• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join free Log in
    Want zero display ads or expanded classifieds tools? Compare plans.

Double Bass Phantom power issues.

basmansam

basmansam

Gold Supporting Member
Feb 11, 2005
703
1,485
Vermont
#1
I purchased a Clarus 4 last year. Works great with UB and BG.
I purchased an AKG C411 condenser mic that requires phantom power.
When I plug it into the Clarus 4 with the phantom power on, it doesn't work. I purchased a rodyweil mic preamp for it too, doesn't work either. What am i doing wrong?
Thanks,
-Sam
 
#2
Try a dynamic mic. If that works, check the ground on the mic cable. Phantom doesn't work without continuity to ground.

1736048864545.png


Pin 1 of the XLR is ground. Measure from pin 2 to pin 1 for 48V. Measure from pin 3 to pin 1 for 48V. If the 48V is not present, the amp is not putting out phantom power. Does the indicator come on when you engage phantom? The manual suggests the indictor is fed directly from phantom power.


Did you try the other channel?
 
  • Like
Reactions: basmansam
#3
basmansam said:
I purchased a Clarus 4 last year. Works great with UB and BG.
I purchased an AKG C411 condenser mic that requires phantom power.
When I plug it into the Clarus 4 with the phantom power on, it doesn't work. I purchased a rodyweil mic preamp for it too, doesn't work either. What am i doing wrong?
Thanks,
-Sam
Click to expand...
Was the mic new or used? The thin wire on the C411 is not terribly sturdy, especially where it connects to the mic. If it doesn't work with either preamp, that's not a good sign for the mic.
 
  • Like
Reactions: basmansam
#4
Wasnex said:
Try a dynamic mic. If that works, check the ground on the mic cable. Phantom doesn't work without continuity to ground.

View attachment 7116552

Pin 1 of the XLR is ground. Measure from pin 2 to pin 1 for 48V. Measure from pin 3 to pin 1 for 48V. If the 48V is not present, the amp is not putting out phantom power. Does the indicator come on when you engage phantom? The manual suggests the indictor is fed directly from phantom power.


Did you try the other channel?
Click to expand...
The Clarus doesn't have XLR connection. It's has a 1/4" with the round connector-same as the speaker connection.
I'll try ohm-ing the inputs. I'll try checking the C411. Thanks for your response.
 
#6
basmansam said:
The Clarus doesn't have XLR connection. It's has a 1/4" with the round connector-same as the speaker connection.
I'll try ohm-ing the inputs. I'll try checking the C411. Thanks for your response.
Click to expand...
I'm confused. The Clarus 4 does, indeed, have XLR inputs....

1736086097985.png


....and, although I hesitate to use the word "never," I have never come across a piece of equipment that provides phantom power for condenser microphones that does NOT do so via an XLR jack, nor seen one that does so via a 1/4" jack (which would have to be a TRS jack with specific protections built in to prevent shorts upon insertion of the associated plug).

Can you post a pic of the Clarus 4 you're using that doesn't have XLR inputs?
 
  • Like
Reactions: basmansam
#11
basmansam said:
My mistake, it’s a 601A
Click to expand...
basmansam said:
Wow!! I didnot know that!! I plugged in the C411, it works!! Thank you every one for your help. much appreciated!!
-Sam
Click to expand...
Yup, to be clear for other readers, that's a combo-jack. You can plug either 1/4" phono or XLR into it. When phantom power is supported, the XLR jack has the support for phantom power.

Regarding 1/4" phono cables, theoretically a stereo (TRS, two channel) 1/4" phono plug could support phantom power (but is generally not intended to), while a mono (single channel) 1/4" phono plug theoretically would not be able to support phantom power. Once again, our friends at Gullihur Music have a nice discussion of the various 1/4" phono cables and their use.
 
  • Like
Reactions: Ric Vice and basmansam
#12
Don Hergert said:
Yup, to be clear for other readers, that's a combo-jack. You can plug either 1/4" phono or XLR into it. When phantom power is supported, the XLR jack has the support for phantom power.

Regarding 1/4" phono cables, theoretically a stereo (TRS, two channel) 1/4" phono plug could support phantom power (but is generally not intended to), while a mono (single channel) 1/4" phono plug theoretically would not be able to support phantom power. Once again, our friends at Gullihur Music have a nice discussion of the various 1/4" phono cables and their use.
Click to expand...
Thanks for your input. I thought it was a speakon/1/4" input. I'm not familiar with Acoustic image amps until this past yr. I still have my 25yr old WW Blue Light ultra, plus a couple polytone combos.
 
  • Like
Reactions: Ric Vice and Don Hergert
#13
As a side note, TRS with phantom power is not that uncommon, guys and gals. Acoustic Image even had some amps like that. I think they came with a TRS XLR adapter. Notice the 48V phantom power buttons on both channels for the SL-2. I think Euphonic Audio might have done this at some point, too?

It's not that often that you see 48V with a TRS connector. Typically it's something less. The Headway EDM-1 H.E. has options for 9V and 18V, for example, the idea being that the 18V should work with most condenser mics, and 9V for mini-mics/electret condensers, I think. I have powered the C411-PP with 9V before using an LR Bags MixPro. The PP came with an adapter that reduced the voltage from 9V to ~1.5V IIRC, which was just enough for the electret condenser. With 48V, it would step down to ~5V.


1736094530736.jpeg
 
  • Like
Reactions: Don Hergert, basmansam and Wasnex
#15
Wasnex said:
I believe power distributed over a 1/4" TS plug is called Tonader power, T-Power, T-12 or, AB Power. Tonader Power (T power) – IPS
Click to expand...
And it is typically used for electret capsules with two contacts only that have the FET on board (usually the cheaper ones and some better ones too).
The decoupling be of signal and power is done by a resistor (for power) and a capacitor (for the signal).

But some (better) electret capsules don’t have the FET on board and need an external one or the same electronics of a externally (phantom) powered condenser mic.
 
  • Like
Reactions: MuseChaser, basmansam, Don Hergert and 1 other person
#16
Here to confirm that the Acoustic Image Series III 601 IA amp uses combo inputs, like Neutrik NCJ9FI-V-0, which support both XLR and 1/4" connectors. On these amps, the phantom power is only supplied to the XLR pins, The central 1/4" input only uses tip and sleeve and does not provide power. The Neutrik supports TRS, but these amps only use the tip and sleeve.

On the Series 4plus Clarus SL-2, both of the 1/4" inputs are TRS and do indeed provide phantom power. The amps were originally supplied with one adapter, which converted female XLR into male 1/4" TRS. The 1/4" inputs were used on this model because of the small physical size of the SL series front panels.
 
  • Like
Reactions: Wasnex and Don Hergert

Latest posts

Top Bottom
Back