mixing and matching cabs - need some input.

red_ice

I've been offered a marshall mbc810 and im very interested in it.. Im also looking at getting an ampeg svt-vr or cl (same as the av). Im just wondering if they are compatible etc? I have a friend in Newyork whos going to buy the amp and get it ready for shipping for me. I also know someone who can get it shipped over a 3 week period for next to nothing.. So im giving it a month or so before i purchase to weigh up my options.

Im not too sure on how the ohms work with amps.. so heres the specs.

the cab is
8x10
1200watt (rms)
2400watt (program)
4ohms

Ampeg SVT-VR
Preamp: Tube (3 x 12AX7, 2 x 12AU7)
Driver Tube(s): 1 x 12AX7, 2 x 12AU7 Power Amp: Tube (6 x 6550)
RMS Power Output: 300-Watts @ 2 ohms
RMS Power Output: 300-Watts @ 4 ohms
Tone Controls: Bass, Mid, Treble
Mid Tone Control: 3-Position Rocker Switch
Ultra Low/High Boosts: Yes
Speaker Connections: Neutrik Speakon® and 1/4"
Balanced Line Out: Yes (Transformer)
Preamp Out/Power Amp In: Yes
Dimensions (W x H x D inches): 24 x 11.5 x 12.75
Weight: 85 pounds

Ampeg CL
Preamp: Tube (2 x 12AX7)
Driver Tube(s): 1 x 12AX7, 2 x 12AU7
Power Amp: Tube (6 x 6550)
RMS Power Output (2 Ohms): 300-Watts
RMS Power Output (4 Ohms): 300-Watts
Tone Controls: 3-Band
Mid Tone Control: 5-Position Selector
Ultra High/Low: Yes
Balanced Line Out: Yes
Preamp Out/Power Amp In: Yes
Slave Output: Yes
Dimensions (W x H x D inches): 24 x 11.5 x 13
Weight: 80 Pounds


For either of those heads, does all look ok with that cab?

Cheers

unclebill98

To be honest with you.

The only way to get a good all round sound with those heads is a 8x10 or at least a 4ohm 4x10.

You should be pumping at least 1200w into that cab. The all tubes heads are a bit different to hybrids or solid states. On paper the heads do not even come close to giving the cab enough power.

Maybe someone can explain why all tubes heads just make a 8x10 come alive.
Them heads are made to be played with a 8x10.

I hope you have someone to help life all that, cause thats on heavy bass rig.

bat boy

Both those heads would be perfect for that cab. You'll have plenty of power. The cab is 4ohm and both those heads are stable down to 4ohm so you'd be getting the maximum power from them. Would love to be able to afford a rig like that myself.

Eoin Madsen

Yeah, both of those would be fine with that cab. Just make sure the amp is set for 4 ohms impedence before use.

Dord

unclebill98 wrote: »

To be honest with you.

The only way to get a good all round sound with those heads is a 8x10 or at least a 4ohm 4x10.

You should be pumping at least 1200w into that cab. The all tubes heads are a bit different to hybrids or solid states. On paper the heads do not even come close to giving the cab enough power.

Maybe someone can explain why all tubes heads just make a 8x10 come alive.
Them heads are made to be played with a 8x10.

I hope you have someone to help life all that, cause thats on heavy bass rig.

I'm sorry but that's just ridiculous. You can't damage a cab by "underpowering" it. If that was the case then my cab is being damaged right now because the amp is off and the cab isn't having any signal go thru it. Ohh noes! :eek: :pac: :rolleyes:


Red_ice, it'll work great with that cab.

Eoin Madsen

Joe Robot wrote: »

I'm sorry but that's just ridiculous. You can't damage a cab by "underpowering" it. If that was the case then my cab is being damaged right now because the amp is off and the cab isn't having any signal go thru it. Ohh noes! :eek: :pac: :rolleyes:

You actually can. If you clip a solidstate amp you can damage the speaker, irregardless of how much power it can handle. And people are much more likely to clip an amp if they're underpowering the speaker. It's a more common reason for damaged speaker cones in PA systems than overpowering. Not really a factor here, because valves don't clip that way. But in this case I think he was more referring to the fact that speakers rated for a high power won't have the same frequency response when you don't send enough power to them anyway.

But a push/pull valve amp on 3 pairs of 6550 is more or less as loud as valve amps get.

red_ice

bat boy wrote: »

Would love to be able to afford a rig like that myself.

Who said i could afford it :pac: Im going without meals here for this rig! Wont be on the drink for a good few months anyways..

If its gotta be done its gotta be done! I want this so bad!

Dord

Eoin Madsen wrote: »

You actually can. If you clip a solidstate amp you can damage the speaker, irregardless of how much power it can handle. And people are much more likely to clip an amp if they're underpowering the speaker. It's a more common reason for damaged speaker cones in PA systems than overpowering. Not really a factor here, because valves don't clip that way. But in this case I think he was more referring to the fact that speakers rated for a high power won't have the same frequency response when you don't send enough power to them anyway.

But a push/pull valve amp on 3 pairs of 6550 is more or less as loud as valve amps get.

Yes, I realise that clipping can cause unwanted frequencies that may cause speaker damage. But this is totally different that what he was talking about.

The only way I can see it being an issue is if he turned the amp up full thru the cab, now I doubt that's going to happen. He probably wouldn't be alive after that! :eek:

Dord

red_ice wrote: »

Who said i could afford it :pac: Im going without meals here for this rig! Wont be on the drink for a good few months anyways..

If its gotta be done its gotta be done! I want this so bad!

I think Dunnes have a special on Koka noodles at the moment. :pac:

red_ice

Joe Robot wrote: »

I think Dunnes have a special on Koka noodles at the moment. :pac:

I actually bought a few packs last week on the random (havnt had em in ages) so i would have something quick to eat before/after footy/rehearsals..

And i dont see myself turning that amp up all the way ever.. although the lads have a great amp setup and could compete, i would like to keep mine in tiptop shape for if i ever needed to sell it!

Eoin Madsen

Joe Robot wrote: »

The only way I can see it being an issue is if he turned the amp up full thru the cab, now I doubt that's going to happen. He probably wouldn't be alive after that! :eek:

You know, you can get maximum power out of an amp without ever turning the volumes all the way up, and you can turn them all the way up and still not use all the amp's headroom. Amplifers are just multipliers. And the volume pots are just input dividers. It's all proportional. :pac: Setting it to 10 don't mean sh*t.

Eoin Madsen

Anyway, the valve output will just distort rather than clipping, and you should know about it long before there's any danger of exploding anything.

unclebill98

Joe Robot wrote: »

I'm sorry but that's just ridiculous. You can't damage a cab by "underpowering" it. If that was the case then my cab is being damaged right now because the amp is off and the cab isn't having any signal go thru it. Ohh noes! :eek: :pac: :rolleyes:


Red_ice, it'll work great with that cab.

Ok, i re-read my post 3 times there. Where do i even mention the word Damage?

Do you feel the need to see words that ain't there?

Cabs have a rating, under powering a cab is pointless. Why get a cab with all that power if your never going to reach its even half its RMS??? Hence why you might as well save money and get e 4ohm 4x10. If your going for a look, then fine or a broken back..

Joe Robot wrote: »

But this is totally different that what he was talking about.

Can you explain this little out burst please?

Anytime i've ever played one of those head, they've always been hooked up to a 8x10. They sounded great.

humaxf1

In PA circles, you should match the amp power to the program rating of the cabinet at the given impedance. An underpowered cabinet will not be too happy about a clipped signal or someone dropping a live mic on the floor.

So, your common 300W RMS @ 8Ω cabinet will have a program rating of 600W. The amp used ideally should have a rating of ~600W @8Ω;. The wattage rating is an indication of the amount heat the driver can dissipate safely. The SPL rating, ie xxdB@1W/metre determines how loud the cabinet plays.

Remember, most people mistake the role of the amp 'volume' controls. These controls are merely signal attenuators. At a low setting with a hot signal being sent from the preamp, full power from the amp can be delivered to the speaker. Read up on gain structure!

darrenw5094

I have a Marshall JVM 100w with 4 independent channels.
Would it be better to set the volumes at 10, gains at 10 and the master at about 2 or 3.

Or to set the volumes at about 5, gains at 10 and master at 5.
I want the gains up full as there is also 3 modes with each channel.

Or WTF is the best setup???

red_ice

I've decided to go for a 4x10, if i have the option of adding a 1x15 under it.. have to make a move in the next 2 months!