Quad matched tubes, neccessary?

[Osse]

Hello, I've got an Laney VH100R with 4 6l6 tubes in the power section, will all of those have to be matched to each other, or is it enought if the pair is matched?

[Leif_Bodnarchuk]

i'm going to throw this out there...

if you had two matched duos...

Let's assume that valve sockets 1+2 are one side of the output transformer and 3+4 are the other side.

i'd stick one matched duo in the 1+4 sockets, and the other matched duo in 2+3.

That way, both "sides" are conducting equally.

Remember, you CAN run a 4-valve amp with only 3 valves, it will just sound not great. The idea is to set up the valves like brakes on a car - as long as the two brakes on the left pull the same as the two brakes on the right, your car should stay in a straight line.

[axeman]

I concur. Basic math

[motorhead_6]

Wouldn't a 4 tube amp with only 3 tubes (that is run class AB) have a hard time with either the positive or the negative half cycle depending on which socket didn't have a tube? Wouldn't it basically be half as much power on one half cycle as it would be on the other? I am not saying I know it would. I am just asking.

[axeman]

That question is way out there, I think they call it Left field, So please tell me why you ask in more detail. I'm not a dick but I never would have imagined in my weed smoking years that someone would ask that. Sorry I'm drinking write now.

[Leif_Bodnarchuk]

Ha ha.....
Yeah, "that" just happened, whatchoo gon do?

The amp wouldn't really have a hard time with any of the cycle, the amp is dumb, it only does what it can. We are the amp's interface to greatness.

[axeman]

[motorhead_6]

If you are asking me the answer is that I am just a guitar player and not an amp expert but I know a little electronic theory (or I am supposed to anyway). Correct me if I am wrong (and I am not being sarcastic either because I am very well aware I might be totally wrong) but I thought in a class AB amp (lets call it a 50 watt to keep it simple) one output tube amplifies the positive half cycle and the other amplifies the negative half cycle which is why if you are going to pull two tubes from a 1oo watter you must either pull the two outside ones or the two inside ones and run the impedance selector at half or double what you normally would. I forget which. And even then its not a perfect match but its closer then setting it where you normally would. You dont have to. The amp will still play but it wont play right.

The reason I don't have all this mess straight in my head is because I figured out a long time ago that in my opinion at least that its much better to NOT pull any tubes out of a 50 watter or a 100 watter or any other one either. I came to this conclusion after doing it a lot (pulling tubes). To me it sounds better if you don't and pulling two tubes from a 100 watter barely and I mean BARELY lowers the volume which is the reason most people do it. So it doesnt really accomplish what you are hoping it will and it also screws up the sound as well as causes an impedance mismatch in my opinion.

[motorhead_6]

I guess I didn't tell you why I was asking the question. I was just curious. I am not going to do it or anything. I probably have a long time ago but I don't remember. In addition to everything I said about me not pulling tubes anymore I also happen to be of the opinion that 100 watt amps sound better than 50 watt amps anyway. Some guys might think 50 watt amps sound better and that is a matter of opinion but I think it is safe to say that there IS a difference in the sound.