D & R Preamps?

I have a DAV, a new Joemeek, and an RNP.

If they're so much the same, why do they sound so very different? :confused:

There must be more to the story than just TI INA 163.
 
I noticed the D & R uses TL-072 and SSM - 2017 OpAmps/chips. I know that different circuits can change how the OpAmps perform but I was wondering if these are decent components?
 
Plenty of decent gear using both of those chips, TL072 would be pretty low spec for a mic pre these days, but then again it would be fine for driving a clipping circuit. (Does the D&R pre have a clipping LED? That would be a clue).

The SSM2017 chips are in loads of modern stuff, Millennia, DAV, Joe Meek etc. I suspect that would be the chip which is amplifying your audio and evidently they are proven to be a good performer.
 
dickiefunk said:
I noticed the D & R uses TL-072 and SSM - 2017 OpAmps/chips. I know that different circuits can change how the OpAmps perform but I was wondering if these are decent components?
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Maybe if they were in a Behringer console or something. Actually, I take that back. Most Behringer consoles have better / faster / cleaner components than that.

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Kevin DeSchwazi said:
The SSM2017 chips are in loads of modern stuff, Millennia, DAV, Joe Meek etc. I suspect that would be the chip which is amplifying your audio and evidently they are proven to be a good performer.
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Actually, those are discontinued. And no one really misses them. There were many issues with them, particularly regarding HF distortion in the audible range. The newer Texas Instruments INA217 was a major improvement, and a drop-in replacement.

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chessrock said:
Actually, those are discontinued. And no one really misses them. There were many issues with them, particularly regarding HF distortion in the audible range. The newer Texas Instruments INA217 was a major improvement, and a drop-in replacement.

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Yet many companies used them with no issue at all. Many of those are also well respected companies with tried and true product. D&R also managed to get incredible specs with an ssm2017 in line. All the way out to 300k. I would call that well outside the audible range. Once again, there are two things possibly going on here. Either Chessrock is wrong, or everyone else in the industry is wrong. Hmmm, wonder which?

The newer D&R stuff utilizes the ssm2019 chip which is the newer version of the ssm2017 and is a drop in replacement.
 
xstatic said:
Either Chessrock is wrong, or everyone else in the industry is wrong. Hmmm, wonder which?
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"Everyone else in the industy" is not touting the virtures of the 2017 chip. :D Let's at least get that one out of the way. At least not the ones that know what they're talking about (Read: not Xtatic).

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I was looking into the Symetrix 528E recently and I found this thread:
https://homerecording.com/bbs/showthread.php?t=49981
I was suprised to see how respectfully Chessrock used to communicate with other board members. I imagine he very well may be that way in person too, but of course, don't know for sure.
Chessrock- what ever happened to the preamp business venture you were considering? Did your research on preamp design contribute to being so cynical about this stuff? Again, as I've mentioned before I know you're trying to help folks a lot of the time, but is it the hype and advertising around products versus the objective stuff what gets you and why you get so combative with some of the proprietors who come on here or challenge people's reports about newer gear?
Also on a technical note, can't things like the output section and power supply make a big difference in how a preamp performs and sounds-- even if it has the same op-amp and/or input section?
 
kojdogg said:
Again, as I've mentioned before I know you're trying to help folks a lot of the time, but is it the hype and advertising around products versus the objective stuff what gets you ...
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Yes. I think it's important to be able to sort out some of the fact from the fiction. And rarely have I seen so much noise being thrown around than that surrounding mic pres.

Also on a technical note, can't things like the output section and power supply make a big difference in how a preamp performs and sounds-- even if it has the same op-amp and/or input section?
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To a degree, yes. But only up to a certain point, before you get in to some rapidly-diminishing returns.

I just really think it's important to try to keep things real. Once you start getting in to a situation where no one can say anything disparaging -- or even questioning -- about a particular product without fear of repurcussion or hurting someone's feelings ... then where's the value of the board? You might as well just go read the advertising copy.

If a D&R rep wanted to come on to this board and refute any of my comments, they're welcome to do so. I've actually asked a rep from their company in the past (some D&R guy used to frequent from time to time), point-blank, what is it that differentiates your product? And he couldn't come up with anything even resembling an acceptable or educated answer.

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Here we go again, with a lot of smoke and mirrors. This thread started out as a discussion of preamps, and now it's turned into a bunch of hooey about chips thanks to Chessrock.

Chips don't matter, nobody should care about what chips are in a preamp. All that matters, *the only thing that matters*, is how it sounds. You can't tell that from the chips.

To say that all equipment that uses the same chips sounds identical is the same as saying that there are only twelve notes in a scale so all music sounds the same no matter who writes it. That's obviously ridiculous, as is discussing the merits of preamps based on what chips are in them.
 
how about negative feedback? i ended up in a back and forth here with harvey gerst that went well above my head. won't some cheaper circuits use negative feedback to reduce noise and boost specs as a cost cutting measure? couldn't you take two preamps that have the same input op-amp, but one would use a lot of negative feedback to get its specs and the other achieves greater gain and noise specs by having better electronics in the circuit, a better output section and a more robust power supply?
my understanding is that negative feedback would boost specs, but create weird phase-like problems that can increase sibilance and other unwanted artifiacts-- particularly in the same frequencies where noise can be the most audible and create a situation where cheap mic plus cheap pre with a circuit where negative feedback is used excessively to achieve performance can result in a subjectively thin and harsh sound.
i don't know for sure, but i wonder if these kinds of differences are at work between different preamps with the same op-amp on the input section that have greatly different costs and reputations.
i'm far from an expert in this subject or preamp design. my understanding of negative feedback is largely based on what i read in the langevin dvc user manual and then s.i.r.o.t.i. (stuff i read on the internet-- where caveat emptor as always).
 
SonicAlbert said:
Chips don't matter, nobody should care about what chips are in a preamp. All that matters, *the only thing that matters*, is how it sounds. You can't tell that from the chips.
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I totally understand where you're coming from on this. And you're right. The kind of chip used has almost no bearing whatsoever on any of this. Whether it's an 217, a 163, or even a 2017 (to a small extent). What we're talking about here is the design / layout of the unit. The deal with these things is ... when something has either one of the three chips I just mentioned above, it indicates something about the design.

Sonic, I know you're a fairly sharp cat, so I think you can get this -- bear with me here. The 217, 163, 2017, or even the 2015 are Instrument Amps. Not just I.C's. They are moreless an "all in one" kind of deal. About 90% of what goes on in any design that utilizes an instrument amp ... is done within the confines of that little chip. So when you look inside and see that it has one of those chips in it, it telegraphs to you what kind of design it is. (Not so if you were talking about a TL-072 or an NE-5532, or any other dual opamp - that's a whole 'nother ballgame)

They do more than a processor does in a PC, and that's not an exaggeration.

Now I completely understand the frustration. We're arguing about components -- who cares, right? It's about performance, right? But the fact of the matter is ... this particular instance is kind of an exception to that rule. I'm not just spouting random crap. In an instrument-amp based mic pre ... this one component really is the heart and the brains of the whole thing. All other things being equal, you can look at a PC's processor ... and get a pretty decent idea of what you're getting in to, right?

It's like if you're looking at a Toyota Corolla and a Geo Prism. They use the exact same engine ... so do you honestly think it would be completely out of line to want to put each of them within a similar classification? (budget, economical, high gas mileage, reliable, etc.) And if, by chance, one of the models were to cost significantly more than the other, wouldn't you want to know what was going on in order to justify that differential? They're both excellent cars for the dough (and I've owned a few) so that's not the issue at all. You following me here?


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chessrock said:
Maybe if they were in a Behringer console or something. Actually, I take that back. Most Behringer consoles have better / faster / cleaner components than that.

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Come on now. I think Behri is so devoted to outdated ICs that they have started manufacturing them :p

And I wouldn't mind getting my hands on some brand-spankin' new BBDs myself :o
 
chessrock said:
The 217, 163, 2017, or even the 2015 are Instrument Amps. Not just I.C's. They are moreless an "all in one" kind of deal. About 90% of what goes on in any design that utilizes an instrument amp ... is done within the confines of that little chip. So when you look inside and see that it has one of those chips in it, it telegraphs to you what kind of design it is.
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So what functions do those all-in-one chips take on, as opposed to chips like the TL-072 or NE-5532?
 
kojdogg said:
how about negative feedback?
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Read this thread:

http://recforums.prosoundweb.com/index.php/t/16557/0/

That is mainly talking about power amp design at a conceptual level. But I don't think there is any difference in preamp design, at least so long as we are talking in terms of IC opamps. The opamp's gain is set as a function of external feedback, so I don't see how a designer would get around that, except by running the opamp at maximum possible gain and attenuating the result. That tends not to work terribly well . . .
 
SonicAlbert said:
So what functions do those all-in-one chips take on, as opposed to chips like the TL-072 or NE-5532?
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Oh boy. :D Not an expert, but I'll give this one a stab. I'm going to try and simplify this as much as possible, and I realize that some of the more technically knowlegable amongst us will have my head for this, but here goes my vastly simplified half-assed explanation ...

An opamp can be thought of as the building block of sorts, for things that require amplification, filtering, signal manipulation, etc. etc. etc. Opamps do this through a series of transistors ... with the idea, basically, to amplify stuff. In an "operational" way, of course.

By itself, an opamp can't perform this function very well for amplifying, say, a microphone signal. Basically what winds up happening is it amplifies not only the source, but all of the DC, noise and other common-mode votages. So all you get, basically, is a lot of noise ... along with some of the signal you're trying to amplify. :D

Now in order to amplify what the mic is trying to pick up, you need to have a way of canceling out all the other junk. This normally requires a series of opamp circuits. And what an instrument amp does is sort of pre-packages all of these circuits in to one monolithic piece ("integrating" the circuits, if you catch my drift). First, it does the whole "gain stage" thing (taking the signal and amplifying it) followed by another stage that removes the "common mode" (basically filtering out all the junk).

To be more precise, it first amplifies the difference between two input circuits, and then rejects anything that is common to them (the junk). An opamp (like a 5532, etc.), by itself, would amplify everythig -- including the junk. And a lot of people think the 5532 is junk btw, but that's a whole nother topic. Anyway, if you get how a balanced signal works, then it shouldn't be a stretch.

So in a very overly-simplified nutshell, the instrument amp is doing all the grunt work of taking the relatively weak signal coming from a transducer (in this case, a microphone), and amplifying it to a useable signal. Basically, it is performing the function of a mic pre. :D Everything else (in the design/layout) just kind of supports what it is doing. Hopefully in a positive way - and therein lies the differentiating factors. bla bla bla.
 
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