Group Buy Interest?

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Marik said:
I did not use Edcor. Although reasonably priced, what turning me off is an advertised high primary DC resistance (0.4 Ohm, IIRC). If true, it can lead to a high noise (hiss).
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Wow. That's eight times the .05 ohm that you'd get if you run the four Lundahl LL2911 primaries in parallel (or with the LL2912, which is prewired in that configuration).

I was going to suggest:

http://www.sowter.co.uk/acatalog/SOWTER_MIC__LINE_INPUT_3.html#a257

but even that is a quarter ohm.

I'm a big fan of the Lundahl LL2911 (and presumably the LL2912). I rewired my Nady RSM-2 with one and it made a world of difference in the sound.
 
I had a thought... a question for the electronic gurus.

See... I'm paranoid about turning on the power to one of these ribbons. :o

Isn't there a little something we can wire into the Mic to Protect it from phantom power? I think I've seen a few ribbon mics advertised that they're "safe" from phantom power.

Any idea thoughts for someone interested in protecting their mic from themselves? :D
 
A diode will not work because it will rectify and distort the heck out of the audio.

Just remember this: It's NOT the smooth phantom DC that hurts the mics.
It's AC! An intermittent "crackly" connection is actually spiking DC at the transformer. Even though a transformer blocks DC, the spiking voltage (i.e. 'change in voltage') looks like AC to the transformer and it allows that changing voltage to see the ribbon element (pop - stretch/tear).

Stiffening capacitors could be great. They would create a time constant allowing the dc voltage top have to ramp up and they would retain some dc voltage for quick intermittent bursts, like with a faulty connector.
Unfortunately they won't work because they'd degrade the audio signal as the caps would act as a LPF sending all those precious high frequencies of the ribbon to ground.

The most cost effective solution is a balanced non-grounded center tapped output transformer.

Interestingly enough, that is how most all modern ribbon microphones are made. There are other, more fail-safe ways of doing it. With an internal head amp. But that will increase production costs and complexity of the mics quite a bit.

Things to avoid:
Plugging ribbon mics into patch bays with phantom power.
Faulty XLR cables / connectors.
Black outs / brown outs with unregulated phantom power from your mic pre.
Plugging / unplugging with phantom power on.

Basically, under normal conditions phantom power will not hurt these ribbons. It's just wise to turn phantom power off because it is unneeded and gives an extra level of protection.
 
You ARE going to document the xfrmr swap in the "3" aren't you?
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i could totally do that. to be honest, i won't really know what the hell i'm doing, but with a $55 mic, i figure i can take a shot and see how it turns out. if i botch it, i can always send it off to MJ for some special treatment. :D

i'm working on the assumption that all one has to do is remove the old transformer, and solder the new one in its place. if i'm wrong on that one, somebody chime in and set me straight!!
 
Ironklad Audio said:
i'm working on the assumption that all one has to do is remove the old transformer, and solder the new one in its place. if i'm wrong on that one, somebody chime in and set me straight!!
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I'm sure you'll hear from someone in the 98% of board members who are more qualified than I am, but to warm up for this yesterday, I did the "transformerless" mod to one of my old SM58s - things came out OK. From the perspective of a newb, the one thing I fear now is that the number and color of wires coming out of the new transformer will be different from those of the old (or worse, one wire will have the same color but a different function). Also, make sure to observe and write down what all the connections are prior to cutting/desoldering anything.
 
Ironklad Audio said:
i could totally do that. to be honest, i won't really know what the hell i'm doing, but with a $55 mic, i figure i can take a shot and see how it turns out. if i botch it, i can always send it off to MJ for some special treatment. :D

i'm working on the assumption that all one has to do is remove the old transformer, and solder the new one in its place. if i'm wrong on that one, somebody chime in and set me straight!!
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It's pretty straightforward. As antichef said, document everything before you start (a digital photo would work.)

Make sure the transformer you order will fit physically in the mic. If it has a dimension (especially a diagonal one, if it's not in a round can) greater than the mic's inside diameter, it won't work. You also may have to do some fiddling to mount or stabilize a different size transformer inside the mic.

The transformer will come with a pinout or lead diagram, either printed on the transformer, or on a spec sheet with lead identifying data. Just hook the input (or primary) leads to the ribbon side of the mic, and the output (or secondary) leads to the connector side.
 
Well I'm in Chicago and it's cold and wet. There is a large order going out on Monday. Fexex sends E-mails to you when the driver scans it when they pick up. Also fedex was the cheapest shipping to Austrailia $299.00 UPS was over $400.00, and USPS would not ship because it was too big
 
is anyone here wanting to sell their 583? at work, we'd really like to pair ours up.
 
i saw those listed as the STOD today...

i would consider getting one, but a)i'm broke, and b)it's got the 6 micron ribbon
 
Well, I retensioned one of my ACM-3’s today. It wasn’t that bad of a job but, wow, that ribbon is thin. It was thinner than paper. Even way thinner than household aluminum foil.

It reminded me of burnt paper. You know how light and dainty paper ash gets after it has been thoroughly burned? The ribbon didn’t crumble when touched, but it felt that lightweight. As if it wanted to float away if I breathed on it.

That Q-tip trick really worked well too. It took me several tries to get it to land straight but I finally got it. Cool! I have three more ribbon mics to check out yet.
 
tried to fix the ribbon myself

OOps! NOw it would cost 125 to get it reribboned... Be really careful if you try this at home
 
Chris Long said:
Are you taking pics of any of this? I'd be curious to see some of the action, if so, since I may be doing the same thing in the future...
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No, I didn't take pics but I have three more mics to check out. If they need done too then I will take pics for you. There are some pics here already a few (6 or 8?) pages back.

The ribbons are real thin like that gold flake (or gold leaf?) stuff they use for designs and patterns on custom paint jobs like Harley tanks. It is so thin you can't even feel it between your fingers.
 
Big Kenny said:
OOps! NOw it would cost 125 to get it reribboned...
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Did you tear it? Yikes!

Big Kenny said:
Be really careful if you try this at home
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I used a razor blade and gently and slowly worked it under the end of the ribbon. I kind of wiggled or walked it under so as to pry upward slightly every few hundredths of an inch. Make damn sure the blade is under it proper and angled downward or you may slice into it. It's a bit like surgery. With the right persuasion, it will slowly release its grip.
 
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