Group Buy Interest?

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kessel said:
I'm looking pretty hard at the ACM-310 SDC. I was wondering if the tube was in a socket or if you have to solder to replace it? Also is the 6J1B-Q tube the same as the 6J1B? I couldn't find 61JB-Q tubes online, but I found a couple of places selling 6J1B tubes.
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I was wondering about this issue too...
 
Yes all the tube mics have "socketed" (is that a word?) tubes.
 
Amount of Gain Needed on Chinese Ribbons?

I might as well post this here. I've been wondering about something: it's always mentioned that ribbon mics need more preamp gain to push them, especially with quiet sources. How much is enough?

The preamp I have right now (an Audio Buddy) tops out at 60dB, and I have no idea whether that is enough for some of the mics in the buy...more would be better, I'm guessing. Any ideas, based upon prior experience with mics that are similar to those listed?

Thanks!
 
isn't the audio buddy the one that has insufficient phantom?
 
It's had enough for the condensers I've used--but the ribbons shouldn't need phantom, I think. They just need more oomph in the gain stage...
 
Chris Long said:
It's had enough for the condensers I've used--but the ribbons shouldn't need phantom, I think. They just need more oomph in the gain stage...
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Yes, phantom power is actually harmful for ribbons.
Also, input impedance is very important for a ribbon. Too low impedance the high frequencies drop of, and you need even more gain because the mic will be loaded down. Three or four times the output impedance of the microphone is a general rule of thumb for the input impedance of the preamp. Higher input impedance is better than too low, but usually there is a sweet spot around three to four times.

I just looked, the ribbons are 250ohm, and the audio buddy is 1kohm. So that's just about perfect.
 
I think I might have to get a stereo pair of ACM-6802T's to try as stereo room mics for drums... Mmmmmmm.
 
Chance,
Are there any updates/is anything more known about when the start of the GB window will be? Thanks!
 
tarnationsauce2 said:
Yes, phantom power is actually harmful for ribbons...
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Yeah, phantom power + ribbon mic = broken ribbon mic. There are actually a few ribbon mics that are designed to handle phantom power in case its flipped on while the mic is hooked up, but for the price of these ribbons i'm almost positive they aren't protected.
 
The main problem would be having the polarity reversed in your mic cable.
I'm still waiting for the final questions to be answered from China.
 
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kessel said:
Yeah, phantom power + ribbon mic = broken ribbon mic. There are actually a few ribbon mics that are designed to handle phantom power in case its flipped on while the mic is hooked up, but for the price of these ribbons i'm almost positive they aren't protected.
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No, that's simply not true. Phantom power applies the same voltage to both pins 2 and 3 of the XLR, so it has no effect on the ribbon. In fact, a steady state DC voltage wouldn't pass through the mic's transformer even if it were applied to just one side of the XLR.

The real risk of phantom power to a ribbon mic happens when you plug in the mic while phantom power is already turned on. In that case, you may accidentally connect pin 3 slightly before pin2 (or vice versa), which can mean that there is a brief moment where the voltage reaches only one side of the mic's transformer. That "pulse" is transferred through the transformer to the ribbon, which can damage it. Fortunately, in that direction the transformer is acting as a "step down" device, so the voltage spike is actually reduced. Nonetheless, there is a risk in that situation.

But in a steady state, phantom power poses no risk for a ribbon mic. It's certainly a good idea to avoid phantom power with a ribbon mic to avoid taking any chances, but the risk isn't as great as you make it seem.
 
Well I apologize for the scare mongering about phantom and ribbons. I looked around on the net and it actually seems to be some what of a debate. Either way it still sounds best just to avoid it.
 
fwiw there are also several ribbon mics now that actually require, not just "handle", phantom power in order to operate including, but not limited to, a couple of royers, a sonotronics mic (i believe), and the karma k-6. i only have the pleasure of owning the k-6 and it's an awesome mic. i would love to pic up some ribbons through this buy as well, and i have a nady rsm-2 w/ headbasket mod in transit to me right now and am eager to make some passive/active ribbon comparisons.
 
kessel said:
I looked around on the net and it actually seems to be some what of a debate. Either way it still sounds best just to avoid it.
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It is wise to avoid it. There's no debate, though, other than perhaps between those who understand the issue and those who don't. It's pretty clear cut.

Some older ribbon mics (going back, say, 50 years) use a transformer with a grounded center tap. That can add some additional complexity to the issue, but even in that case, the mic is safe in normal usage. The risk to a ribbon mic is due to a pulse, not a steady current. A steady DC voltage cannot pass through the transformer.

(Of course, it may damage the transformer by magnetizing its core, but that is a different issue. And even that can't happen with a standard phantom power configuration because the same exact voltage is applied to both pin 2 and pin 3.)
 
Sorry for the delay guys but I wasn't recieving any replies from the manufacturer. I just learned why. They were at the show in Germany. I should be up to date this week
 
Hey
Can someone put together some sort of poll to get an approx count of each mic that might be purchased? I need to get some idea of interest
 
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