Can you have too many tubes on a track like you can have too

[wendylanders]

Hi all,

Having a tube pre-amp (cheap, Art portable), just saved me on my last production when my condenser mic went out. So now

I'm thinking about getting the tube mic that Fett recommends (MXL V69 Mogami) , but I don't know how that would work with a tube pre-amp. Do they compete or cancel each other out?

With reverb, if you've recorded instruments in different rooms listeners can notice the difference in reverb among the different instruments. Does something like that happen with tubes?

Thanks so much!

[andygabrys]

IMO

.... tube mic that Fett recommends (MXL V69 Mogami) , but I don't know how that would work with a tube pre-amp. Do they compete or cancel each other out?

They will work fine. If you are super keen at hearing / very experienced, you might prefer to pair a tube mic with a solid state preamp, or vice versa, or all solid state, or you might like all tube. Its like the 80/20 IMO. 80% of the sound is a great vocalist and performance, 20% is nitty gritty with various preamps, outboard and convertors.

You might want to research mods available for the MXL mic. That might make more difference that the preamp you use with it.

[wendylanders]

Thanks Andy!

[mojobone]

No, tubes don't cancel each other out, they're gain devices and as such, they tend to multiply noise when driven hard and used in series. Older tube designs tend to be noisier than the most modern ones, but everything depends on the context; a preamp tube used in a guitar pedal to produce gain and distortion will also provide some amount of noise and hiss, but a tube used in a mic preamp, especially a modern one, will be far cleaner and quieter. It may not be universally true, but tubes generally have a rounder, sweeter character than equivalent solid-state circuits, and most folks have noticed that passing digital signals through a tube stage tends to decrease harmonics that are considered harsh, but this kind of signal conditioning has become less important as digital converters have improved.

The upshot of all this is that multiple tube stages in your signal path won't usually hurt anything as long as you pay attention to proper gain-staging; in fact there was a time when all the signals went through multiple tube stages, cuz tubes was all we had, and people still love the sounds produced on the vintage tube gear at Sun Records and Motown.

[wendylanders]

Thanks, Mojo!

Wendy

[Len911]

http://www.theaudioarchive.com/TAA_Reso ... _State.htm

In the tests conducted for the AES journal article:

“Further listening revealed that it was only in the range of early overload where the amplifiers differed appreciably in sound quality. Once the amplifiers were well into the distortion region, they all sounded alike -- distorted. In their normal non-overload range all three amplifiers [transistor, hybrid op-amp, and vacuum-tube triode] sounded very clean.”

“Vacuum-tube amplifiers differ from transistor and operational amplifiers because they can be operated in the overload region without adding objectionable distortion. The combination of the slow rising edge and the open harmonic structure of the overload characteristics form an almost ideal sound- recording compressor. Within the 15-20 dB "safe" overload range, the electrical output of the tube amplifier increases by only 2-4 dB, acting like a limiter. However, since the edge is increasing within this range, the subjective loudness remains uncompressed to the ear. This effect causes tube-amplified signals to have a high apparent level, which is not indicated on a volume indicator (VU meter).

You can study the whole article and come to your own conclusions, but it seems to me that if you never overload your tube circuit, you don't really get the tube "effect", other than possible tube noise. Then there's the tubes themselves, NOS tubes are new, but were mfg. years ago and have sat on a shelf and aged (deteriorated?), there are new mfg. tubes, however, whether they are as good? as the old ones might be debatable.

The Art Tube MP,
http://www.soundonsound.com/sos/feb05/a ... tubemp.htm

Low-voltage tube circuits like this don't offer the same flavour of warmth as high-voltage designs, but the results here are still very musical and don't tend to go muddy as some low-voltage designs do.

http://www.soundonsound.com/sos/1995_ar ... ubemp.html

the valve (in this case a 12AX7/ECC83 dual triode) is accompanied by a significant amount of solid circuitry, including a dual op-amp and a handful of transistors, so I suspect that a low noise, solid-state front end is being fed through a valve buffer stage biased to add a noticeable dose of valve coloration. This is fair enough, as it's not easy getting an all-valve front end to run very quietly, even when you have a lot more money than this to throw at the design.

In common with a lot of budget valve equipment, the usual '250V DC plus' lethal high tension power supply has been replaced by a much lower voltage system, which does affect the valve's overload characteristics, as well as reducing the overall headroom, but if done properly, this approach can yield very pleasing results. In fact, the power comes from an external 9V AC supply, but I assume a voltage multiplier is being used somewhere, otherwise the maximum possible DC supply would be around 25 Volts, and the 48V phantom power switch on the front panel proclaims that this clearly isn't the case.

You don't have the valve's overload characteristics, and don't have the overall headroom. Hmmm, so basically, you don't have the overload harmonics and limiting effect of a tube, the whole reason for using a tube,lol!

It's almost as if you really wanted a tube sound, playing with the harmonics and a limiter, in software, could be a better option??

[mojobone]

Thanks, Mojo!

Wendy

You're welcome!

[ochaim]

I've been considering getting a tube mic as well. Unfortunately the only tube mic my local music store has to rent is apparently a crappy apex mix in the $300-400 range.

The V69 looks to be in the same price range and if Fett recommends it it's probably worth considering. The one I've had my eye on is the Rode NTK which is closer to $700.

I found a short A/B test here:

https://www.youtube.com/watch?v=t0dFX88bVH4

Mojo and Andy, can you recommend either from this small test alone?

I've read that the V69 has a sibilance issue, and I can sort of hear it, if I'm looking for it. But I'm not sure. I've also found a few gearslutz posts about swapping tubes and getting a much better sound from it.

[mojobone]

Sibilance is usually more about the singer than the mic. How you reduce sibilance is part of who you are as a producer; there are many ways to skin that particular cat. (not being mean, here; I luv my kittez) That being said, the Rode has superior bass response, and sounds smoother, overall, BUT results would differ, given a different input. What I mean is, stick the same mic in front of a bari sax and the frequencies will be read differently. There's no ideal mic for all situations.

[andygabrys]

IMO - yes some singers have sibilance problems because of the way their mouths and teeth are. Fine. And this more than any other thing might determine how "sibilant" a certain vocalist sounds.

And when it comes to mics:

the issue with a lot of lesser expensive mics that have a combination of a certain capsule (modeled after a certain vintage German mic) with the electronics of a different model of German mic. But they don't necessarily combine well. You can google U67 capsule and U47 electronics for example. The result is usually a mic that is overly hyped in the top end and sounds bright, brittle, and can exacerbate sibilance.

So if you want to buy a cheap tube mic, then the next thing is to consider having it modified, or buy a ready made mic that is already modified, or get DIY parts to modify it yourself.