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does anyone know the slew rate of an evo2 amp when bridged
i am plannig on a purchase ,the slew rate is apparently very important
thanks in advance
andre
Follow Ups:
...which is over 10x faster than a conventional analog amp. The eVo2 rate is probably similar. This comes from BC's web site white paper under "Support".Planning to use this amp with your Signature 805s?? Or have you picked up a pair of S800s?
no enzo ,i have found a pair of audio physic medea in germany
i had the evo2i for a while ,flipping good on a caldera ,but i will need 2 evo monos on a medea
these amps are ridiculously cheap ,i had a accustic art amp2 hc (a monster )the evo2i bettered it in every aspect just no comparison at all
It is...checkout some high slew rate (800V/uS) AVA amps at www.avahifi.com It makes things just sound right.
Where did you find the Slew rate for the AVA amps? Frank doesn't publish his specs (so he can't be sued perhaps?)so where did you find this spec? If it isn't published it means squat.Don't get me wrong the AVA amps are very quick sounding and are a great buy, but you keep giving out this slew-rate and I just need to know where you got it.
I should mention that slew rate alone means nothing. You only have to be able to slew your amplifier's rail voltage into a load at the fastest rate that the audio signal requires. And that is a LOT slower. Now settling time...that is something I would like to see published in an amps specs.
With a band-width of 100khz the amp with only 100volts per microsecond is still 10 times faster than it needs to be! Hmm, and with cd-audio limited to 22khz....well, you get the idea.
Go to www.avahifi.com Call up the Dyna PAT-5 rebuild page, says 800V/us ckts.
Read the paragraph son, it is talking about the *integrated circuits* (as in $2.00 op amps) in his *preamp*. Not his power circuits on his *power* amp.Show me something that is saying 800v/Usec on the *Power* amp.
It's in his literature, he also has .01 distortion specs, with the extremely FAST slew rates, e-mail him and ask him, you will see
He is pretty weak on the specs. The distortion is fine, as is that of many other fine amps. But there is no mention of the exact value of the slew rate.
I looked, and the following is all the spec material that appears on his web site:"Our OmegaStar amplifiers sound bigger, tighter, much more dynamic, stunningly smoother, and absolutely transparent. They have a power bandwidth extending to nearly 500 kHz, slew rates of hundreds of volts per microsecond..." (How many hundreds he doesn't say. If it isn't published it don't means squat because you can't hold him to it.)
"Fet Valve 550Ex hybrid vacuum tube amplifier. 250 watts per channel 20 to 20 kHz at less than 0.01% THD. 17" wide, 13" deep, 7" high. Shipping weight 38 pounds. All new AVA designed black chassis with black anodized faceplate and high efficiency black anodized extruded rear mounted heat sinks with 12 high current TO-3 case power MOSFET output devices. For 2 ohm loads and up."
The Omega III I beleive is 500v/uS..the OmegaStar are 800V/uS. AVA is great stuff
The only place on the website that I see the figure of 800v/uS is on the preamp page where it refers to the speed of the buffer. I saw no such reference to the power amps.Buffers are very quick as a rule; it is hard to design a slow one. And if he is using one of the off-the-shelf high-quality op amp buffers that are available there are models that offer 1000v/uS. But neither speed is required for audio and really has nothing to do with the good sound his equipment has. Or I should say it is only a factor and not the most important one.
This isn't exactly true, but 50V/us is a reasonable minimum for a 100W power amp. This is based on TIM distortion theory.
Thanks John. Was I close enough for government work though?I remember Scott saying something to the effect that to avoid TIM one had to make the input able to take twice the input voltage that is required for the full power operation of the amp? Do I remember it correctly?
I don't know, but I do know the measurements, Walt Jung, Matti Otala and I have made more than 25 years ago. We settled on 50V/us, or 1V/us for every output volt peak. So a 100W amp would have a +/-50V supply, and that makes 50V/us. This was found with difficult inputs, such as MC phono cartridges, but it would be the same today for SACD or DVD sources.
Is that because the dynamic range of microphones (and by extention,recordings) is so limited? In other words an amplifier does not really have to swing a rail-voltage through a 120db range but merely a 30db or at most a 50db range?
TIM is caused by high level, high bandwidth, pulses. These are generally formed by clipping somewere in the audio chain. When playing a record, it was caused by mistracking that happened all the time. It is difficult to get classical TIM with an ideal CD, but SACD and DVD will easily allow it.
TIM is only the primary reason for having higher slew rate. Actually, the whole circuit is improved, in general, by increasing the slew rate above a few volts/microsecond, where it is with the cheapest components.
Just as an additional comment, Seeing how well an amp can reproduce square wave through a scope can provide some useful info in comparing amps.
Not too much useful info any more. Unless you have a scope with great resolution most all SS amps look pretty much the same on square-wave. And most tube amps look like crap, but still sound good.
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