Ohms and amps

[Craigster]

Hi all, can you'll help? 

I'm a complete retard when it comes to tech so I need some clear advice that a total novice like me will understand.... 

I have an old 600w (4 ohm) bass amp head ( ashdown 600 Mag) and I'd like to run a 4 x 10 450amp 8ohm cab. 

Are the impedance values compatible and can i drive the hell out of the speakers?? 

Also, can i stack an additional passive cab using the same amp to boost the volume output?? 

If so, do I need some kinda splitter / adapter from the amp? 

Yep, you're prob thinking I'm a complete moron but I really am clueless. I would really value anyone's help tho. 

Thanks so much 👍

[Lozz196]

Yes that will be fine. Your amp is 600 watts at 4ohms so connecting an 8ohm cab to it approximately halves the amount of power delivered to it, so 300 watts, which your 410 will handle. If you connect up another cab, as long as it’s another 8ohm cab effectively each cab will then receive 300 watts, so make sure this cab is also capable of handling 300 watts or more (the theory says the best second cab should be the same as the first one).

[Craigster]

Thanks lozz196 really great advice, so I wouldn't be able to use a second cab with a lower amp rating than 300 Watts then? Could I get away with say 250 Watts? 👍👍👍

Edited May 3, 2021 by Craigster

[Killed_by_Death]

 

If it's a solid-state power-section, the 4 Ohms is the minimum Impedance, so 4 Ohms or greater is fine.

If the amp doesn't have two speaker outputs, you'll have to daisy-chain speaker cables from one cab to the next for two cabs & it's best to have two identical cabs:

if your cabinets only have 1 input jack, you can either install a 2nd jack in either or both or make up a speaker cable to daisy-chain

 

[Craigster]

7 minutes ago, Killed_by_Death said:

 

If it's a solid-state power-section, the 4 Ohms is the minimum Impedance, so 4 Ohms or greater is fine.

If the amp doesn't have two speaker outputs, you'll have to daisy-chain speaker cables from one cab to the next for two cabs & it's best to have two identical cabs:

if your cabinets only have 1 input jack, you can either install a 2nd jack in either or both or make up a speaker cable to daisy-chain

 

Ok cool, I'd need to get a tech to install that then or could I get an adaptor to "T" off from the first cab input? 

[Craigster]

This is my cab... 

[Killed_by_Death]

 

just connect one cab to each of the TWO speaker outputs:

https://ashdownmusic.com/products/mag-600h-evo-iii

 

Edited May 3, 2021 by Killed_by_Death
new info about amp

[BassBunny]

19 minutes ago, Craigster said:

Thanks lozz196 really great advice, so I wouldn't be able to use a second cab with a lower amp rating than 300 Watts then? Could I get away with say 250 Watts? 👍👍👍

You can use a 250w can, just don't overdrive it. It's unlikely you would be in a situation where you are driving the amp to max. Just trust your ears.

Regarding connecting your amp to cabs. There are 2 speaker out jacks on the back of your amp?

A cable from each output to each cab. Nothing else needed.

[Woodinblack]

The mag600 has two speaker outputs so you can connect one to each cab

[BassBunny]

Just now, Woodinblack said:

The mag600 has two speaker outputs so you can connect one to each cab

This.

[Lozz196]

23 minutes ago, Craigster said:

Thanks lozz196 really great advice, so I wouldn't be able to use a second cab with a lower amp rating than 300 Watts then? Could I get away with say 250 Watts? 👍👍👍

You’d get away with it, be careful and don’t push too much low-end and you should be ok, use your ears to determine if the cab is struggling - though in all honesty having a 600 watt head myself I can’t envisage being in a situation where I’d ever be pushing it to full power.

[Killed_by_Death]

21 minutes ago, Craigster said:

I'd need to get a tech to install that then or could I get an adaptor to "T" off from the first cab input? 

IF was included above, because I didn't know about the amp, but now I see it has two output sockets.

Also, don't use adapters, that's just asking for a failure.

 

[Craigster]

26 minutes ago, BassBunny said:

You can use a 250w can, just don't overdrive it. It's unlikely you would be in a situation where you are driving the amp to max. Just trust your ears.

Regarding connecting your amp to cabs. There are 2 speaker out jacks on the back of your amp?

A cable from each output to each cab. Nothing else needed.

When you say don't overdrive it, do you mean lay off the input gain? 

Or keep input gain to a minimum? But I could still max out the volume though? 

[Downunderwonder]

1 hour ago, Craigster said:

When you say don't overdrive it, do you mean lay off the input gain? 

Or keep input gain to a minimum? But I could still max out the volume though? 

He means don't over drive the cabinets as in don't blow them up. Easier said than done at war volume with 2 cabs and 600 w on tap.

Volume is a result of applying power to cabs.

Whether it's gain applied at the input or the output doesn't matter a whole lot. Volume is volume.

The bit that can really screw with you is purposely distorted tones. At high volume it's very hard to distinguish between sounds of bass glory and the sounds of your speakers being tortured.

As you are playing a solid state amp it's quite easy to explore the limits with a clean tone to find where the cab starts to cry. If you are using a pedal to get boss tonez make sure it doesn't push too much extra volume.

You are going to need earplugs or you will go deaf.

[BassBunny]

31 minutes ago, Downunderwonder said:

He means don't over drive the cabinets as in don't blow them up. Easier said than done at war volume with 2 cabs and 600 w on tap.

Volume is a result of applying power to cabs.

Whether it's gain applied at the input or the output doesn't matter a whole lot. Volume is volume.

The bit that can really screw with you is purposely distorted tones. At high volume it's very hard to distinguish between sounds of bass glory and the sounds of your speakers being tortured.

As you are playing a solid state amp it's quite easy to explore the limits with a clean tone to find where the cab starts to cry. If you are using a pedal to get boss tonez make sure it doesn't push too much extra volume.

You are going to need earplugs or you will go deaf.

What he said.:-)

[Chienmortbb]

On 03/05/2021 at 23:13, BassBunny said:

What he said.:-)

I did not hear him!

[abarson]

The MAG 600H has two Speakon speaker outputs and will operate with a minimum load of 4 ohms: do not go below 4 ohms. You can connect either one or two cabinets to this head.

Here are valid combinations that you can safely connect to this amp:

• 1 x 8 ohms cabinet, total 8 ohms load. Use one Speakon cable between the amp and cabinet.
• 1 x 4 ohms cabinet, total 4 ohms load. Use one Speakon cable between the amp and cabinet.
• 2 x 8 ohms cabinets, total 4 ohms load. Use one Speakon cable between the amp and each cabinet.

NEVER CONNECT TWO CABLES BETWEEN YOUR AMPLIFER AND ONE CABINET!

All other combinations (4 ohms + 8 ohms, etc.) may cause damage to your amp.

[Craigster]

Top bloke, thanks for your advice 👍 

[Craigster]

31 minutes ago, abarson said:

The MAG 600H has two Speakon speaker outputs and will operate with a minimum load of 4 ohms: do not go below 4 ohms. You can connect either one or two cabinets to this head.

Here are valid combinations that you can safely connect to this amp:

• 1 x 8 ohms cabinet, total 8 ohms load. Use one Speakon cable between the amp and cabinet.
• 1 x 4 ohms cabinet, total 4 ohms load. Use one Speakon cable between the amp and cabinet.
• 2 x 8 ohms cabinets, total 4 ohms load. Use one Speakon cable between the amp and each cabinet.

NEVER CONNECT TWO CABLES BETWEEN YOUR AMPLIFER AND ONE CABINET!

All other combinations (4 ohms + 8 ohms, etc.) may cause damage to your amp.

Are you saying that by connecting 2 x 8 ohms cabs with a total load of 4 ohms is a result of splitting the load between 2 cabs to the amp? 

Am i correct to asert that the load rating is carried from the cab to the head given that the ohms rating ( capacity) is greater on the cab, likewise the load rating ( capacity) is lower on the head? 

Thanks again 👍 

[Downunderwonder]

It's perfectly fine to use two cables from your amp to two 8 ohm cabinets!

Cabs put a load on the amplifier via cables. You are very confused in your questions.

[Downunderwonder]

50 minutes ago, abarson said:

NEVER CONNECT TWO CABLES BETWEEN YOUR AMPLIFER AND ONE CABINET!

All other combinations (4 ohms + 8 ohms, etc.) may cause damage to your amp.

This is flat out wrong.

Never connect two amplifiers to one cabinet.

On 04/05/2021 at 07:29, Killed_by_Death said:

 

If it's a solid-state power-section, the 4 Ohms is the minimum Impedance, so 4 Ohms or greater is fine.

If the amp doesn't have two speaker outputs, you'll have to daisy-chain speaker cables from one cab to the next for two cabs & it's best to have two identical cabs:

if your cabinets only have 1 input jack, you can either install a 2nd jack in either or both or make up a speaker cable to daisy-chain

 

I dunno what's up with that graphic. I have a Mesa tube amp with 8 ohm and 4 ohm outputs labelled like that. The 4 ohm ones are parallel to connect 4 ohm worth of two 8 ohm cabs.

Dollars to donuts OP amp is a bog standard solid state MAG with parallel outputs. Connect two 8 ohm cabs however you fancy. 4 ohms job done.

Egads what a mess.

[itu]

Power has a bit to do with the volume. But only a bit. If your amp has 10 watts, the next step is to buy a 100 watt amp. Next similar change requires a 1 000 watt amp. The difference between 100 W and 300 W is not so big.

dB is about the volume.

Sensitivity can help you to calculate how much volume you can get from the cab and amp.

Impedance is like a stick. When it gets smaller (32 - 16 - 8 - 4 - 2 - 1), the stick gets thinner (from baseball bat to a needle) and it is harder to push with your finger. Amp gets warmer the smaller the impedance. This is because the amperes (A) start to rise which warm the amplifier section.

If you double the number of cabs, you get smaller impedance, higher amperes (if your amp can push more watts to a harder load), and slightly more volume. This is around 2 - 6 dB, which can be heard, but it definitely is not so big change. It is common, that the placement of the cab can help player to hear details of the instrument far better than simple increment of power.

[abarson]

@Downunderwonder I'm not wrong in the least, but it may simply be a matter of verbiage.

The amp (like many others) has two speaker output connectors. Most cabinets have two connectors, one as input from the amp and the other in parallel to daisy chain to another cabinet.

Never connect both outputs of the amp to one cabinet. Doing so shorts the output of the amp.

Your comment to never connect two amplifiers to one cabinet is also definitely valid and should be heeded.

And I agree that the Mesa illustration wasn't the most helpful.

[Bill Fitzmaurice]

19 hours ago, itu said:

If you double the number of cabs, you get smaller impedance, higher amperes (if your amp can push more watts to a harder load), and slightly more volume. This is around 2 - 6 dB, which can be heard, but it definitely is not so big change.

When you add a second identical cab in parallel you get a 6dB increase in both sensitivity and maximum output. That's the equivalent of quadrupling the power into a single cab, so it is most definitely a big change.

Never connect

both outputs of the amp to one cabinet. Doing so shorts the output of the amp.

That would only happen if the two cords weren't of like polarity. The reason why they say not to do so is because it won't add to output, and you might have two cords that aren't of like polarity.

[abarson]

20 hours ago, Craigster said:

Are you saying that by connecting 2 x 8 ohms cabs with a total load of 4 ohms is a result of splitting the load between 2 cabs to the amp? 

Am i correct to asert that the load rating is carried from the cab to the head given that the ohms rating ( capacity) is greater on the cab, likewise the load rating ( capacity) is lower on the head? 

Thanks again 👍 

I don't know what capacity means to you, but it isn't related to any of this discussion. Cabinets have a impedence load that the amp drives by providing power to it.

When resistance or impedance is connected in series the sum is additive: 8 + 8 = 16.

When resistance or impedance is connected in parallel the sum is inverse: 8 || 8  -->  1/8  + 1/8 = 1/x  -->  x = 4 

Cabinet connections are as a rule made in parallel. This is accomplished in one of two ways:

1. The two speaker outputs on your amp are in parallel. You can connect one 8 ohms cabinet to each output and the amp will see a total load of 4 ohms. This is appropriate for your amplifier.
2. One speaker output is connected to cabinet A (8 ohms), which then has a daisy chain connnection to cabinet B (also 8 ohms). The amp will see a resulting total load of 4 ohms. Note: this doesn't apply to the Ashdown 410 cabinet that you posted. Yours has a 1/4" jack that has been sealed, which usually would have been used for daisy chaining.