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2019 Transparent, High Gain, Low Noise and Very Fast Mic Preamps
Old 19th July 2019
  #31
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cheu78's Avatar
Quote:
Originally Posted by producerxtr View Post
Is Hardy a fast preamp? Also is it transparent and neutral enough (without color)
I am asking this because of the effect of input and output transformers.
it uses the 990..in a twin servo configuration..just saying..

I'd say it will for sure not be coloured, besides the xformers.. it sounds huge, but clean ime, I do feel it might fit the sm7 very well.
Also the Hardy M1 has transformers, but I'd not consider it a coloured preamp.

anyway..
I'd strongly suggest to find a dealer that has 4-5 candidates (or several dealers in case)..and test some of the candidates out for yourself.

with you EARS and TASTE..

in the end you got good suggestions.. but what if what I (or another user) like and define a clean preamp and it's not your cup of tea?

at these prices I'd not rely on any forum advices (not even mines) to find what preamp is the best for YOUR application (and mic).

Btw just a thought that crossed my mind..fwiw..

you're looking for a very clean and fast preamp to mate it with a dynamic mic, which (while I like it on several vocals/sources) I'd not call it particularly clean and neither fast and even more important not noiseless..

I'm not saying that it will not be a good idea to mate one of these high end preamps with an SM7, what I'm saying is that the differences in noise specs and how "clean" a preamp is, will be rather pointless with an SM7 (or a mic with similar specs).

I'd look into a low noise LDC from Sanken, Lewitt, Austrian Audio, Neumann, etc..(if you're concerned about noise specs and a CLEAN presentation).

I hope this helps,



Cheu
Old 19th July 2019
  #32
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Just for a reference I recorded just noise (150 ohm resistor into pre with 66dB of gain) to a CD burner adjusted with a 0dB input for close to full scale.
This is a quiet pre, IMHO...
Attached Files

TRK 19 jm530 115.wav (1.86 MB, 1137 views)

Old 19th July 2019
  #33
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Another one, same set up 150 Ohm ect but 63dB of gain, different pre (990).
Attached Files

TRK 21 530 990.wav (3.96 MB, 1116 views)

Old 19th July 2019
  #34
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Last one, same as above 150 Ohm load this is around 63dB of gain thru console Bus line out.
Attached Files

trk18 5b.wav (3.73 MB, 1119 views)

Old 19th July 2019
  #35
Gear Nut
 

Quote:
Originally Posted by nosebleedaudio View Post
Just for a reference I recorded just noise (150 ohm resistor into pre with 66dB of gain) to a CD burner adjusted with a 0dB input for close to full scale.
This is a quiet pre, IMHO...
What pre? You didn't mention its name..
Old 19th July 2019
  #36
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Quote:
Originally Posted by cheu78 View Post
.....
I'd look into a low noise LDC from Sanken, Lewitt, Austrian Audio, Neumann, etc........

Cheu
What does LDC stand for?
Old 19th July 2019
  #37
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Quote:
Originally Posted by siddhu View Post
What does LDC stand for?
Large Dia Condenser
SDC would be Small D C
Old 19th July 2019
  #38
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Quote:
Originally Posted by producerxtr View Post
What pre? You didn't mention its name..
Was just trying to give an example of how much noise a high gain pre produces all by its self..Real world.
The 66dB gain sample is a custom pre I built, JT-115 input transformer, Discrete Op amp (RED-25 IM trying out) & output transformer..
Old 19th July 2019
  #39
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FYI... You can get the Hardy M1 without output transformers if that's your thing.
Old 19th July 2019
  #40
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Quote:
Originally Posted by David W. Jones View Post
FYI... You can get the Hardy M1 without output transformers if that's your thing.
But then it would be Unbalanced..
Old 19th July 2019
  #41
Gear Nut
 

Quote:
Originally Posted by siddhu View Post
What does LDC stand for?

Large Diaphragm Condenser
Old 19th July 2019
  #42
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BTW, another excellent thread worth reading:

Gordon vs. Pueblo (vs. Forssell, Pendulum, NPNG, Audio Upgrades...)
Old 19th July 2019
  #43
Gear Addict
 

Quote:
Originally Posted by nosebleedaudio View Post
But then it would be Unbalanced..
From John Hardy concerning the output.....

Regarding the outputs of the M-1 and M-2 mic preamps, if you do not have the output transformers installed, the output is properly described as "Impedance balanced". The output of the 990 op-amp goes to pin #2 of the output XLR through an "output isolator", which is simply a 39.2 ohm resistor with a 3.6uH inductor in parallel with it. Pin #3 of the output XLR goes to ground through another output isolator. Therefore, both pin #2 and pin #3 present the same output impedance to the input of the next piece of equipment. This provides the ideal circumstance for common-mode rejection at the input of the next piece of gear.

The output isolator looks like zero-ohms from DC to well beyond the audio bandwidth because of the presence of the inductor. This provides full signal transfer. Well beyond the audio bandwidth where cable capacitance could become a problem for the 990, the impedance of the inductor has risen to the point where the 39.2 ohm resistor is the lower impedance. So, you get zero ohms of impedance in the audio bandwidth, 39.2 ohms at frequencies far above the audio bandwidth, isolating the cable capacitance from the output terminal of the 990 where it might otherwise cause instability.

Note that I added the 2nd isolator seven or eiight years ago. Earlier M-1 preamps have just one isolator, in series with the output of the 990.

If the output transformers are installed, the first isolator goes to the high side of the primary, the second goes to the low side.

The Jensen JT-11-BMQ output transformer can be installed by the end user. First you bolt it in place. The four wires coming out of the transformer (two for the primary, two for the secondary) are terminated with a 4-position plug. Plug the 4-position plug into the 4-position receptacle on the main p.c. board. If you do not have the output transformer option, there is a 4-position jumper plug installed in the receptacle. I regularly offer to prospective customers to include the little plug-in jumpers so they can unplug the output transformer and install the jumper in its place for comparison purposes during the 15-day trial period. They can send the transformers (or the whole preamp) back for a refund if they wish. I've had dozens of customers take me up on that offer, and nobody has sent the transformers back.

Also note that I added the 4-position plug around the same time that I added the 2nd isolator. Earlier M-1 preamps were harder to deal with, using some insulation displacement terminals for the four wires of the output transformer and jumpers.

The JT-11-BMQ is Jensen's best output transformer. and the Jensen JT-16-B is Jensen's best mic-input transformer.

Thank you.

John Hardy
The John Hardy Co.
Old 19th July 2019
  #44
I use a Grace m101 exactly for that, but I feel like the Hardy preamp is probably a lot better. I need to get my hands on one.
Old 19th July 2019
  #45
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Quote:
Originally Posted by bcgood View Post
Well if budget isn't an issue then Gordon is the obvious choice.

Nothing else touches Gordon.

Especially if you want to use it with a bunch of different mics. It excels in that..


Couldn't have said it better myself.
Old 19th July 2019
  #46
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i like cranesong preamps (and other gear) a lot.
Old 19th July 2019
  #47
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FWIW you can pick up a used Grace M101 on eBay dirt cheap. Might be a low cost way to get your feet wet.
Old 19th July 2019
  #48
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daaronhoffman's Avatar
Worth checking out a RTZ 9762 if you can find one...incredible sounding and built like a tank. It was originally recommended to me by Randy Kohrs who owns 80 preamps and has tried or owned pretty much everything made. This is his dessert island preamp of choice. His style/vibe is very clean and he likes his mixes “like a military bed...” lol

Definitely worth checking out...if you find one. The cost of quality parts didn’t make the price point profitable so they have not been made further.
Old 19th July 2019
  #49
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Plush's Avatar
A so-called "fast" preamp is judged by listening, not by slew rate specs. So those written specs won't help you and no preamp manufacturer lists slew rate specs because that figure does not matter.

Go for excellent sound as your only criterion.

Here I endorse: (NOT in any order)

Crookwood Paintpot
Pueblo JR2/2
John Hardy M-1, M-2, or "Sony Classical Edition."

for your purposes.

The OP need look no further. Stop screwing around and place your order.
Old 19th July 2019
  #50
On chasing leprechauns

There is a theoretical limit to how quiet a mic preamp can be in practice. That limit is the self-noise of a 150 ohm resistor. (Why a 150 ohm resistor? Because that's the output impedance of your SM7B, and many other mics have similar output impedance.) Virtually all of the top-tier transparent mic preamps come within a dB or two of that theoretical minimum. You can pick any one of them from the (alphabetical) short list -- Gordon, Grace, Millennia, Pueblo -- and expect the RMS noise level to be quite similar when tested the same 150 ohm microphone.

If you find the noise level is too high in your application, then the chances are that you are simply using the wrong mic. I would suggest you look up the self-noise of a SM7B in its data sheet, but I know that's a fool's errand: it is not specified. (Can you guess why?) For reference, my Neumann TLM 193 has a specified self-noise of 21 dB (per CCIR) or 10 dBA (per DIN/IEC). This is equivalent to the noise floor in the most carefully-built studios on the planet. Your room is not that quiet.

There is also a limit to how fast a slew rate any microphone preamp needs. Once they exceed that threshold, the slew rate is limited by the inertia of the microphone's diaphragm. It's possible to make electronic circuits slew much faster than any mechanical system can move, but it's not actually helpful. Most modern transformerless preamps are plenty fast. But I can take any such product and make it even faster by retuning its feedback loop so that it becomes marginally stable. Doing so will increase its slew rate, but it will also ring like hell. That is not a good idea. OTOH, if you are using a transformer-based preamp and want "faster" switch to a transformerless one.
If you've already done that and are still not satisfied, then is your microphone that's too slow.

"Fast" microphones are the ones with low inertia in their moving parts. Therefore, condenser mics are faster than moving coil mics, and small diaphragm condensers can be slightly faster than large diaphragm ones. The fastest would be a 0.125" measurement microphone, but these also have high self-noise.

Top-quality mic preamps also have very flat frequency responses. That might lead you to think that they all sound the same, but they don't. The lesson there is to stop obsessing about data sheet specs, and start listening.

I could tell you a lot of details about how some of the top-tier mic preamps work inside. In fact, I have done so. But telling you how they sound is a lot more helpful. Follow the link for my impressions of the Grace and Millennia designs, which are both excellent.

David L. Rick
Seventh String Recording
Old 20th July 2019
  #51
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^

Useful post.
Old 20th July 2019
  #52
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Brent Hahn's Avatar
 

Quote:
Originally Posted by David Rick View Post
I could tell you a lot of details about how some of the top-tier mic preamps work inside. In fact, I have done so. But telling you how they sound is a lot more helpful. Follow the link for my impressions of the Grace and Millennia designs, which are both excellent.
But having someone tell you how they sound isn't the same as deciding for yourself. And you can only do that by spending some serious time with a few of your finalists. Even if you have to narrow it down to a handful, buy one of each, and then return all but the winner.

For example, many highly regarded people love the Millennia; for me it has a "tell" that I don't care for. But I only arrived at that opinion by living with one for a week.

I also can never remember how many l's and n's there are in "Milllennnia," but that's probably not a good reason not to like it.
Old 20th July 2019
  #53
You can get pretty good stuff for cheap these days. Example: the PIP module and SSM2015 PIP modules will do -132 db EIN at 50 ohms. Many modern mics are now 50 ohms, not 150 ohms so that will make a measurable difference.

Slew rate is 25v/us, bandwidth is 400k hz, CCIF IMD is 1.5 ppm and they do rail to rail outputs and will drive 600 ohm loads. Not too bad for fifty bucks.
Old 21st July 2019
  #54
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Thank you all for your compliments and descriptions of my mic preamps.

John Hardy
Old 4 weeks ago
  #55
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cheu78's Avatar
Quote:
Originally Posted by John Hardy View Post
Thank you all for your compliments and descriptions of my mic preamps.

John Hardy
Dear John,
Nice to see you here!
Maybe you posted somewhere else and I missed it..
Do you have any information about your twin servo as a 500 series module?
Is it still coming or you abandoned the project?

In any case..Thank you for your great products!
Take care,



Cheu
Old 4 weeks ago
  #56
Gear Maniac
 

Cheu;

Quote:
Do you have any information about your Twin Servo as a 500 series module?
Is it still coming or you abandoned the project?
Still coming. I had modules assembled, then discovered that a critical part (LED bargraph driver) was discontinued. So I am redesigning the meter and making additional mods and upgrades to tighter tolerance parts, etc.

Thank you.

John
Old 4 weeks ago
  #57
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chipss36's Avatar
 

anyone read the specs on the Shelford?
Pretty impressive.
Old 4 weeks ago
  #58
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Quote:
Originally Posted by David Rick View Post
.(...)Follow the link for my impressions of the Grace and Millennia designs, which are both excellent (...)
i'm glad you mentioned that you wrote about your 'impressions' of the above mentioned preamps, otherwise i would have thought it's a paid post - there's certainly nothing wrong with liking one pre somewhat better than another, we all do (i assume); funny enough, i did compare the exact same pres with aphex, focusrite, studer and yamaha, along with those in the mci jh500 - and came to vastly different results...

we both seem to like the m-103 in certain situations though!
Old 4 weeks ago
  #59
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cheu78's Avatar
Quote:
Originally Posted by John Hardy View Post
Cheu;



Still coming. I had modules assembled, then discovered that a critical part (LED bargraph driver) was discontinued. So I am redesigning the meter and making additional mods and upgrades to tighter tolerance parts, etc.

Thank you.

John
Thank you for the update John!


Any date for when they'll be avalaible?



Cheu
Old 4 weeks ago
  #60
Gear Maniac
 

Quote:
Originally Posted by cheu78 View Post
Thank you for the update John!


Any date for when they'll be avalaible?



Cheu
No date yet. Lots to do on the new meter design. It will be a big improvement over the original design.

Thank you.

John Hardy
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