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Rolls PM351 questions

stratovani

stratovani

Nov 18, 2007
3,653
1,131
Spencer, MA, USA
#1
I'm looking to make a wired in-ear monitor system for myself. Lots of times I have a bit of difficulty hearing myself play while at a gig, even with ear protection, so after doing my research on YouTube I decided to use a PM351 as the cornerstone of a wired in-ear system. A couple of days ago I won an auction for a PM351 and I then downloaded the instructions for its use. This brought up a couple of questions for me which I hope someone here can answer.

1. For the Instrument Input it states "1/4" TRS stereo jack for connection to an instrument
or line level signal such as a guitar processor,keyboard, or instrument preamp output." My gigging amp is a GK MB115 combo, with a headphone out and a DI out. If I use the headphone out into the PM351 it will cut the amp speaker out, so I'm thinking of using a XLR (F) to 1/4" cable from the DI. Will this work? I'm thinking it will but I'm not sure.

2. The unit came without a power supply. Will a One Spot wall wart work?

Other than these concerns it looks like this could work. I'm planning on using JVC Xtreme Xplosive HA-FX1X earphones in one ear, so I can hear myself sing and play bass, and ear protection in the other so I can hear the band play.
 
#2
I recently picked up. A PM351 as well thinking of using a Bluetooth transmitter and wireless earphones for iem's. Unfortunately the latency was too great.
I can't answer your first question, but I can tell you that for practicing I've been using a multi-plug to power my PM351 with no issues. It's not a One-spot, but it works on the same principle. I believe the Rolls unit lists an operating range for power and your One-spot should be just fine unless you're already running a whole bunch of pedals.
I'm curious why you would choose to only use one ear from the Rolls. You could run a line from the board for the band mix, and also your mic and bass signal to both ears. Is it because some of your band's signals aren't running through the board? Because if they are, it would seem less efficient to only use one ear. I'm not criticizing, I just don't understand running it that way.
 
#3
Esquillama said:
I
I'm curious why you would choose to only use one ear from the Rolls. You could run a line from the board for the band mix, and also your mic and bass signal to both ears. Is it because some of your band's signals aren't running through the board? Because if they are, it would seem less efficient to only use one ear. I'm not criticizing, I just don't understand running it that way.
Click to expand...

It's only because I can already hear the overall band mix just fine. If anything, I would only need our singer's vocals, since that's what everyone in the band keys on. Once I have everything set up I'll try it my way at rehearsal, and if it doesn't work out then I'll try it with a line from the board. Unfortunately that will only work if we're providing the sound at our gigs. At some of the clubs we've played the mixing board is really far away, unless of course they have an aux send in the stage snake.
 
#4
I just started using a PM351.

1. It should work. You may have to futz with the mono/stereo switch to get it in both ears.

2. As long as it provides 9v-15v, 300mah, and a negative center, yes.

I've been using ME Electonics Sport-Fi M6s in both ears and hear the onstage mix just fine, if a bit muffled. It's a lot like wearing foam earplugs except you can hear you mic and bass clearly. You could run an ambient mic into the line input but I've found it unnecessary. I plan on getting customs made when I get some extra cash.
 
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#5
The instrument jack can be used with stereo (TRS), but it will also take regular (mono) instrument input. With a two-output pedal tuner, you could save some cable spaghetti between your mic position and amplifier if you use a pedal tuner with two outputs. (I keep a Korg DT10 for situations like this.)

The PM351 will work with a One-Spot (or a standard Boss style supply).
 
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#6
I would definitely suggest using the search function, search for PM351, IEM, and also "one ear". The one ear technique can be particularly bad for your hearing.

To get a line off the desk, you don't need to necessarily plug into the desk. I get a line to my IEM splitting off the powered sub on my side of stage. I either use the full range parallel out, use a Y cable to split the signal going into the sub if there's no parallel out. Both these methods can also be used if there are power amps running passive FOH also. I now use a splitter box rather than a Y cable incase there is an earth loop, so I have a ground lift switch.
 
#7
UPDATE: This past Wednesday my PM351 arrived. I ran some tests on it and this is what I came up with:
1. A OneSpot will power the unit.
2. The Line Input, Mic Input, and Instrument Input work as expected.
3. I tried running an instrument cable from my amp's headphone out into the Instrument In, and got no sound at all. Same thing with running a cable from the Active jack into the Inst in.
4. I tried running an XLRF to 1/4" TRS cable from the DI out of my amp into the Inst In. Got lots of loud buzzing and distorted noise. Definitely lot the answer.
5. I tried plugging a Vox AmPlug to my bass and running the headphone line out into the Inst In. Worked like a charm, no noise at all.
So the problem now is how to get a signal from the PM351 into my amp. Any suggestions? FYI my amp is a GK MB115 combo.
 
#8
ANOTHER UPDATE: I think I've solved the problem, thanks to derrico1's post (thanks!). My Boss TU-2 tuner has an Output and a Bypass, so what I've done is run the Output into the amp like usual, and run the Bypass into the PM351's Inst In. Works fine now, but I only have sound in one ear since I used a cable with TS jacks on it. I've ordered the parts to make my own TRS cable (from Redco Audio) so I can get my sound in stereo.

I think what was confusing me was that I didn't know what instrument level and line level was. There's a good explanation over at bongomania's Ovnilab website. It helped me to understand how the PM351 worked. Thanks, bongo!

Line level, instrument level, mic level explained
 
#9
stratovani said:
but I only have sound in one ear since I used a cable with TS jacks on it. I've ordered the parts to make my own TRS cable (from Redco Audio) so I can get my sound in stereo.
Click to expand...

There are mono/stereo jumper settings for the inputs. Set the instrument input's jumper to mono to use a TS plug. Here's the manual.
 
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#14
The PM351 is like a DI. Usually, you plug your instrument into the input, then cable the output to your amp. If you are using effects/pedals, cable out of that into input.

The reason your amp XLR didn't work, is because that TRS is a balanced output, not a stereo.

For the line in, you have your choice of a balanced main or custom monitor feed from the board. This way, you can mix between the band, your bass, and your vocal (if you're using a mic).
 
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#15
dreamadream99 said:
The PM351 is like a DI. Usually, you plug your instrument into the input, then cable the output to your amp. If you are using effects/pedals, cable out of that into input.

The reason your amp XLR didn't work, is because that TRS is a balanced output, not a stereo.

For the line in, you have your choice of a balanced main or custom monitor feed from the board. This way, you can mix between the band, your bass, and your vocal (if you're using a mic).
Click to expand...

Thanks for the reply but I think you're responding to the OP. I dredged up this zombie because it was essentially asking the same question...I just needed a different answer! I appreciate the input though!
 
#16
I'm assuming that I can just run a feed direct from an audio source such as MP3 direct to the unit and mix it against my direct (also to the Rolls) instrument signal. Rolls is incredibly vague on their website about this aspect but numerous folks seem to use it for such with great results. I see the "headphone practice amp solution" topic come up quite a bit and I'm surprised this unit isn't mentioned more.
 
#17
petrus61 said:
Rolls is incredibly vague on their website about this aspect . . .
Click to expand...


Rear connections (edited from the Rolls official shots to align with the top and front pics below):
RollsPM351_RearConnections.jpg


Top view
RollsTopAndFront.jpg


From left to right:
  • Use the PM351's line input to monitor your mp3 (or whathaveyou) line-level audio source, via a cable that ends in stereo TRS on the Rolls 351's side. (Alternatively, feed this jack a mono signal, and set the "line in" jumper on the side of the unit to mono.)
  • Send the "mic thru" signal to FOH, etc. Feed the Rolls PM351's "mic input" from your vocal mic. (If you don't sing, you could feed this any other mic level signal—such as a cabinet mic, etc.) The jumper beside the "mic thru" is a switchable ground lift.
  • Run your bass (or other instrument) into the 351's "inst in" jack. (Select mono or stereo via the middle jumper—the one closest to the 1/4" instrument input.) If you want to take the bass's FOH signal from the Rolls, then run from the 351's instrument "mono/left out" to FOH. (The jumper between the two instrument-out XLR jacks is a switchable ground lift.)

As you can see, the Rolls gives you individual volume pots for line in, mic, and instrument levels.
 

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#18
EastCoastThump said:
Rear connections (edited from the Rolls official shots to align with the top and front pics below):
View attachment 1138931

Top view
View attachment 1138932

From left to right:
  • Use the PM351's line input to monitor your mp3 (or whathaveyou) line-level audio source, via a cable that ends in stereo TRS on the Rolls 351's side. (Alternatively, feed this jack a mono signal, and set the "line in" jumper on the side of the unit to mono.)
  • Send the "mic thru" signal to FOH, etc. Feed the Rolls PM351's "mic input" from your vocal mic. (If you don't sing, you could feed this any other mic level signal—such as a cabinet mic, etc.) The jumper beside the "mic thru" is a switchable ground lift.
  • Run your bass (or other instrument) into the 351's "inst in" jack. (Select mono or stereo via the middle jumper—the one closest to the 1/4" instrument input.) If you want to take the bass's FOH signal from the Rolls, then run from the 351's instrument "mono/left out" to FOH. (The jumper between the two instrument-out XLR jacks is a switchable ground lift.)
As you can see, the Rolls gives you individual volume pots for line in, mic, and instrument levels.
Click to expand...

Very helpful! Much thanks.
 

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