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LETS COMPARE TUBE AND SS AMPS. TECHNICAL

I am seeking some very technically minded people to chat about differences in sound quality, dbs, and power ratings. I have not dived into this much yet but in my past study, I find that some SS amps are uniquely rated (lie about it). Maybe there is special "sound watt" used when comparing input fusing and wire size to rated output. When looking at tubes, their rating for power is much lower. 50-120wpc seems about right. However, I hear people say it comes down to "current" BUT, current and watts are directly related. Since the voltage or wave amplitude depends on the sound to be reproduced, it only makes sense that the only variable is the current, thus the wattage. I run a Rotel RB1080 on my RF-7s at 400wpc. I have to wonder the difference in dbs from a comparable tube amp.



Sure sounds like tube is way more expensive but can really give some nice sound. My experience with tube is only on guitar amps and I would not touch a SS guitar amp now!



Has someone compared tube with SS directly for dbs, accuracy, THD, etc??
viper6383
marakanetz's avatar
marakanetz
5,473 posts
 
Atmasphere, there's one important detail missing on your link mentioned by T_bone and which you perfectly might know as engineer is meaning of ideal source vs. non-ideal. It can also be explained in simple language to the public.

Tube or even transistor output devices can't be ideal by default: What device is closer to ideal source tube or transistor? The total impedance including impedance of the source should've been mentioned as part of the integrated source --> load circuit. There figures will come quite different especially in terms of current passing through the load.
atmasphere's avatar
atmasphere
7,068 posts
 
Marakanetz, true enough- but since this **is** the real world, an ideal source exists in dreamland only- we can safely ignore it as a result.

So, what is, is tubes and transistors. Either can have a high or low source impedance, and a price is paid either way, and both (high and low source impedance) have very distinct advantages.

IMO/IME, there is no such thing as an ideal source, and I am not even sure that there is even a good consensus about what that even is. Keep in mind, the reason I used the word Paradigm in the way I did is that those who operate inside one Paradigm will by definition be unable to accept any way of thought that exists outside of that Paradigm. So what is an 'ideal source' for the Voltage Paradigm is very different from that of the Power Paradigm, and if you re-read the paper, you will see the issue clearly addressed.
magfan
1,583 posts
 
Watts is Watts, at least into a resistor, which NO load is, as far as I know.

One major difference is the delivery of power into reactive loads, which to a greater or lesser extent includes ALL speakers. Huge phase angles at low impedance will take the wind out of many amplifiers sails.
Transistors typically do better. I don't remember which, but tubes don't like either Capacitive or Inductive loading, again as a general rule.

The articles ref'd to in an above post are a good read. Thanks! Also, Nelson Pass has at least 1 article on the web concerning Current Source amplification vs Voltage Source along with extensive testing of some single driver systems.
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