Why not horns?

Al, I too was unfamiliar with the design of the circuit, but one does not have to know anything about it to know that it is impossible to get more power without more voltage.

Some are assuming that paralleled output tubes will somehow would drive more current into the load when we both know that for a given load the amount of current delivered is a function of voltage. These are voltage source amps, not current sources. I tried to explain this and as a result received an email telling me I was insolent, a complete and utter fool, and a coward.

So my interest was piqued and I sent an email to BAT. I figured maybe they used a higher tap on the secondary of the power transformer to get B+ up a bit. Close, but wrong. They do parallel the channels but as I've proven that does not raise the voltage. They also use a higher tap on the output transformer to raise the voltage. Very clever.

So for those who thought me to be an utter fool for saying you must raise the voltage, well, I guess we know who looks foolish now. Now that we have that settled I'll let the horn haters bash it out with the horn lovers.

Interesting thread, learned a bit about conical horns.

Oh, and distortions do not average out.

.

Prez, I hate to keep beating you down but your analysis with dB is also off

Not sure where you got 26dB but that does not equate to 400W. Here is how it works.

The sensitivity of the amp is 1V, that means it takes one volt to drive the amp to maximum output.

Of course these amps won't do it but to get 400W into 8 ohms you would need an output voltage of 57V. If you had one volt in that is a gain of 57. A gain of 57 is 35dB = 20 log 57.

To get 75W@8ohms you need 25V out. That is 28dB.

To get 75W@4ohms you need 17V. That is 25dB.

To get 150W@8ohm you need 35V. That is 31dB

I rounded things off but that is real close. It has a different amount of gain for each scenario because you use different taps on the output transformer to get different voltages.

.

Hi Herman,

I, of course, agree with your technical statements about amplifier power, etc., as far as they go. And they are not inconsistent with my previous post. However, keep in mind that the amps we were discussing as examples are solid state amps. So rather than using higher taps on the output xfmrs, I would guess (as I indicated earlier) that either the voltage rails on the non-paralleled amp configurations are the same as on the otherwise similar paralleled configurations, or can be internally selected between voltage values appropriate to each configuration.

As you will realize, the paralleled configuration simply provides the current capability and/or heat dissipation capability necessary to support the application of the higher voltage to the given 8 ohm or other load.

And Prdprez has now agreed that we are talking about maximum power ratings, not about paralleled output stages forcing more current into a load without a voltage increase.

Prdprez,

All three of my examples have listed specs of 26dB gain. This equates to 400W, correct? (under ideal circumstances)
Yet the other specs are listed as 150W and 300W. The maximum wattage is not specified for paralleling the largest amp (VK-600m) So we can probably assume that it tops out at 400W maximum (still 26dB gain) with overkill ability on the current side.

I don't think we can say how much power the VK-600m can supply, without more information than appears to be provided on their site. Besides there being no spec on maximum output power, unless I missed it there appears to be no spec on input sensitivity (i.e., how much input voltage is required to produce the rated output).

26db gain (the spec for the VK-600 and VK-255SE) simply means that the output voltage will be 20 times larger than the input voltage, provided that the output voltage, current, and power, and the corresponding heat dissipation, do not exceed the amp's capabilities.

Thanks for the nice words.

Best regards,
-- Al

ALL speakers have colorations. Pick the ones which annoy you the least.

"ALL speakers have colorations."

All recordings do as well. Same true with every piece in every system out there. So the idea of no coloration is not reality and not worth losing any sleep over. If you enjoy what you hear, then that's about as good as it gets.