MuckedUpFunkies Posted March 23, 2011 Share Posted March 23, 2011 I've finally got round to leaving my beloved Trace Combo behind and decided to get something a lil bit more powerful. Long story short I got a good deal on an Ampeg B2-RE head and im now running it through a crappy old Peavy speaker which needs to be updated but I dont have a clue about ohms! The B2RE is 250 at 8 and 450 at 4 so do i just get a cab that is 8ohms at 250 or could i get one thats 300 at 8 like most are and not have trouble? Sorry I realise this has probably been asked thousands of times Thanks Dan =) Quote Link to comment Share on other sites More sharing options...
Balcro Posted March 23, 2011 Share Posted March 23, 2011 Hello MUF's The amp rating at 4 and 8 ohms indicates it's happy to work with either resistance. So any 4 or 8ohm cabinet of your choice, but not lower than 4ohms. The wattage ratings are based on a thermal characteristics. Therefore I would play safe by giving the speaker a little headroom to cope with the inevitable abuse. So an 8ohm cabinet at 300w and upwards, or a 4ohm cabinet at 500w and upwards. I'm old school on this. If it were me, I'd look at 400+ watts for an 8ohm cab and 600+ at 4ohms. A higher wattage rating on the cab does [u]not[/u] mean it will be louder than one of a lower wattage rating. Balcro. Quote Link to comment Share on other sites More sharing options...
BOD2 Posted March 23, 2011 Share Posted March 23, 2011 All that the rating on the Ampeg tells you is the power that it will output into the attached impedance - i.e. if you attach an 8 ohm cab(s) then the Ampeg can produce up to 250 Watts of power, and if you attach a 4 ohm cab(s) then it can produce up to 450 Watts of power. When you select a cab you can safely go above those power ratings (e.g. 300W or even 400W at 8ohms) but it's best not to go below them. There's no impedance selector switch on the Ampeg so there's nothing to worry about there. Note that if you choose an 8 ohm cab now, then you could add a second 8 ohm cab in the future and connect both safely. You can NOT connect two 4 ohm cabs though as this would result in the total load being less then the specification. So go ahead and get any 8 ohm cab at 250 Watts RMS or higher. Quote Link to comment Share on other sites More sharing options...
stevie Posted March 23, 2011 Share Posted March 23, 2011 [quote name='MuckedUpFunkies' post='1173098' date='Mar 23 2011, 11:22 AM']Sorry I realise this has probably been asked thousands of times[/quote] You're right about that. Have a look at the pinned topics at the top of this section. Impedance is the one you want. Quote Link to comment Share on other sites More sharing options...
MuckedUpFunkies Posted March 23, 2011 Author Share Posted March 23, 2011 Perfect! Thanks ever so much for the quick reply and useful info =) Dan Quote Link to comment Share on other sites More sharing options...
chris_b Posted March 23, 2011 Share Posted March 23, 2011 If your amp is 250 at 8 ohm I'd get a 300 watt 8 ohm cab. Then add another cab when you want the full 450 watts. If you want to run your amp any where over half way you should be using a second cab anyway. Also, get sensitive rated speakers so your watts sound louder. Quote Link to comment Share on other sites More sharing options...
Happy Jack Posted March 23, 2011 Share Posted March 23, 2011 I used to get sent brown envelopes with OHMS written on them. They were usually really boring, so I threw them all away. Quote Link to comment Share on other sites More sharing options...
icastle Posted March 23, 2011 Share Posted March 23, 2011 [quote name='Happy Jack' post='1173143' date='Mar 23 2011, 12:07 PM']I used to get sent brown envelopes with OHMS written on them. They were usually really boring, so I threw them all away.[/quote] And how are things in Pentonville Jack? Quote Link to comment Share on other sites More sharing options...
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