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Need Phantom Power Blocker

ArtechnikA

ArtechnikA

I endorsed a check once...
Feb 24, 2013
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www.artechnika.com
#1
Harp player brought out some ancient Shure mic.
Sounded great - until I switched on the phantom power for the drum overheads.
Big horrible popping noise sounds; clearly _that_ doesn't work...
My Soundcraft mixer/audio interface has Phantom On/Off - nothing switchable per-channel.
Searches at Sweetwater and MusiciansFriend turned up nothing.
Amazon has -one- and they want $50 for it...
Wikipedia suggests that a 1:1 transformer will block it - is that what's in the $50 widget?
First time I've needed this in 10 years, and only on one channel.
I've got a big box of condenser mikes and phantom-powered DI's; I'd prefer not to go buy another big box of individual phantom power supplies so I can continue using those devices.

Is there a better alternative ?
 
#7
Paulabass said:
Go into a cheap Behringer mixer, set to unity, and use the line in for that channel.
Click to expand...
Interesting...
I already have a cheap Yamaha mixer which has the advantage of being already paid for...
But I also have an ART tube preamp that I bet would also do the trick, and might add some nice harmonic color besides.,,
Thanks !
 
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#8
The Ebtech Hum Eliminator XLR is a pair of 1:1 isolation transformers. Not sure what sort of signal to noise ratio your going to get with a mic level signal. It's useful problem solving gadget to have if it doesn't work out for the mic. Hum Eliminators

upload_2020-5-25_3-25-20.jpeg
 
#10
thumbknuckle said:
In a pinch you could wire two passive direct boxes in series and end up with a 1:1 transformer. I've never actually tried, but it seems like it should work.
Click to expand...
thought about that, doable with an XLR turnaround to go into the "wrong end" of the first DI box

maybe not ideal fidelity, but "harmonica mic" does not spell "hi fi reproduction" to me anyway
ArtechnikA said:
Harp player brought out some ancient Shure mic.
Click to expand...
is this mic even XLR?

sounds like the harp player is going for a funky blues tone, in which case they'd be better off sticking that mic into a little guitar amp and you mic'ing that
 
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#11
walterw said:
is this mic even XLR?
Click to expand...
I plugged it into my board myself. Yup. I donno what he had upstream of the cable he handed me. Based on what I've read about dynamic mics and phantom power, I wouldn't be surprised if there weren't a 1/4" to single-ended XLR adapter somewhere in there...

sounds like the harp player is going for a funky blues tone, in which case they'd be better off sticking that mic into a little guitar amp and you mic'ing that
Click to expand...
No, he's a funky blues player, going for a Mickey Raphael Willie Nelson tone. We're trying for a 'quiet room' recording environment with everyone direct, but it was less than successful on many fronts. Got 3 weeks until we're doing video recording for a webcast to figure it out. Bad enough 'Willie' insists on running his acoustic through an amp for "the Willie tone." And needs it loud, which means the vocals are loud, which means everybody else turns up... Trying for a headphone/in-ear session but I'm not holding out much hope...
 
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#13
DWBass said:
This or have him use one of your mics.
Click to expand...
That's always an option, but A) I want to be able to put him in charge of his tone if possible and B) these days, we're trying to be smart about droplet transmission. He's offered to use a SM58 which we can try to see if he'll like the sound. This is recorded, not live, so there are still post-process options....

Can his mic use a battery as an alternative?
Click to expand...
It's dynamic - no power supply required. I think it's a single-ended (1/4" TS) design originally intended to be plugged into an amp. If that's the case, I don't know how his conversion to XLR is wired, but it's pretty unhappy with the phantom power.

I think I'm going to try the tube preamp first, and if that doesn't work (we'll know right away) I'll take him up on his offer to use his SM58.

Vocalist is using one of my 58's but with a washable foam windscreen.
 
#14
ArtechnikA said:
That's always an option, but A) I want to be able to put him in charge of his tone if possible and B) these days, we're trying to be smart about droplet transmission. He's offered to use a SM58 which we can try to see if he'll like the sound. This is recorded, not live, so there are still post-process options....

It's dynamic - no power supply required. I think it's a single-ended (1/4" TS) design originally intended to be plugged into an amp. If that's the case, I don't know how his conversion to XLR is wired, but it's pretty unhappy with the phantom power.

I think I'm going to try the tube preamp first, and if that doesn't work (we'll know right away) I'll take him up on his offer to use his SM58.

Vocalist is using one of my 58's but with a washable foam windscreen.
Click to expand...

Is it one of these?
upload_2020-5-26_16-22-15.jpeg


I remember using one with our band when I was in Germany. It hummed like crazy. I can't believe I didn't suggest this right off the bat. Try a line matching transformer like a Shure A95U.

upload_2020-5-26_16-25-4.jpeg


A95U - Line Matching Transformer (Male XLR to ¼” Male Plug/Female Jack)

If the mic has a 1/4 end, it's high Z, so you need a line matching transformer instead of an isolation transformer. The line matching transformer will match the impedance.
 
#15
Wasnex said:
Is it one of these?
View attachment 3844670
Click to expand...
No.
That's kinda what I was expecting.
( and BTW - the Bulletini [ Bulletini Harmonica Microphones by BlowsMeAway Productions ] is quite popular among harp players here locally... )
He said it was a Shure (if he said the model number I didn't catch it) given to him personally by Paul Butterfield.
I've never seen anything like it. Almost looked like a podium mike from an old church - not very ergonomic. Sounded good...
No hum, no hiss.
If he'd mentioned it was a high-Z mic I'd have been happy to accommodate -- the mixer has half-a-dozen Hi-Z inputs...
 
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#16
ArtechnikA said:
That's always an option, but A) I want to be able to put him in charge of his tone if possible and B) these days, we're trying to be smart about droplet transmission. He's offered to use a SM58 which we can try to see if he'll like the sound. This is recorded, not live, so there are still post-process options....

It's dynamic - no power supply required. I think it's a single-ended (1/4" TS) design originally intended to be plugged into an amp. If that's the case, I don't know how his conversion to XLR is wired, but it's pretty unhappy with the phantom power.

I think I'm going to try the tube preamp first, and if that doesn't work (we'll know right away) I'll take him up on his offer to use his SM58.

Vocalist is using one of my 58's but with a washable foam windscreen.
Click to expand...
My bad. I misunderstood. I was thinking HIS mic was a condenser mic. How about your overhead condensers.....can they be battery powered?
 
#17
DWBass said:
My bad. I misunderstood. I was thinking HIS mic was a condenser mic. How about your overhead condensers.....can they be battery powered?
Click to expand...
There are phantom power supplies/power injectors. Good ones are $50-100/channel.
I've got 14 condenser mikes and 4 phantom-powered DI's.
Since there are so many good alternatives for dealing with the one component that's presented a problem, that's the component I want to address.
I'll know in 10 seconds if the isolated preamp will work; if it doesn't, we'll swap in a SM58 and call it good.
I'm glad it happened to me, in a technical rehearsal, rather than the BL's BIG board, on gig-day. He's a nice guy and technically competent, but he's out of his depth on sound.
 
#18
ArtechnikA said:
No.
That's kinda what I was expecting.
( and BTW - the Bulletini [ Bulletini Harmonica Microphones by BlowsMeAway Productions ] is quite popular among harp players here locally... )
He said it was a Shure (if he said the model number I didn't catch it) given to him personally by Paul Butterfield.
I've never seen anything like it. Almost looked like a podium mike from an old church - not very ergonomic. Sounded good...
No hum, no hiss.
If he'd mentioned it was a high-Z mic I'd have been happy to accommodate -- the mixer has half-a-dozen Hi-Z inputs...
Click to expand...

It would be beneficial to find the specs on the mic if possible. Then you could figure out whether you would be better off with a 1:1 transformer like the Ebtech or a impedance matching transformer like the Shure.

A lot of harp players like to plug into a small tube amp so they get some distortion. Not sure plugging straight into a mixer is going to get you where you want to go. I believe the idea is to hit the front in of the amp hard enough so it breaks up a bit. You might try running the mic through an OD pedal like TS9 or BD2 first. Or maybe running the pedal in the channel insert if that is an option.
 
#19
Wasnex said:
It would be beneficial to find the specs on the mic if possible. Then you could figure out whether you would be better off with a 1:1 transformer like the Ebtech or a impedance matching transformer like the Shure.
Click to expand...
Maybe. I'll try to get a model number, but I doubt even the current owner knows the actual specs.

A lot of harp players like to plug into a small tube amp so they get some distortion. Not sure plugging straight into a mixer is going to get you where you want to go.
Click to expand...
Yeah - that's the blues approach. And it's valid in that genre, but this ain't the blues. It's Willie Nelson - jazz/country.
e.g.

harp solo at about 2:10



In the short term, where I want to go is a quiet room for live recording. I can stick a small amp in an adjacent room (where I'd like to put Willie's guitar amp...) but it sounded fine direct. No problems with the sound. I just want the mic to be able to play nice with the other equipment...
 
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