Ok although i know this amp forwards and backwards (kinda) i need help buying a cab for my blue voodoo 300 watt head.

I'm buying a bass 410 cab to go with it. Before you start calling bloody murder for using this amp as a bass amp, look it up, because many many pro bands use em, and it sounds hella good (i've already played with it a few times with my band)
But obviously a 412 GUITAR cab isn't going to have the best sound especially in tight bass response. I've noticed some muddiness in some of the lower notes. Just enough that i don't mind thinking about getting a dedicated bass cab.

So anyways onto the question.

The 300 has 6 output places. 2 neutrik and 4 1/4in ones. It has a selector switch for 2ohm and 4ohm.

Normally i play with one cab connected 1/4in and have it selected on 4 ohm. (its a cab that is 4ohms mono, 8 ohms stereo or 16 ohms mono, i use it 4ohm.)

The cab i'm looking at is 8 ohm. So just me thinking about it, i guess i would put it on 4ohm and plug one cab into it? I'm prety sure i'm fine how i have it now because i've played it loud many many times and i've had it for quite sometime, so i'm assuming the impedience is matching as it should.

Here is some extra info that might be able to better judge this connection. The table that they give to give the person an idea what to plug in and what not is as follows.

Cab imped ......# cabs..........Total impedience
16 .....................8 ...................2
16 ......................4 ..................4
8 ...................... 4 .................. 2
8 .......................2 ...................4
4 ........................2 ..................2

Hmm i may have just figured this out. I need to double check that i am using the settings on my cab that i think that i am.

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Two cabs, 4+8 ohm in parallel ( stereo: one speaker cable to each ) will be a total of 6 ohms on your amp.

Your amp has a max of 2 ohms resistance handling ( nice ), so even if you keep the amp set at 4 ohms you are in the clear no matter how you wire the cabs ( parallel or series ). As long as the load ( speakers ) is greater than the amps ohm setting you are ok, but you will be running the that amp at a lower relative wattage due to the extra loading. This will only saturate your tube amp into distortion at lower volumes though.

Did I miss anything?

Edit: I hope I got this right, haha

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The thing is i want one 410 cab. I should have waited on posting this till i got home and DOUBLE CHECKED the exact getup that i have going. I could have sworn the cab was an 8ohm cab, but this other setup is saying 4ohm.

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If the cab is 8 ohms and your amp is set at 4 you are still ok.

Remember this:

Amp ohm lower than speaker ohm. SAY IT WITH ME, BITCH!

AMP OHM LOWER THAN SPEAKER OHM
AMP OHM LOWER THAN SPEAKER OHM
AMP OHM LOWER THAN SPEAKER OHM
AMP OHM LOWER THAN SPEAKER OHM
AMP OHM LOWER THAN SPEAKER OHM
AMP OHM LOWER THAN SPEAKER OHM

Know this and you will forever be safe.

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I'm saying it i'm saying it.

So lets progress this a little bit. So if the speaker ohm is HIGHER is the problem that the amp is facing too much resistance is that the deal? Therefore overworking it?

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In a way yes, the amp is overworked, but that will only mean saturation faster.

Great for tube amp distortion tone, but bad for tube life. The output transformer is still safe.

Very bad for solid state amp tone no matter what.

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So wait... ha you just reversed what you said.

I know the problem is the transformer. I think i blew my old peavey 212 because i switched speakers i'm almost POSITIVE i had it wired correctly and it blew after some mild pushing during a mini show in my room.

So what is it doing when the amps output ohms lets say 2ohms is less than the cab ohms lets say 8ohms.

Then what happens with the reverse to that?

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The reverse of what I said is that you end up with a nearly instantaneous run away current through the output transformer.

Magic smoke escapes from the amp.

Match ohms when you can but always remember,
AMP OHM LOWER THAN SPEAKER OHM.

You might overload a output transformer but it is highly unlike it will brake down. Short the bitch and I promise it will burn in glory

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Ok so amp 4ohm and speaker 8ohm = Good to go?


Ok well this is my next question is how do you think the setup is done on the amp?

I guess its parrallel? I guess the biggest thing that i should realize is that combining multiple cabs is where teh issue will be. Whether i set them in series or parrallel. Not so much a single cab. Because i guess as long as the cabinet isn't 2ohms (never heard of this) and the amp is set on 4ohm it should be fine. Right?

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Good to go You will have tube saturation/overdrive/distortion at lower volumes though.





You said the amp had four 1/4" speaker outputs. I'm just working from deductive logic based on modern amp design, but all modern amps use parallel speaker outputs. Your amp has 2 and 4 ohm settings, right? I'm just guessing here but I bet the amp has dual parallel outputs.

This list assume you run a cable from the amp to each cab:

4 cabs ( 16 ohms each ) = 4 ohms on the amp ( matched )

4 cabs ( 8 ohms each ) = 2 ohms on the amp ( matched )

4 cabs ( 4 ohms each ) = no fucking way!

4 cabs ( 2 ohms each* ) = no fucking way!

2 cabs ( 16 ohms each ) = 4 ohms on the amp ( good to go )

2 cabs ( 8 ohms each ) = 4 ohms on the amp ( matched )

2 cabs ( 4 ohms each ) = 2 ohms on the amp ( matched )

2 cabs ( 2 ohms each* ) = no fucking way!

1 cab ( 16 ohms ) = 4 ohms on the amp ( good to go )

1 cab ( 8 ohms ) = 4 ohms on the amp ( good to go )

1 cab ( 4 ohms ) = 4 ohms on amp ( matched )

1 cab ( 2 ohms* ) = 2 ohms om amp ( matched )

*No modern stock guitar speaker cabs rated 2 ohms without being custom made.

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Ok thanks.

yeah i think you're right and now i have looked exactly at what i use.

I have it set on 4 ohms and the cabinet is indeed 8 ohms. (the one i had been using for so long)

My new cabinet i use 4ohms on amp and its the 4 ohms i was talking about before.

So obviously if what you said wasn't true, one or the other of my amps should have fried by now i'm sure.

Granted i haven't really pushed my new one. (my 150 watt one with the 4ohm cab) But i'm sure i would haev noticed something by now.

What i'm guessing is kind of what you said about parrallel pairs of inputs.

But if thats teh case, then thinking about it, it should make the 4ohm cabinet 2ohms if its in parrallel.

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