...thanks I'll check it out. The ones I gave you the part number for are definitely too big. I think the part # you gave may do the trick. Thanks.

Michael

Whoa!!!!!!!!

I just had the wierdest thing happen. I was recording some acoustic guitar with my 1050 and the polarity of the capsule changed right in the middle of the recording. Crazy.

There is a big pop and then all of a sudden the acoustic becomes very distant sounding (because it's now on the backside of the capsule! [had it in cardiod])

Anybody have an idea what could cause this?

Weird, sorry HonkyJ, can't help with that...you ever figure out what happened?

Ok, I've got a couple of mic observations. First C4 in the 1050 is usually a useless piece o' capacitor junk. It's a polystyrene cap, which supposedly is a good high quality choice...but in 6 of 7 of the mics I've mod'ed for myself or others it's been microphonic....it's actually something I never really noticed, as I usually handle my mics with kid gloves when using them. Glad I did notice. I replaced it with the same value Multicap, film capacitor, and things are now well. BTW, Lucio, thanks for the .01 cap recommendation for C4, I did that to one of the mics I've got and it's nice, sort of fat sounding, very cool. I'm not going to change all the mics I've done with it but I've got one that I've been trying get to sound a bit like a 47 and that mod is worth at least checking out.

One other thing. I've got a AMI-TAB Funkwerk BV314 tranformer in one of the mics. It's actually a mic that doesn't have some of the fancy sort of parts that the other mics I've mod'ed has. And that thing sounds pretty darn amazing IMO. It's really expensive ($180)but, it really sounds a bit more open and musical than the cinemags I've put in. Cinemags are great but the other transformer sounds pretty killing. Oh, as far as I tried it won't really fit in a 1050, even with dremmeling down of the bottom jack holding part. It will (barely) fit in a 460, without the can and you will have to cut down the plastic/rubber tube retainer to make it fit...sort of fit is more like it. Anyway Oliver at Funkenwerk describes it as a BV8 core with a C12 ratio, it certainly sounds nice.

Also, I've got 6 different versions of 1050/460 mics right now. I'm planning to do a somewhat organized and scienctific (as much as possible) shootout between them (they are all diferent) and see what's up. If anyone of you out there has a server that I might be able to put up the results let me know. And let me know if you guys are interested in hearing this stuff.....

MPCNYC,

If you want to take the U47 mod further, change R10 from 1KM to 100M (which is what's used in the U47). This will thicken the mids.

Also, the microphonics of C4 can be tamed with a dab from a glue gun touching the cap and the board. I did this to the polystyrene cap in my 1050 (before changing it to .01) and it took care of the microphonic noise. Got this tip from a picture I saw of the inside of a Peluso 2247 that had the same cap in that spot.

Man. I'd love to hear the differences between your mics, that would be very cool. I wish I could help you with the server issue, but I haven't got one. Hopefully someone can.

Listen, I also changed out R2 and R7 with some Dale resistors, this definitely made the mic sound smoother and a bit less harsh. I changed the values to get a bit closer to the original mics, 100k/1w and 2.49k/.5w respectively.

I've also noticed that both the C12 and C24 used 500k resistors where the 270k's are in the Apex/Nady. I think I may try it and see. The C12 also used a 400K instead of 100k in the R2 spot. I'm not sure what that'll do, but I might try that, too.

I hope you can find a server, 'cuz that'll be very helpful to hear.

Lucio

Lucio, I've got a folder of schematics AKG emailed me. Let me know if you want me to email it to you.

Michael

Michael,

Oh man, that would be great, thanks!!!

Lucio

Wow,

Lucio. I tried both the 100M R10 change, and also the C4 change. Great mods, those.

I was testing this 1050 against a U87 and an AT 4050 at school the other day on acoustic guitar, and I thought the mids were the area that it wasn't quite there in comparison to the U87.

This was prior to the last two changes, so I'm curious to compare again.

(Today) I first changed C4,then R10.

C4 seemed to get it going in the direction of more presence w/ the mids, but I think the R10 change is a REALLY cool, and noticable difference, even more so than C4. It really has some meat in the mids now.

It's boomy though. A lot of low end (I have the 47 type Peluso capsule) I had a 1uF C8 cap in there, and I just changed it out to a .68uF. I'm undecided as to which I like better. My first impression was that the 1uF might be smoother even though it has too much low end. Does that sound odd?

Anyway, my testing environment isn't scientific or anything, but these have been my impressions today.

Also,

Looks like R2 is already 100K. You just changed the wattage to 1watt instead of 2?

I see the R7 change from 2.7K to 2.49

honkyjonk,

Glad you're liking it!!

Yea, I've got the Peluso 47 capsule also. The C4 change fills out the bottom and R10 beefs up the mids. I actually have a 3.3uf Black Gate in C8 on mine. You can always roll off the extreme bottom with a High Pass Filter, but you can't as easily add it in. You can also back up from the mic and still have a full bottom end.

I can't remember, are you working on a Nady1050 or an Apex460? This will make a huge difference in the response of the capsule. I've got the 47 capsule in a 1050.

Also, do you still have the cathode follower or did you remove it? I still have mine in the 1050, but removed it on the 460.

You're right, R2 is 100k/2w stock and I dropped to 1w (couldn't find 2w and a 3w was too bright. U47 used .25w), but I think the better Dale resistor had something to do with it sounding better, too.

I also used a Dale for R7. I just figure it can't hurt to get the specks as close to the original values as I can. Of course the R7 changes are C12 specks not U47, but we are messing with an AKGish circuit.

The other thing that helps with the U47ish sound is to remove C7 but leave C6 in.

Do you have a Black Gate in C6? You might wanna try putting the original cap in (I did), as the Black Gates will brighten the mic some. I left it in my Apex 'cuz I wanted that extra clarity up there, but I want my 1050 "warm and fuzzy", so to speak. Althogh it still sounds very smooth.

The only other things I'm gonna try on the 1050 (have other plans for the 460, too) is to drop R6 to 100M (U47 actually uses a 60M but I can't find one and "most" of these schematics have the R10 and R6 position the same value) and I'm gonna try a "regular" 3.3uf electrolytic in C8, just to see if it mellows out the upper range.

Glad to hear your feedback on this. Let us know how the next mic comparison goes.

This is very cool stuff.

Lucio

Yeah,

I have a 1050. I have an auricap .68uF for C8 right now. We'll see if I leave it in.

And yes, I have a black gate for C6. I think the "N" series. I've had to mount it down by the transformer because it's so huge.

I don't know if I'd put the original electrolytic back in, but it might be fun to try a Nichicon or something.

Do you have any idea what kind of electrolytics were in U47's if any? Sprague?

Why hasn't anyone tried a paper and oil cap for C8? Sure it won't fit right in the holes, but I think it would fit in the mic.

This place has some NOS siemens paper and oil caps that are 2cm X 3cm X 3.6cm for a 1uF/250v cap http://www.machmat.com/sales/capapo.htm

I havn't researched this much. Are there companies that make new paper and oil caps?

Anyway, even with .68uF for C8 in there my tcm1050 w/ the 47ish capsule has too much low end for my tastes.

I'm at a point where I want a couple utility mics, so I'm sort of torn between getting a couple AT 4050s, or perhaps 2 more 1050s and a couple of the 67ish capsules, and going from there with the mods that I know now.

Hmmm. Michael, those a/b tests sure would be cool!

I can see the 47 type mic right now getting used for vocals, but it seems like it might just be out of control bass wise for things like acoustic guitar. I like the high end enough (a/b'd against a U87 it was a lot more creamy) that I'm temped to try to make a couple w/ the 67 capsules. I wonder if in the end they'd be as usable as a couple At 4050s. I know totally different mics, but whatever. I'm torn between having a something natural sounding or something that adds to the source.

honkyjonk,

Not sure if you knew already, but the U47 actually used a .5uf/250 in the C8 position. That might take care of your low end problem.

Here are some paper in oil caps, but there huge. Even for a
.47uf/400v. Some are VERY expensive, too.

If there's one thing I've discovered since I've gotten these different mics is you really do need the different "flavors" for different voices/instruments. I've been amazed at how good a nice warm tube mic will sound on one voice and totally unusable on another, because their voice calls for something more neutral or transparent.

If you can afford to do it, I would (I did and I really couldn't afford it, but I made it happen somehow and am glad I did).

I like how you can change to a different tube and it's like a new mic. Very versitile IMHO.

Do what's right for you. Ultimately, your gut is usually right.

Hope that helps some.

Lucio

P.S. I should be getting my caps/resistors tomarrow. I'll let you all know how these last (hopefully) changes work out.

Okay, I tried a .47 panasonic film I had around. God, that thing sounds like crap compared to the auricap, and it didn't seem to take care of the low end. Just completely muddified the mike. Wierd. I'd think it would be a lot closer.

I'm starting to wonder if there's some sort of bump down there that makes it sound like there's more low end when it's a lesser value cap, and if I put say a 2.2uF in there, maybe it would extend that bump down past 20Hz. Just speculating though. I don't really know enough about how this circuit works.

So this is my mic right now:
1-Peluso CEK347
2-Peluso U47 type tranny
3-.68uF Auricap for C8
3-Black Gate "N" series for C6 (100uF/50V)
4-Wima .1uF/63V for C7
5-.001 Wima for C4 (changed from .0001)
6-56V zeners in the p.s.
7-R10 changed to 100Mohms
8-All resistors changed to Dale (I think) 1% metal resistors
9-All other caps replaced with panasonic films
10-cathode follower removed

I'm awaiting a nady headbasket because I ripped out all the screen material. I doubt this is contributing to the big low end.

Any suggestions?

The lower the value the cap the higher up the bass rolloff should happen. The Panasonic cap doesn't sound quite as nice as the auricap. I really like the sound of the auricap, it's really 'fast' and has the most natural sound IMO. Did the .47 panasonic give you less low end? Is there a .47 Auricap?

Also as far as I know changing those high value resistors associated with the capsule should allow you to tune the sound by changing the loading of the capsule.

Also, I really didn't like the sound of the 56v zeners at all. The mic sort of sounded really small to me with those. It also lowers the voltage to the capsule to a level which I think is too low. To me the 75v are the minimum I'd put in. I like the 82v best. A higher value there will give you a bit more high end and give you a mic that has a more usable dynamic range IMO.

Also doesn't removing the cathode follower change the impedence going to the transformer more in a direction away from the original spec that the 47 transformer originally had?

"Also doesn't removing the cathode follower change the impedence going to the transformer more in a direction away from the original spec that the 47 transformer originally had?"

Ah. Well, maybe I'll change that and see what happens.

yeah check it out I know that the impedence of the 2480 is very different than the 2461, which is what I'm using in most of the mics I did. If the Peluso is similar in the way that it could be a direct replacement for the BV8 then it should have a similar sort of spec. Like I mentioned before AMI-TabFunkenwerks, BV314 may be a good match as well because it works well with the tube type we have in the 1050.

The other thing I was thinking was if there's a way to convert the mic to an EF86 tube??? It would require doing a lot to the circuit.

honkyjonk,

What tube are you using?

A 12AT7 and 12AY7 sound very different in this mic.

I agree with MPCNYC about the 56v zeners. I'm currently using the 75v which, as he said, is the minimum I'd use also.

The cathode follower does change the impedance more in the direction of the U47.

If the Panasonic cap wasn't a polypropylene then you will lose high end clarity. This is also the difference the Black Gate's add over standard electrolytic caps.

I got my shipment in and hope to try these parts out in the next few days.

Lucio

I have a GE 6072 like a lot of folks.

I guess I didn't realize, but correct me if I'm wrong. The cathode follower removal is probably more sutiable if you're going in the AKG direction, no? W/ a CEK12?

Anyway, I'll change the zeners again. I keep going back and forth, and see what that gets me but first I'm gonna put the cathode follower back in.

Man, it's crazy how mushy and wooly the panasonic sounded in C8

The CF removal does make the mic more or less pretty close to a C12.

So many things are different about a 47: impedence, pentode tube, etc....it's hard to compare. But, leaving CF in does make for a cleaner mic (which may or may not make it sound like a 47, as there's so many variables) and one that will not be as much of a mismatch for the transformer you've got. AFAIK that Peluso transformer is a little bit dirtier (which can be a good thing) in the low end compared to the 2461. So, perhaps with the CF in it may sound good.

You may want to really reverse yourself and see if the original DT mod would be better with the transformer and capule you have; if you went back to the CF version you may want to remove C6/C7 (which would clean the mic up further) again. Perhaps, keeping the C4 change you did along with the other resistor change. Then you may be able to go back to that Auricap.

There are some cool vintage Sony and Altec mic the use CF in their circuit that are awesome.

Do you guys have the voltages that should be going to the tube pins?

I guess since I have 56 zeners in the p.s. it's gonna be different.

But anyway, I went back and put the cathode follower back in today, but I'm getting nothing. I'm wondering if I possibly have a cold joint somewhere.

Also, to meausure different tube pin voltages (w/ the tube out) do I just stick the hot DMM lead down in the the socket and then the black lead somewhere on the board's ground?

It's getting something because the tube lights up.