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Hey All,

I was just curious what determines the exiting voltage at my speaker terminals on my EL34 Ultra Linear tube amp.

Are there any relatively easy mods that I can use to experiment with the voltage going to my speakers?

I was just puzzled why crossover caps come with 250V and 600V ratings, when it appears to me that most audio equipment doesn't produce that kind of voltage. Or does it, and I have just never seen that?

Wouldn't a change in voltage going to my speakers create a change in sound quality in some meaningful way?

Thanks,

Chris

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Walt

Thanks Walt!

So you can't change the voltage by adding or subtracting anything before or after the transformer?
I kind of thought that's how it worked.

I have tried the 4 ohm taps but I like the 8 ohm taps better. An overused word, but better "fidelity", which to me means "sounds more delicate".

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Walt

Hey Walt,

So the transformer lowers the voltage for the speakers. I wouldn't have imagined that. The bias on my output tubes is 300mV. Is the voltage higher somewhere else in the circuit?

This is where I break from other audiophiles: I'm looking for "richness", not SPL . It's kind of an elusive quality I have invented myself for something that doesn't seem to be explained by common audiophile knowledge.

When you think of sound as a combination of Frequency and Magnitude, I like to add another qualifier I call intensity, which is neither a change in magnitude or a change in frequency, but a change in "richness of the signal quality.

I'm not sure how to explain it in any other way, but I have developed it ALMOST as much as possible in my speakers, and I seem to think the next magic manipulation falls somewhere in the amplification stage.

Hey Chris. I am loathe to post here fire fear is I've again having it pointed out to me what a fucking moron I am.

But it seems you are getting bits and pieces of information.

Here goes. The voltage at your speakers is a function of the power you are putting into them.

The power formula is W = E x I or volts times amps. Substituting values from Ohm's Law, we can also say that W = voltage squared divided by the impedance of your speakers. And, Wattage equals Current squared times your speakers impedance. Apologies for errors here, I'm on a cell phone.

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Walt

So, if you have eight ohm speakers and you are putting sixty ways into them, then 60 x 8 = 480. The square root of which is 21.9. So you are putting 21.9 volts RMS into your speakers. Peak to peak voltage is 2.828 times that value or about 62 volts. That is the voltage the caps must withstand.

I completely agree with Soundmods. Pick up Morgan Jones' Valve Amplifiers. It's not an easy read but every moment reading that wonderful book is a revelation!

I can look for that book, but as you can probably tell, I really need basic electricity first. The more elementary the better!

I have seen some good illustrated videos on Youtube. Any other suggestions?