Is it better to have the speaker jacks on the preamp tube or output tube side?

[Mike_J]

The output transformer for my sluckey inspired Plexi/800 project sends the OT secondaries between the preamp and output tubes to an impedance switch on the back of the amp.  Is there any opinion as to whether the speaker jacks should be on the preamp side or the output side of the impedance switch?  I thought I read years ago that it is best to try to keep the output jacks away from the preamp but it has been so long since I read it that I though it might be a good idea to verify it with the experts on this site.

Thanks
Mike

[sluckey]

...keep the output jacks away from the preamp...

yep

[Mike_J]

...keep the output jacks away from the preamp...

yep

Sluckey

Thanks again for your help.

Mike

[John]

...keep the output jacks away from the preamp...

yep

I agree with you,  For the sake of us with concrete for brains, could you explain your reasoning. 

Thanks

Preamp section is more prone to picking up everything, including any noise coming off the speaker wires from the jack. Plus, it would seem that the jacks would be closer to the power tubes anyway. At least, that's my reasoning. :)

[HotBluePlates]

...keep the output jacks away from the preamp...

yep

I agree with you,  For the sake of us with concrete for brains, could you explain your reasoning. 

Is it better to have your anus near your mouth, or far from your mouth?

In electronics, you should keep outputs away from inputs. You don't want the stuff at the output going back into the input.

[floyd]

...keep the output jacks away from the preamp...

yep

I agree with you,  For the sake of us with concrete for brains, could you explain your reasoning. 

Is it better to have your anus near your mouth, or far from your mouth?

In electronics, you should keep outputs away from inputs. You don't want the stuff at the output going back into the input.

this "moderator" needs to be taught how to speak to people.. I guess if he has to ask, he doesn't know his mouth from his anus.

[kagliostro]

HotBluePlates 

 

may be that way the explanation can sound a bit rude

I find it hilarious and very comprehensible by all in his simplicity

no many people is able to explain such a (not simple) concept

in a so simple and immediate way

K

[HotBluePlates]

Is it better to have your anus near your mouth, or far from your mouth?

In electronics, you should keep outputs away from inputs. You don't want the stuff at the output going back into the input.

this "moderator" needs to be taught how to speak to people..

No offense was intended to anyone Floyd. It's simply a strong mental image that communicates the general rule in a way you'll always remember. My "problem" is I usually give long, technical answers.

That long answer is that electric current and voltage sets up a field around the conductor carrying the current/voltage. Output tube plates have the highest-voltage a.c. signals in the amp, where speaker jack wiring carries the highest-current a.c. (aside from some portions of heater wiring). So the output section wiring also has the largest fields around its wiring.

Preamp signals are low-voltage/low-current. They are also high impedance. The stray fields around output section wiring easily induce signal currents in that high impedance, and the resulting induced signal voltages can be big compared to the intended guitar input signal at that point in the preamp. The result is output signal fed back into an earlier stage, and oscillation.

This is the long way of saying what Sluckey in the 2nd reply. If you were able to build a human from scratch, you might intuitively know that placing the human's anus next to the human's mouth is a bad choice. The rule might be less obvious in an electronic device. But I guarantee now you'll never forget. 

[sluckey]

No offense was intended to anyone Floyd.

I think Floyd's purpose is to occasionally drop by and take pop shots at the forum. This is not his first shitty comment. To see what I mean take a look at his last two posts. I'm considering speaking with Doug about him.

[kagliostro]

Tanzan and Ekido were once traveling together down a muddy road. A heavy rain was still falling.

Coming around a bend, they met a lovely girl in a silk kimono and sash, unable to cross the intersection.

"Come on, girl" said Tanzan at once. Lifting her in his arms, he carried her over the mud.

Ekido did not speak again until that night when they reached a lodging temple. Then he no longer could restrain himself. "We monks don't go near females," he told Tanzan, "especially not young and lovely ones. It is dangerous. Why did you do that?"

"I left the girl there," said Tanzan. "Are you still carrying her?"

The attitudes of some people are not to be taken into account, forget it

Franco

[PRR]

I was going to say something about my well and septic-tank, but thought *that* might upset somebody.

And the "input output" analogy does not generalize well. Suppose it were my well and my water filter. It is acceptable for filtered water to leak back to the well.

[shooter]

HBP, don't change a thing!, when I taught God to teens I would do the same thing, 15yrs later, the "kids" still tell me They got more outta my "style" teaching than any other teacher they had.

[tubeswell]

Anus is in fact the correct scientific terminology.


http://dictionary.reference.com/browse/anus

[HotBluePlates]

Between stints in both the Navy and Army, "correct scientific terminology" is sometimes not my first impulse... 

[tubeswell]

Well in my defence, that definition was in a scientific dictionary. Enough said already.

[Willabe]

Between stints in both the Navy and Army, "correct scientific terminology" is sometimes not my first impulse...