Please recommend caps for microphones

[mtl777diy]

Yeah, I'm a part-time **** myself.
But don't tell anyone. 

Hey, could you please post pictures of the PCB? 
Guosheng shows the PCBs on his own site (nice treat), but your model is (still) rare and doesn't get mentioned on the site, yet.

As your prize for getting my tube mic correct, here are the pictures of the PCB... 

 

[mtl777diy]

Oops, this forum allows only one picture per post.  Here's the second picture.

 

[mtl777diy]

Hey guys, what are some of the best caps (not electrolytic) for microphones?  What brands of caps do you use for your projects?

Thanks! 

There are many things that affect the sonic quality of a microphone: capsule is #1, transformer, if any, is #2, circuit topology is #3, caps are about #13, just before the solder brand and the pubis hair colour of the designer...

Pubic hair, LOL.  ;D  If caps are that low in significance with regards to effect on sonic quality, you have just saved me from wasting my time on the caps.

I think the capsule of the tube mic is great, the circuit topology is most likely great (I don't know enough electronics to be a judge of that), and the transformer may not be the best but it works well.  The transformer is a GZT-12 made by the designer/manufacturer of the mic.  I asked what I could replace the transformer with, and he said I could try an AMI T14 (12:1 transformer) and the mic will have more articulation but less warmness.  I'm not sure I want less warmness because this mic will be used mostly for vocals.  Any other suggestions for the transformer?

 

[ln76d]

To be honest i wouldn't waste the time for these transformers.
For the caps - there's few points where you could change some, same as resistors.
Tube? Could be also upgraded. What tube sits here?
Is it multipattern or cardioid only?
If you will put few pics of the boards close up view , especially small one, there probably would be few points to upgrade
With the capacitors, you could try 0.5uF MP (PIO, MBM etc.) at the output insted WIMA 1uF MKP.
You should notice difference due to capacitor value as also the type (yeah - pubic hairs!).
If there's cathode capacitor in the circuit you could also try to swap for different value (best is test with few values).
I bet that high ohm resistors are 1G, these could be changed for lower value from 100M to 500M. Also you should notice pleasant difference.
For know we don't know how the input is wired (capsule to first grid), this is the point where you can also do some improvements and the small board pics should give the answers
Doesn't capsule is too bright a little? Always there's option to change a little HF response.
First what you could make - try to remove two green caps (between big red 1uF and transformer).
From what i see these are RF capacitors (better pics could be better to verify) - not always but sometimes can change the sound in the better way.
Always you can put it back in the circuit

 

[micaddict]

Good idea to come over to this forum. You'll love it.
Many very knowledgeable and friendly folks here. 
Did you know Dennis Stone (kidvybes) was a member here, too?

As your prize for getting my tube mic correct, here are the pictures of the PCB... 

Thanks a lot. This gives a better idea of what kind of animal we're talking about. Should you really want to get in depth, the wise will need close ups (but still in  focus) as well as naming of values. That way the whole circuit can usually be reconstructed, which would help a lot for suggesting sensible mods.

the transformer may not be the best but it works well.  The transformer is a GZT-12 made by the designer/manufacturer of the mic.  I asked what I could replace the transformer with, and he said I could try an AMI T14 (12:1 transformer) and the mic will have more articulation but less warmness.  I'm not sure I want less warmness because this mic will be used mostly for vocals.  Any other suggestions for the transformer?

As you know, ADK has some overlap with 3UAudio. ADK's prime line is their custom series Z-mod. Those are expensive (more so than the GZ) and use trannies like Jensen, Lundahl and Sowter. Jensen and Lundahl may be too clean for vintage mojo. Sowter transformers are known for character, especially in the mids.
Haufe still makes the T14/1 that was used in the Ela M251. (!) Not a bass monster, but great for vocals and such.
Marik (who is a member here, as well) of Samar Audio makes really good ribbon mics and also fantastic trannies. They are huge though, so fitting them may be a problem.
The stock tranny may be better than some would expect BTW.

The first "mod" that comes to mind would be replacing the EH 6072 for a nice, new old stock, vintage tube. Good GE 5 Stars are getting hard to find, though.  Some folks have switched from 6072/12ay7 to 6201/12at7. E.g. David Bock (also a member here) uses it in his 251. For optimum performance some slight mods are needed.

 

[micaddict]

Piotr, you were quicker than me (again). 

Tube is an Electro Harmonix 6072.

The capsule is tuned less bright than the one in the GZ12.
More about this later.

The mic is multipattern (continuously or stepless, I believe).

 

[micaddict]

OK, for those who don't know 3UAudio mics, I'll elaborate a bit.

The owner/designer is a guy named Guosheng Zhuang. This sounds Chinese and he is. The address on his site is an apartment in Sydney, Australia, though. And he does speak better English than most Chinese. It seems like he, at least partly, resides in Australia.
Guosheng worked for 797 Beijing Audio from 1983-2004. At the time 797 made the best Chinese K67 capsule (e.g. for the Rode NT2).
From 2004-2012 he worked for Feilo, if I'm not mistaken.
In 2012 he became self employed. He now has his own factory in the Ganyu District of Lianyungang, Jiangsu province. Yes, communist China has changed a bit.

Guosheng is a capsule maker first and foremost. He makes his own capsules and tunes or voices them to liking. So, although they may look like the usual suspects (hardware showing the Chinese capsule bloodline) these ar not your regular OEM Chinese capsules.
BTW, both 797 Beijing Audio and Feilo are not typical OEM manufacturers, either. The usual OEM suspects are Alctron,  Shanghai ShuaiYin and Ningbo TongXin.

Also worth to keep in mind is that 3UAudio mics are not meant to be clones. The only reason why familiar numbers are used is because customers like that. They tend to ask about ballpark sound and the big five or six are always the reference for LDC mics.
So the mics are no clones and the circuits are always basically flat (but with options like FET, tube etc). Tuning is done by working on the capsules. E.g. the CK12 style comes in three versions at least. There's a relatively bright one for C12 style mics, a slightly darker one for M251 style mics and an even darker one that almost sounds like a ribbon.
U67/87 style mics have a K67/87 style capsule, but without de-emphasis in the circuit. So, they sound overly bright? Nope, he manages to really tame the capsule, from subtly bright down to flat or dark even. Quite an achievement, or so it seems, if we realize that the original K67/87 is very bright by nature.
K47 style capsules are tuned so the mic either sounds more like a U47 or, alternatively, more like an M49.

I'll add that Guosheng himselfs hates the overly bright and harsh mics that China has a reputation for.
He really tries to distance himself from this.

So microphones are made in China, but with high quality control in a privately owned factory.
And they can be ordered directly from the maker which skips the links for wholesale and especially retail. This makes them very competitive indeed, particularly the series below the GZ series.

Not affiliated.
Just sharing what (I think) I know.

 

[ln76d]

Piotr, you were quicker than me (again). 

Recently I get up early

The mic is multipattern (continuously or stepless, I believe).

Definately worth to check (and improve if needed) input configuration.

The first "mod" that comes to mind would be replacing the EH 6072 for a nice, new old stock, vintage tube. Good GE 5 Stars are getting hard to find, though.  Some folks have switched from 6072/12ay7 to 6201/12at7. E.g. David Bock (also a member here) uses it in his 251. For optimum performance some slight mods are needed.

Personally i don't like 12AT7 in plate followers but i think 12AV7 is worth to check. It has gain similar to the 12AY7. I didn't tried it, but someday i will These are cheap as hell.
I would buy even used GE 12AY7, most should work like charm instead modern 6072/12AY7.

 

[mtl777diy]

Hey guys, thank you so much for your suggestions!  Really appreciated. 

Unfortunately, I have become very busy and will not be able to do all of them.  I have been on the modding path before and it took so much of my time that I completely forgot what I built my studio for -- to create music.  You know, modding is addicting. 

So I will just focus on the easiest mods to do -- replacing the tube and transformer.  Maybe I will revisit the other mods later when I have time.

For the tube replacement, I'm considering the GE 5 Stars.  That's a 6072, correct?  What's the difference between 6072 and 6072A?  Which one should I get?

For the transformer, I'm considering either a Sowter or Haufe.  Will either of these really be a big improvement over the current GZT-12 transformer in my mic?  @In76d, do you still think it's a waste of time to change the transformer?

Thanks again!

 

[micaddict]

You'll get the bug again.  ;D

And it will only inspire you musically. 

Hey, and the last time around you didn't have the support you'll get now.  8)



The -A indicates low noise, but this doesn't mean you can't have low noise without it. (How's that for a triple negative?)
The trouble with the GE 5 Stars is that they've become disproportionally expensive plus what's left is the dregs, mostly. They've been sorted out, sifted through and cherry picked over and over again. So if you want one, don't buy on the bay, but from a reputable supplier. I'd give Bowie a hollar in that case. Yup, he's here, too.

I wouldn't hurry with the tranny.
Eventually you may even want or need one with a different ratio. Who knows?
Get a fine tube first. 

Could we try to figure out the schematic?

 

[ln76d]

mtl777diy - i sent you PM, check it

Hank - to be honest!

I bought at least 10 GE on ebay (from different sellers, used and nos) for the price which you will probably have to paid for one-two tubes from "reputable supplier". Gues what? Nine is perfectly working, one is slightly microphonic. Even if five would be damaged, still left five of working
Also here and other forum, from time to time, you will read that not always tubes from "reputable supplier" are perfectly working...

 

[micaddict]

I bought at least 10 GE on ebay (from different sellers, used and nos) for the price which you will probably have to paid for one-two tubes from "reputable supplier". Gues what? Nine is perfectly working, one is slightly microphonic. Even if five would be damaged, still left five of working

Some have all the luck ...

Also here and other forum, from time to time, you will read that not always tubes from "reputable supplier" are perfectly working...

The good thing of a truly reputable supplier, though, is that he will make up for it.
From what I know (looking from our side of the pond) Bowie is a class act.

But maybe you have a spare to send to our new friend? 
Hey, and while you're at it ... 

 

[ln76d]

I'm not the luckiest man in the world, definately, but most of the tubes which am buying, used, nos etc. is usual in great working condition. I could say i had no luck with 1-2% of my overall tube buying and am buying lot of tubes
For now i have only 5pcs of GE and need to bought more spare for myself

 

[micaddict]

Can't blame ya.  ;D

 

[mtl777diy]

Hey guys, I took three more pictures -- close ups of the GZ251 guts.

Here is the first one.

 

[mtl777diy]

Here is the second one.

 

[mtl777diy]

And here is the third one.

 

[micaddict]

Better pictures for sure. 

 

[mtl777diy]

I found some pictures of the guts of an ADK ZMod 251.  Here's the first pic.

 

[mtl777diy]

And here's the second pic.

What do you think of the ZMod 251 tube mic?  Any similarity to my GZ251 tube mic?  How do they compare?