Topic: Will this set up work?

[KooterB]

Hi, thanks in advance for any info.
Can you connect mics to a phantom power
supply and then straight to a Edirol R-09.
Or do I need a preamp?
This is the setup I'am looking at:
M-Audio Pulsar 2 matched mics to a Arts phantom 2
power supply, connected to the R-09 with a Hosa stereo  xlr to mini-plug.
Will this work?
Thanks again,
KooterB

[setboy]

What kind of music will you be taping?

[KooterB]

Mostly open mic bands, some indoor some, out door.
Electric and acoustic. I just need to know
if this type of setup is compatible?

[setboy]

I'm not real sure about it. But if you want to tape open mic and acoustic stuff you will want a pre amp

[KooterB]

thanks

[DSatz]

KooterB, when trying to arrange a hookup like the one you propose, the problem you come up against is that the microphones were designed for connection to balanced inputs, and you're connecting them to unbalanced inputs. There are several possible ways of dealing with this problem. To know which one(s) will work at all, or which one will work best, depends on the particulars of your microphones and your phantom power supply.

The only technique that always works is to use a transformer at the input of the unbalanced device. But good transformers tend to be expensive. Also, they're not necessarily a complete solution if you're using the microphone inputs of the R-09, since if its plug-in power can't be shut off as a control option, it would need to be blocked (with series capacitors) from flowing through the secondary windings of the transformers.

--best regards

[drewloo]

Also, they're not necessarily a complete solution if you're using the microphone inputs of the R-09, since if its plug-in power can't be shut off as a control option, it would need to be blocked (with series capacitors) from flowing through the secondary windings of the transformers.

You can shut off the plug-in power on an R-09 via the menu.  I've gone Peluso>Denecke ps-2>R-09 and it worked.  I think the fact that the Peluso's run pretty hot helped a bit, but still had to run the r-09's gain pretty high.  I was running line-in, however, but could have (perhaps should have?) gone mic-in.

[Belexes]

You can shut off the plug-in power on an R-09 via the menu.  I've gone Peluso>Denecke ps-2>R-09 and it worked.  I think the fact that the Peluso's run pretty hot helped a bit, but still had to run the r-09's gain pretty high.  I was running line-in, however, but could have (perhaps should have?) gone mic-in.

I ran C4's > PS-2 > Lo-Hi Transformers > R-09 (line-in)

The transformers really did the trick in this chain.  I asked before I ran this to the board here and some wise people said to stay with line-in given I had those transformers. I didn't have to run the R-09's gain so high.

[KooterB]

First thanks for all the input.
It does work this way, the ART phantom 2 has balanced
inputs and out puts, and I do have the mic power off in the R-09.
I got it to work, but the sound levels are real low, but haven't
got to use it in the field yet.
I guess a mic preamp would be what I need for low volume shows?
Most of the shows I'll be recording will
be loud rock, so I hope to be ok.
Thanks again, 

[Belexes]

Pre or the transformers should do the trick.

[DSatz]

I'd just like to explain a little about transformers. You are connecting a balanced signal source (your microphones and phantom power supply) to unbalanced inputs (your recorder). This is a problematic situation from the beginning. Transformer function number one is to be a solution to that problem--letting the signals from your microphones get through to the recorder at all.

With some types of microphone and phantom power supply, the solution to this problem can be simpler because you can use a plug adapter at the input of your recorder which shorts (directly connects) one of the two signal leads from each microphone to ground on its respective channel. That's easy enough--but it only works if the microphone and the phantom power supply happen to have three particular circuit characteristics. If one of the three characteristics is not present, you may get no recording, a distorted recording (or a recording that is limited to much lower sound pressure levels than your equipment could otherwise handle), drastically shortened battery life if your phantom supply is battery-powered, and/or possibly severe damage to the microphone, recorder and/or the phantom supply.

Recording industry standards are concerned mainly with connecting balanced equipment to other balanced equipment, which makes two of the three issues non-issues while the third one becomes just a "maybe." Even if the standards said that these three characteristics should always be present, some manufacturers probably would ignore the standards anyway, or declare their own "standards." So the main advantage of using an input transformer is that it will work regardless of the presence or absence of those three circuit characteristics--it's the only safe and reliable "one size fits all" approach. (Otherwise I would have suggested the simpler way.)

The second advantage (or use) of an input transformer is that it provides what is called "common mode rejection" at the input to an otherwise unbalanced recorder. This provides substantial immunity to interference, hum and hash from power and lighting cables, Blackberries, etc., which an unbalanced recorder (input) would otherwise be vulnerable to. If you've ever had a recording ruined that way, you'll know why that's important. If that has never happened to you (yet), you may not care (yet), but I predict that some day you will.

The third potential (no pun unintended) advantage is an "if" situation, and it's the real reason I'm writing all this. In this discussion thread you can see one or more people who are using transformers as a way of adapting microphone signals to the line inputs of their recorders. In almost all cases they are using what are known as "step-up" transformers to do this. But not all transformers are "step-up" transformers, so it's important to be aware of the distinction. If you use a "1:1" transformer (one that doesn't step up the incoming voltage), you may well have to connect your microphones to the microphone inputs of your recorder in order to get enough gain (amplification within the recorder) for your recording.

Please note: I'm not saying that using a step-up transformer is a better choice than using a 1:1 (non-step-up) transformer. There can be real problems with step-up transformers, and I've already said more than enough for one message so I don't want to go all into that right now. I'm just saying: Be aware of the distinction, and don't assume that all transformers will let you connect your microphones to your recorder's line inputs. (Nor is it necessarily better if they do allow this; in some cases it can be, while in other cases it definitely isn't.)

--best regards

[KooterB]

Thanks DSatz for the comments on transformers.
What are your thoughts on this item:
BeachTek DXA-2:

http://beachtek.com/dxa2s.html

It has two transformer balanced XLR connectors and
One unbalanced mini plug, it's passive, too.
Thanks again
KooterB aka Fred 

[DSatz]

> What are your thoughts on this item: BeachTek DXA-2

It certainly looks nice, the gain controls could be useful, and the brochure uses many of the right words in the right places. I get the feeling, though, that they're leaving themselves "wiggle room" to use transformers from any number of different suppliers, possibly to save costs. There's a place for saving costs in most equipment, but audio transformers can vary enough to make a real difference in the quality of your recorded sound. The +/- 3 dB frequency response specification is the giveaway--there's really no reason for such a wide tolerance with appropriately chosen, first-quality audio transformers, which can be within 1 dB from top to bottom.

Many manufacturers of high-quality preamps that have input transformers will say quite openly whose transformers they are using; they bank on the good reputation of the transformer manufacturer. For example, both John Hardy and D.W. Fearn (makers of very high-end studio preamps) use Jensen transformers, while Sound Devices equipment uses Lundahl. Those are currently the two leading names in audio transformers. These preamp manufacturers would never mess around with other, unknown transformer suppliers; it would harm their reputations.

Personally I use Jensen "ISO-MAX" boxes for most balancing or unbalancing of audio signals. You can see the whole product line on http://www.jensentransformers.com/iso_aud.html if you're interested. I have no connection with them other than as a customer. The MS-2XX is the model that would be most relevant here, I think, and it can be ordered with unbalanced output connectors such as RCA sockets.

Lundahl also has in-line 1:1 microphone input transformers with XLR inputs and a variety of output connectors. But as of the last time I got a price quote from the U.S. distributor (they're made in Sweden), a pair of them cost more than one two-channel Jensen box--and I actually believe that the Jensen transformers are slightly better, especially if you record music that has very low frequencies and/or if you use high-output condenser microphones and the music reaches high sound pressure levels at your microphones.

In all fairness, I should admit that I'm a bit snobbish about the transformers I use, and that less expensive ones can actually be quite OK sonically. I just enjoy using what I feel is the best available--a holdover from my past life as an audiophile, perhaps.

If you do decide to use transformers without active output circuitry, they must be kept close to the inputs of the device that you're sending the signals into--the cables at their outputs must be kept quite short in order to avoid capacitive loading and consequent high frequency losses.

--best regards

[KooterB]

Thanks for the recommendations and input,
it is much appreciated.
Fred