Germanium Vs. Motu pres

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AudioJunky
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Germanium Vs. Motu pres

Post by AudioJunky » Tue Aug 15, 2006 10:45 pm

Ok.. so before you call me nuts - I have been sitting around all evening recording a passage of vocals with my Germanium- and after a while I thought, "I wonder how this sounds compared to my so called, "shitty" motu preamps." I recorded in all areas of my room.. finally finding the deadest sound by simply laying my mic on the bed and singing into it that way.

I was using an AT 3035 mic for all of this.

So I gave it a shot- and which passage did I prefer at the end??... for some reason I liked the MOTU 828 pre sound better than my Germanium. This is a bit frustrating to me, since I just did drop a lot of cash for the Germanium.

To me- the motu 828 pres sounded tighter and clean- definitely some more high end.

The germanium to me sounded like it got way more room in the sound (not particularly a sound that I want) and more noise along with a darker, less defined sound. I will say that the Germanium definitely sounds smoother/rounder.


Somebody smack me in the face and tell me that I'm on crack. After showing the recordings to a couple people without telling them which preamp it was, they both chose the motu over the Germanium.

Maybe someone could suggest a different mic that would work really well with the Germanium- along with some settings they have found to be good? Maybe my cheap AT 3035 just works really well with the Motu pre?

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Post by Family Hoof » Tue Aug 15, 2006 11:33 pm

I don't think this is surprising. Consider for a moment what the designers of each mic pre were probably aiming for.

MOTU = generic (as in general purpose), low-cost, barebones. They had a strict price and set of specifications (very good ones, technically speaking) to achieve. Fortunately this is easy to do with a diff pair in front of a modern IC op amp. Low-noise, (measured) transparency, but no magic or useful distortion.

Chandler = a unique, expensive, "special effects" unit. They probably didn't start out with any numbers in mind and instead looked to creative use of archaic (and thus pricey) topology in order to deliver a specific coloring effect, something which is purposely NOT just the sound coming out of the mic. Noise? uneven frequency response? of course!

I think it seems vey clear in the Germanium marketing literature that this unit is overtly colored, thus implying you're not going to want to use it on everything. Judging by your description, I'd say you're taking the right approach in evaluating your selection. Plug in the mic and try them all out until you've found the mic pre that's right for the particular track. The "right" one might be a different one everytime. That's why you keep a variety on hand.

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Mics

Post by AudioJunky » Wed Aug 16, 2006 12:39 am

Well- in between my post and your response I fiddled around more with an SM Beta 58 instead of my AT 3035- and now my opinion is almost the opposite!

Since the SM Beta 58 doesn't really pick up the room noise that the AT 3035 does, I found the Germanium "color" to be much more desirable with that mic than the MOTU pre.

This has kind of lead me to a couple problems that, if cured, might improve my condenser use with the Germanium. I have a room with no insulation- so I'm thinking about hanging some moving blankets since the Germanium seems to pick up the wood beneath my feet warping. Also, I'll be switching to a much more quiet computer- my dual 867 in the closet makes a hum that just ruins the vibe with the Germanium.

Hopefully with those modifications, I'll love the at 3035 with the Germ.

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Post by fremitus » Wed Aug 16, 2006 6:23 pm

glad i read this all before posting. when i first saw the topic i was ready to reply with some explitives and such just to feel cool or something.

good evaluations though and hells yes for comparing it. now go crank up that germanium and put everything through it like a MAN!

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Post by puffpastry » Wed Aug 16, 2006 9:06 pm

The germanium to me sounded like it got way more room in the sound (not particularly a sound that I want) and more noise along with a darker, less defined sound
It's likely that the operating bandwidth of that germanium transistor circuit is much lower than that of the opamp used in the MOTU. That lower bandwidth will translate to a more 'rolled off' sound, and it also means the circuit is slower, since bandwidth and slew rate would likely be linked.

The thing is, though, that the larger physical size of those transistors should give you a 'bigger' and 'meatier' soundstage than that tiny IC opamp will give you. I say 'should' because I've prototyped a couple of IC-based mic preamp circuits that have yielded wide and complex tonal characteristics similar to the sound of some commercially available discrete designs--theory and application don't necessarily always agree with each other.

I'm positive that the Chandler has more headroom than the MOTU does (26dB is probably about all of the headroom that MOTU will muster). Listen closely to the two of them side by side--you'll hear the 'depth' that the Chandler has.

Noise performance will differ between these two because the MOTU uses a FET opamp for its mic pre, and germanium transistors are...well, they're just noisy. But most vintage designs are noisy anyway, right? And some people will complain that MOTU shouldn't be using a FET opamp in a mic pre, but who cares? So maybe it's a moot point? I don't know...
I found the Germanium "color" to be much more desirable with that mic than the MOTU pre.
Well, I'll wager that this has to do with the way that the germanium transistor behaves across the audio spectrum. All transistors will exhibit distortion that rises in volume as frequency goes up. It's just an unavoidable fact. The 'good' news is that it's largely 2nd and 3rd harmonic, which is pleasing to our ears.

I have very little personal experience in working with germaniums, so you'll want to ask Chandler about this, but I suspect that the germanium transistors are worse than their silicon transistor counterparts. I'll bet that they exhibit MORE 2nd and 3rd harmonic distortion than silicon transistors do. Allegedly, germaniums have a degree of 'sizzle' in the high end. Have you noticed this in your experiments?
Fortunately this is easy to do with a diff pair in front of a modern IC op amp. Low-noise, (measured) transparency, but no magic or useful distortion.
MOTU doesn't use a differential pair in the 828mk2 preamp. They use a Burr Brown OPA2134 opamp, and then follow it with one of those crappy LM833 things.

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Post by emrr » Wed Aug 16, 2006 9:15 pm

FWIW,I've got both RCA and GE germanium preamps from roughly 1960, and they are quiet as a mouse with their original transistors. There's germanium that gets noisy, due to humidity and leaky outer cases, and there's germanium that is truly hermetically sealed and not prone to increasing noise over time. RCA kept using all germanium in one particular high gain program amp until the mid 1970's, long past the point that conventional wisdom would have called it unlikely.

And most GOOD vintage designs are maybe only 3db noisier than the average modern pre, which might be a problem if you are recording crickets with ribbon mics.
Doug Williams
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Tape Op issue 73

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Post by puffpastry » Thu Aug 17, 2006 7:59 am

And most GOOD vintage designs are maybe only 3db noisier than the average modern pre,
Really? I would have thought it was much higher than that, especially given the thermal behavior of all those old resistors.

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Post by emrr » Thu Aug 17, 2006 10:31 am

A lot of late period tube gear (mid-50's to early 70's) is also quieter than most mid-grade professional SS gear up until at least 1980ish, if you put them side by side. I know it's apples and oranges to say that, but it's the impression I almost always have. Early transistor gear can be very quiet, but a lot of it is hissy compared to older tube stuff.
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