Interesting Read on Tubes and SS amps

[blackraven]

Here is an interesting read that I am posting to stimulate some discussion around here.

Valve / Solid-State Amps (http://lenardaudio.com/education/14_valve_amps_7.html)


The guy failed to mention SS amps that do not use negative feedback.

[blackraven]

And here is a short pretty basic youtube video from the founder of Parasound talking about watts and current.

Audio Advisor Insight - Parasound Amplifier Power - YouTube (http://www.youtube.com/watch?v=Y_22XOakyxM)

[Bill K Davis]

Modern audio equipment is made to operate with other modern equipment? I have wondered how much this applies to cds and other digital formats. Is anyone keeping track of which speakers were designed for tube amps and which for solid state? This article seems to say that ideally, speakers should be solid state or tube. Has this occurred in other equipment interfaces? Should I stay with older equipment to listen to old vinyl? I even question whether the new vinyl is made for newer equipment. The people producing today's media have different (God of Music?) musical Gods ,than people of other eras.

[Feanor]

Here is an interesting read that I am posting to stimulate some discussion around here.

Valve / Solid-State Amps (http://lenardaudio.com/education/14_valve_amps_7.html)


The guy failed to mention SS amps that do not use negative feedback.
This is a very interesting article and well worth and careful read -- so far my reading is cursory but I'll get back to it.

Meanwhile there a few categorical statements that are questionable in terms of real world results, e.g. ...


"When listening to a valve amp, the bass and hi-frequencies appear to spring to life with clarity and detail, or may appear to sound exaggerated. If given the opportunity for comparison, every human with ears will hear the difference and choose a Valve amp as the preferred listening option."

Hummm.

Towards the end is a reference to Rod Elliott's site which is also well worth a visit. Elliott has written there a series of articles, HERE (http://sound.westhost.com/articles.htm), on a range of technical topics. In addition to the one linked by Lenard, I think we should all read THIS ONE (http://sound.westhost.com/articles/distortion+fb.htm) on the topic of negative feedback. Elliott is definitely on the side of using negative feedback and lots of it!!!

[Feanor]

And here is a short pretty basic youtube video from the founder of Parasound talking about watts and current.

Audio Advisor Insight - Parasound Amplifier Power - YouTube (http://www.youtube.com/watch?v=Y_22XOakyxM)
That's an interesting but brief intro to the topic amplifier power supplies.

Note the it's focused on standard AB s/s amps. For what I understand the following caveats apply:


Class D amps can get by with slightly less heavy duty powers supplies because they draw, on average, less current
Somewhat analogous to class D in terms of power supply requirements are class G and H amplfiers
Class A amps require significantly more power because on average they draw much more current
Switching-mode power supplies (SMPS) are much smaller because the supply power instantaneously depending on the output requirement and thus need much smaller transformers and filtering capacitors.


Again there are a few articles by Rod Elliott that shed light on power supply requirements/design. It seems to me that THIS (http://sound.westhost.com/power-supplies.htm) article is essential reading on the topic. On this topic Elliott is something of contrarian when it comes to the audiophlle conviction that the larger the filtering capacitors, the better.

[Mr Peabody]

I noticed the writer of the article in post one went another direction on a couple points as well from other things I've read. In researching a certain topic on electronics I've come to realize that even the engineers are not in agreement on some things. One year "zero feedback" will be the hot buzz and another it is something else, ie high current or low distortion, we just have to learn to trust our own ears. Also, with any technology, application, is key, one design may take a topology and make a stellar amp where another may have tomorrow's dog..

[Feanor]

I noticed the writer of the article in post one went another direction on a couple points as well from other things I've read. In researching a certain topic on electronics I've come to realize that even the engineers are not in agreement on some things. One year "zero feedback" will be the hot buzz and another it is something else, ie high current or low distortion, we just have to learn to trust our own ears. Also, with any technology, application, is key, one design may take a topology and make a stellar amp where another may have tomorrow's dog..
You're so right, seems to me.

[E-Stat]

Here is an interesting read that I am posting to stimulate some discussion around here.
I, too tuned out once the writer displayed ignorance of even remotely current technology with this awkward comma splice:

"A conventional solid-state amp cannot function without Negative feedback, therefore there is no choice."

[E-Stat]

On this topic Elliott is something of contrarian when it comes to the audiophlle conviction that the larger the filtering capacitors, the better.
I wonder if he ever experimented himself? I first did that as a teenager when I had a Van Alstine modified PAT-5 (nee FET-5) back in the 70s. That was the day when FVA added an outboard bank of caps to the "Double Dyna 400". Following his lead, I did the same with a nice 100 watt per channel Audire amp driving Magneplanar MG-IIs. I added another 80,000 uF to the existing 20,000 uF supply IIRC. And updated with a 30A bridge to prevent a meltdown during power up!

The result was a more dynamic sound with better bass impact and a cleaner top. Those were 50V caps so I'm guessing the rails were running no more than about 45V - which increased the number of joules to about 130. Which ends up slightly higher than the 110 joule supply of my Threshold Stasis for equivalent power. And far less than the 500 joule supply of the MB-450s on a per watt basis.

[Feanor]

I wonder if he ever experimented himself? I first did that as a teenager when I had a Van Alstine modified PAT-5 (nee FET-5) back in the 70s. That was the day when FVA added an outboard bank of caps to the "Double Dyna 400". Following his lead, I did the same with a nice 100 watt per channel Audire amp driving Magneplanar MG-IIs. I added another 80,000 uF to the existing 20,000 uF supply IIRC. And updated with a 30A bridge to prevent a meltdown during power up!

The result was a more dynamic sound with better bass impact and a cleaner top. Those were 50V caps so I'm guessing the rails were running no more than about 45V - which increased the number of joules to about 130. Which ends up slightly higher than the 110 joule supply of my Threshold Stasis for equivalent power. And far less than the 500 joule supply of the MB-450s on a per watt basis.
I guess a lot of people have had similar experiences to yours. Pretty much the only time I experimented, upped the capacitors on my current amp from 6 x 4700uF to 6 x 10,000uF. I noticed no difference, but then I don't listen very loud and this is a class D amp ... so my experience isn't worth much one way or the other.

[E-Stat]

I guess a lot of people have had similar experiences to yours. Pretty much the only time I experimented, upped the capacitors on my current amp from 6 x 4700uF to 6 x 10,000uF. I noticed no difference, but then I don't listen very loud and this is a class D amp ... so my experience isn't worth much one way or the other.
Double it again and you would have the equivalent energy per watt of the Threshold if only half the transformer current capability.

You would need to more than quadruple it to match the VTLs.