Hi,
Don't think they stopped... but that's not the point anyway.
But the input xformer in your proposed cct has a step-up of 1:5, so I fail to see the point unless you consider input ctrl with some other device.
Consider this, according to your reasoning: most people have a preamp with a linestage having 20dB of gain fed from a CDP with a 2VRMS output or 6V P2P.
You propose another 1:5 stepup at the input of the source follower amp... what for?
Those people in posession of said preamps better start adding attenuation networks before that MOS-FET flies way up to the speakers, right?
Even clamping diodes aren't going to help much there, I am afraid.
In conclusion, the 1:5 step-up would only be useful to people with passive preamps with a buffered output capable of driving the 1K5 Zin of the Xformer in the first place.
I don't know of that many linestages that are just that, except one I built myself, do you?
So, while I can live with the concept, the execution is somewhat lacking.
Cheers,😉
Don't think they stopped... but that's not the point anyway.
But the input xformer in your proposed cct has a step-up of 1:5, so I fail to see the point unless you consider input ctrl with some other device.
Consider this, according to your reasoning: most people have a preamp with a linestage having 20dB of gain fed from a CDP with a 2VRMS output or 6V P2P.
You propose another 1:5 stepup at the input of the source follower amp... what for?
Those people in posession of said preamps better start adding attenuation networks before that MOS-FET flies way up to the speakers, right?
Even clamping diodes aren't going to help much there, I am afraid.
In conclusion, the 1:5 step-up would only be useful to people with passive preamps with a buffered output capable of driving the 1K5 Zin of the Xformer in the first place.
I don't know of that many linestages that are just that, except one I built myself, do you?
So, while I can live with the concept, the execution is somewhat lacking.
Cheers,😉
fdegrove said:
If they didn't stop, it's special order. If memory serves, they wanted to optimize for a 1:1. But as you say, that's not the point.
I didn't say most people have a preamp with 20dB of voltage gain. I said most preamps (i.e. as opposed to attenuators or buffered attenuators) have 20dB of voltage gain.
I offered up the 1:5 schematic because Fuling originally said he wanted an amp, not a buffer.
I mentioned preamps driving buffers rather than amps because I don't know what anyone has and was just a suggestion for those who may have preamps with enough voltage gain to get enough power to their speakers just using a buffer.
Don't know what you mean here. Clamping diodes aren't going to help much where?
Most anything can drive a 1.5k load. That's not a problem. If you're just going from the output of a CD player, you're talking no more than a few volts. That's just a couple of milliamps. Even at 20 volts, you're looking at just 13 milliamps.
Driving 1.5k isn't a problem. It's just a matter of output impedance and how much attenuation and high frequency rolloff is acceptable for you.
Last I looked, this place was called diyAudio.com. I was under the impression "diy" meant "do it yourself." Am I in the wrong place?
The concept was all that I offered in the first place.
se
Hi,
You'll have to DIY in this case for there's little out there with enough current drive to come to terms with such an engineering flaw.
DIY, is the operative word here so throw all you've got out of the window guys...Steve Eddy is going to set new standards from now on.
Any other standards you'd like to throw out of the window?
Cheers,😉
You'll have to DIY in this case for there's little out there with enough current drive to come to terms with such an engineering flaw.
DIY, is the operative word here so throw all you've got out of the window guys...Steve Eddy is going to set new standards from now on.
Any other standards you'd like to throw out of the window?
Cheers,😉
fdegrove said:
You get the grip. 1.5k ohms is no big deal. Your basic NE5532 opamp can swing +/- 12 volts into a 600 ohm load. What the hell do you think's driving those 600 ohm loads so common in pro audio gear?
What are you telling us, Frank? That your preamp doesn't even have the drive capability of a 25 cent opamp?
se
fdegrove said:
So I guess all those 600 ohm loads in all those pieces of professional audio gear are engineering flaws? Funny that the professional audio community doesn't seem to have any trouble finding devices with enough current drive. They just use 25 cent opamps.
What "standard"? The closest thing to a standard as far as input impedances go is the pro audio standard of 600 ohms. And even that's not really a standard. So just which standard are you referring to?
First show me the first standard I threw out the window.
se
Oops. Just checked NE5532 pricing at Mouser and for onesies twosies they want 54 cents. But then you get two opamps in that package so we're talking 27 cents per opamp.
My apologies.
se
My apologies.
se
I have to admit that my preamp doesn't have the drive capability of a 27 cent opamp. But it glows, which is more than I can say for a 5532.
SY said:
Oh you can make a 5532 do more than glow. Only problem is you can only do it once. 🙂
se
SY said:
No, I said more than glow. *BANG!* 🙂
Happens to me all the time. Think I should use some protection diodes? 🙂
se
Steve Eddy said:
American Chopper is cool..
Time to build some theme amplifiers,
people think I'm a fool (well, true)..
Powder coat green chromed heatsinks
for the Incredible Hulk amplifier.
The amplifier will have a detector,
if you hit clipping, it boost rails
voltage 2x because it's angry... /hehe
This past weekend I was doing listening
tests on my SA8535 planar, 103db
sensitivity tweeter, 13 ohm.
Then I connected this tweeter direct
to the cheap old Sony portable CD
player's headphone jacks and drove
the tweets directly, loud enough
to hear them from 5 feet away..
Then I tried it with my preamp which
uses 5532, no probs... same results,
it worked.. Then I paralleled another
set of tweeters for 6.5 ohm load.
This was just to prove one point,
can I drive those tweeters with no
real power amp... /hehe
/silly
tests on my SA8535 planar, 103db
sensitivity tweeter, 13 ohm.
Then I connected this tweeter direct
to the cheap old Sony portable CD
player's headphone jacks and drove
the tweets directly, loud enough
to hear them from 5 feet away..
Then I tried it with my preamp which
uses 5532, no probs... same results,
it worked.. Then I paralleled another
set of tweeters for 6.5 ohm load.
This was just to prove one point,
can I drive those tweeters with no
real power amp... /hehe
/silly
thylantyr said:
Hehehe.
Well the 5532 current limits at 38 mA so you should be able to get about half a volt across those tweeters so you're talking what, about 19 mW? 🙂
se
Re: Hey Steve.......
Sure. Though lately I haven't been very active. Been going through a bit of a heatwave here. Temperatures up to 105, unusually high humidity, and I don't have air conditioning, just an evaporative cooler which isn't very effective when the humidity goes up. Makes it pretty miserable to do much more than bang on the keyboard.
se
Jocko Homo said:
Sure. Though lately I haven't been very active. Been going through a bit of a heatwave here. Temperatures up to 105, unusually high humidity, and I don't have air conditioning, just an evaporative cooler which isn't very effective when the humidity goes up. Makes it pretty miserable to do much more than bang on the keyboard.
se
Re:Re:Hey Steve...
Hi,
That explains it...
Since those pieces of equipment were designed with that standard in mind no, of course not.
All we have left to do now is adapt all our gear to that standard and we're all happy.
Didn't I tell you that you're a trendsetter?
Cheers,😉
\Going balanced all the way next time I build something...
Hi,
That explains it...
Since those pieces of equipment were designed with that standard in mind no, of course not.
All we have left to do now is adapt all our gear to that standard and we're all happy.
Didn't I tell you that you're a trendsetter?
Cheers,😉
\Going balanced all the way next time I build something...
Re: Re:Re:Hey Steve...
What do you have to do to design to that standard when even the cheapest opamp will drive it?
What is there to adapt? Whose gear can't muster what a 25 cent opamp can? Is that how we're to define high end audio? Can't even beat a 25 cent opamp?
"I spent $5,000 on this preamp and it can't even do what a 25 cent opamp can do!"
se
fdegrove said:
What do you have to do to design to that standard when even the cheapest opamp will drive it?
What is there to adapt? Whose gear can't muster what a 25 cent opamp can? Is that how we're to define high end audio? Can't even beat a 25 cent opamp?
"I spent $5,000 on this preamp and it can't even do what a 25 cent opamp can do!"
se
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