Doing Research: Prosumer Mic Pre Circuits

[JuniusRecordingCo]

I'm writing up an article on preamplifers for the home studio and would love to know the basic range of differences in topology and components found in prosumer mic preamps, specifically those found in USB audio interfaces from the likes of Focusrite, Prosonus, M-Audio and others.

My suspicion is that they will all be remarkably similar, but I'm finding it hard to locate schematics or specifications detailed enough to check.

Got any information?

 

[JohnRoberts]

Maybe ask them...?

These days you can buy off the shelf mic pre amp ICs that are quite good...

I doubt they want to see too specific info reported.

I suspect most are using the "Cohen" topology (I dislike calling it that) whether IC or discrete, or hybrid.

JR

 

[Pip]

I'm writing up an article on preamplifers for the home studio and would love to know the basic range of differences in topology and components found in prosumer mic preamps, specifically those found in USB audio interfaces from the likes of Focusrite, Prosonus, M-Audio and others.

My suspicion is that they will all be remarkably similar, but I'm finding it hard to locate schematics or specifications detailed enough to check.

Got any information?

I suggest also that you contact the manufacturers of the preamps that you want to compare.

Component choice and even circuit similarity can be greatly influenced by a myriad of other factors not the least of which is layout and power and grounding schemes and manufacturing tolerances etc.... Associated feature sets also play into a piece of equipment's value in the recording chain. There is also a big difference in AD/DA differences and Analogue only solutions as now you have the conversion factor and other chip sets in the mix!

IMO I question the use of the term Prosumer and offer maybe, Entry Level or better yet Project Studio or maybe Portable. I will give an example if I may ART Tube MP Project series vs PreSonus AudioBox USB same price vastly different which would you want?

 

[JuniusRecordingCo]

Pip, you're certainly right about "prosumer"--I don't want to be pejorative. I'm in fact advocating the use of the stock preamps over outboard for the novice home recordist in the article.  I'll see what I can get from manufacturers, but I'll certainly welcome additional comments!

 

[JohnRoberts]

Pip, you're certainly right about "prosumer"--I don't want to be pejorative. I'm in fact advocating the use of the stock preamps over outboard for the novice home recordist in the article.  I'll see what I can get from manufacturers, but I'll certainly welcome additional comments!

If you are looking for bang for the buck,  the best value is a small mixer... Most modern preamps these days are quite good. For some reason people are prejudiced against mixer pre amps as somehow being inferior to the more expensive stand alone pre's. .  Don't perpetuate that old myth. 

What do you think it cost extra to put each preamp in it's own chassis, with separate line cord and separate power supply? More expensive does not automatically mean better, just more expensive.  Get a small mixer with inserts or direct outs (less common), but insert jacks can be used for tracking.

JR

 

[PRR]

> advocating the use of the stock preamps over outboard for the novice home recordist in the article

Bad plan. The outboard preamp makers buy ads. Or not, if the editorial content disses them.

 

[JuniusRecordingCo]

Bad plan. The outboard preamp makers buy ads. Or not, if the editorial content disses them.

Not on my company's blog, they don't.

What do you think it cost extra to put each preamp in it's own chassis, with separate line cord and separate power supply? More expensive does not automatically mean better, just more expensive.

This is exactly the thinking, and as this article (blog post without paid advertisers, to make it clear) is pointed especially towards voice artists building a home studio, then using the clean, uncolored stock preamps in today's audio interfaces are an obvious way to save money for things that make a bigger difference, like the mic and acoustic treatment.

I am still interested in the differences in design between them, and really appreciate the group's input.

 

[JohnRoberts]

Bad plan. The outboard preamp makers buy ads. Or not, if the editorial content disses them.

Not on my company's blog, they don't.

What do you think it cost extra to put each preamp in it's own chassis, with separate line cord and separate power supply? More expensive does not automatically mean better, just more expensive.

This is exactly the thinking, and as this article (blog post without paid advertisers, to make it clear) is pointed especially towards voice artists building a home studio, then using the clean, uncolored stock preamps in today's audio interfaces are an obvious way to save money for things that make a bigger difference, like the mic and acoustic treatment.

I am still interested in the differences in design between them, and really appreciate the group's input.

You don't need to second guess the inner design differences which will probably be minor. The important thing is "performance" differences and as has been often repeated around here, the differences between mic preamps are insignificant compared to the differences between mics (even same model mics), then different mic placement, then different room acoustics, then maybe mic preamps if its a really bad preamp.  :-\

JR

 

[FETlife]

Doug Self touches on this in Small Signal Audio Design.

 

[gar381]

This skitz is from a 1977 tangent bar mixer.

This circuit and its variations have been used for years
by many different companies.

This circuit is about the same as the cheap current Nady
8 channel rackmount pre... 2 transistors and
an opamp per channel.  Couldn't get simpler and this
pre sounds quite good for what it is.

The Nady is about $100 street thats about $12.50 a channel. 
Hope thats prosumer enough ;D

Best..

GARY

 

[JuniusRecordingCo]

Doug Self touches on this in Small Signal Audio Design.

Could you elaborate? Or even point me to the section in the book?

 

[abbey road d enfer]

I'm writing up an article on preamplifers for the home studio and would love to know the basic range of differences in topology and components found in prosumer mic preamps, specifically those found in USB audio interfaces from the likes of Focusrite, Prosonus, M-Audio and others.

My suspicion is that they will all be remarkably similar, but I'm finding it hard to locate schematics or specifications detailed enough to check.

Got any information?

You may want to check the 7th circle website.
They have several types of preamps and the schemos are published.

 

[FETlife]

Doug Self touches on this in Small Signal Audio Design.

Could you elaborate? Or even point me to the section in the book?

Chapter 13: Microphone Preamplifiers.
Well worth a look imo.

 

[Pip]

Doug Self touches on this in Small Signal Audio Design.

Could you elaborate? Or even point me to the section in the book?

http://www.douglas-self.com/ampins/ampins.htm