Simple Acoustic Signal Chain Troubleshoot help

[funkymonk#9]

I set up an acoustic guitar P.A. today with items I have had for too long before hearing, much of it with strong recommendations from the elder statesman and passionate amongst the researchers here.

I have a Mcintyre Feather Bf-30 High impedance piezo that I run to the xlr input of a Soundcraft EFX 8 Channel Mixer, mix out to a Hafler P3000 amp mono out to a Daedalus Speaker.
I was also using a Canares TRS 1/4" to xlr to the mixer.
I had the gain to like 6-7, the fader to 7ish and the masters to 7ish. Didn't see any real signal coming to the amp but not sure what to look for. i didn't have the pfl switched on so couldn't see how much signal was coming through either. It was probably the same volume as my fender twin on 1-2.

I don't have much signal, I know they recommend a preamp but I thought the Mixer would be able to boost it enough. I was previously plugged into a Yamaha amplifier and it gave me enough headroom but was cranked a bit.

Feel free to pass on any delusions I am currently under.

[sdelsolray]

Originally Posted by funkymonk#9

I set up an acoustic guitar P.A. today with items I have had for too long before hearing, much of it with strong recommendations from the elder statesman and passionate amongst the researchers here.

I have a Mcintyre Feather Bf-30 High impedance piezo that I run to the xlr input of a Soundcraft EFX 8 Channel Mixer, mix out to a Hafler P3000 amp mono out to a Daedalus Speaker.
I was also using a Canares TRS 1/4" to xlr to the mixer.
I had the gain to like 6-7, the fader to 7ish and the masters to 7ish. Didn't see any real signal coming to the amp but not sure what to look for. i didn't have the pfl switched on so couldn't see how much signal was coming through either. It was probably the same volume as my fender twin on 1-2.

I don't have much signal, I know they recommend a preamp but I thought the Mixer would be able to boost it enough. I was previously plugged into a Yamaha amplifier and it gave me enough headroom but was cranked a bit.

Feel free to pass on any delusions I am currently under.

The connection between the pickup and to the XLR on the Soundcraft is your problem. That is not a compatible connection.

[funkymonk#9]

Originally Posted by sdelsolray

The connection between the pickup and to the XLR on the Soundcraft is your problem. That is not a compatible connection.

Gotcha, so a TRS balanced cable is ok as long as it's 1/4" to 1/4" then.
Or a direct box to match the impedance/voltage to an XLR.

I should have known better, the years have made me wise and also forgetful.

Thanks for your quick response!!

[jseth]

You don't need a TRS cable if the output of The Feather is a standard mono 1/4" socket... the TRS cable is only going to confuse the issue... you only want a TRS cable if you have a dual/stereo output of the source and the output is low impedance. You can use a TRS cable if you intentionally want/need to split the output signal to two separate sources, as well, but you run the risk of having weaker signal strength on both of the outputs that are being "split", if the signal is not a low impedance signal.

You want to go from your guitar to the mixer with a standard guitar cable and plug in to a standard 1/4" input... frequently, a mixer will have both for each of the inputs that have an XLR input. You DO want to use the preamp section of that mixer's channel, though.

The XLR input is for a LOW impedance signal; the 1/4" input is for a HIGH impedance signal. Plug your guitar in and adjust the input gain/trim on that individual channel so that the light "lights", until the input "clips" (distorts) and then back it off until it doesn't clip. You wil want to be playing as aggressively as you normally would when you set that input gain. If your guitar has a volume control, have it set to maximum when you adjust the input gain. Then back it off if you desire...

You are going to want to have the main volume/gain ont he mixer all the way down when you do this exercise, and then raise the individual channel's volume to a mid position and THEN increase the overall volume setting.

Hope this helps you!

[funkymonk#9]

Originally Posted by jseth

You don't need a TRS cable if the output of The Feather is a standard mono 1/4" socket... the TRS cable is only going to confuse the issue... you only want a TRS cable if you have a dual/stereo output of the source and the output is low impedance. You can use a TRS cable if you intentionally want/need to split the output signal to two separate sources, as well, but you run the risk of having weaker signal strength on both of the outputs that are being "split", if the signal is not a low impedance signal.

You want to go from your guitar to the mixer with a standard guitar cable and plug in to a standard 1/4" input... frequently, a mixer will have both for each of the inputs that have an XLR input. You DO want to use the preamp section of that mixer's channel, though.

The XLR input is for a LOW impedance signal; the 1/4" input is for a HIGH impedance signal. Plug your guitar in and adjust the input gain/trim on that individual channel so that the light "lights", until the input "clips" (distorts) and then back it off until it doesn't clip. You wil want to be playing as aggressively as you normally would when you set that input gain. If your guitar has a volume control, have it set to maximum when you adjust the input gain. Then back it off if you desire...

You are going to want to have the main volume/gain ont he mixer all the way down when you do this exercise, and then raise the individual channel's volume to a mid position and THEN increase the overall volume setting.

Hope this helps you!

Yes, no doubt, all very good. I obviously made the setup more complicated than it needed to be.
Just for curiosity's sake. So no advantage to using a direct box in conjunction with using the XLR input on the mixer?

[sdelsolray]

Originally Posted by funkymonk#9

Yes, no doubt, all very good. I obviously made the setup more complicated than it needed to be.
Just for curiosity's sake. So no advantage to using a direct box in conjunction with using the XLR input on the mixer?

The ¼" input jack on each channel is a lower impedance line level input, not a high impedance instrument (pickup) input. Thus, you must use either (i) a DI or (ii) external pickup preamp between your guitar and the Soundcraft. A DI will run to the channel mic XLR input on the mixer using a XLR cable and an external pickup preamp will run to the channel line input on the mixer using a TS cable.

[fotofantom]

Originally Posted by sdelsolray

The ¼" input jack on each channel is a lower impedance line level input, not a high impedance instrument (pickup) input. Thus, you must use either (i) a DI or (ii) external pickup preamp between your guitar and the Soundcraft. A DI will run to the channel mic XLR input on the mixer using a XLR cable and an external pickup preamp will run to the channel line input on the mixer using a TS cable.

Glad to see this confirmed by an expert (sdelsolray) as I have found it to be important. If I plug my K&K equipped guitar into the line input on my Peavey mixer and run that to an amp, I lose a lot of tone that EQ won't restore. The line input on the Peavey is 10Kohms, same as your Soundcraft mixer. A typical instrument input should be at least 1 Megohm. (Some mixers have dedicated instrument or guitar inputs.) So a preamp, or even an effects pedal, between guitar and mixer would be appropriate. Also, do you need the mixer? Are you mixing instrument and vocals? If not, you should be able to eliminate the mixer and run instrument to preamp to power amp to speaker.

Playing amplified is fun but it can be frustrating!

[funkymonk#9]

Originally Posted by fotofantom

Glad to see this confirmed by an expert (sdelsolray) as I have found it to be important. If I plug my K&K equipped guitar into the line input on my Peavey mixer and run that to an amp, I lose a lot of tone that EQ won't restore. The line input on the Peavey is 10Kohms, same as your Soundcraft mixer. A typical instrument input should be at least 1 Megohm. (Some mixers have dedicated instrument or guitar inputs.) So a preamp, or even an effects pedal, between guitar and mixer would be appropriate. Also, do you need the mixer? Are you mixing instrument and vocals? If not, you should be able to eliminate the mixer and run instrument to preamp to power amp to speaker.

Playing amplified is fun but it can be frustrating!

I could bypass the mixer except it is basically my eq and I thought in the future using it for live applications where I could use it for vocals or other mic'ed instruments, or perhaps a stereo mic application. But certainly doable. Thanks everybody, necessity is starting to force me to dive a little deeper into the physics.

[sdelsolray]

The better signal hygiene while using a Halfer P3000 and Daedalus passive speaker requires a +4dBU nominal signal level entering the Hafler. Your Soundcraft mixer provides a +4dBU nominal signal level output. All but a few internal or external acoustic guitar preamps do this.

As mentioned above, making your signal chain work correctly only requires a simple addition between the guitar and Soundcraft.

On another point, depending on which single Daedalus speaker you are using, you may want to bridge the Hafler's output to mono (there's a switch on the back of the Halfer to do this). If your Daedalus is an S-82, W803 or SC-1203, bridging makes sense. It would not be needed for an S-81, although doing so won't hurt.

[funkymonk#9]

Very Nice, I have a single W803. I will indeed make sure the switch is set to bridge. If you have a second, I wouldn't mind knowing the how that affects the signal.

I know Radial is a standard, have also been looking at a Fire-eye.
I know down the road I may venture into stereo or piezo/mic options and would benefit from a blender 2 channel preamp and have more than a few on the back burner when my pockets fill back up.
But for now, any recommendations?
I know you said most preamps would ultimately do the job of getting the +4dBu as i would probably go the external route.

[sdelsolray]

Originally Posted by funkymonk#9

Very Nice, I have a single W803. I will indeed make sure the switch is set to bridge. If you have a second, I wouldn't mind knowing the how that affects the signal.
...

Running a P3000 in mono/bridged mode increases the RMS output wattage @ 8 Ohms from 150 watts to 400 watts. The result, all other things being equal, will be more volume coming out of the W803.

Originally Posted by funkymonk#9

Very Nice, I have a single W803. I will indeed make sure the switch is set to bridge. If you have a second, I wouldn't mind knowing the how that affects the signal.

I know Radial is a standard, have also been looking at a Fire-eye.
I know down the road I may venture into stereo or piezo/mic options and would benefit from a blender 2 channel preamp and have more than a few on the back burner when my pockets fill back up.
But for now, any recommendations?
...

DIs are inexpensive. Borrow one to see how it works and if it is satisfactory then you can buy one. If you go dual source later you can either (i) use two channels in the Soundcraft or (ii) replace it with a dedicated external 2x2 or 2x1 acoustic guitar preamp.

Originally Posted by funkymonk#9

...
I know you said most preamps would ultimately do the job of getting the +4dBu as i would probably go the external route.

What I meant in my above post is that most acoustic guitar preamps do not operate at the professional standard +4 dBu nominal level. Some do, such as the Pendulum Audio SPS-1, Rane AP-13 and Grace Felix (there may be a few others I can't think of right now).

Using an acoustic guitar preamp which operates at the consumer -10 dBV nominal level isn't the end of the world. There's usually plenty of wiggle room in the system's gain staging to get a satisfactory result running a -10 dBV preamp into a +4 dBu amplifier.

[funkymonk#9]

Originally Posted by sdelsolray

Running a P3000 in mono/bridged mode increases the RMS output wattage @ 8 Ohms from 150 watts to 400 watts. The result, all other things being equal, will be more volume coming out of the W803.


DIs are inexpensive. Borrow one to see how it works and if it is satisfactory then you can buy one. If you go dual source later you can either (i) use two channels in the Soundcraft or (ii) replace it with a dedicated external 2x2 or 2x1 acoustic guitar preamp.


What I meant in my above post is that most acoustic guitar preamps do not operate at the professional standard +4 dBu nominal level. Some do, such as the Pendulum Audio SPS-1, Rane AP-13 and Grace Felix (there may be a few others I can't think of right now).

Using an acoustic guitar preamp which operates at the consumer -10 dBV nominal level isn't the end of the world. There's usually plenty of wiggle room in the system's gain staging to get a satisfactory result running a -10 dBV preamp into a +4 dBu amplifier.

Thanks sdelsolray, you were pretty much the reason I got most of this setup, from reading your posts from months/years past. You definitely got my eyes on the Daedalus.
The Pendulum and Grace are definitely out of my price range right now, especially since I really want a better bike for that type of price. But the Rane AP-13 can be gotten used at the same price as some higher end consumer models, and has 2 channels so it might be a safe smart buy.

Again

[sdelsolray]

Originally Posted by funkymonk#9

Thanks sdelsolray, you were pretty much the reason I got most of this setup, from reading your posts from months/years past. You definitely got my eyes on the Daedalus.
The Pendulum and Grace are definitely out of my price range right now, especially since I really want a better bike for that type of price. But the Rane AP-13 can be gotten used at the same price as some higher end consumer models, and has 2 channels so it might be a safe smart buy.

Again

You're welcome, although I may have suggested a path of no return.

As to the Rane AP-13, it is one of the heros of acoustic guitar preamps, and yes, they are silly cheap these days used. Its design limits you to (i) either a passive or active pickup on channel 1 and (ii) either an internal mic or active pickup on channel 2.

I've put my AP-13 in my upstairs "practice rack" along with a Rane DMS22 stereo mic preamp/eq which connects to the AP-13's expand input jacks. This results in a 4x2 topology with separate eq for each channel, stereo and mono mix busses for all 4 channels and a headphone out for the final mix. For live performing, it could handle a duo, each with a pickup and vocal mic, so it ends up being like a mixer.

[funkymonk#9]

Year Later and I still have questions, imagine that.
I appreciate the knowledge greatly.

I am have been borrowing a preamp and am ready to get a Rane.
I don't yet have a mic style pickup in the guitar. Down the road, it is on my list to have a dual source.
But for right now the McIntyre pickup through the Daedalus sounds great.

So will the Rane AP-13 not work for me because I don't have dual source pickups, it only has a TRS input?
Plainly, can I use the Rane AP-13 with just one pickup, so I would have the right Preamp when I get the dual source.

If not, is there a recommendation for a Rane preamp with 2 separate channels and also TRS? Or is it one or the other: or both in your case
Perhaps the DMS-22

Appreciate the continued vigilance.

[sdelsolray]

Originally Posted by funkymonk#9

Year Later and I still have questions, imagine that.
I appreciate the knowledge greatly.

I am have been borrowing a preamp and am ready to get a Rane.
I don't yet have a mic style pickup in the guitar. Down the road, it is on my list to have a dual source.
But for right now the McIntyre pickup through the Daedalus sounds great.

So will the Rane AP-13 not work for me because I don't have dual source pickups, it only has a TRS input?
Plainly, can I use the Rane AP-13 with just one pickup, so I would have the right Preamp when I get the dual source.

If not, is there a recommendation for a Rane preamp with 2 separate channels and also TRS? Or is it one or the other: or both in your case
Perhaps the DMS-22

Appreciate the continued vigilance.

funkmonkey#9:

Are you still planning on using the Soundcraft EFX mixer in your signal chain?