Using a 550w amp with 250w cab...

[pantherairsoft]

Quick one for guys with more technical knowledge.

I'm in a situation where it seems I will soon have a Euphonic Audio 550 Micro. The can I need it to work with is my EA Wizzy 10 which I used to use my MarkBass Littlemark 250.

The Wizzy is 250w at 4ohms, the Micro is 550w at 4 ohm (oddly the lowest wattage amp they now make). Usually I would think this was destined to blow the speaker to bits... Bi it seems odd that the lowest powered amp they make is too hot for a cab that sell loads of!! So I asked the guys at EA.

I was told it was pretty safe to use as long as the amp didn't peak... In fact I was told it would be safer than say, using a 300w amp as the 550w head would have more headro before peaking and only peaking over the cabs wattage would damage it. Is this all true?

Does that mean a 1000w amp is safe to use with a 100w speaker as long as the amp doesn't peak!? Surely not

Shep

[voxpop]

Yes its true, distortion is the thing that blows speakers. Keep it clean and it will work fine. Use your ears they will tell you if the speakers start to complain.

Edited April 13, 2011 by voxpop

[warwickhunt]

[quote name='pantherairsoft' post='1198648' date='Apr 13 2011, 08:26 PM']Quick one for guys with more technical knowledge.

I'm in a situation where it seems I will soon have a Euphonic Audio 550 Micro. The can I need it to work with is my EA Wizzy 10 which I used to use my MarkBass Littlemark 250.

The Wizzy is 250w at 4ohms, the Micro is 550w at 4 ohm (oddly the lowest wattage amp they now make). Usually I would think this was destined to blow the speaker to bits... Bi it seems odd that the lowest powered amp they make is too hot for a cab that sell loads of!! So I asked the guys at EA.

I was told it was pretty safe to use as long as the amp didn't peak... In fact I was told it would be safer than say, using a 300w amp as the 550w head would have more headro before peaking and only peaking over the cabs wattage would damage it. Is this all true?

Does that mean a 1000w amp is safe to use with a 100w speaker as long as the amp doesn't peak!? Surely not

Shep[/quote]
It's a mine field when you start talking of power ratings and a MAHOOSIVE can of worms is opened when you start discussing under/overpowering speakers but it is safe to say that a 500w amp will not by simple fact of being plugged into a 250w cab cause drivers to blow! I've ran speakers of less than 250w with 1000w pre/power combos and I've never blown a driver; in fact I'm busy using my 550w Thunderfunk with a H&K 250w 2x10 cab and I'm getting some seriously nice sounds and I'm not worried in the slightest with blowing anything up... just use a bit of common sense and your ears. If the cab is complaining then turn the amp down a bit or roll off a bit of the low end.

[pantherairsoft]

That's good enough for me guys!

Cheers

[JTUK]

[quote name='warwickhunt' post='1198659' date='Apr 13 2011, 08:33 PM']It's a mine field when you start talking of power ratings and a MAHOOSIVE can of worms is opened when you start discussing under/overpowering speakers but it is safe to say that a 500w amp will not by simple fact of being plugged into a 250w cab cause drivers to blow! I've ran speakers of less than 250w with 1000w pre/power combos and I've never blown a driver; in fact I'm busy using my 550w Thunderfunk with a H&K 250w 2x10 cab and I'm getting some seriously nice sounds and I'm not worried in the slightest with blowing anything up... just use a bit of common sense and your ears. If the cab is complaining then turn the amp down a bit or roll off a bit of the low end. [/quote]


this....
but I would add that where volume is concerned, you may not be hearing it all as well you would like..so therefore do not hear any distress.

It is possible but I'd only do it myself in very controlled...and by that I mean, quiet, circumstances.
i.e, in a practice situation , then ok...when all hell is breaking loose...er...no..!!

[pantherairsoft]

It will be gigged... But only with a Cahon and acoustic guitar... Soft finger funk. Kinda sit down acoustic gig/open mic circumstance. Nothing too loud/aggressive etc etc.

[xgsjx]

Use your ears & you should have no probs. Are you using the big board with this finger funk?

[JTUK]

I'd have no worries then..

[pantherairsoft]

[quote name='xgsjx' post='1198751' date='Apr 13 2011, 09:38 PM']Use your ears & you should have no probs. Are you using the big board with this finger funk?[/quote]

No no no... That lives at the studio with my EBS rig. This is a side project, and also used as my home practice rig.

Shep

[pantherairsoft]

[quote name='voxpop' post='1198655' date='Apr 13 2011, 08:31 PM']Yes its true, distortion is the thing that blows speakers. Keep it clean and it will work fine. Use your ears they will tell you if the speakers start to complain.[/quote]

What about playing slap?? I do dabble... By nature the impact of the string often causes small peaks...

[xgsjx]

You could always pop a compressor in your line for the slap parts.

Edited April 13, 2011 by xgsjx

[pantherairsoft]

[quote name='xgsjx' post='1198776' date='Apr 13 2011, 09:55 PM']You could always pop a compressor in your line for the slap parts.[/quote]

Yeah... I'm just concerned about being in a situation where by if I don't have a compressor my rig isn't safe to use. I want to plug in and play like anyone else. Hmmmm

[warwickhunt]

[quote name='pantherairsoft' post='1198822' date='Apr 13 2011, 10:29 PM']Yeah... I'm just concerned about being in a situation where by if I don't have a compressor my rig isn't safe to use. I want to plug in and play like anyone else. Hmmmm[/quote]

Honestly it's not a big issue! I play in a 6 piece band with a loud drummer doing Springsteen, Skynyrd etc and I've no probs taking either the 2x10 or my Aggie 1x12's (though I almost always gig these as a pair, I'd not be worried about using one... I just like to feel the air moving with two ) and my 550w amp and that's from almost 30 yrs of gigging experience.

[Bill Fitzmaurice]

[quote name='voxpop' post='1198655' date='Apr 13 2011, 03:31 PM']Yes its true, distortion is the thing that blows speakers.[/quote]
Distortion doesn't blow speakers. High levels of distortion will be heard, however, if speakers are pushed hard enough where damage could occur. When that happens turn it down.

[JTUK]

[quote name='Bill Fitzmaurice' post='1198980' date='Apr 14 2011, 03:27 AM']Distortion doesn't blow speakers. High levels of distortion will be heard, however, if speakers are pushed hard enough where damage could occur. When that happens turn it down.[/quote]


This..

and this is why you play in situations where you can hear everything happening..ie, if in doubt, you need a quiet gig for mismatched set-ups..IMO.

[alexclaber]

Read this: [url="http://barefacedbass.com/technical-information/mythbusters1.htm"]Amp mythbusting![/url]

The Wizzy cabs have very low excursion limited power handling so you'll hear the increasing distortion (with clean sounds) well before thermal failure occurs. The risk from slap is causing such high excursion that the speaker doesn't just distort but completely runs out of travel, thus creasing the cone, buckling the voice coil or damaging the suspension. I think that's fairly unlikely to happen with that woofer but to be sure see if EA can tell you the ratio of Xlim to Xmax.

[chris_b]

Why would you believe us as opposed to the guys at EA?

Anyway, it doesn't matter what the maximum rating of your amp is, it's how loud you play it that counts. I use a 550 watt amp through a 300 watt 112 with an acoustic guitarist. That's what the volume controls are for.

[ThomBassmonkey]

Something I've wondered about this train of thought.

If you run a 500w amp at half*, is it only putting out 250w of power? Or does it not work like that?

Obviously it's easier to just listen out for distortion and knock it down when you get it, but it would mean it was easier to see that powerful amps would work with lower rated speakers when people ask.

* assuming everything's (hypothetically) running 100% efficient, perfectly flat response over the whole volume range and there's an even volume increase so 5 on the volume dial is actually exactly 50% of the output from 10 on the dial.

[Monckyman]

For me the best setup is over amping. Amps trying to punch above their weight produce square waves (clipping) and your driver won`t like that.
Headroom on the amp means lovely squiggly waves like it`s supposed to be.
Just don`t use any power (volume) you don`t need, no need to compress if you don`t want.

[alexclaber]

[quote name='ThomBassmonkey' post='1199250' date='Apr 14 2011, 11:59 AM']If you run a 500w amp at half*, is it only putting out 250w of power? Or does it not work like that?

* assuming everything's (hypothetically) running 100% efficient, perfectly flat response over the whole volume range and there's an even volume increase so 5 on the volume dial is actually exactly 50% of the output from 10 on the dial.[/quote]

No, absolutely not. It will be putting out 250W only at the moment when the voltage hitting the amp (which depends on how hard you're hitting the strings, how loud your pickups are, any gain your onboard preamp is adding, any gain FX are adding), multiplied by the gain applied by the amp (which depends on gain, EQ and volume knobs), then squared and divided by the speaker impedance equals 250W. Pluck a bit harder or a bit softer and the same point in the note could be putting out 500W or 125W. Pluck a lot harder or softer (like twice or half as loud) and your amp could be clipping hard as it tries to produce 2500W (thus you get 500W for a longer portion of the note) or producing just 25W.

And I bet in the course of any gig you play with a dynamic range of more than just going up and down fourfold (20dB).

[alexclaber]

[quote name='Monckyman' post='1199283' date='Apr 14 2011, 12:28 PM']Amps trying to punch above their weight produce square waves (clipping) and your driver won`t like that.[/quote]

No, they won't give a damn. Read the link I posted earlier. If clipping was so bad how would we amplify guitars and synths without forever blowing drivers?

[Krysbass]

I use my Ashdown Little Giant 1000 with two 250 watt cabs without any problems. For the uninitiated - that's two 500 watt power amps, each going into a 250 watt cab.

I get all the volume I need in my rather loud originals rock band without any problems. I think it's just a question of using your ears - if the cabs start "pharting" (and mine haven't yet) then it's time to rein things in. I have this setup to ensure the amp is always well within headroom, which will hopefully help with long-term reliability - it certainly never seems to get hot and bothered, which I know is a problem some Little Giant owners have reported.

[ThomBassmonkey]

[quote name='alexclaber' post='1199348' date='Apr 14 2011, 01:21 PM']No, absolutely not. It will be putting out 250W only at the moment when the voltage hitting the amp (which depends on how hard you're hitting the strings, how loud your pickups are, any gain your onboard preamp is adding, any gain FX are adding), multiplied by the gain applied by the amp (which depends on gain, EQ and volume knobs), then squared and divided by the speaker impedance equals 250W. Pluck a bit harder or a bit softer and the same point in the note could be putting out 500W or 125W. Pluck a lot harder or softer (like twice or half as loud) and your amp could be clipping hard as it tries to produce 2500W (thus you get 500W for a longer portion of the note) or producing just 25W.

And I bet in the course of any gig you play with a dynamic range of more than just going up and down fourfold (20dB).[/quote]

Ok haha, I'm obviously way out of my depth. I'm guessing (from what I understand of that, it was a very technical explanation ) that I was along the right lines though that less volume from your amp means that less power is being pushed into your cab.

Ultimately I'm just asking "if you play quietly, even if your amp's wattage is higher than the speaker's rating, then you won't be pushing too many watts through it?".

The whole thing's very confusing and I would never judge an amp's compatability to cabs by it's wattage. I used to run a 700RB-II at 480w through two 210RBHs rated at 400w each and if I pushed it then they'd distort and that wasn't anywhere near full volume, so I'd always use my ears either way.

[Monckyman]

[quote name='alexclaber' post='1199358' date='Apr 14 2011, 01:24 PM']No, they won't give a damn. Read the link I posted earlier. If clipping was so bad how would we amplify guitars and synths without forever blowing drivers?[/quote]
From Martin Audio`s own website:

"Care should be taken to avoid amplifier clipping. It is important to
understand that a low power amplifier driven into clipping is more likely to
damage a loudspeaker than a higher power amplifier used within its ratings.
This is because music signals have a high peak-to-average "crest" factor.
When an amplifier is severely overdriven, its output waveform is clipped
(its peaks are squared off) – reducing the crest factor. In extreme cases,
the waveform can approach that of a square wave. An amplifier is normally
capable of producing far more power under these conditions than its
undistorted rated power output.
The use of very high power amplifiers with outputs greater than those
recommended is discouraged."
I reckon they know what they are doing.
MM

[alexclaber]

And they are talking about PA speakers! As someone who designs and builds BASS GUITAR speakers I'd contend that my advice is more relevant and thus more accurate. If you take the time to read everything here:

[url="http://barefacedbass.com/technical-information.htm"]http://barefacedbass.com/technical-information.htm[/url]

and here:

[url="http://barefacedbass.com/bgm-columns.htm"]http://barefacedbass.com/bgm-columns.htm[/url]

you may then understand what I'm talking about.

If you already know all about power density, the lowpass filtering of voice coil inductance and the crest factor of typical bass guitar vs typical program material then my apologies for wasting your time.