Zoom H4 not usable with 48V phantom powered mics?
 

Just recently I tried to use Zoom H4 portable recorder with my AKG blueline mics and I got some horrible hissing when gain was set anything than minimum.

Is this normal that when phantom power is turned on the silence turns into some kind of hi-tone hiss and peeping when access led lights up?

Damn, even my $5 mini-plug shotgun sounds better on H4 than the $500 shotgun on 48V.

Is this the reported peeping problem due the cheap capacitors in the circuitry of Zoom H4? Should I always carry external batteries to give it proper power so it won`t introduce the hiss? So much for the portable XLR 48V recorder...

Thanks in advance,
T

I've read several places where the low level beep with the flashing access light is a known problem with the H4. Zoom's tech support's suggested fix is to run it on AC when possible or on an external battery pack. As for a the hiss, that sounds like a level setting problem. AKG rates their Bluelines as operating with phantom supplies as low as 9 volts so I doubt it's due to an insufficiency in the phantom power.

To start with, did you get good levels on the AKG at gain setting: H, M or L?

The H4 beeping problem shouldn't be a concern in normal recording situations, and the ambience noise would certainly cover it. You are reporting hissing, which might be related to other things, like a manfunctioning mic, H4 or cable.

I have been using AKG Bluelines for a long time, and have never had any problem. They work with any voltage. Have you tried the AKG on another preamp?

To see if the problem is supply related, power the H4 with the external supply and see if the hissing persists.

Please don't be offended, but are you experienced with balanced connections and all that?


Carlos

Carlos, yes as you can assume from my "damn" and "$5" I`m not an experienced sound engineer but have learned the basics back in the college with appropriate equipment.

Any other mics I`ve used have had batteries as well as balanced connections so I could switch between batt and phantom and the hissing only occurs on H4 when I turn phantom power on - less with 24V and more with 48V.
As I don`t have any appropriate PSU with the tip being "-" to power my H4 I´m left with the paranoia generated on the net and my medium to high gain and volume settings.

So far it seems that it`s exactly the problem that is acknowledged by Samson as "use the included power supply to get rid of the noise when on phantom".

BTW Carlos, do you have any experience on booming the CK98, should the boom op be worried about the direction of the vents on the top of the module?

Thanks,
T

I never said sound engineer. But you need to know some basics on phantom power and balanced connections.

So you used the AKG at 24v and it worked fine?

Once again: have you tried the AKG on another mixer or supply?

There's no need for any paranoia. The H4 should bring an AC supply: use that for your tests.

The AKG should work fine at mid gain, and volume settings in the middle.

No one reported any noise when using phantom. Go here and put your question there:

http://www.2090.org/zoom/bbs/viewforum.php?f=15

Not really. Worried about what? As any hypercardioid mic you should point it to your subject all the time.


Carlos

No need to worry about the direction the side ports are pointed as long as none of them are blocked off by a mic mount or something. The vents sort of tune the tube so that off-axis sounds are cancelled out but it's the hole at the end end of the mic tube that points directly toward the desired sound source and that's the aiming that matters.

AKG CK98 is quite different from the traditional shotguns as it does not have openings or hole in the end...
... but it works so far.

T

I don't have one to look at in person but the photos on the AKG site look like the end of the tube is enclosed by metal bars curving over a dark coloured fine mesh screen. Are you saying it's actually solid under the bars???

I was almost going to say you were right, when I remembered I had one to look at. Toenis is right. The end of the tube is solid.

Sound get through the side vents and on one side only.

That doesn't change anything though. The point of the mic should be directed to the subject mouth, as on any directional mic. The vents were designed to make it directional, so trust them. It's a great capsule.

Even if my favourite is the CK93. Great for music and dialogue.



Carlos