How to Reduce Signal from an Ampified Connection to a simple line level?

MNAirHead · #1 11-05-2010, 02:00 PM

Howdy.

What is the process to go from an amplified signal down to a non active?

Scenario.. a band uses a power amp and passive speakers.. I want a feed to run to my DI or active speaker.

I'm guessing it would have to be some type of attenuator or pot?

Looking to learn

Thanks..

Tim

PS.. more info here
DI/IEM board - please critique the order

MNAirHead · #2 11-05-2010, 03:59 PM

My thought was a countryman 85 should reduce the signal

GregShadoan · #3 11-05-2010, 09:21 PM

A 30db pad might work. Essentially what the 85 is in "speaker" mode.

Trevorus · #4 11-05-2010, 09:24 PM

We have a DI box at church that does this. Cannot remember who made it. I'll find out and let you know.

EDIT: Here's one: http://www.sweetwater.com/store/detail/Zdirect/

Passinwind · #5 11-05-2010, 10:38 PM

Quote:

Originally Posted by MNAirHead

Howdy.

What is the process to go from an amplified signal down to a non active?

Here's one way, from the Jensen Transformers website.

walterw · #6 11-06-2010, 12:09 AM

what's the point?

the right way is to get at the signal going into that power amp, which is already line level.

a simple Y-cable splitter will do.

TL5 · #7 11-06-2010, 06:01 AM

walterw, that's sort'of my thought as well. IMHO, best case is to just route the AUX/Monitor send from the console to MNairHead's Rolls PM351. It'd be line level, no futzing required.
My guess though (based on his linked reference thread), is there's a reason he needs to use a speaker level signal. Maybe he's the only one using the IEM set-up and he needs to use a parallel line from another monitor wedge or something.

My first thought was that Radial makes a DI that does this. I haven't used on nor have a researched which model it is.

RustyAxe · #8 11-06-2010, 10:05 AM

Quote:

Originally Posted by walterw

what's the point?

the right way is to get at the signal going into that power amp, which is already line level.

a simple Y-cable splitter will do.

The point would be to get the signal to the board from the amp post-EQ and post-FX ... I would assume.

walterw · #9 11-06-2010, 05:03 PM

Quote:

Originally Posted by RustyAxe

The point would be to get the signal to the board from the amp post-EQ and post-FX ... I would assume.

the line-level signal going into that power amp would be post EQ and post FX.

you're thinking of tube instrument amps, where the output tubes and transformer are part of the tone, and the in-line box between the amp and speaker gets that tone into the board.

as far as i can tell, this is about getting a signal from the board to a monitor mix of some sort. as such, there's no good reason to screw around with speaker-level DIs.

uhdinator · #10 11-13-2010, 10:16 PM

Im guessing you want to get the same signal going to the PA system into another powered
speaker/monitor?

IF so see if the Amp that is powering the PA has a parallel input (used for slaving)
Most amps have this and what ever signal (line level) is going into the PA amp
is also present at the parallel jack next to it.

If its a 1/4 inch phone jack it is probably TRS (tip ring sleeve balanced) 3 conductor like a mic cable.

If so all you need is a TRS to XLR cable to run to another powered speaker
then adjust volume on that speaker as needed

If you use a splitter instead it will drop the level to the PA but can adjust the input gain on the amp up a couple DB

walterw · #11 11-13-2010, 11:32 PM

correct, except that a splitter cable is just parallel like the second input jack on an amp, so electronically they would behave the same.

typically with line-level signals there would be no significant volume loss.

you could even skip the balanced line and just use a guitar signal cable from the second amp input to the other feed.

if the amp just has one 1/4" and one XLR, you could use an XLR turnaround to come out of the amp's XLR and go into the new feed. (at that point it might make sense to go XLR into that amp in the first place so its 1/4" input can be jumped over to the new feed.)

MNAirHead · #12 11-15-2010, 09:32 AM

Why?

I work in reality.. In all of reality there are commonly little gizmo boxes that help me from running a bunch of cabling and trying to get a sound guy to stop and install Y cables.

I'd like to have a solution ready for the time when I have 5 minutes to setup.. and the nearest signal I have is a passive wedge monitor 5 feet a way.

I do tons and tons of church gigs.. it's common for the sound people to be unaware of how it's setup.. or worst yet (for Y cable suggestion) to have all of the power amps in a closet.

MNAirHead · #13 11-15-2010, 09:33 AM

Quote:

Originally Posted by walterw

what's the point?

the right way is to get at the signal going into that power amp, which is already line level.

a simple Y-cable splitter will do.

Many times doing session work I have no time or access to do this Y cable solution.. this may add a VERY long cord to a facility that doesn't want a LONG HiZ cord running 30 feet to the back of the room.

Many qualified sound guys really would prefer I'm not dorking with their signal chain.

walterw · #14 11-15-2010, 10:32 PM

but they don't mind you putting stuff in between their amps and their speakers, where (in their minds) things can actually get blown up? (as opposed to accessing things line level like you're supposed to, which while it might be a PITA, will never damage anything.)

walterw · #15 11-15-2010, 10:36 PM

OK, you could indeed just put a DI box designed to take speaker-level signals into an extra parallel jack on whatever wedge you're stuck trying to get signal from. that puts the box in parallel with the speaker without interrupting the amp-to-speaker connection, so it shouldn't risk too much.

i can't say how good it would sound, though.

MNAirHead · #16 11-16-2010, 04:30 AM

Quote:

Originally Posted by walterw

but they don't mind you putting stuff in between their amps and their speakers, where (in their minds) things can actually get blown up? (as opposed to accessing things line level like you're supposed to, which while it might be a PITA, will never damage anything.)

No.. just getting a signal from the monitor chain.

greenboy · #17 11-16-2010, 07:03 AM

I usually just Y the line-level signal going to my rig's power amp. Simple. Cheap.

MNAirHead · #18 11-16-2010, 07:56 PM

There's no amp/cab for my DI setup --- and this doesn't help the monitor signal.

greenboy · #19 11-16-2010, 08:45 PM

Maybe you need to draw a diagram of proposed signal flow. Maybe my reading skills are shot, but I'm not seeing what your problem is.

walterw · #20 11-16-2010, 10:16 PM

Quote:

Originally Posted by walterw

but they don't mind you putting stuff in between their amps and their speakers,...?

Quote:

Originally Posted by MNAirHead

No.. just getting a signal from the monitor chain.

yeah, between their (monitor) amps and their (monitor) speakers.

if i were the soundguy i probably wouldn't be comfortable with anyone messing with my speaker lines. a short from an unknown rig-up could cook my amp!

(more to the point, i would make the effort to get you the line level signal that you should be getting, from the input to the monitor amps.)