Talk to me about Mic Preamps

[ibarakishi]

Like the title says, i am interested in knowing more about peoples experiences with mic pres. This coming year i am looking at putting together a tiny decent rack set up for recording that will be extremely minimal and budget oriented, but will hopefully be something that i can continue to grow into and keep around for a long time to come. These are some of my questions:

1.) What type of mic preamps have people used? What have you liked and what haven't you liked?
2.) In your experience, are the more expensive units a great deal better than the more budget priced ones?
3.) I have currently been looking at the ART Pro MPA II and am really interested in it. Also units like the ART Pro Channel II look interesting too. Some people have talked here on ILF about the Behringer Ultragain Pro MIC2200 too, but not really anything in depth yet. Does anyone have experience they could share about these units? Reading through things on other forums is full of tons of people hating anything that doesn't have a huge price tag and isn't associated with blues rock albums, and thus isn't really entirely helpful. I would love to try any of these or others in person, but where i live there isn't any way that would be possible.
4.) On kind of a side note, are there any rack compressors or other things that people use regularly and like that simply don't seem to be able to be substituted by what is available in your DAW? Are there any other things that i should be checking out that are a favorite of yours that you use often when recordings

In case it matters, i mainly work at the moment with recording stringed instruments, but will be / have been working with other things too.

Any information would be great and would help me a lot. I haven't really seen a dedicated thread for this yet, so if there is already one let me know

[Dr. Sherman Sticks M.D.]

art pro mpa gold is my jam. been using it for years. its the older version of the mpa II.

best pre for the buck. 2 channels!
i swapped out the tubes when i got it, made a nice difference in sound

everything i record gets run thru it before my interface.

[ibarakishi]

Dr. Sherman Sticks M.D. , thanks for the info. The people that use it that i have read online seem to either love it or hate it. But the people that hate it seem to never really a decent reason as to why, other than it doesn't sound as good as a 500-600 USD preamp. The people that love it seem to be in the same camp as you, in that it has come to be their 'go to' preamp. It is one the top of my list and would be the one that i would probably purchase first for the simple fact that it has 2 channels like you said.

Have you used any other preamps too? And what interface are you using currently with the ART? From the sound of it, the ART preamps were something that really sounded better to you and replaced you using the stock preamps in your interface now correct?

EDIT: and what tube/tubes have you tried in yours? What were the differences in sound? Is there anything specifically that you personally look for in a tube before you purchase it for your unit (example: clean, high headroom, ect?)

[Dr. Sherman Sticks M.D.]

yea 2 channels is pretty much why i got it. had a GAP Pre73 before (was also the jam),
that i sold to fund the MPA Gold, w/ a nice lil stack afterwards which was also a motivating factor.

i've been using an rme babyface i think since i got the MPA.
the babyface pre's and converters are pretty dope, its already a nice interface but its better w/ the external preamp,
and for me, easier to adjust levels to different situations, given i only have 2 channels to record.

i actually only tried the stock tubes and the tubes that i am using now, which are some Telefunken NOS.
tbh, i liked the name, TELE-FUNK! and they weren't too expensive ($40-$60ish for the pair i think? it was awhile ago).
but they actually made a big difference. (was kinda skeptical before i swapped)

honestly, i think i coulda spent endless amount of time researching which pre, and which tubes to get
spent a lot of money and tried a bunch of different things.
but i did a lil research and didn't fuss about it too much.
i'm glad i didn't, b/c u can spend thousands of dollars on this type of shit in a blink and is it really worth it?

[ibarakishi]

Thanks for the information, that is really helpful to know. From what you have said, it sounds like my initial thoughts with the ART is what i am hoping it will be for me. I agree with what you are saying, i could never spend thousands of dollars on this stuff. I just mainly would like to hear everyone's personal experiences with their gear that they have tried so far and what problems, if any, they have had with their choices

[crochambeau]

I just mainly would like to hear everyone's personal experiences with their gear that they have tried so far and what problems, if any, they have had with their choices

I have no first hand with anything you've mentioned so far, but I have hung a mic or two... I'll begin with mixing boards, because that's the bulk of my experience - hopefully any information that slips out will be of use.

TOA RX-212. Early 1980s mixing board. Input transformers on the microphone feed (I love iron in my signal path), 4558 opamps doing active duty. I like the desk for noise & synth work, as the input is enriching (the output of main stereo bus and two foldback (effect sends) channels are also transformer fed). The summing section does not have nearly enough headroom so the mixer will distort like a motherfucker when it's tasked with big sounds. Phantom power section was also really dirty and noisy, which inspired me to buy a fucking Behringer 602 mixer for condenser work, as it had clean power. This was the year 2000 if memory serves, these days I'd just fix the fucking phantom. Lovely noisy board with many beers spilled and rust on the inside. I need to repair the PSU in that one, but I liked it enough to accept an RX-208 in my life to do fill in duty while the 12 channel is hobbled.

Behringer MX-602. Sterile but clean, (while I owned it) I purchased this for phantom power alone. Did the trick, but I have a deep hatred of the sound that modern high slew rate low noise budget circuits make when abused, so I miss that one not. To recap:

Fostex 454, Biamp 1621, Fender MX-5200. I believe all of these are (were) input transformerless operational amplifier based circuits preceding the Mackie VLZ topology that Behringer borrowed above which ushered in the "new era of clean" across the board. These old circuits are not without their charm, but they suffered greatly from congestion in the summing stage and inherently thin and noisy channels. It can be a useful sound but I wouldn't want to subject my entire mix to it. In my opinion, you can reap whatever gains you would get out of this class of circuit by going into strange channels, like old video SEGs, galvanometer or piezo amplifiers and doing away with the mixer altogether. Not that it is a fantastic path, mind you, it's just nice to have a source of contrast between elements.

Ramsa WR8210, Ashly SM-16, IRL Voicematic....

Holy fuck, what am I doing here? Gotta cut to the chase or I'll be at this shit all day:

Transformer input with discrete transistor topology (Langevin) this thing can sound awesome, but it is particular about what microphones it loves and there's a lot of inconsistency across the channels. I feel that going primitive (statement includes tubes) can reap the biggest rewards - but is the most demanding on synergy between source and capture. One day it can sound amazing, the next you're riding a pogo stick into a pond of muck. Old stuff will also have noise floor prominence over almost anything around today - unless you're made of money and have hired a self important guru (AKA not slave labor, before anyone tries to beat me down over the self important part - fucking assholes ) to manually search for the perfect part to lovingly embed in the rectal canal of your vintage piece of gear.

Ooof, sorry, I think my PTSD is showing.

Rolling tubes can be fun and informative, but the impact the tube has on the sound is going to hinge a lot on the circuit the tube is in. My favorites are, unfortunately, in line with common opinion regarding the old stuff. Telefunken (flat plate over ribbed, most of the time), Amperex (Bugle Boy), and Mullard can be fantastic, but so can black plate RCA, Sylvania and a multitude of others. There are duds, these were made with more actual fingers in the process than with modern production techniques - but the accepted metallurgy allowed for far more toxic recipes to be employed - which results in slightly different operation which can be construed as superior in some circumstances.

Operational amplifiers resolved a lot of inconsistency across earlier topologies, but they have kind of done so at the expense of the magic I tried to describe above. You can buy back the most consistent aspects of that magic through using a transformer (let's be honest, there is essentially an EQ network embedded with the root function) or grabbing a tube (losing a PN junction is often like finding a $20 in the pocket of a coat you have not worn in a long time. Voiced circuits are awesome, but they are supported by dead clean and neutral circuits, so I guess my advice is to grab something that crosses your path/is in your price range, and then don't rule out maintaining a vigil around that particular watering hole.

I guess while I'm at it I'll plug a project I am working on (that's right, all that garbled mess above that I'll probably read again in two days and edit the ever loving shit out of is nothing more than the build up to an advert, HAHAHAHA)(j/k). I've drafted a microphone preamp based on Deane Jensen's 918 discrete operational amplifier publication from 1977 (you can find links to the document through google I am sure). Since this is not an RMA design I don't really plan on building these out (I don't think I have the throughput power to do that at the moment anyway), though if the PCB is a success (tonally speaking) I'd be happy to sell boards to the DIY sort:



It's not the simplest of builds, though I'm trying to support a variety of implementation on it, including output section based on ECB TO-92 or BCE TO-220 if the output is driven transformer or just a direct unbalanced cap coupled output, and the option of an SMD matched pair or two throughhole transistors at differential input.



Again, the actual purpose of these is to infill a small mixer I'm building, but DIY remains a huge option on the microphone preamp front.

Sorry about the huge post, been chewing on it for a while..

[ibarakishi]

thanks for such a detailed post crochambeau, this gives me a lot to read about and learn about as well. What you are saying interests me a lot, so i will have to take some time as well to look over it all and try to be more educated about everything you said

[ibarakishi]

read up on most of the stuff you talked about / listed. I am by far most excited about this 918 discrete opamp you are talking about. Is there any other info about it that you can share as to what type of character yours is going to have? When do you plan on testing it out and seeing how it works? I know that you said it would probably be available as a DIY, but if successful, would you be open to personal orders as well? If this was available as a full mic preamp, i would be really interested in trying it out.

[crochambeau]

I don't have a lot of info on the 918, just the original document (found here: http://www225.pair.com/audio/waltzingbe ... ensen.html). I know that a lot of the big manufacturers of mixers and preamps shifted away from the early "single ended" circuits when split supply opamps became a solid technology, as it resolved a lot of issues. The early monolithic ICs can be considered as uniformly terrible for audio work (this is from the standard of "proper" audio engineering, in my opinion everything has a place), so in many ways the functional circuit was built out with discretes.

My Autogram AC-8 mixer (simply a stereo in per channel, originally built for radio stations) boils down to input transformers feeding a DOA (not the 918) for summing/mixing which feeds another DOA to drive the output transformer. Dead simple and sounds great, runs +/- 24 volts for 48 volts of headroom, which may play a part.

The 918 is just one of many, and that particular lineage turned into the 990 (on which there are many designs offered even today). I've built a few 918s on proto, and drew up a PCB a while back, they have a sound quality that is worthy - even when built wrong they can distort nicely. I have no idea if my rendering of the design will work well as a clean preamp, but I fully expect it to deliver in dirt/synth realm. While I have played with one powered from 9 volts standard they prefer wider, preferably bipolar power rails. I'd be happy to sell complete units, I just don't know if I'll do that outside of a request. I'll need to resolve power supply issues if I build a complete unit, and if the design is solid I will certainly have it on offer as a DIY resource based on the first paragraph of Deane's paper.

I have some PCB tweaks yet to execute (including that unconnected trace I captured above) before I order, I'll probably order a small run of testers around the end of year.

Here's some insight on Mr. Jensen, who died in 1989:

[rustywire]

(I love iron in my signal path)

This. (not to throwaway the rest of your thorough post...but rather emphasize that point)
Transformer-coupled gear seems to bring out the most musical aspects of everything and anything it (esp) front-ends.
This is why I would save money to increase budget and get some legendary discrete circuits built-for-a-bargain.
Golden Age and Warm Audio are doing impressive things. TB12, WA76, EQP-WA, WA-2A. I want 2 of each!

Pro gear like that was once prohibitively expensive. It still aint cheap, but now it's within closer reach and the value one can unlock from these tools is hyperbolized and fawned-upon for good reason.

Tracking with mid-century American mic pre circuits is super enjoyable [esp w/elec bass from the moment you plug in direct].
RCA, GE, Altec, API all have their well-deserved reputations for bringing massive low end response, particularly API for its punch and tightness.
FME a general rule for transformer-coupled pres:
Octal tubes in the circuit = greasiest/slowest response
miniature tubes in the circuit = greasy-tight
transistors in the circuit = tight-greasy
op-amps in the circuit = tightest and fastest response
but this is just a hard & fast note I've made. You've gotta treat each circuit individually; it's mostly about the circuit design itself. The most straight-forward, simplest circuits are going to be more affected by changing a single component's topography.

Some mic pres REALLY benefit from being able to attenuate them after being hit hot & hard (output knob on new APIs is essential for this, you can also use something like an 1176 or mixer with high headroom)

Edit: reminder not to take this as gospel

[ibarakishi]

crochambeau : That helps a lot, thanks for sharing. Please keep me/others updated with your progress on that, and if it comes out being something that you like, i will definitely be interested in trying it out if it is done in a mic preamp format.

rustywire : This is extremely helpful too. I have been interested in the Warm Audio stuff for a long time now too, but a lot of it is just out of my price range, and almost never came up at a reasonable price used on ebay/reverb. But now that seems to be changing, and units are starting to show up online used quite a bit. Do you have any experience using the Warm Audio units personally, and if so, which ones did you enjoy?

[rustywire]

Unfortunately I lack hands-on time with any of the WA stuff.
Fortunately, there are numerous resources available of users posting their recordings and results, insight and even some demoes in the first page of googoo search results.

They weren't available when I committed to building up my front-end with secondhand TubeTech and UA RIs, over many months of layaway. From what I've been able to glean from demoes and others' a/b recordings, WA76 & EQP-WA shine like gems, they're the 2 I've researched the most, since their release.
I still have plans for (2) channels of WA goodness. If I had the resources I'd run dedicated 1176 circuits in the a/v rig.

[ibarakishi]

so i did it. I found a used ART MPA II on Ebay and ended up winning it for a little over half the price of a new one. I won't be able to test it until probably April next year (it will be brought in the backpack of someone i know coming to visit me from the USA to save on shipping/customs fees) but i am really excited. This will most likely be my last big purchase going well into next year, but i am excited to try it out when it comes. It will be a while, but when i actually get it in my hands and sit down to work with it, i will be sure to update here about it. In the meantime i will be looking into the Warm Audio stuff and seeing about those as well for the future, as i would ideally like to have a few options of preamps to work with and mix/match with mics.

[crochambeau]

Nice haul!

[ibarakishi]

Nice haul!

yeah i am really excited to get my hands on it and put it through some tests. in looking through the warm audio stuff, i am really leaning towards the Tone Beast. But much like the ART, i will just have to wait until a deal pops up on ebay most likely so that i can grab it for crazy cheap. Just keep sitting with my line in the water waiting for a snag...