Matching output impedance question

[pdf64]

I would worry about the Bass speaker, which is the "main customer" by far.

So your cabinet has an 8 ohm woofer, a 16 ohm tweeter and already a crossover that works that way?

Then you have an 8 ohm cabinet, for all practical purposes.

Conect it to amp 8 ohm tap and sleep like a baby.

anode dissipation in a Super Reverb can reach 100W.
So my thought was that the introduction of further significant phase shifts, especially within a frequency band where there’s lots of signal content, might exacerbate that.

I was thinking that as it's a 250Hz crossover, it may be a something of a different scenario to a woofer-tweeter?

[The Dude]

There are many variables here. The crossover itself makes a big difference. The slopes and overlap at the crossover point matter. However, you can reasonably assume that, for the most part, any single frequency is only going to be responded to by one of the cabinets in this example. So, I think Juan's post is still a good answer.

Edit: This assumes that the crossover is in front of both cabinets and contains a LPF and a HPF. If the bottom cabinet is run full range, we have a whole new ballgame.

[Helmholtz]

To make sure, resulting impedance over frequency response could be measured at either the 8 Ohm or the 16 Ohm tap with all speakers connected to the OT.

[pdf64]

I realise that it’s my concern ather than the OP’s, but won’t a 2nd order crossover introduce 2 more extreme phase flips? And as it’ll be occurring in a part of the freq band where there’s a lot of signal power, compared to a (resistive) calculated loading, the power valve anode dissipation might greatly increase there. So it kinda ends up being pertinent to what was possibly motivating the OP’s query

[Helmholtz]

I realise that it’s my concern ather than the OP’s, but won’t a 2nd order crossover introduce 2 more extreme phase flips? And as it’ll be occurring in a part of the freq band where there’s a lot of signal power, compared to a (resistive) calculated loading, the power valve anode dissipation might greatly increase there. So it kinda ends up being pertinent to what was possibly motivating the OP’s query

I understand your concern.
But I have no idea how to do a risk assessment without taking all the effort Zollner did. (BTW, his plate dissipation results are shorttime average values, not instantaneous peak power).

So I prefer not to have an opinion .

[catalin gramada]

My previous experiments shows the tube amps outputs are significantly affected by crossover networks. Not necessary in frequency range as in "presentation way" . It works like a strange compensation network in effect, and not in a good way. The best results I reached with a minimal intervention as: not filtered bass speaker and the mid/high overlapped with a minimal series cap.A minimal attenuation to keep the resonance peak under control was a good thing. So in conclusion I.ll be aware using inductances and large capacitances over the output as its effects are very hard previsible, maybe more tolerated by extremely imune outputs as SS are... The general theory point mosly what is happen after but is same important what is happen before with reflected reactive loads in case of a tube amp I guess..facts which are more hard to predict. .