Mic preamps with seemingly deep sound stage (depth of field)

[JW]

I thought I'd ask folks here because I'm certainly not going to go out and buy some premade fancy schmancy thing when there's so many mic amplifiers that are fairly easy to build associated with these forums!

Lately I've been thinking a lot about the depth of the sound stage that some pieces of equipment seem to reveal more than others.

As an aside, (though I don't really want to start a discussion about this exactly) the most obvious thing, to me, about the difference between analog tape and digital recordings, is the deeper sound stage of the former, and the lack thereof of the latter. The picture seems to go further back with analog. I find the difference between LP's and CD's to be similar in that regard, maybe even more pronounced. I think there's a lot of folks here who would agree to that phenomenon.

But my question is about mic preamps. Seems like some preamps, same mic, same spot, same source, somehow capture the depth of field better than others.

I'm gonna keep my API style 7th circle preamps, and sell the Neve style ones (N72's), not because I don't like the Neve sound, it's just that I find these to be a little murky, and not that great when they're cranked, which is consistent with what Neve folks say about trying to squeeze two much out of what is essentially a 1272 amp.

I think the API's are pretty badass, but they're right up front, on the edge of the speakers, so though they're really fast and rock and roll sounding, I wish for something with a deeper sound stage.

Am I right in thinking that the Troodent A Range preamp might be a good idea to try and build up to satisfy this desire? Certainly for the price, it seems very reasonable.

Anyway, I'd love to hear other's opinions on projects here (or elsewhere) that fit your definition of preamps with a seemingly deep sound stage.

 

[dbmorton]

JW,
This is my first ever post on this forum. Yay, newbie!
I agree with most everything you have said about perceived depth-of-sound-stage, and have myself tried to achieve that, both with my recording techniques and the gear I use. Interestingly enough, I don't consider myself a genre purist (as in "I can only listen to jazz or classical") and I don't mind compression, sometimes even LOTS of it. But, I find that modern recording and mixing tastes and techniques really go a long way towards restricting or eliminating sonic depth-of-field. This was really driven home as I listened to my Beatles mono remasters (from the "Mono Box" of 2009) and found them to sound incredibly dimensional, despite the supposed handicap of having one less track than most music I usually listen to.
Anyway (to my actual point), one of my favorite mic pre's that I own (or, for that matter, have ever used) is the Universal Audio 2-610. I've heard complaints here and there about this and that, mostly around tone or lack of headroom (which I completely do not understand), but for me it was, and continues to be, a DEEP sounding unit. Paired with either my Lawson L47 or L251 tube mics, I can hear sounds into the distance with ease and fidelity. No hype, just effortless reproduction. That doesn't happen with my Vintech x73i. Don't get me wrong, I own that piece for a reason and I do like the "Neve 1073" thing, but for realistic depth, the 610 beats it hands down. I don't know if it's the tubes or input impedance or what, but as long as you don't get crazy and drive it too hard, it's a beautiful thing.
As always, your mileage may vary, but it's a thought and something to look into.

 

[mitsos]

since you like and own 312s, might want to try a 990 opamp.  There is a simple mod to bias it properly in a stock 312 (ideally it should also have a lower ratio input trafo, not sure how badly that will effect it).  I don't know the actual resistor values, but it shouldn't be hard to calculate or just ask john hardy when you order.  Very nice sounding opamp, open, 3D, all those keywords. 

I too like the 610, on voice and acoustic guitar.

 

[micaddict]

Have you considered the SCA J99?
http://www.seventhcircleaudio.com/J99/J99R36/j99_about.htm
Less character than either the Api or Neve "clone", but with trannies and not sterile (although boring to some, no doubt). Hardy-ish. Openness and depth are terms that are not seldom used when these are described. As always, the proof for you will be in the eating of the pudding.

Another idea, on a somewhat similar DIY level I guess, might be the Hamptone tube pre kit. (Two channels.)
http://www.hamptone.com/hvtp2_info.html
http://www.hamptone.com/micpres.html

Here's one short "review" I pulled from the Gearslutz forum:

So while I no nothing about single ended vs, push/pull sonic intricacies, I can say from first hand experience that the HVTP2 is an exceptional piece of kit that sounds deep and fat with the air you expect (hope for) from a good tube pre. Compound that with it's exceptional value and rock solid build (and I mean rock solid, built like a tank) it's pretty damn sweet!

 

[abbey road d enfer]

Lately I've been thinking a lot about the depth of the sound stage that some pieces of equipment seem to reveal more than others.

There are probably as many definitions of "depth of the sound stage" as there are members in this forum, but it is true that some units seem to "reveal" more than others.
In my experience, I've always been capable of tracing that to the nature of distortion - in that specific case, I would also include noise as a form of distorsion, when some units have such a characteristic noise that is imprints some kind of sonic imprint on the signal. 

the most obvious thing, to me, about the difference between analog tape and digital recordings, is the deeper sound stage of the former, and the lack thereof of the latter. 

  This is quite debatable 

I find the difference between LP's and CD's to be similar in that regard, maybe even more pronounced. I think there's a lot of folks here who would agree to that phenomenon. 

I wouldn't. If you compare a 1981 CD with a 1981 LP, your opinion is certainly true. Converters of the era were absolutely flawed with non-linearities.
Today, it is perfectly possible to produce a digital recording indistinguishable from the best analog recording.
However, it is not always the case, one of the causes being the inadequate matching of the analog chain to the digital chain.
Many SE's operate their gear at too high a level, which is not a problem for the digital chain, but is a problem for most of the analog gear, particularly if it is some kind of vintage gear, that is meant to operate at moderate level. 

But my question is about mic preamps. Seems like some preamps, same mic, same spot, same source, somehow capture the depth of field better than others.

As I said earlier, distortion is key. For me, the less transformers there are in the chain, the better. But that is not all. Some people believe the less components in the signal chain, the better. It's not true; it's not the number that counts, it's the way they're put together, in one word: the DESIGN. It is perfectly possible to make a mic pre with just one transistor and a few res/caps. Would it be the best sounding pre? No. You need to provide high enough input impedance, low enough output impedance, the right amount of gain control, ... That takes some more components, for a better result.
I like clean mic pres; some call them sterile, I call them reliable, in the sense that I never find myself in a situation where I wished I had used a less coloured chain. I'm pretty confident that I can add colour without distortion.
For me, distortion is what blurs the "micro-details" (I hate to use this term, but in the absence of a better one, I use it). This doesn't mean that the pre with the smallest THD figure will necessarily be the "deepest". The spectrum of distortion is quite important too. That's probably the reason why some SS pres with stellar THD figures do not necessarily sound as "deep" as some tube preamps with much higher figures. Low-order distortion components tend to agregate with the fundamental, whence high-order harmonics stick out like a sore thumb.
You're looking for recommendation (something you should NEVER do on a forum  ), so I would say that I don't really like my Focusrite ISA430MkII, I like my Avalon 737SP (I will be booed for that!), I like my ART Pro Channel, but not the Voice Channel, I like my SPL Pro Mike, hate my tc Gold Channel and love my LA610 MkII. And I like the pres on my Tascam DM4800!

 

[micaddict]

Excellent post, abbey!

To add to my last post, I do have a trannyless pre that I use both as a reference as for its superb (non)sound. It's the Gordon 5. An incredible mic pre with a high tech, point-to-point circuit. And it matches well with all mics, no matter if they're condenser, moving coil or ribbon, no matter if they're high or low output, and no matter if they're high or low impedance.
It's very expensive, too. And not easy to clone as a DIY project, I would say, if it all.
Not sure if I deserve to own it, but I saved long and hard for that once in a lifetime thing. And for a mic lover, it does make sense I guess to be able to know for sure that any coloration you're hearing is in the mic, not the pre.
And yes, depth is there, and then some. Not to mention detail.

All that said, there is something special to old analog recordings and yes, they can have amazing depth. Tube pres were just a small part, but if we focus on that for a moment, there likely is something added that sounds so musical and enhances the feeling (!) of depth. When, say, it comes to a (well-executed) single ended example (vs. push-pull), it is truly hifi and largely pretty clean, too, but yes, some second harrmonics are added. Those are both low order and even, so the ear doesn't perceive them as distortion, in any case not dirty, non-linear trouble. Overly simply put, it adds an octave layer on top of things. And that's just a very small part of the whole story which is not always easy to understand, but I believe it's too obvious for the ears to deny.

Disclaimer: IMOAE
Also, I'm more of a music lover and musician than a technician who was born with a soldering iron attached.
I do like it here, though. 

 

[JW]

Hmmmm.
Some interesting things. Thanks guys. I sort of half expected to hear "it's all about the room" in regards to this perceived depth discussion, which of course I know is true more than any one piece of gear, but which I can't change at this time. I guess what instigated my desire to ask this sort of question about preamps is because these API style pres are so punchy and out front, that of course I have the desire for something opposite but of equal value in terms of usefulness, since I've decided I'd like to sell the N72 dealios. I feel like opposite of the API pres would be something lush and deep.

Abby said: "There are probably as many definitions of "depth of the sound stage" as there are members in this forum, but it is true that some units seem to "reveal" more than others"

I don't know if that's really true. I would presume most folks have a pretty clear idea of what that is. If we were to perceive the musicians or instruments on a visual stage, we're talking about what's in the back, the furthest away from the listener. That's why I also put "depth of field" in the title.

"Today, it is perfectly possible to produce a digital recording indistinguishable from the best analog recording.
However, it is not always the case, one of the causes being the inadequate matching of the analog chain to the digital chain."

I'm sorry, but I haven't heard this yet. I have the Otari Radar II converters, which everyone and their brother raves about all the time and they don't even come close to my narrow format Tascam 58 in terms of depth. I've never heard a cd that sounds as deep as the record on a the same system. I am intrigued by the enormously expensive Burl converter thingies, but I haven't personally heard what they can do. Anyway, I guess I'll not reply from here on out concerning analog vs. digital 'cause I didn't really want to get into that, though I suppose I stoked the fires as it were.

Anyway, just thinking of replacing my N72's with something different, like a prodigy pro project! And I didn't expect to hear about that UA unit, considering how many people trash it. I wonder if us lay people will ever be able to piggyback on one of you genius' dissection and subsequent under the radar kit availability of the original Putnam 610.

 

[canidoit]

Hmmmm.
Some interesting things. Thanks guys. I sort of half expected to hear "it's all about the room" in regards to this perceived depth discussion, which of course I know is true more than any one piece of gear, but which I can't change at this time. I guess what instigated my desire to ask this sort of question about preamps is because these API style pres are so punchy and out front, that of course I have the desire for something opposite but of equal value in terms of usefulness, since I've decided I'd like to sell the N72 dealios. I feel like opposite of the API pres would be something lush and deep.

I wondered whether this could be fully true though because people are still capable of getting 3 dimensional recordings using a dead vocal booth. I mean if the booth is dead, then wouldn't the room theory not be feasible?

 

[lassoharp]

Anyway (to my actual point), one of my favorite mic pre's that I own (or, for that matter, have ever used) is the Universal Audio 2-610. I've heard complaints here and there about this and that, mostly around tone or lack of headroom (which I completely do not understand), but for me it was, and continues to be, a DEEP sounding unit. Paired with either my Lawson L47 or L251 tube mics, I can hear sounds into the distance with ease and fidelity. No hype, just effortless reproduction

I'd call that a good assessment for quality tube pres > DAW.  The nice mic certainly helps!

I've read the stream of complaints on the UA pres and although I've never owned one, on the issue of headroom I suspect a lot of users have been used to using any high output mic with any SS preamp and throwing the kitchen sink at it and expecting no audible distortion - ie poor technique with a tube preamp.  The many DIY tube pres that I have probably have a little less headroom than the UAs and I've not run into any issues with headroom during sensible use.


I had recorded on analog for some 15 years before using a DAW and the technique must be adjusted for sure in order to get similar results.  I'm not sure exactly what style sound you're wanting to achieve.  For a big vocal sound with rich bass (which doesn't seem popular for a lot of modern recordings) similar to what you hear on records from the late 50s to early 60s a tube chain is a natural for this.  For me, the more tubes & transformers the more dense and perhaps "deep" the sound.  I'll qualify the last statement by saying that you do have to be careful stringing transformer I/O gear together.  Two pieces that sound as they should on their own may not interface as expected, giving rise to smearing, excess rising response or unintended loss of high freq response.  There can be so many contributing factors in a long tube/iron chain - esp where vol controls are set  - that it's kind of impossible to write some reliable formula for what works best.  The good news is that it's often fairly easy to dial in a good sound, and when you get the right combination it sounds wonderful.  Again, this is in reference to the type of sound I described above, and working on a DAW. 

I do think digital has gotten very close to what I think folks mean when they reference front to back depth but I often feel there is still that last 5 or 10% missing from digital which is no great sin IMO.

Some of us need flattering, some of us need dead accuracy. 

 

[abechap024]

Everytime I hear someone say "3d" sounding, I think of nice Tube gear. When I think of nice Tube gear, I think of 2nd harmonic distortion. I know that is probably almost too simplified...but like Abby was saying the distortion "footprint" has very much to do with the sound....it is the sound! I've heard solid-state circuits that sounds "tubey" because of their pronounced 2nd harmonic distortion, and visa-versa. Still nothing sounds like tubes, but tubes. I love em...wait what were we talking about again...sorry I get sidetracked.

 

[Balijon]

The detail perception difference between an LP and CD is largely caused by 2 things:
- Compression used on LP's to limit the dynamic range
- Noise-floor of the listening-room and playback-level of the loudspeaker system
Details on CD's that are below the noise-floor are not noticed anymore. As LP's are compressed during cutting, the amount of program that stays above the noise-floor is relative larger.
Another contributing factor is the ability of the loudspeaker system to reproduce with low distortion over a wide dynamic range. With limited dynamics of a LP this becomes relative more simple.

Although digital recording certainly has its merits, it has a fundamental problem that has not yet been resolved after 3 decades: The lower the level, the less bitts you have available to describe the wave-patern. Relative distortion increases when level goes down. These factors are most clearly noticeable when you digitally record a (analog!) reverb decay like from a church. Clearly you loose detail in low level details in digital recorded material. If you mix digitally then these effects are enhanced by 'bit chopping' of the low level material when you reduce mix-level of a track. Analog mixing does not change the wave-patern this way and it clearly has more detail in the low level spectrum in my opinion.

Theo

 

[Kingston]

Balijon,

you seem to have a severe misconceptions on how digital audio works on a fundamental level.

Also the notion that "Compression used on LP's to limit the dynamic range" is actually completely the opposite these days. Sure LP's had brick wall limiting to prevent cutting lathes from making broken records, but for more than a decade CD's have been limited much more severely then LP's ever were.

It's really quite simple. If you like LP's you are enjoying distortions of many types, severe bandwidth limitations and noise. Nothing wrong with that, just don't try to explain it away with pseudo-science.

 

[0dbfs]

Anybody have samples (finished/mixed/un-mixed/released/other) that you may be able to share?
ie;
- This source in this recording has "deep sound-stage".
- This source in this recording does not have "deep sound-stage".

Just to provide an example of what you are referring to so to better quantify the intent and desired result.

Finished commercial albums would be great examples because IMO what it sounds like to the end-listener is what matters most.

Cheers,
jb

ps. The quantization steps between the bits are "the-same" even if the signal is at -80 dBFS or -6 dBFS...

 

[Balijon]

Kingston,

since when do LP's have the same dynamic range as CD's?
An LP has a dynamic range of 60-65db at very best, a CD 96-98db....

That some productions are compressed to death on CD may very well be, but technically there are clear explainable differences.
BTW I am not a diehard record player, but I understand why people appreciate them.
I have been involved in many productions that had both a CD and LP version, in the days that this was common.
We always produced on the maximum dynamic capabilities of the CD in the studio.
For the LP's we had to limit the dynamic range and some EQ when cutting lacquers. (from a digital master btw!)
It was very interesting that some audio purists liked the LP version better than the CD on detail.

The noise-floor of a average living-room is much higher than in a mixing-room of a studio, also it is common not to playback at the same level as in a studio. So very simple your dynamic listening window in db's is far less, anything under the noise-floor you will not hear.

grT

 

[buildafriend]

Kingston,

since when do LP's have the same dynamic range as CD's?
An LP has a dynamic range of 60-65db at very best, a CD 96-98db....

grT

Interesting fact. Thank you for sharing.

 

[Balijon]

ps. The quantization steps between the bits are "the-same" even if the signal is at -80 dBFS or -6 dBFS...

The amount of bit resolution available is evenly 'stepped' over the total dynamic range (for example 65536 steps for 16-bit)
So a sine-wave at -80 dBFS is described by less bit-steps than at -6 dBFS.
The resolution does not dynamically scale with the level of the signal, it is fixed.

grT

 

[lassoharp]

For the LP's we had to limit the dynamic range and some EQ when cutting lacquers. (from a digital master btw!)

Also very interesting.  Was digital master use on modern projects only or do you mean that some old masters that originally existed on tape were first transferred to digital before cutting the vinyl.  I'm always interested in knowing source chains for older material on CD and detailed info is rarely available.  Would love to hear more.

 

[Balijon]

For the LP's we had to limit the dynamic range and some EQ when cutting lacquers. (from a digital master btw!)

Also very interesting.  Was digital master use on modern projects only or do you mean that some old masters that originally existed on tape were first transferred to digital before cutting the vinyl.  I'm always interested in knowing source chains for older material on CD and detailed info is rarely available.  Would love to hear more.

Yes, in some projects were we had a mix from digital and tape and we did what you described, because the CD version was leading in the mastering process.
In the early days of digital mastering (Sony F1 etc), we were so happy with the improvement compared to the limitations of mastering on tape, that we used this as our main platform. Both the CD and the LP came from the exact same digital-master-tape.

 

[lassoharp]

Both the CD and the LP came from the exact same digital-master-tape.

In your opinion would you say the LP from DM retained the same characteristics ( I know this could be endlessly subjective) as LP from tape?

I read that Donald ***en's Nightfly was tracked on one of the early Sony DASH machines and presumably made into a digital master.  I have the LP and can hear some sonic differences between it and Steely Dan's Gaucho which preceded it by only a year or so and was AFAIK an analog project at least on the tracking end.



EDIT: - on a sidenote - I didn't put those asteriks in there . . which is kind of interesting given the current climate on internet censorship. Or it may just be a glitch.

 

[Balijon]

Both the CD and the LP came from the exact same digital-master-tape.

In your opinion would you say the LP from DM retained the same characteristics ( I know this could be endlessly subjective) as LP from tape?

No, certainly not the same.

Tracking and the mixing/mastering process are two different steps in the process. As soon as digital mastering came available we used used it because it was less coloring than a tape-master with Dolby sound reduction. I remember my first session with a rented Sony-F1 on betamax (still got one). The first mix we recorded on it (in parallel with a Studer-A80 and Dolby-A), we simply could not believe it that it came back exactly as we send it. We played it back for 2 hours without exchanging one word, we were simply stunned. We used analog tracking for quite some time, for the simple reason that not that many studio's could afford a Sony-DASH... and then you were kinda stuck to that studio.

There are so many chains in the analog tape path that can change/color the material in a way. First of all the recorder (and alignment) at the record cutting-plant is not exactly the same as the machine you created the master-tape on. The Dolby noise reduction system will color your sound to those differences. Often in the mastering process you can have the effect of generation loss (as a result of tape editing). All those effects are minimal, but the all contribute a little bit.
On the other hand going A/D and D/A again does not come free either, the advantage is that it is at least consistent and repeatable through the process.
We learned that the most consistent process was to mix as much as possible on digital, create a CD-master from this with analog masters transferred to digital (which we needed for the CD version anyway), and use this master for the cutting of the lacquers. Of course the additional (analog) processing to create the lacquer changes the character (and dynamics), but at least it was as close as meant to be.

grT