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Which decent tube for budget tube mic?
Old 28th August 2010
  #1
Gear Head
 

Which decent tube for budget tube mic?

Hey there, the title says it all - I'll soon have a budget LDC tube mic and I would like to know will I benefit if I replace the stock tube with a 3rd party one... and which one would you suggest?
Thanks!
Old 28th August 2010
  #2
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onespecial's Avatar
 

Which decent tube for budget tube mic?

most likely, the mic will come with a 12ax7 tube in it. if you replace it with a tube with a lower gain rating (12at7, 12au7, etc.) you will be able to boost the gain without the sound 'breaking up' as much.
personally, I have no love for a 12ax7. I think they overdrive so easily that you lose a lot of clean or lightly-overdriven tonal possibilities. I prefer the flexibility of a 12at7.
as far as what brand of tube to use, that's as subjective as choosing a guitar or drum head.
most people will claim older tubes (New Old Stock or NOS) are better. but using a 30 year old tube is a lot like using a 30 year old light bulb. also nos tubes can be pretty expensive.
your best bet is to try a few different tubes and form your own opinion.
me? my favorites are nos GE 12au7 and pretty much any 6072a.
Old 28th August 2010
  #3
Lives for gear
Most budget tube gear (mics,preamps,compressors) will benefit at least some from upgrading the tube(s), as long as the circuit's not too horrible. Sometimes the difference will be extremely subtle, other times (but not too often) it will be huge. You need to try out the mic with the stock tube first, then decide what's lacking in the sound. Then it's a matter of how much $ you want to spend. Most budget tube mics use the 12AX7/12AT7 family of tubes which are extremely plentiful and the choices are seemingly endless. Most folks here (myself included) favor NOS stuff like Telefunken,Siemens,Mullard,Amperex, and many others. But there are some really good tubes in production now (JJ/Tesla,Groove Tubes,etc.) that are much less pricey than NOS and substantially better than most of the stock Chinese tubes that you'll find in budget mics. You didn't say which mic you're buying (maybe you haven't decided yet), but a search of previous posts may reveal a lot of good suggestions. If that fails, post a new thread asking for tube recommendations for the specific mic. There's a lot of great folks here who are happy to share their experiences once you provide enough info. Hope this helps.

Larry
Old 28th August 2010
  #4
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stagefright13's Avatar
 

Well if the mic is using lethal voltages for the tube then an NOS tube WILL make it sound better. What mic?

John
Old 29th August 2010
  #5
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Quote:
Originally Posted by nervirasme View Post
Hey there, the title says it all - I'll soon have a budget LDC tube mic and I would like to know will I benefit if I replace the stock tube with a 3rd party one... and which one would you suggest?
Thanks!
If it uses a 12AX7 (ECC83), replace it with a 5751, preferably a GE Five Star or GE JAN. It will clean it up nice given the lower gain characteristics of the 5751. If, however, you're looking for a brighter quality, try an Amperex 7025. I have found that Amperex tubes in general sound brighter. Or if you want to slightly darken the tone, a Telefunken ECC83 smooth plate.

If the mic uses a dual triode of low mu like the 12AT7 (ECC81), you might want to try a Mullard, Siemens or Telefunken. The EI ECC81s with the long smooth plates are very musical and excellent for audiophile applications and I've also used them in tube mics, since it isn't microphonic like some of the EI ECC83s.

Look for tubes on Ebay that have been tested for value, emission, shorts and mutual conductance. Even a used Telefunken or Mullard 10M series will outlast and outperform most of the firecrackers being passed off as tubes today.
Old 29th August 2010
  #6
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glenn Taylor's Avatar
 

Tubes make a big difference.
GT.
Old 29th August 2010
  #7
If you are on a tighter budget, consider my personal favorite new production tubes from JJ--I pick them up from Eurotubes: Eurotubes Get a gold pin 12AT7 for the reasons people already expressed.

If you have a better budget, spend $25.00 to $50.00 on an NOS 12AT7 and get any one of the tubes already mentioned, or one of some others like an Amperex or a Sylvania. I have had nothing but good experiences with the NOS 12AX7, 12AT7, 12AU7 and 12AY7 bottles I have picked up. They all have their own little thing going on, but they are all doing good things to the sound, so I think you'll be happy with whatever NOS tube you end up with.
Old 29th August 2010
  #8
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...many of the cheap chinese tube mics are based on circuits that were originally designed to utilize one triode of a 12AY7/6072 tube (C12, ELAM 250 & 251, etc)...somewhere along the lines, the chinese manufacturers substituted 12AX7 and 12AT7 tubes, probably due to availability and cost factors...

...there's a reason why the 6072 tubes were preferred (lower noise, low gain output)...you can substitute any of the 9-pin 12**7 family of tubes, but in most cases the best choice is a NOS 6072/12AY7 tube...the 12AX7 has the higher gain output (100), which is great in guitar amps, where distortion is often preferred, but not so desireable in a vocal mic...the 12AT7 has a bit lower gain (60) so it tends to sound cleaner and more balanced than a 12AX7...the 12AY7 is again lower (44) and is excellent in microphone applications...the 12AU7 drops again (20) and may be too low for optimum performance in some mics...

...some options for swapping can be found on this chart:
BRENT JESSEE RECORDING; Tubes Used in Professional Tube Microphones
Old 29th August 2010
  #9
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Ron Vogel's Avatar
 

Also, don't be afraid of the "firecrackers" comment. We are talking preamp tubes here...they hardly ever go bad...Telefunkens are rated for 50,000 hours! (that's 5.7 years of continous use.) If that's like a lightbulb...well I've never owned a lightbulb that lasted that long.

I have a huge stockpile of 12AY7's, 12AT7's, and 12AX7's...in the past couple of years I have been through hundreds of old tubes (and new), and I've run across 1 bad tube, and 2 microphonic tubes (and the microphonic ones came in a brand new guitar amp)!
Old 29th August 2010
  #10
GrooveTubes offers the 5751 and it would be the most suitable replacement in my opinion. A 12AX7 is too hot for a mic tube and results in early distortion. The 5751 runs at aproximately 80% of the gain as the 12AX7. If you want to go lower still, the 12AY7 would be your next choice at 50%. I would not advise the use of the 12AT7 or the 12AU7 as they are not intended for use as preamp tubes and will result in poor audio.
Old 29th August 2010
  #11
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pasarski's Avatar
 

Not all the budget tube mics use 12a*7 family tubes.
Old 29th August 2010
  #12
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kidvybes's Avatar
 

Quote:
Originally Posted by johnny nowhere View Post
I would not advise the use of the 12AT7 or the 12AU7 as they are not intended for use as preamp tubes and will result in poor audio.


Preamp Tubes
http://www.vacuumtubes.com/preamp.html


Quote:
Originally Posted by pasarski View Post
Not all the budget tube mics use 12a*7 family tubes.
...obviously, but since the OP has not alluded to any details beyond "budget LDC tube mic", we have to go with the most common denominator...
Old 29th August 2010
  #13
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Quote:
Originally Posted by kidvybes View Post
.. Some options for swapping can be found on this chart: BRENT JESSEE RECORDING; Tubes Used in Professional Tube Microphones
Those charts by Brent Jesse are a great primer for familiarising yourself with the different classes and families of tubes.

Regards RAy

Last edited by ray_subsonic; 29th August 2010 at 04:07 PM.. Reason: economy of language
Old 30th August 2010
  #14
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BudgetMC's Avatar
Contact Bowie, ask which tube he recommends, and then buy it from him!

Bowie Rulz for Tubz!
Old 30th August 2010
  #15
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Marcadiablo's Avatar
 

Quote:
Originally Posted by BudgetMC View Post
Contact Bowie, ask which tube he recommends, and then buy it from him!

Bowie Rulz for Tubz!
+1

Bowie IS the man!
Old 30th August 2010
  #16
Lives for gear
You should say what mic you're talking about. I suspect the right solution would be to get a better version of whatever tube it already has. Example: For an MXL V69 you'd upgrade the 12AT7 to a better one (I changed to Mullard). 6072 (12AY7) upgrade is a popular replacement in mics that use that as stock (I think basically C12 type mics).
Old 30th August 2010
  #17
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kidvybes's Avatar
 

Quote:
Originally Posted by PhilDW View Post
You should say what mic you're talking about. I suspect the right solution would be to get a better version of whatever tube it already has. Example: For an MXL V69 you'd upgrade the 12AT7 to a better one (I changed to Mullard). 6072 (12AY7) upgrade is a popular replacement in mics that use that as stock (I think basically C12 type mics).
...the problem is that many of the Chinese mics say they have a "6072", but it actually turns out to be a chinese (unmarked) 12AT7...I've got a bunch of these that came out of various MXL, Studio Project and other chinese branded mics...a local tube tech/dealer ID'd them as 12AT7 tubes...as I said earlier, most of these mics are utilizing circuits based on the 6072 tube and substituting cheap 12AX7 or 12AT7 tubes to keep costs down...
Old 30th August 2010
  #18
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Openreel24's Avatar
 

MXL Tubes

Well, it comes as no great surprise that the tubes in some of the MXL mics are 12at7's, especially as that's the way we describe them in the technical specs on both the web site, and in the product literature. The exceptions being the Revelation, which uses an EF86, and the Genesis, which uses a genuine Mullard CV 4024, which is also known as the ECC81, 12AT7, and E81CC. I know these are genuine Mullard nos tubes, because I bring them over personally from the UK. With the Mullard name having been sold to a Russian tube manufacturer it was the only way I could ensure the tubes were truly Mullards, and not ****** tubes with the Mullard logos etc.

Roy - MXL Mics
Old 30th August 2010
  #19
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kidvybes's Avatar
 

Quote:
Originally Posted by Openreel24 View Post
Well, it comes as no great surprise that the tubes in some of the MXL mics are 12at7's, especially as that's the way we describe them in the technical specs on both the web site, and in the product literature. The exceptions being the Revelation, which uses an EF86, and the Genesis, which uses a genuine Mullard CV 4024, which is also known as the ECC81, 12AT7, and E81CC. I know these are genuine Mullard nos tubes, because I bring them over personally from the UK. With the Mullard name having been sold to a Russian tube manufacturer it was the only way I could ensure the tubes were truly Mullards, and not ****** tubes with the Mullard logos etc.

Roy - MXL Mics
Roy...no offense meant, but I'm referencing earlier models like the V77s that incorporated circuits that were originally designed for 6072/12AY7 but were implemented with 12AT7 tubes due to the lack of availabilty of 6072 tubes...it was I who originally suggested to Scott at MXL that they look into the Mullard CV4024 tubes which were more readily available in larger quantities in England (back when the V76t was first being produced)...Cascade was using those very same tubes in their V55 Valve mic at that time (sE was actually manufacturing that mic for Cascade)...

Cascade V55 Tube Microphone
Old 1st September 2010
  #20
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Openreel24's Avatar
 

12at7

Ah, the V77. As you know that has been out of production for some time.

When we released the Genesis, it was after long and exhaustive, (as well as exhausting) testing with pretty much every 12AT7 type tube. The Mullard was eventually chosen because to the ears of the development team, it had an overall more pleasing sound than any of the other candidates. We did however limit ourselves to the more mainstream tubes available, we didn't try cryogenically treated tubes or tubes dipped in pure unobtanium, the cost of such tubes tend to become prohibitive, and those that I have tried in other applications exhibited marginal improvements.

All of our current mics utilize tubes for which the circuit was specifically designed, and as such give IMHO great performance.

I appreciate your observations, and expect we will exchange views from time to time.

Regards
Old 1st September 2010
  #21
Here for the gear
 

Quote:
Originally Posted by nervirasme View Post
Hey there, the title says it all - I'll soon have a budget LDC tube mic and I would like to know will I benefit if I replace the stock tube with a 3rd party one... and which one would you suggest?
Thanks!
To answer your first question: YES. It will benefit you to replace the stock tube... They buy the cheapest tubes in bulk that are decent enough to make the equipment work, tone is not of concern to the manufacturer.

What is the exact model number of the LDC microphone? Different part numbers almost always result in changes of the level of gain. In order to get a good recommendation, it is critical that those recommending know what part number the microphone calls for.
Old 3rd September 2010
  #22
Gear Head
 

Hey guys,
first, to all of you I owe an apology cause it looked like I started the thread and left it afterwards... Thing is that I have this project with very tight deadlines and I was unable to dedicate myself to anything else (and it's the sleep that I miss the most).
Anyway, I sincerely want to thank to all of you for great info and inputs!!
As for the type of mic - well to tell you the truth, I was looking to maybe buy one of these german "thomann"-branded mics that are supposed to be suprisingle good bang for a buck. They are supposed to be differently branded SE Electronics mics, or something like that... I'm just looking into experimentation, modification, and I'm not hoping for anything. If, in the end, it turns out to be good investment then great! Otherwise, I don't have nothing to lose except few euros (but the price of my curiosity and eagerness to experiment are higher anyway)...
Thanks again to everyone!
Old 4th September 2010
  #23
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kafka's Avatar
Quote:
Originally Posted by nervirasme View Post
Hey there, the title says it all - I'll soon have a budget LDC tube mic and I would like to know will I benefit if I replace the stock tube with a 3rd party one... and which one would you suggest?
Thanks!
I think I can say almost categorically "yes", you will benefit if you replace the stock tube with the right 3rd party one. BUT, that's only because you get somewhat different flavors with different tubes. In other words, while you may like the chocolate ice cream that comes out of the carton, it's most likely possible to make another chocolate ice cream that you will like even more.

Yes, there are differences in reliability between NOS JAN tubes and modern tubes. I won't get into that because it's well covered elsewhere. But withstanding any discussion on reliability, any other conversation is one about taste. And specifically, your taste. So, yes, it's usually not too hard to find a tube you like more than whatever one you're using now - no matter what that is.

I have a shoebox of tubes in the 12ax7 variety that I pull out whenever I think I might want my amps to sound a little different. The differences between tubes typically isn't all that subtle. Trying them out the various combinations is fun and rewarding.

As far as *which* tube to get, that depends on the mic, and what you want out of it.
Old 4th September 2010
  #24
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Quote:
Originally Posted by Marcadiablo View Post
+1

Bowie IS the man!
Another + 1 here. Reccomended.

Few people that know there stuff are also equally patient and helpful.

I suspect he might suggest a GE 6072.
Old 15th November 2010
  #25
Gear Head
 

Quote:
Originally Posted by chet.d View Post
Another + 1 here. Reccomended.

Few people that know there stuff are also equally patient and helpful.

I suspect he might suggest a GE 6072.
Thanks guys for letting me/GS Community about Bowie. Also, here is a simple to follow and great link for tube gain factor (I know the thread isn't specifically for guitar amps, but they're discussing the 12XX7 family, and the link is great imho):

Guitar amp tweak - change the gain factor of your pre-amp

Last edited by Toy Robot; 15th November 2010 at 04:49 PM.. Reason: Required Clarification
Old 16th November 2010
  #26
Wait a minute. How did I get that you were replacing a tube in a preamp? I can't blame it on drugs anymore, and I'm not on meds.

A microphone tube is normally not a preamp tube, and there are big differences. Usually a tube mic uses a phase inverter tube, such as a 12AT7 or the 12AU7. These are built much sturdier and are manufactured not to "drive". The 12AU7 is made to take handle higher currents to the plate, but the 12AT7 is usually the first choice.


*Kidvybes: If a 12AT7 or 12AU7 is in an preamplifier circuit, it serves as a phase inverter and is usually closet to the power amp section. If one of these is substituted in the preamp cascade, it will not sound as good, but it would work if you were really strapped. http://groovetubes.com/preamplist.html

Last edited by johnny nowhere; 16th November 2010 at 04:15 PM.. Reason: addendum
Old 16th November 2010
  #27
Quote:
Originally Posted by johnny nowhere View Post
Wait a minute. How did I get that you were replacing a tube in a preamp? I can't blame it on drugs anymore, and I'm not on meds.

A microphone tube is normally not a preamp tube, and there are big differences. Usually a tube mic uses a phase inverter tube, such as a 12AT7 or the 12AU7. These are built much sturdier and are manufactured not to "drive". The 12AU7 is made to take handle higher currents to the plate, but the 12AT7 is usually the first choice.


*Kidvybes: If a 12AT7 or 12AU7 is in an preamplifier circuit, it serves as a phase inverter and is usually closet to the power amp section. If one of these is substituted in the preamp cascade, it will not sound as good, but it would work if you were really strapped. Groove Tubes
I mean no dis-respect, but you are quite mistaken regarding the rolls of these tubes. 12Ax, 12At, 12Ay, 12Au are all preamp tubes. When used as a phase inverter in a guitar or bass amp, they are working in a different sort of function, but they are STILL preamp tubes. They are built neither any better or any worse than any other preamp tube by the same manufacturer--from one manufacturer to another there may be quality differences, but because one tube is a 12AX7 and another is a 12AT7, does not mean one was built to a different structural tolerance than another.

What is the big different between these tubes is the amount of gain they produce. See here: Preamp tube gain factor It is my understanding that in tube mics, generally a preamp tube that produces a lower amount of gain, like a 12AY7, is a better choice than something like a 12AX7. I do not personally own a tube mic, but I am guessing the floor noise is increased too much with a higher gain tube.

Again, I mean no dis-respect to Johnny Nowhere, I simply want to clear the waters in the often cloudy knowledge base of tubes, as I know them and the little bit I know about them.
Old 16th November 2010
  #28
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Quote:
Originally Posted by nervirasme View Post
I was looking to maybe buy one of these german "thomann"-branded mics that are supposed to be suprisingle good bang for a buck. They are supposed to be differently branded SE Electronics mics, or something like that...
I don't think the SE thing is true. They're just normal Chinese OEM mics - mainly Alctron I think - sold under many brands, Nady, Apex etc...

I've fooled around with there a little and must say that they are indeed good bang for the buck, no need to pay for a brand name and assumed extra QC (you can always send back the bad ones).

http://www.deeringamps.com/workbench...460_mic_md.jpg

It's STC800 at Thomann. (EDIT: Thomann version is cardioid only with single sided capsule) .The one I have is different brand but almost the same mic. It had 12ax7 in it, 12at7 is the one it's desiged for. I swapped a NOS 12at7 in it and it became a little smoother. 12ax7 is little too hefty for the stock trafo.

But I have to say it was not a night and day difference. Removing some extra mesh helped also a little. Changing the grid and transformer coupling caps was an improvement, like was removing the RF filtering caps after the trafo too. I also inverted the capsule as described here: apex 460 mod for free... try this trick if you can... That was the biggest change in sound.

Like you can see I've done quite many mods, and while the mic is now decent, the sound of it is still restricted by the stock capsule, which is the most important part of any mic if you ask me. I wouldn't give too much weight for the tube swap, when there are so many other things degrading the sound in the signal path.
Old 16th November 2010
  #29
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kidvybes's Avatar
 

Quote:
Originally Posted by nervirasme View Post
I was looking to maybe buy one of these german "thomann"-branded mics that are supposed to be suprisingle good bang for a buck. They are supposed to be differently branded SE Electronics mics, or something like that...
...actually, early on in Thomann's branded mic offerings, sE was the one of their primanry suppliers (sE, although they claim to not provide OEM product for other brands, they did just that for both Thomann and Cascade microphones)...as Pasarski said, Thomann now source most of their mics from ShuaiYin Electronics, who's products are distributed by Alctron...

http://www.shuaiy.com/news/class/

Quote:
Originally Posted by johnny nowhere View Post
*Kidvybes: If a 12AT7 or 12AU7 is in an preamplifier circuit, it serves as a phase inverter and is usually closet to the power amp section. If one of these is substituted in the preamp cascade, it will not sound as good, but it would work if you were really strapped. Groove Tubes
...I can't speak to the phase inverter reference, but I frequently use tubes of the 12AT7 family (12AT7WA/6201 is one of my favorites) in my tube mics with excellent results...most of the chinese tube mics have circuits built around the 12AT7 (while they tend to equip them with 12AX7 tubes for some reason)...in many of these mics, a 12AY7/6072 does wonders by lowering the mic's gain stage and infusing more tube vibe, but in others I find the high grade military 12AT7 tubes to work wonderfully...12AU7s gain rating is a bit low for use in some mics, just as 12AX7s gain can be too high resulting in distortion and a higher noise ratio...

...while the difference between high quality preamp tubes is subtle when swapped in microphone applications, there are circumstances where the difference between the stock OEM tubes (usually Chinese or Russian in origin) and high quality NOS tubes is just enough to tame high-frequency "grit" and tighten low-end response...this improvement was most notable in my Rode (K2 and NTK) mics, as well as some of the OEM Chinese mics like the Apex/Nady variety...

...I just swapped out the stock Electro-Harmonix 12AY7/6072 (better than the typical OEM tube) in a friend's AA CM47 mic for a nice NOS triple-mica, black plate GE 6072 with positive results...clarity in the mic's top-end was improved (as acknowledged by both of us comparing sound files)...subtle, but worth the expense IMHO...
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