D from BC wrote:
>
>> Wow ...3 threads at same time for mic amps.
>> "Improved mic amp posted on Rapidshare"
>> "A Better Microphone Amplifier Yet"
>> "Is S.E.D. actually sci.electronics.dummies"
>>
>> I'm surprised mic amps are a lively topic on here.
>> I thought it would be a beaten to death topic like audio power
>> amplifier design.
>> Also, by now shouldn't the ultimate microphone amp be a well known
>> cookbook circuit?.
>
>
>Mic pre design is a complex trade off. There is no perfect design, that's
>why there are so many.
>
>Ian
Trade offs.... I'm aware of: noise gain PSRR CMRR distortion dynamic range stability (DC bias and feedback) power efficiency PCB size cost
"D from BC" wrote in message news: snipped-for-privacy@4ax.com...
I think this is a point that Graham has been trying to make. For a musician or sound engineer, there is a certain sound to micpres, etc., and maybe that's why his design was successful. In technical terms, I suppose it's probably some lack of quality (I'm not saying this about Graham's design BTW) in the design that imparts a difference in tone to whatever's being recorded. This explains why you see Neve channel strips going for a couple grand on eBay, even though Rupert himself admits that today's designs are far better. This may also help explain why the high end boutique micpres can fetch a similar price, even though there couldn't possibly be enough spent on actual components or R+D or whatever to justify the cost. Maybe Phil's right and the engineer types are deluded, but they seem convinced that there is a difference, and maybe there is - this mysterious tonal quality that certain designs impart. Whether it is better for the sound or not is a matter of opinion and personal taste. I'm a musician myself, and what I record is largely classical guitar, which requires a very low noise micpre, which the SSM2017 is able to deliver. The noise contributed by the micpre itself, with whatever resistors or other noisy passives I have in there is miniscule, and for all intents inaudible, so this one works great for me. I've not had the fortune to A/B it with a Focusrite to see if the latter has a better 'sound', although a local studio owner has invited me to bring my micpre and go head-to-head with his Focusrite. Maybe I'll take him up on it some day, but I figure that my playing itself needs more work than my recorded sound anyway. ....
Welll...I have some audiophoolery for yah... :) The mic amp difference is... the distortion. (Here comes the tomatoes... :) ) Some distortion sounds nice. But it's gotta be the right flavour of distortion.. Something to do with even harmonic content sounding better than odd harmonic content.. (A gross example is the Tony Iommi (Black Sabbath) guitar sound. But much more subtle in a mic amp.)
I keep showering but the audiophoolery doesn't wash off.... :)
More scientifically I'd get an Audio Analyzer from:
formatting link
And test the mic amps for a difference. It's rentable.... D from BC
Condenser mics have * pre-amps* inside them !!!!!!!!!
Almost always, the noise level coming OUT of these internal per-amps is way MORE than the input noise level of typical mic-pres in mixing consoles and elsewhere.
There is no noise benefit in using a low noise pre-amp UNLESS it is being used with a dynamic mic.
This is what the EIN figures always refer to a 150 ohm or 200 ohm source impedance - ie a DYNAMIC mic !!
It all goes RIGHT OUT THE WINDOW when a condenser mic is used.
I think that the mic preamp has reached its state of the art, and further improvements are probably found in reducing the cost while keeping the performance. It's not all that difficult to build a mic preamp that measures flat from single-digit hertz to 200 kHz over a reasonable gain range.
Anyways, I think the most obvious reason for differences in the sound of mic preamps is simply the input loading. Change the input impedance and how it reacts with a dynamic mic changes.
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.