard, bypassing protection circuits will eventually, IMO, result in letting the magic smoke out of the amp.
The amp has power meters on it...what are they showing when it cuts out? Are they maxed out much of the time?
Is there a protection light on the amp that comes on when it cuts out?
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bowtie427ss
Lunatic Member
Check the DCR of the speakers. I'll wager they dip too low for the amp, and i'll further wager you get a DCR reading of less than 4 ohms. Am i having deja vu?
CV's specs are minimal and mostly useless, since they contradict themselves on the sensitivity claiming 97db in one place and 96db in the manual, this undermines the credibility of any other specs they publish, the focus seems to be purely on marketing IMO.
EDIT: i should also add that CV's impedance rating with the addition of the word "compatible" is quite meaningless, and it should be a strong hint that things are not exactly as they've been made to appear.
I can almost guarantee that a modern "pro" amp will remedy your situation, but this is not to say that there's anything wrong with your Kenwood, it's more than likely a simple impedance mismatch.
CV's specs are minimal and mostly useless, since they contradict themselves on the sensitivity claiming 97db in one place and 96db in the manual, this undermines the credibility of any other specs they publish, the focus seems to be purely on marketing IMO.
EDIT: i should also add that CV's impedance rating with the addition of the word "compatible" is quite meaningless, and it should be a strong hint that things are not exactly as they've been made to appear.
I can almost guarantee that a modern "pro" amp will remedy your situation, but this is not to say that there's anything wrong with your Kenwood, it's more than likely a simple impedance mismatch.
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whoaru99
Epic Member
That may be possible too.
However, when I've overloaded inputs, there was usually distortion even at low volumes.
Should be easy enough to determine. Connect the music source directly to the preamp, bypass the EQ, and see what happens running just source > pre amp > power amp > speakers.
However, when I've overloaded inputs, there was usually distortion even at low volumes.
Should be easy enough to determine. Connect the music source directly to the preamp, bypass the EQ, and see what happens running just source > pre amp > power amp > speakers.
Well, interestingly enough, there is no distortion. Well, that is, once the bass is lowered, but there isn't that overmodulated distortion you would expect if over-driving inputs at each component. On the contrary, it's actually a very clear and quite booming sound -- until the heavy bass notes kick in and kill the amp.
Problem is, these speakers sound awful flat. They are "bass-intensive" speakers, or at least that's how they were advertised, and rightly so, in my opinion.
So... with this setup, I need "some" bass. But it appears that the bass required to acheive booming sound from these CV's also shut down the amp.
I guess that means, I'll need to lower the bass and possibly use a subwoofer? What are your opinions and suggestions there? Would a sub work with this setup? Or would that just give me more problems?
Problem is, these speakers sound awful flat. They are "bass-intensive" speakers, or at least that's how they were advertised, and rightly so, in my opinion.
So... with this setup, I need "some" bass. But it appears that the bass required to acheive booming sound from these CV's also shut down the amp.
I guess that means, I'll need to lower the bass and possibly use a subwoofer? What are your opinions and suggestions there? Would a sub work with this setup? Or would that just give me more problems?
I'd still like to learn the procedure. Could you explain eaxctly how to:
Thanks.
I don't understand what this means. Would you explain?
Let me explain a bit more about myself, because apparently I'm being confused with a "DJ" or similar. I am not, and haven't done any live spinning in over 15 years. And when I was into the hobby -- I said hobby, not profession, I mostly made tapes via multiple input sources on a reel-to-reel; the type of "bits and pieces" tapes you might find at your local car wash. The occasional live spinning was done free of charge at parties for friends and family.
So, while I did have some talent mixing records and making tapes (that I sold on Manhattan Beach in Brooklyn in the early 80's), that's about the extent of knowledge I have with respect to components. Minimal enough to get the job done. And using many of those same components you see in the pictures (that's how old they are).
So if you guys would be paitent with me and explain exactly what you mean, I would be grateful
whoaru99
Epic Member
These tests are pretty straight forward.
1. Disconnect the speaker wire from the speakers and from the amplifier, and make sure the ends of the wire are not touching each other or any other metal.
2. Set the mulitmeter to read resistance (the upside down horseshoe-looking symbol (Omega)). Touch the two multimeter probes to the speaker terminals. An 8 ohm speaker will typically have something on the order of 6 ohms, give or take 1 or 2 ohms, DC resistance (DCR).
Anything much different, especially lower, may indicate a problem in the speaker. Almost certainly so if you read very low like 0 ohms (short circuit) or even 1-2 ohms.
3. Touch the two mulitmeter probes to the two speaker wires, one probe to each wire. You should read an open circuit/infinite resistance (often shown as "OL" on the multimeter). Anything other than open circuit indicates a problem/short in the speaker wires. (Note: some high end cables with attached circuits could be an exception to this)
4. Reconnect the speaker leads to the speaker and touch the probes to the wires at the amplifer end of the cables. You should read about the same, or just a little higher than what you measured directly at the speakers.
If you read more than what you got in step 2, plus about 5%, either there is a bad connection, or you should consider thicker wire for the connection.
1. Disconnect the speaker wire from the speakers and from the amplifier, and make sure the ends of the wire are not touching each other or any other metal.
2. Set the mulitmeter to read resistance (the upside down horseshoe-looking symbol (Omega)). Touch the two multimeter probes to the speaker terminals. An 8 ohm speaker will typically have something on the order of 6 ohms, give or take 1 or 2 ohms, DC resistance (DCR).
Anything much different, especially lower, may indicate a problem in the speaker. Almost certainly so if you read very low like 0 ohms (short circuit) or even 1-2 ohms.
3. Touch the two mulitmeter probes to the two speaker wires, one probe to each wire. You should read an open circuit/infinite resistance (often shown as "OL" on the multimeter). Anything other than open circuit indicates a problem/short in the speaker wires. (Note: some high end cables with attached circuits could be an exception to this)
4. Reconnect the speaker leads to the speaker and touch the probes to the wires at the amplifer end of the cables. You should read about the same, or just a little higher than what you measured directly at the speakers.
If you read more than what you got in step 2, plus about 5%, either there is a bad connection, or you should consider thicker wire for the connection.
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redcoates7
still learning...
Mixers+Conventional hifi gear =BAD
Your Kenwood M2A is designed to achieve maximum output with an input voltage of somewhre between 1V and 2V. Feeding more voltage than that to your amplifier will cause it to clip, regardless of output level or type of speaker connected.
If you're tweaking the bass knobs on your Gemini AND increasing the gain on the various channels and main outputs, you are almost certainly producing WAY more voltage than your Kenwood was designed to acccept at its input, which results in it trying to produce WAY more power than it is capable of...which is turn engages the protection circuitry.
First step IMO is to connect a standard CD player to an input of the Kenwood C2 preamp. Connect the preamp's Main Outputs to the M2 amplifier (completely bypassing the mixer) and connect the speakers to the Kenwood amplifier.
In this conventional setup, I believe you will find you can play the CD player to ridiculously high volumes without a problem. If you MUST use the DJ mixer, I would reccommend connecting it to a preamp input of the Kenwood CD (TAPE input for instance) and adjusting gain on the Mixer so that you're never over-driving the preamp. You'll be able to tell very easily, by simply connecting a set of headphones to the C2 (power off the M2A amplifier) and just listen...if the sound from the Gemini distroted and/or way to boomy, you need to adjust your mixer until you get a good clean signal...you will be able to easily compare the output of the mixer with the output of the CD player to check by simply turning the C2's input selector to "CD" from "Tape"
I wouldn't worry about cabling and all that...sounds like a very simple case of too much gain,
Good luck
Your Kenwood M2A is designed to achieve maximum output with an input voltage of somewhre between 1V and 2V. Feeding more voltage than that to your amplifier will cause it to clip, regardless of output level or type of speaker connected.
If you're tweaking the bass knobs on your Gemini AND increasing the gain on the various channels and main outputs, you are almost certainly producing WAY more voltage than your Kenwood was designed to acccept at its input, which results in it trying to produce WAY more power than it is capable of...which is turn engages the protection circuitry.
First step IMO is to connect a standard CD player to an input of the Kenwood C2 preamp. Connect the preamp's Main Outputs to the M2 amplifier (completely bypassing the mixer) and connect the speakers to the Kenwood amplifier.
In this conventional setup, I believe you will find you can play the CD player to ridiculously high volumes without a problem. If you MUST use the DJ mixer, I would reccommend connecting it to a preamp input of the Kenwood CD (TAPE input for instance) and adjusting gain on the Mixer so that you're never over-driving the preamp. You'll be able to tell very easily, by simply connecting a set of headphones to the C2 (power off the M2A amplifier) and just listen...if the sound from the Gemini distroted and/or way to boomy, you need to adjust your mixer until you get a good clean signal...you will be able to easily compare the output of the mixer with the output of the CD player to check by simply turning the C2's input selector to "CD" from "Tape"
I wouldn't worry about cabling and all that...sounds like a very simple case of too much gain,
Good luck
MOPAR3
Super Member
I think your gonna need a bigger amp if your speakers check out ok. Those CV's are pretty rugged so I'd start looking on craigs list for a used pro amp of some sort. If those speakers will handle 500watts i'd look for something with at least that much power. More is better. Whoaru should be able to recomend something. I'm quessing for under 500.00 you'll be able to play as loud as you want.
whoaru99
Epic Member
I agree, this could be the case. But, as mentioned before, if one is overdriving the input level you'll generally hear distortion even at low volume, and the OP seems to indicate it's "clean" until things get cranky and shut down.
Besides, the input sensitivity of 1V - 2V of most home amps is the same range as input sensitivity of most pro audio amps.
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I want to thank everyone for their thoughtful suggestions and opinions, however I have decided to take another course of action and replace the old Kenwood stuff with something more modern (and perhaps, compatible) with my pair of CV-215's.
For that, I'll post a separate message.
One last question regarding the clipping, however: I never grounded the amp to anything. Just noticed that the other day. Would adding a ground help in this case?
Thanks again
Jeff
For that, I'll post a separate message.
One last question regarding the clipping, however: I never grounded the amp to anything. Just noticed that the other day. Would adding a ground help in this case?
Thanks again
Jeff
I've used the M2A to push "stacked double Original Large Advents" to fairly loud levels for extended periods of time with no problems. I've read where this set-up of speakers at times presents a difficult sub 4 Ohm load.
I'm going to suggest that an M2A in good working condition with proper ventilation should be able to handle most speaker loads just fine. I'm with some of the others - I think your problem probably lies elsewhere.
Good luck in overcoming your problem.
I'm going to suggest that an M2A in good working condition with proper ventilation should be able to handle most speaker loads just fine. I'm with some of the others - I think your problem probably lies elsewhere.
Good luck in overcoming your problem.
What are the specifications of the speakers you used? The Cerwin-Vega is supposed to be rated 500 watts @ 8 ohms.
The only thing I haven't done in the way of testing is to take the Kenwood Basic M2A for a service call. The amp plays perfectly; the speakers sound great, then as soon as I reach some threshold, you can hear the sound become "limited" and "flatten out"; then the thermal protection kicks in, the amp shuts down and the power indicator flashes.
The amp is still cold to the touch, however!
The only thing I haven't done in the way of testing is to take the Kenwood Basic M2A for a service call. The amp plays perfectly; the speakers sound great, then as soon as I reach some threshold, you can hear the sound become "limited" and "flatten out"; then the thermal protection kicks in, the amp shuts down and the power indicator flashes.
The amp is still cold to the touch, however!