Great, thanks for the advice...8 ohms it is then.
Here in the UK we don't have many options, 4 ohms is usually especial order and with that a price increase over the 8 ohms version.
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Ohms FAQ
- Thread starter IvanMike
- Start date
Great, thanks for the advice...8 ohms it is then.
Here in the UK we don't have many options, 4 ohms is usually especial order and with that a price increase over the 8 ohms version.
I'm still a bit hazy on understanding the formula. My head doesnt have a way to set how many ohms I'm running but it allows 2,4, and 8 ohms (Carvin b2000). I'm running this head through an ampeg pr810h that can run 8 or 4 ohms and a peavey 215 cab that runs at 8 ohms. How many ohms am I running? How can you tell? Below are links to my gear and their specs.
[Invalid or Expired Link Removed]
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Couldn't find a manual for the 215.
Any light shed on the situation would be most appreciated.
[Invalid or Expired Link Removed]
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Couldn't find a manual for the 215.
Any light shed on the situation would be most appreciated.
If you setup the 810 for 4 ohm operation and add the 8 ohm 215 the combined load to the amp is 2.667 and the amp will be fine. SS amps (in most every case) don't have a switch for output loads, that is more a tube amp thing.
Back up. I think you'll find the ampeg cab can run as one 8 ohm cab or 2 4 ohm cabs in the same box. You'll have to to run it as 8 ohms, otherwise it's going to be 2 ohms just for the 8x10.
That is not correct. The manual says that each 4x10 unit is 8 ohms. They can each by driven by a separate amplifier carrying a 8 ohm load. OR they can be connected together externally by a cable from the top jackplate out to the other jackplate in, presenting the amp at that point with 4 ohms.
If the 2x15 is 8 ohms then the final load is 2.667 ohms.
OR
If the 2x15 is 4 ohms, the final load when that is connected in parallel is 2 ohms.
Either will work fine BUT if the 2x15 is connected is an 8 om cab, and the loads are connected in parallel, then the 2x15 will get 1/3 the POWER. 1/3 will go to the top 4x10 and 1/3 will go to the bottom 4x10.
If the 2x15 is 4 ohm, it will get 1/2 the power.
Open up the Peavey and see what speakers are in it. Note comments from Bill Fitzmaurice in this thread if it is old or has similar spec speakers.
http://www.talkbass.com/forum/f15/help-peavey-215-cab-588954/
3 dB is not the smallest change in volume a person can hear. This is a canard that keeps getting passed along and I feel it is quite misleading. Reference the link below, you will see, and hear, that 1 dB is close to the Just Noticeable Difference (JND), sensibly enough. A 3dB difference, while still not a lot, is clearly audible.
Even better in the link below are sound samples, about 1/4 of the way down, that demonstrate white noise in decreasing volumes; first by 3 dB steps, then by 1 dB steps, and finally by 0.3 dB steps. You can clearly hear for yourself that a 3dB difference is easily audible, well above the JND.
http://www.animations.physics.unsw.edu.au/jw/dB.htm
Point well taken. And having studied some psychophysical auditory phenomena along the way, I beleive that is completely correct from the POV of the human auditory system, though I am not sure at which SPLS that may not be true. Does that article deal with anything over 100db for example. You know, metal band time?
IvanMike is off in cyberspace somewhere, and I will make the appropriate edit. Or, if you would like to edit that paragraph and PM it to me, I will insert it after looking it over. I would like to review the link you sent as well.
(I have a jam I am about to be late for, but thank your for pointing out the canard, we will marinate it now and cook it tomorrow.)
As always, we welcome helpful suggestions and corrections to posted material.
IvanMike is off in cyberspace somewhere, and I will make the appropriate edit. Or, if you would like to edit that paragraph and PM it to me, I will insert it after looking it over. I would like to review the link you sent as well.
(I have a jam I am about to be late for, but thank your for pointing out the canard, we will marinate it now and cook it tomorrow.)
As always, we welcome helpful suggestions and corrections to posted material.
I believe Bell labs defined 3dB along the lines of the smallest "significant" difference where average listener didn't have to prick up his ears, so to speak, to identify a change.
I've done the tests too. 6dB is "now we're cooking" kind of a bump. 3dB "isn't anything to write home about", if I'm bumping myself up it's got to be at least that.
If I'm upgrading 300w to 500w, less than 3db extra headroom, "I payed how much?, I was ripped off".
I've done the tests too. 6dB is "now we're cooking" kind of a bump. 3dB "isn't anything to write home about", if I'm bumping myself up it's got to be at least that.
If I'm upgrading 300w to 500w, less than 3db extra headroom, "I payed how much?, I was ripped off".
I have done a bunch of reading here but can't find a really specific answer to my questions.
I picked up a used Genz Benz Shuttle 6.0 a couple of weeks ago and last Friday I picked up an Eden Nemesis 410 4ohm cabinet.
After getting the 410 home and dialling in a happy tone (with a Sadowski preamp pedal), I decided to "experiment" with my old 8ohm 115 cab.
Yes that's right I did bad. Plugged in the 4ohm 410 (500 watts) AND the 8ohm 115 (300 watts) into the Shuttle 6.0 rated at 4ohm minimum load, and played for around 20 mins with the master volume on less than 1/2 of 1 (less than 0.5 on a scale of 0-10). The two cabinets were plugged in separately from the two Shuttle speaker outputs.
Of course, I only read this thread the next day..:scowl:
There were no strange noises or smells at the time, and the next day the happy tones seemed to remain (although it is very hard to tell, I have fiddled around with both shuttle eq/gain/enhancement controls and sadowski controls a lot, dialling in different tones).
My questions are:
1) How do I really know if I have damaged the Shuttle, without taking it to the amp mechanic?
2) Is there any way to know for sure using my ears?
3) What are the chances of having damaged the Shuttle at such low volumes, or does the master volume setting make no difference in this case?
P.S. Talkbass rocks and the amount of information and opinion here is astounding, I have learnt so much over the past couple of months. As a guitarist who has suddenly become a bass player, this forum is priceless. Thank you to all the people involved.
Cheers
I picked up a used Genz Benz Shuttle 6.0 a couple of weeks ago and last Friday I picked up an Eden Nemesis 410 4ohm cabinet.
After getting the 410 home and dialling in a happy tone (with a Sadowski preamp pedal), I decided to "experiment" with my old 8ohm 115 cab.
Yes that's right I did bad. Plugged in the 4ohm 410 (500 watts) AND the 8ohm 115 (300 watts) into the Shuttle 6.0 rated at 4ohm minimum load, and played for around 20 mins with the master volume on less than 1/2 of 1 (less than 0.5 on a scale of 0-10). The two cabinets were plugged in separately from the two Shuttle speaker outputs.
Of course, I only read this thread the next day..:scowl:
There were no strange noises or smells at the time, and the next day the happy tones seemed to remain (although it is very hard to tell, I have fiddled around with both shuttle eq/gain/enhancement controls and sadowski controls a lot, dialling in different tones).
My questions are:
1) How do I really know if I have damaged the Shuttle, without taking it to the amp mechanic?
2) Is there any way to know for sure using my ears?
3) What are the chances of having damaged the Shuttle at such low volumes, or does the master volume setting make no difference in this case?
P.S. Talkbass rocks and the amount of information and opinion here is astounding, I have learnt so much over the past couple of months. As a guitarist who has suddenly become a bass player, this forum is priceless. Thank you to all the people involved.
Cheers
Jim Carr
Dr. Jim
- Jan 21, 2006
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So the danger here is that using two mismatched cabs can potentially heat-up the power amp inside the Shuttle to the point of meltdown? And the Shuttle has built-in thermal shut-off protection to stop it from cooking? So basically you're saying the amp knows when it is getting too hot?
Do you think this thermal shut-off protection is reliable?
I just want to be sure...it's very hard to tell soundwise as I had only just gotten the cabinet home and am not that familiar with it's tone...
Do you think this thermal shut-off protection is reliable?
I just want to be sure...it's very hard to tell soundwise as I had only just gotten the cabinet home and am not that familiar with it's tone...
You got away with it once, I wouldn't risk the amp doing it again. It's rated 4 ohm minimum for a reason.
Not quite - it's not the fact they are mismatched, it's the fact that the two cabs together present a load less than the Shuttle's minimum load.
Thermal protection is usually reliable - but nothing is 100% reliable, so why push it?
There is no need to ask
No chance with the ears, unless the amp is dead or farts out.
No chance at room volume level.
So don't do that mismatching anymore.
If the amp have a defect one day means you don't have to ask if ohm mismatching was the reason.
But if you do the mismatching again you will assign the reason for any possible defects due to the ohm abuse.
But if your amp is off or no signal is present at the output means the load can be anything.
After much reading on ohms an watts as well as how it effects the amp, I've got a question.
The amp head is 300 watts at 4 ohms and 175 at 8 ohms. It comes with two cabs which are both 150 watts at 8 ohms. If I understand correctly, running them in series would put them at a 4 ohm load and running them parallel would put the ohm load at 16 which would cut the watts to around 100. Am I better off running them in parallel or running in series and just making sure not to turn them up too much to reduce the risk of damaging the speakers until such time as I have enough money to replace the cabs with one's that match the head?
The amp head is 300 watts at 4 ohms and 175 at 8 ohms. It comes with two cabs which are both 150 watts at 8 ohms. If I understand correctly, running them in series would put them at a 4 ohm load and running them parallel would put the ohm load at 16 which would cut the watts to around 100. Am I better off running them in parallel or running in series and just making sure not to turn them up too much to reduce the risk of damaging the speakers until such time as I have enough money to replace the cabs with one's that match the head?
You have it backwards.... parallel (which means just plugging into the two outputs on the back of your amp or ... assuming it is a solid state amp and not a tube power section...... or just daisy chaining the cabs from one amp output) will result in two 8ohm cabs showing the amp a nominal 4ohm impedance.
While the power rating of cabs is a relatively useless spec, your amp will put out a power level right at the 'max thermal' ratings of each cab, which should be fine in the standard parallel connection.
As with any rig, use your ears. If you hear distortion, or if the rig stops getting louder after you turn up to a certain point, turn down
Thanks. Definitely backwards on that. Too much info bouncing around from all this research.
The amp in question is a hybrid. Eden WT300 Traveller solid state with a tube pre amp.
So, is it safer to run parallel making sure to keep it below the distortion level or run in series thereby lowering the wattage output of the amp?
The amp in question is a hybrid. Eden WT300 Traveller solid state with a tube pre amp.
So, is it safer to run parallel making sure to keep it below the distortion level or run in series thereby lowering the wattage output of the amp?
Series rarely makes sense, and surely doesn't make sense in this case. Yes, run parallel and be happy!
