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SEQUENTIAL/DSI => Prophet => Prophet Rev2 => Topic started by: Sabana on October 13, 2020, 02:17:10 AM

Title: How do i connect a Guitar Pedal to the REV 2
Post by: Sabana on October 13, 2020, 02:17:10 AM
Newbie question sorry. But i have never used a guitar pedal on a synth before. I dont know which  output on the Rev 2 to plug the FX pedal into? Is it safe to do so? And i have a mixer. If i want to form a chain do i plug the pedaliinto the synth or the miser?

Cheers.
Title: Re: How do i connect a Guitar Pedal to the REV 2
Post by: maxter on October 13, 2020, 03:42:43 AM
Best way would be to plug the Rev2 Main outputs L+R into the mixer. A stereo channel or 2 channels panned L and R. Then use the FX send or Aux send from the mixer to the guitar pedal. Then guitar pedal goes back into mixer, on a separate channel, so you can mix the levels, raw sound of Rev2 with the effected sound from the pedal to your liking. You may want to set the pedal to 100% wet. You can also EQ just the effected sound on the mixer this way.
Title: Re: How do i connect a Guitar Pedal to the REV 2
Post by: Sabana on October 15, 2020, 02:47:45 PM
Hey thanks for that Maxter. It clears up the workflow. I will do what you suggest.  :)
Title: Re: How do i connect a Guitar Pedal to the REV 2
Post by: cornguy on October 24, 2020, 09:40:55 AM
I just bought an eventide space to use with the Rev2.  I was curious if it would work to plug my Rev2 Into the Space with 2 1/4 for stereo, and then take the output of that into my headset.  I dont have an amp yet, I'm just using a headset.  I want to take it into my headset in stereo.  If i just plug my headset into the main output the sound only comes out of one side of my headset.  The guy at guitar center told me to buy this https://livewire-usa.com/sy06tfq/ when using that, the sound I'm hearing through my headset is super quiet.  I guess I can get a mixer but I wish there was a way I could just use my headset.  Will any quality be lost with the mixer, I'm not quite ready to get another expensive thing right now hehe.
Title: Re: How do i connect a Guitar Pedal to the REV 2
Post by: maxter on October 24, 2020, 12:33:13 PM
I'm not really a tech guy, but I suspect the impedance of the Eventide Space and the headphones don't go together well? As the output isn't designed for use with headphones, perhaps. Just a wild guess, but I don't know what else could cause the output to be so low, if all your connections are good. Many headphones have low impedance.
The ES has 470 ohms output impedance, and "recommended load impedance: 10K ohms or greater" and the load would be the headphones. Just looked up my headphones impedance, AKG K702, just 62 ohms. So the output would probably be very low if connected to the ES.

https://www.eventideaudio.com/support/product/691/specs

A video describing it: (around 4:00 may be your problem)
https://www.youtube.com/watch?v=SpTsWVLI-ig
Title: Re: How do i connect a Guitar Pedal to the REV 2
Post by: cornguy on October 25, 2020, 04:10:26 AM
Thanks Maxter, 1 more question, I am not very techy. 
In the manual its describin bypass, I am not sure which one to pick.
from the manual
Bypass
It’s important to select the Bypass function that works best with your setup. gives you
the choice of Bypass type – DSP Bypass, Relay Bypass or DSP+FX Bypass. ’s default
Bypass setting is DSP Bypass.
DSP Bypass
When set to DSP Bypass, bypassing sends the audio at the DSP’s inputs directly to the outputs
without any effects processing. This type of bypassing works well in most situations, and
protects against gain and tone changes when bypassed.
Relay Bypass/True Bypass
Some guitarists prefer a “true bypass” in which the pedal’s electronics are completely
disconnected from the signal path. When [RELAY] Bypass is selected uses relays to
“hard wire” your inputs to your outputs. (In fact, whenever ’s power is off, ’s
electronics are completely bypassed by the relays.)
Relay Bypass is not a good choice, however, if ’s input is your guitar and you’ve
connected ’s output directly to a non-instrument level input device or have connected
to your amp over a long cable. Non-instrument inputs are often low impedance (typically
<10k ohm) and will load the guitar output and change its tone. DSP Bypass allows to
act as a buffer, providing a low impedance output (500 ohm) capable of driving any device
input or cable length.
Note: Relay Bypass should not be used if the Input/Output Lvl switches are set opposite to
one another. Specifically, if the Input Lvl switch is set for GUITAR and the Output Lvl switch is
set to LINE or the Input Lvl switch is set for LINE and the Output Lvl switch is set to AMP,
will not have unity gain. In this case, using Relay Bypass will result in a level change
whenever you Bypass .
DSP+FX Bypass
When [DSP+FX] is selected, Bypass sends the audio at the DSP’s inputs directly to the outputs
with the decaying ‘tail’ of the current effect mixed in.

I don't even have enough knowledge to begin pieces this together lol.  What do you think is the one I'm suppsed to use?
Title: Re: How do i connect a Guitar Pedal to the REV 2
Post by: maxter on October 25, 2020, 05:29:31 AM
Use the default, DSP Bypass! The other modes will abruptly cut off the FX sound when you press bypass (so the effected sound instantly disappears), possibly with an added "click" noise too, like when you insert a cable. Those other modes are mostly for guitarists I think.

I'm looking to get a dedicated headphone amp myself, possibly a Schiit. Looked up the output impedance, 0,2 ohms. Near the end of the video above, the guy says a good rule of thumb is to have headphone impedance at least 8 times (or more) higher than the amp they're connected to. So I think you'll "have" to get a mixer, audio interface (there are quite good & cheap ones) or similar to do the job. Many AI's don't need to be connected to PC, but you'll also have the option to record to PC, or add FX in a DAW etc. It will only improve the sound compared to plugging headphones directly to the ES.

Good luck!
Title: Re: How do i connect a Guitar Pedal to the REV 2
Post by: cornguy on October 25, 2020, 07:11:57 AM
Ok thanks Maxter :) I have an audio interface, just didn't want to use when I'm not recording because it sometimes will go red and I have to lower the volume.  I might get a mixer today, I guess I'll get a cheap one, as long as it doesn't lower the quality of the sound Ill be happy.
Title: Re: How do i connect a Guitar Pedal to the REV 2
Post by: ryankm on December 01, 2020, 03:30:39 PM
Use insert to if you got it.  Some times auxiliary send can be tricky and insert will do the job.  Most mixers have them you'll need 2 stereo 1/4inch to dual mono one for each channel.  One channel will be send and the other is return.  That way it'll be on a much simpler circuit and the instrument can communicate on a more personal level much like a guitar effects pedal.  And send both left and right with stereo to the balanced 1/4" inputs of one channel of the mixer from the Prophet.
Title: Re: How do i connect a Guitar Pedal to the REV 2
Post by: ryankm on December 02, 2020, 01:01:04 PM
or if your guitar pedal has trs balanced inputs you can just put the left right channel as stereo jack straight in.  It'll work just fine.  Or get a mono splitter cable to converge both channels into mono.
Title: Re: How do i connect a Guitar Pedal to the REV 2
Post by: maxter on December 02, 2020, 01:21:34 PM
or if your guitar pedal has trs balanced inputs you can just put the left right channel as stereo jack straight in.  It'll work just fine.  Or get a mono splitter cable to converge both channels into mono.

I wouldn’t do that, balanced signal is not the same as stereo. It may ”work”, but... The second channel in inversed, or has reverse polarity, I’m no techy so I don’t know the proper terms, but it expects the Ring to be an inversion of the Tip of the cable signal. So I suspect there would be phasing issues, and that the sound definitely wouldn’t be the same as running the Rev2 into a stereo channel on the mixer, and an aux/fx mono send to the pedal.

But I agree that inserts can work fine if running the Rev2 into 2 mono channels on the mixer, if the effect pedal has stereo inputs, and if you don’t want to send anything else from the mixer to that pedal.
Title: Re: How do i connect a Guitar Pedal to the REV 2
Post by: maxter on December 02, 2020, 01:37:25 PM
I found a good post by someone techier at soundonsound.

”Ah yes, the classic case of an 'unbalanced stereo' output feeding a balanced mono input!

The key to understanding the problem here is to remember that:

1. a 'balanced input' always employs a differential receiver (whether constructed from a passive transformer or active op-amps).

2. a differential receiver is only interested in the difference in signal voltages between its two input terminals (hot and cold, or plus and minus).

3. anything that presents the same voltage to the two terminals (the so-called common-mode condition) will be ignored, which is where the 'interference rejection' property comes from.

So, in this case, you end up presenting the left channel to the differential receiver's hot terminal, and the right channel to its cold terminal. The output will be the difference between the two, and anything that is the same on both will be ignored (and removed).

Consequently, anything panned centrally -- kick drum, bass, vocals etc -- all disappear, and all you're left with is any instruments panned widely, and the stereo reverb! Or, if the source was 'dual mono' -- such as a talking book where the narrator us panned centrally -- very little at all!

There are two solutions. Mike mentioned using a special adapter that mixes the left and right channels together into a mono unbalanced signal and presents that mixed signal to the hot terminal, while the ground reference of the unbalanced source is wired to the cold terminal.

The other solution is a Y-split cable that presents the left channel to one mono unbalanced TS plug, and the right channel to a second unbalanced TS plug -- these would then be plugged into two separate mono channels, or the left and right inputs of a stereo channel, depending on what was available.”

https://www.soundonsound.com/forum/viewtopic.php?f=15&t=57712