UM57/ CMV 563 sound so boring, whats up?

[hitchhiker]

ya Dave ,
the Lundhal are too long. I read somewhere about taking a jensen out of it's shell and putting them in mics. That was something like a 11 : 1 I think.
Maybe there is a suitable Jensen that you can remove from it's shell.

If you think you've got a very good M7 then in the long run you'd not be
sorry for expensive Tab transformer. I only went for it because I suspected my best capsule had lots more to give.

Lance

 

[mattmoogus]

[quote author="Gus"]Matt

What other microphones did you compare it to? The reason I ask is sometimes a microphone can sound good untill you compare it to a REF microphone.

A ref microphone in this post means a good one that you "know well"

Gus[/quote]


Im comparing it to my other mics: Beyerdynamic, Calrec, Rode, Shure etc, aswell as Joe's first batch C24, and various other Neumanns Ive used around the place. Ive never used a better mic for accoustic guitar and female vocals. Everyone else who has used it agrees, including some well known producers here.

Maybe I have a particularly good one, or maybe were all deaf, who knows. Ill post some examples soon and you guys can decide.

Oh, (those swapping transformers) you have changed all the caps and the tube and checked the resistors values right? Just checking!

Matt

 

[Gus]

Matt

Thanks for the feedback. The two I heard with different capsules were both different Both were OK Some things were tried but nothing exciting happened. The two M7 capsules did sound different. The bodys had what could be different lam alloy transformer sounds.

Now with upping the circuit gain you are hitting the lams harder and maybe in a better part of their input signal level for the BH curve of the alloy used.

I think it is possable you have both a good transformer and M7.

FWIW I have 3, 692 geffels and even with cap upgrades they still don't sound great even with the very nice Ni m70 capsule or a UM70 head( I wonder what circuit I could intall?). I guess it is possable there is some truth to the story that before the fall of the wall in 90 the east made microphones might have been built with what they had.

I did not mean anything like you are deaf. The web is limited, and I respect people who do tests and mods and share the information.

Maybe Dave can fill in with what the changes were to his ears.

 

[mattmoogus]

[quote author="Gus"]
I did not mean anything like you are deaf. The web is limited, and I respect people who do tests and mods and share the information.[/quote]


Hey Gus,

Didnt mean to imply that you did! I was merely canvassing the possibility that I am (deaf) :grin:
No disrespect taken!


Well thats interesting, you may well be right. I remember reading somewhere that the transformer quality varied once the wall went up, and maybe mine is an early example. It is a 551 after all.

Were going to spectrally test the electronics of mine next week and see whats going on. It would be interesting if others could do the same, we might find whats going down with this mic.

ps, Ive just gotten my valve Calrec mic going as of yesterday, running off 48V and a AA battery for the filament until we make the little inverter circuit. Its not much bigger than a KM74, cant wait till its ready to record :green:


M@

 

[chriss]

[quote author="squib"]these mics are great. My tip ... clean the capsule. Adjust the PSU HT to get 80V onto the capsule rather than the usual 60V..they like it!![/quote]
I have heard of MV582s that were modified this way. But it should not be that easy with the UM57. Its front-capsule is at ground and the plate at 60V, so the capsule ist in fact at -60V - right? To bring the back-caspule to 60V you need to put 120V in it. So for 80V you'd have to change the voltage-divider R6/R7 to bring the plate to 80V. But now to have the back-capsule work at 80V you need to feed 160V here.
Any experience with this mod anyone?
Any mistakes in my thoughts?

Chris

 

[kruz]

I've just bought an UM57 from a trusted shop in germany,
they fully serviced it and they also have tweaked the psu to put out 180v for less noise.
I still have to recieve it so i can't comment more.
There is also a company always in germany that sells a new psu for the gefell mics:
http://www.powertechnik.com/produkte/Tubelife-257_e.htm
and i see that they can mod it to deliver 160v but that will make the psu suitable only for the um57 and no more working for the cmv563 and m582

 

[chriss]

i see that they can mod it to deliver 160v but that will make the psu suitable only for the um57 and no more working for the cmv563 and m582

If I understood erverything right, it won't be working with standard UM57 either, because if you put 160V on the back-capsule it sees 100V in real wich is probably too much for it. And I doubt that 160Vto the tube-plate is the right way to go, so the PSU should put out 5,8V - 120V and 0-160V.
But this again means that it could still work with CMV563 and M582, because the 160V only appear at Pin 6 of the plug wich should not be connected in these mics. So the only incompatibility is between modified PSU and not-modified UM57.
I could be wrong either.
May I ask what you have paid for yours kruz?

Chris

 

[kruz]

I've just sent you a PM, Chris

 

[martthie_08]

> From the Horch-distributor I heared that those mikes
> use MBHO OEM Capsules. Those mikes are really really
> decent. They easily blow most other mikes away.
> Maybe MBHO sells in small quantities...

hmmm, I am not sure if this is correct. I can check for certain though, the guy does studio maintainance for my flatmates facility. They have two very early Horch mics in the studio with original m7 and k47 capsules and also the newer rm2j, those are sweet as well, they have a really solid low end.

 

[Gus]

The raising the voltage mod is something I don't understand with a cvm um57.

Raising the capsule voltage might sound good on paper but in the real world just for S/N??? with an old capsule???

Raising the B+ voltage without adjusting other things is not something I would do. There are A LOT of little things that affect a "standard" tube microphone circuit(the triode plate out stage).

Remember a "standard" tube microphone circuit has more going on than some people "see" The more tests I do the more I chuckle with what I read on the web.

IMO there appear to be only a few real tube and transistor microphone smaller company designers that did/do their homework and realy understand the fine details that seperate the great from the good.


Don't ask I am not going to share. There are a lot of hints in the posts at the lab. Some people were subjected to me talking about and showing some of my findings with microphones.

 

[chriss]

Raising the capsule voltage might sound good on paper but in the real world just for S/N??? with an old capsule???

Well - that's what I'm waiting for: experiences that people made with real-life mods - not only guesswork.

Raising the capsule voltage might sound good on paper but in the real world just for S/N??? with an old capsule???

Why not? What speaks against it?

Remember a "standard" tube microphone circuit has more going on than some people "see" The more tests I do the more I chuckle with what I read on the web.

I understand that very much. I'm very careful in deciding if to mod or not mod Equipment. But with the GDR-condensors there is one thing that I think could have been done just for compatibility: The use of 60 Volts for the capsule - small or big membrane, just for the hell of using the same PSUs for all of them. So if the big membranes take advantage of more power - why not use special PSUs for them? But I'm not sure if it really brings advantages.

Chris

 

[dale116dot7]

Big capsules tend to have the diaphragm get sucked into the backplate (from electrostatic attraction) at around 100 to 130 volts, and releases at about 70 volts. Thus, it is safe to use around 60 volts because even if a puff of air (plosive) causes the diaphragm to bottom out, it will snap back on its own accord. You can tension a diaphragm higher to take advantage of a higher voltage but then the low frequency response starts to disappear.

Some small diaphragm condensors are charged with much higher voltages, but those are pretty much measurement microphones with very stiff diaphragms. Measurement mics tend to have very high tensions, or in the case of the Altec M11, a glass diaphragm which is pretty stiff, even if it is not tensioned in the manner that a traditional nickel or plastic diaphragm is.

But most mylar diaphragm SDC's have a similar tension vs area as an LDC and electrostatic pull happens at about the same voltage level, so the voltage should be about the same for LDC's vs SDC's.

 

[soundguy]

I screwed around with one of my cmv's and with gus' help got it to sound pretty good. I had a second one that I couldnt do a thing with, just sounded terrible. I sent it to gus and got back an insane sounding microphone. insane.

gus knows.

dave

 

[chriss]

Dave,

what did you do with the CMV? Please, please let me know!

Chris

 

[frenzy]

Hi all!

This is a very interesting thread.

I just want to share my experience with my CMV-563. Bought it on Ebay and used it for a while. I thought it sounded pretty good with a nice midrange and the high frequencies rolled off just a bit.
Then one day it broke down and I really had no idea how to fix it. I let a techie take a look at it and he changed the cap closest to the capsule. It worked for a while then the mic broke down again (producing almost no signal and a lot of noise).
So I sent it to the guys at Microtech Gefell to take a look at it. After a month or so they told me that the M7 (long-neck) capsule needed to be fixed and that someone had changed the output tranny which probably made the output signal lower. I asked if they could change it back to a NOS tranny, which they could.
Then I waited another two months, because they had a lot to do at the factory, and finally got my mic back.
Warming it up and singing into it, I was totally blown away! It's a new microphone and it sounds absolutly STUNNING!!!
The lowend is firmer, the highend is much more open and crisp, and the midrange...well, it's boiling...just the way I want it...
Now it really has that funky midrange that only old tube microphones seem to have. I haven't heard it in any new tube mics, not even close.

Bottomline, if you think that your CMV-563 sounds boring, then it's broken!!!

Sent it to Gefell and have them fix it for you. They aren't the fastest service guys in the world, but they are very friendly and definently know their craft. And they are cheaper than Neumann.

Just my two cents.


Cheers
Fred

 

[Gus]

Fred

Thanks for the Gefell repair information.

 

[3phase]

a friend of me just developed a mod for the cmv 563... even compared to perfect condition one its an awesome boost...

of cause very expensiv capaciators play a role there...

I usually prefer them un altered...but his mod really is a boost beyond the matter of taste.

 

[synthi]

Can you describe the mod?

Synthi

 

[3phase]

no..he is a bit secret about it..he just optimized some values and used some extra vagant expensiv components...
He made quite a few mods..the final one is really a step forward while his earlier ones was more a matter of taste for me..and as long its that i allways would stick to the vintage design... I had my own cmv´s refurbished with original parts instead recapping with new caps and higher capsule resistor values just to keep the look original... But his mod brings out more detail better seperation of different instruments... i havent heard it on a voice yet but it did a brillant job on an acoustic guitar... all scrap from the plec just gone ...smoother and more detailed would describe the sound of the mod...

I think his problem is that he has to remake the bottle because it dont fits after the mod anymore ;-)...
so nothing for collectors

 

[saint gillis]

Hello CMV 563 users and tweakers, I've read the thread and opened here a specific thread about noise :
Neumann Gefell CMV 563 - quite noisy !