Hi Guys, OOPs. The Zener's add up to 119 but when I measure it with the FLUKE I get 121 volts and the voltage at R3, 4 & 5 is 62.9 volts.

Anyway its not too hard to switch some zener's in and out to change the sound a db or two. I think the Peluso K47 capsule and a slightly lower polarization voltage will yield a very smooth sound in the 1050/CM47 microphone.

We will probably add an internal switch on our CM47SE model.

Cheers, Dave

Can anyone tell me what the stock cap for C4 is on the 460? I ordered one but don't have it yet and I am trying to decide what parts to source. From reading similar threads I found one reference to a ceramic there, one reference to a polystyrene (which is what I want to use there) already in place, and in the comparison shots between the M16 and 460 i see NO cap installed at C4.

C4 is a polystyrene cap that is mounted to the back of the board on the 460, which is why you don't see it in the photos.

The ceramic must have been in very early versions.

Lucio

quote:

Originally posted by MPCNYC:
Lucio, I've noticed that polystyrene cap at C4 in a 1050 to be microphonic more often than not. Replacing it makes a difference IMO.

Lot's of those older mics did use polystyrene. Not so sure if it make a huge difference if you want to get those vintage type caps. My Wunder CM7 sounds pretty awesome with modern caps. Most vintage mics you see today will have caps replaced anyway....those old caps tend not to have the shelf life.

Polystyrene caps are almost always microphonic if they are allowed to vibrate freely. I usually just bend the leads so the cap rests against the board and can usually silence it this way. A glue gun works too, but beware. Some polystyrene caps are easy to melt.

No need to change the cap. It isn't due to a faulty part. It's just how they are when in free air.

I disagree. Change the cap IMO. The gluing down does help, but my experience in changing out the cap really has me feeling that the mic performs better with a quieter cap in there. I put in a Multicap and it sounds great. it just does make sense to me to have something so sensitive to vibration in the mic. New cap, no clunking sounds when handling the mic, and no suseptability to floor vibration, that has been my experience.

Are you suggesting changing the cap to a different type (i.e. polyprop)? THat will solve the microphonic susceptibility for sure, but keep in mind that Styrene caps are particularly suited for use here, and you'll get smoother high end using them. I have tried Wimas and like them too, but polystyrene is usally my favorite in the grid position.

Yes. A different type. I've tried a few things and settled on the Multicap. All caps types and brands will yield differing results in terms of sound. I'm sure you can get an awesome sound with a cap other than polystyrene in that position.

Hi, C4 is 1000 pf. Polystyrene would be fine. I would stay away from a ceramic as they can become noisy over-time in my experience.

Do not loose a lot of sleep over the capacitors. Differences in the capsules and capsule polarization voltage will make a bigger difference to the sound than the input capacitor.

There is no math to support the difference in capacitors that folks put forth.

Cheers, Dave
www.aamicrophones.com

Hi, Check the power supply voltage? The 1050 microphones quite often come with a 150v supply which is divided by two to polarize the capsule.

The polarization is just too high and diaphragm was pulled into the back-plate. Generally, the 32mm 3 micron ecomical capsules used in the 1050 will fail like this at about 60 volts.

I have one supply set for 160 volts and use this to test the capsules and if the fail the higher voltage polarization voltage then they are replaced.

Cheers, Dave Thomas
www.aamicrophones.com

Hi everyone,

I'm new to this forum, though I did read this thread end-to-end about a year ago, and again with renewed interest last night (it's remarkable how much has been added).

I was a kit builder as a kid, but apart from knowing my way around Ohm's Law, am a little light on electronics theory (although I'm generally a quick study).

I'm going to start by modding my Apex 460. Come to think of it, I could use some initial insight from the get go. The last time I used the mic, it started going dead after 1 to 2 hours of use. Turning the PS off then on again would fix the problem for another hour or so. Eventually it seemed to stop doing it and I got through the session. My fears were a bad transformer winding, or maybe the tube. Did I read something here about the cathode overheating? Any ideas? I've still got the original Chinese tube in it.

Now for the real reason for my post. I've been talking to the guys at Canadian Audio Distributors about their mod kit for starters. I could use some additional advice on capsule selection:

I found a fairly exhaustive mic comparison audio download on the web (foolishly or not, I decided to pay the $25 CAD), so was able to listen to a C12 (which I had never heard before) versus a U67, as well as many others. I like the darker sound of the C12, and admittedly have always found the U67 a bit bland in the mid and lower mid-range (compared to the U87, say). By design, I understand the capsule used in the original U67 was extremely bright and had to be darkened down for use on German radio.

My thinking at this point is that if I go with the U67 mod, I will not really be able to fatten the mids much (you can't add what didn't go in through the capsule), whereas if I go with the C12 mod, maybe I can brighten it slightly if I find it too dark. Does this make sense?

Since this is my first mic mod, I don't really want to get into tearing the cage apart. I'll likely just do the basic mod (capsule, transformer, tube and the one capacitor at C8) at first, and listen to the mic for a while. Then maybe change out or remove the other caps, take out the envelope follower, etc. later (all of which is getting a bit theoretical for me this early in the process). My concern with the C12 mod is can I get it to cut through a mix?

Though Ashton Price at Morph Productions did put up a couple of modded and unmodded guitar tracks for comparison, a while back, it's really difficult to decide which capsule to go with, when the results are for the most part sound unheard. I'd appreciate whatever thoughts or suggestions anyone might like to offer at this point.

Thanks in advance and kind regards to all,

-Wayne

quote:

I like the darker sound of the C12, and admittedly have always found the U67 a bit bland in the mid and lower mid-range

I'd disagree with this assessment of the C12, as I'd characterize it as a bright mic. Also, the mids and low mids of the U67 are what I find appealing about the mic. Of course, this is rather subjective.
Craig

Interesting, Craig.

In my case, it's more a subjective impression than an assessment, based on 3D Audio's 49 mic comparison CD, as I've never heard a C12 in any other context. Over the years, I've generally found the U87 to be a warmer mic than the U67, subjectively as well of course.

Maybe it was just the particular recording; I'll listen some more.

In any case, would you care to comment on the issue of controlling the modded 460's response - CEK 12 vs CEK 367/67/89 - and what you think might be possible in terms of achieving a warm sound that can still cut through a mix well ...

... and anyone please chime in here. For example, is anyone familiar with the characteristics of the three Peluso capsules available for emulating the U67.

Some time ago, Dave Thomas had this to say:

"The 460 with the tube/capacitor upgrade CEK-89 capsule and cinemag output transformer does a great impersonation of a U67 and probably sounds somewhere between the U67 and the M269c. In my experience the CEK-89 is not as "nasty" in the low mids as the KK-67 and has a nice lift in the 10k to 13k range. One client after comparing the CM-67(460/cek-89) to a Neumman U67 ordered 2- more CM-67 microphones from me."

I'd appreciate anyone's views on the capsules I've mentioned (given also that the mod kit offered by CAD includes the BV11P transformer), and how the 460 might be tweaked to get the kind of sound I'm looking for, as subjective as these things obviously are.

I realize that what I'm asking for is a certain amount of hand holding, to get me going. Hope that's ok.

Cheers,

-Wayne

....this is sort of off topic, but still sort of on topic. I tried a Studio Projects CS1 mic on an acoustic guitar this last week. A/B'ed it against a U87, and actually thought the SP CS1 was really nice and actually used it instead of the U87. @ about $400 it's a bit cheaper than a fully mod'ed 460.....worth a look IMO.

Hi MPNYC,

Good to hear from you, off topic or not. It's largely your and Lucio's input to this thread which convinced me to try the 460 mod in the first place. Thank-you both for so generously sharing your experience and ideas.

Currently, I have only a few mics in my "locker" (I do have an SP C1, which I consider just ok for limited applications - I'm sure the CS1 is a whole different animal, but wouldn't consider it without hearing it in a comparison similar to the one you've done).

In fact, I have a Rode K2, along with a UA Solo 610, on order. As you can see, I'm just beginning to build a decent front end in my little demo studio. The reason I'm asking about the Apex 460 mod is that I already have that mic, and would like to improve its sound.

Just re-reading this thread and throwing my first post up, plus a couple of days to think things over, has made up my mind. I'm going to go with the C12 mod, primarily because it has the most detailed information (read "easy to follow instructions") from everyone here.

Obviously, security is a big issue for me when it comes to getting my hands dirty with electronics (a common theme here too I've noticed).

Thanks to all for bearing with me during my meanderings. Will let everyone know how it's going once I begin.

Cheers,

-Wayne

Good luck! You'll end up with something that you'll like if you keep at the mod.

Last week I did a CD and the sax player picked the 1050 I mod'ed and a Apex 205 I mod'ed over a Coles 4038 and my Wunder CM7....that was a surprise!! It was interesting. I may have actually gone with the Wunder and Coles myself if it was only my choice. But the 1050 really has a hyped sound to it that must of worked for him. CM7 had more detail and less lows. The 1050 had tons of headroom and a really cool gauss-y sort of sound. It was the 1050 I did that was really close to Lucio's "47" sort of schematic. Mine uses a 2.0 Auracap for C8 and a Cinemag 2460 transformer....it sounds pretty sweet.

I'll post when the CD comes out. There's actually a CD out by John McNeil/Bill McHenry called "Rediscovery" on Sunnyside records. I use the 1050/Apex 205 combo on the sax and a Coles on the trumpet....all live in a small room. Nice playing, by some stellar jazz musicians....anyway the mod'ed mics are on there....and a mod'ed apex 205 on the standup bass. Should be on iTunes if you want to take a listen.

Still don't have my mic yet so my thinking is theoretical...

I wonder if there's really any point to removing the cathode follower from the circuit. I mean all it does is add current gain, and needed or not it seems that if the tube is good there shouldn't be much difference in the sound. I can't see why any more noise or distortion would be added by the second stage running at unity, so is there really a point in removing it?

I understand you don't need the impedance conversion it provides in order to drive the 10:1 or 11:1 transformers people are using, but it seems that the reason people are removing it is because the C24 doesn't use one.

I am also surprised people haven't experimented with lower ratio transformers here too. Is it because of the cramped layout and inability to fit most stuff?

Is it really all that profound of a step?

I think the mic sounds better with the cathode follower remove. Way more open in my opinion and when you hit it with a bit of volume it seems to stay open with cathode follower it sounds boxier to my ears. There are very few "cool" mics with with cathode follower if I recall correctly (Sony C37A, I think, and some Altec mics)most of the older german ones don't have it. It just sounds a little more classic to my ears without it.

Yes I think people were inspired by C12/C24. I was a relatively late convert. I kept mine with cathode follower for awhile.

As far as transformers go: I've tried many 2480, Tab-Funkenwerk, Peluso....etc. I even put in a large Cinemag 2460, which has a quite different impedence, but it still works quite well. I actually like the 2460 a lot. It did take quite a bit of milling of metal to get it to fit in a 1050 body....but it works. It sounds sort of bigger to me....hard to describe.

All variables are worth exploring....tubes, caps, transformers.

Different tubes will yield a variety of different tones. Expensive NOS ones may not be better for what you are after. I settled on a NOS GE (about $50) for most of the mics I made. There's a noticeable difference in the way the mids and highs sound in the tubes I tried out.

JJ 12AT7's sound nice too. I may start messing with some 12AU7 and see what that gets me.

There is definitely a difference in the sound with or without the cathode follower, regardless of the technical differences.

The low end becomes clearer and it's more open for sure.
With the cathode follower it's a bit thicker which is why it may be better to keep for a more U47/VF14ish character.

Incidentally I talked with John Peluso recently about the 47 capsule voltage and he told me that he has a BV8mini tranny that he uses in the 1050 type mics. It's small enough to fit into the tranny case but sounds like the BV8. I'm gonna get one for my 1050 when I can.

Michael,

Did you notice more low end and a fuller sound with the 2461 vs the 2480?

I'm thinking that the BV8 "sound" is what's missing from my 1050. Otherwise it sounds great. I did change R3 & R4 to the 3M & 2M resistors and removed R5. It dropped the voltage to the capsule and it sounds better actually. Just wondering about the tranny.

Lucio

sorry I referred to the 2461 as the 2460, and yes I do think that the 2461 has more low end.

Micheal,

Sorry if I've missed this in your previous posts, but how did the TAB transformer compare to the Cinemag models?

Craig