Tube Amp Question:

[Ryan.]

So I have my Marshall 1/2 stack.

 

When I went to do some recording like 2 years ago, I was told by the engineer we hired that I should run my stack in stereo. So since then I've been running the cab stereo (can't tell you the switch settings ohms and all that.)

 

BUT, the main question is... will this just burn out my tubes faster, for the sake of being able to tear people's faces off (which I don't do anyway).

[tlbonehead]

you aren't running anything in stereo unless you are running two heads into it. Did he mean just use 2 of the 4 speakers? Either way, make sure you match impedances.

[Ryan.]

All I know is that I'm running two cables from the head into one cab. :

[Mogwix]

[Rezrover]

My old Marshall 2X12 cab had stereo inputs.

[Ryan.]

 

Like so...

[Ryan.]

in reply to mog: its been working fine and sounds great.

 

i don't think its a mistake, i was just told by a friend that its just using more juice than i'd ever need, and draining my tubes faster than necessary...

[GCDEF]

You need to stop listening to people who have no idea what they're talking about.

 

There's no advantage to running two cables like that, and as you're running into two 8 ohm speakers in parallel, your amp should be set on 4 ohms, not 8. Setting to 8 could be hurting your amp.

 

You'd be better off for the sake of simplicity setting your amp at 16 ohms and running ONE cable from the 16 ohm output of the amp into the 16 ohm input of the cabinet, OR setting your amp to 4 ohms and running from one of the parallel jacks on the amp to the 4 ohm input on the cabinet. Two cables is silly and unnecessary.

[Ryan.]

 

You need to stop listening to people who have no idea what they're talking about. There's no advantage to running two cables like that, and as you're running into two 8 ohm speakers in parallel, your amp should be set on 4 ohms, not 8. Setting to 8 could be hurting your amp. You'd be better off for the sake of simplicity setting your amp at 16 ohms and running ONE cable from the 16 ohm output of the amp into the 16 ohm input of the cabinet, OR setting your amp to 4 ohms and running from one of the parallel jacks on the amp to the 4 ohm input on the cabinet. Two cables is silly and unnecessary.

 

 

No advantage? I think the advantage was sending a higher amount of watts to the left speakers and the right speakers. instead of a lower amount to all 4.

[soul-x]

.

 

That's all wrong. You are running a 4 ohm load: the two 8 ohm sides paralleled internally on the amp. But your amp is set to use the 8 ohm transformer tap. You could potentially damage things.

 

You can set the tap to 4 ohms and run it with the cabling the way you are, or you can use one output on the amp (still tapped to 4 ohms) to the 4 ohm mono input (with the cab set to mono) on the cab. Both are functionally the same -- one parallels the speakers inside the cabinet, one inside the amplifier.

[mshifflett]

You need to stop listening to people who have no idea what they're talking about. There's no advantage to running two cables like that, and as you're running into two 8 ohm speakers in parallel, your amp should be set on 4 ohms, not 8. Setting to 8 could be hurting your amp. You'd be better off for the sake of simplicity setting your amp at 16 ohms and running ONE cable from the 16 ohm output of the amp into the 16 ohm input of the cabinet, OR setting your amp to 4 ohms and running from one of the parallel jacks on the amp to the 4 ohm input on the cabinet. Two cables is silly and unnecessary.

 

+1

[Ryan.]

My current set up isn't wrong is it?

 

Its just more than necessary?

 

Don't think I'm not taking you guys seriously, just trying to get to the root of everything.

[Ryan.]

 

That's all wrong. You are running a 4 ohm load with the two 8 ohm sides paralleled internally on the amp and you are set to the 8 ohm transformer tap. You could potentially damage things. You can set the tap to 4 ohms and run it the way you are, or you can use one output on the amp (still tapped to 4 ohms) to the 4 ohm mono input (with the cab set to mono) on the cab. Both are functionally the same -- one parallels the speakers in the cab, one in the amp.

 

 

Ok so it IS wrong.

[Ryan.]

 

That's all wrong. You are running a 4 ohm load with the two 8 ohm sides paralleled internally on the amp and you are set to the 8 ohm transformer tap. You could potentially damage things. You can set the tap to 4 ohms and run it the way you are, or you can use one output on the amp (still tapped to 4 ohms) to the 4 ohm mono input (with the cab set to mono) on the cab. Both are functionally the same -- one parallels the speakers in the cab, one in the amp.

 

 

Doesn't the switch set to 8ohms make it so both the outs are 8ohm?

 

And since both the ins are 8ohm, how does that not match?

[soul-x]

 

Doesn't the switch set to 8ohms make it so both the outs are 8ohm?

 

 

The two outs are paralleled. They are just a Y connection inside the amp.

[dboomer]

You are running in parallel either way. What you have done is to use 2 cables instead on one. You basically have the same result .. but your impedance switch is set to 8 instead of more properly set to 4 ohms.

 

Stereo involves two discrete amp channels.

[Ryan.]

I see.

 

So the two cable output really has NO effect?

 

Would anyone be willing to draw on my picture to show me where and what the simple effective CORRECT set up would be?

[Ryan.]

Also why would a stereo option be available on ONE cab unit? For a rotary speaker type thing?

[GCDEF]

 

I see. So the two cable output really has NO effect? Would anyone be willing to draw on my picture to show me where and what the simple effective CORRECT set up would be?

 

 

I explained it pretty clearly. Pictures shouldn't be necessary. One cable. 16 ohm out to 16 ohm in.

[GCDEF]

Also why would a stereo option be available on ONE cab unit? For a rotary speaker type thing?

 

 

In case you want to use a stereo amp or two amps. It's just an option they can add with almost no cost. You don't have a stereo amp, so you can't get any benefit from it.

[soul-x]

Two ways to hook it up, both functionally the same:

 

[Ryan.]

 

I explained it pretty clearly. Pictures shouldn't be necessary. One cable. 16 ohm out to 16 ohm in.

 

 

Well both sides say 8ohms thats what I'm not getting?

[soul-x]

 

I explained it pretty clearly. Pictures shouldn't be necessary. One cable. 16 ohm out to 16 ohm in.

 

 

Correct, except -- look again -- his cab isn't wired for 16 ohm. It is 8 ohm/side stereo, or 4 ohm

mono.

 

Use the 4 ohm amp setting.

[Rezrover]

Maybe if you used a two channel amp with one channel wet & the other channel dry.

[soul-x]

 

Well both sides say 8ohms thats what I'm not getting?

 

 

This is one reason why powered speakers are often suggested versus separate components on this forum. Are you familiar with Ohm's Law?