Apex 460 capacitor change?

  • Thread starter Thread starter EdgeGuy
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I think removing the pc boards would cause more problems that it would fix. You can get resistors at www.mouser.com or www.digikey.com

Another thing that I found is that all capsules, even the original ones, seem to work better with less voltage. Stock, the power supply delivers about 196V to the mic. All older tube mic designs chose closer to 100-110V. Replaced the stock 1N4761 zener diodes with 1N4758 56V zener diodes. This dropped the voltage down to about 112V. Both modded and unmodded mics sounded better with this change. Two zener diodes for less than a buck a piece.
 
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This makes a difference. I have 2 mics. I changed out the zener diodes in one PS and tested them side by side. The gain drops a bit, but all the harshness is improved. The mic sounds much smoother and open. The detail is better and there is less fuzz. Another added benefit is the tube seems to warm up slower, so it means longer tube life.
 
Well, I guess the gain is not affected as I thought. I swapped diodes in the other PS and there was still a gain difference between mics. I had a bad tube in one. Swapped it and now they are even.
 
Got my Black Gate capacitors today and swapped them out for the stock 100uF electrolytics.

WOW!!!!

I had no idea there could be such a difference. Every mod I've done so far has just made the Apex that much better. I think this just might have pushed it over the top. The zener diode change was a pretty big jump as well. This is now a REAL mic.

Things done so far:

Upgraded the tube to 6072 (tried other tubes, but after all mods this is still best)
Replaced all low value caps with mylar or polypropylene.
Removed 2 inner layers of grill mesh
Replaced capsule
Replaced zener diodes in power supply
Replaced 100uF 25v with Black Gate of same value

Last thing would be to replace the transformer.

I've already gone this far...
 
Oh, and I painted the body so it doesn't say "Apex" anymore...






... 'cause it AIN'T!!!!
 
Wow!


You can almost see the tumbleweeds rolling through this thread... :(
 
Nah, I'm still around. What capsule did you use? Post of pic of the painted body, I'd love to see that. What do you like for paint?

re: Black Gates, yeah, they really are the special sauce in some applications.
 
Well, I started out using a capsule from a CAD E-350, which was good but I wanted to save it for another project. I later swapped for another double sided capsule I had in another mic. I believe it's a 797 capsule. I may go back to the CAD capsule and see if it's better or not.

The paint I used was a grey hammered finish, but I sprayed it light and in few coats, so it doesn't loook hammered. I've attached a pick of a Nady TCM1100 I modified which has a beige hammered finish that looks pretty vintage. Pardon the diamond. It looks like crap and I'm going to remove it. I was just testing what it might look like with a badge. I may try that beige hammered paint on the Apex.
 

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That former-460 is looking sa-weet with that paint job. Capsule looks like a 797 with the white retainer ring.
 
The paint job looks great. As you probably suspect, a different transformer does make a fairly large difference to the response of the mic. I have the Cinemag 2480(?) AKG replacement transformers in mine and they sound great. About $45 each.
 
mbrebes said:
The paint job looks great. As you probably suspect, a different transformer does make a fairly large difference to the response of the mic. I have the Cinemag 2480(?) AKG replacement transformers in mine and they sound great. About $45 each.
Click to expand...

That's exactly where I'm headed!

Michael, did you try Black Gates in yours? I've lost track of who's done what.
 
Oh, I just have an academic interest. I don't own one. But I use Black Gates in some of my mods.
 
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Hi Phil, I did some tests with the different tubes in a 460 by removing the capsule and feeding my signal generator through a 50 meg resistor into the grid to simulate the capsules input impedance. With the 12AT7 I measured 2-3 db more headroom that the 12AX7 while the 6072a garnished 6-8db more headroom. With a 12AX7 I measure +12dbm at the output of the transformer before distortion and +18dbm with a 6072a tube. The Chinese transformer starts to distort at about +12dbm while the Cinemag Cm-2480 will handle +18dbm with less than 1% distortion across the audio bandwidth.

The 460 with a Peluso CEK-89 is very nice for backing vocals as it has a natural lift between 10k and 14k but is a bit smoother in the mids than a Neumann KK67 capsule. the Peluso capsules are much more consistent and one major Studio who send their 460 for upgrade with a CEK-89 compared it to a $5000 U67 and could not hear and $4500 difference. The told me that maybe the U67 sounded a bit "richer". They love their CM-67 on backing vocals.

Cheers, Dave Thomas (Advanced Audio Microphones)
drthomas@telus.net

PhilGood said:
The ones I replaced are marked C1, C2, and C8. They are all 1uF. I used 1uF 250v mylar capacitors. Watch out, they are pretty big!

It can be tricky! There is not a lot of room and you'll need to bend the leads around so that the caps can lie flat, don't touch other leads and the case can still go back on.

I also used a Telefunken for replacing the tube, except I used a 12AT7 instead. I tried a 12AY7 also, but went back and forth until I decided the 12AT7 sounded best.

I've done so many changes to this mic I don't remember how it sounded originally and I don't use it much. I thought I would! I used it for some backing vocals once and thought it sounded fantastic.

I have aquired mics that I use more often, but I'll have to use the modded one in a session again and see how it now compares to the better mics I have.

Don't really know why I lost interest.
Click to expand...
 
Hey Dave!! Glad to see you around here! Looking forward to all the input you have!

Have you tried it with the CEK-367 or CEK12? I'm about to make the leap but can't decide which one. Good to know the 89 sounds good too. Did you read all the way through this post? Mberes made a great discovery changing the power suppy zener diodes so the output is around 112v. MUCH smoother sounding. Also changing the 100uF electro to a Black Gate cap has a significant improvement to the sound.

Glad you're on board!

Phil
 
Please, could you show me wich cap(s) to change, I think c8 was the most important one but wich is it in this one? Is it easy to change the transformer
to a Cinemag, I`m bit glumsy with these. Peluso capsule in is easier to change
as you easyly see the contacts...
Regards
Matti
 

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I only see three electrolytic caps in this circuit. They are the three circlular ones. (Aluminum on top)

You have to read the values on the side. I don't know if it's worth changing any since we don't have a schematic for this mic. Can you get one? Most likely the brownish one is a smaller value and part of the audio section.
 
If that's a Peluso mic I'd leave it the hell alone!

I don't think you could make it better.
 
Oh sorry, I was absent minded. It`s a GA TC-1, similiar to ADK Generis and
without doubt from Alctron. Only difference to the ADK is the hp and pad switches I think. GA TC-1 is from Swedish Golden Age Audio.
So the C8 to change could be the nearest to the transformer? It says
450v 1 uF the strange looking "u" on it.
There are actually 4 of them see the lousy pic. if it helps.
Regards
Matti
 

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