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Dt25 Effects Loop Impedance (buffer Needed?)


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#1 ghostrider25

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Posted 16 September 2013 - 07:22 AM

Does the FX loop send a low impedance or a high impedance signal out of the "Send" jack?

 

I'm thinking of mic'ing my amp in a room off-stage which would require ~25ft of cable (each way) and I'm trying to figure out if I would need a buffer at the start of the "Send" to make it to my pedal board where my effects loop pedals would be ~25ft of cable away. One of the pedals in the loop has a buffer for the return 25ft trip back to the amp and I do have a buffer from my pedalboard before the amp input. I don't want to spend the money on the cables if I'm going to have to buy another buffer in order to make it work.

 

The setup looks like this...

 

Guitar => buffer => pedals => ~25ft cable => amp

 

FX loop send => (buffer needed?) => ~25ft cable => 2 pedals (one buffered) => ~25ft cable => FX loop return


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#2 spaceatl

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Posted 16 September 2013 - 08:49 AM

I use my old BCB-60 with my DT25 quite often. My pedalboard snake is 4CM and is 25' for the gtr (NS2 buffer), send and return...the buffer in the DT25 send is fine for me...Here is what I have going on. pretty sure it's 10K line level...

 

GTR->NS2-(25' cable)->DT GTR Input

 

Gain stomps are in the the NS2 send return...(Strymon OB.1, FZ-5 and DS-1)

 

DT Send-(25' cable)->BF2->DM-3-(25' cable)->DT Return


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#3 ghostrider25

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Posted 16 September 2013 - 11:34 AM

I use my old BCB-60 with my DT25 quite often. My pedalboard snake is 4CM and is 25' for the gtr (NS2 buffer), send and return...the buffer in the DT25 send is fine for me...Here is what I have going on. pretty sure it's 10K line level...

 

GTR->NS2-(25' cable)->DT GTR Input

 

Gain stomps are in the the NS2 send return...(Strymon OB.1, FZ-5 and DS-1)

 

DT Send-(25' cable)->BF2->DM-3-(25' cable)->DT Return

 

That looks like a pretty close scenario to what I'm looking at (25ft to send and then 25ft to return). Have you tried running that setup with your FX loop pedals off and then compare it to not using the FX loop at all? And no treble roll off noticeable?


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#4 spaceatl

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Posted 17 September 2013 - 06:29 AM

Sure...not enough change for me to ever worry about...DM-3 has a pretty killer output buffer....It actually changes the tone, but it's the bandpass attenuation that most old analog delays have that I really like...If you did not come up playing of Memory Man delays or DM-3s you might not be familiar with this...but the Analog Delay in the POD does nearly the same thing...It's actually quite accurate in the regard IMHO....but there is nothing like the real deal...

 

The highend attenuation you are alluding to doesn't happen with stock BOSS pedals because they are buffered...So the level really does not get affected all that much and I think you could go as far as 50' with a BOSS before signal started dropping off where you might notice...attenuation does not really happen with buffers because they are not loading like a passive guitar does (different animal)....

 

Really, the only line you really have to worry about high end attenuation on is the the one from you guitar to your first pedal...And then you really only have to worry about that if your guitar is passive...If you have an active guitar, that does not happen because the guitar is buffered and not loading like a passive one does....True bypass pedals are a different topic...just make sure you have a buffer in the first and last pedal and you should be fine...


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#5 ghostrider25

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Posted 19 September 2013 - 12:54 PM

Sure...not enough change for me to ever worry about...DM-3 has a pretty killer output buffer....It actually changes the tone, but it's the bandpass attenuation that most old analog delays have that I really like...If you did not come up playing of Memory Man delays or DM-3s you might not be familiar with this...but the Analog Delay in the POD does nearly the same thing...It's actually quite accurate in the regard IMHO....but there is nothing like the real deal...

 

The highend attenuation you are alluding to doesn't happen with stock BOSS pedals because they are buffered...So the level really does not get affected all that much and I think you could go as far as 50' with a BOSS before signal started dropping off where you might notice...attenuation does not really happen with buffers because they are not loading like a passive guitar does (different animal)....

 

Really, the only line you really have to worry about high end attenuation on is the the one from you guitar to your first pedal...And then you really only have to worry about that if your guitar is passive...If you have an active guitar, that does not happen because the guitar is buffered and not loading like a passive one does....True bypass pedals are a different topic...just make sure you have a buffer in the first and last pedal and you should be fine...

 

Right, I understand all of that. My question is only from Effect Send -> 25ft of cable -> Buffered pedals. I'm not worried about the return because at least one pedal in the loop is buffered. If the Effect Send is low impedance already, then I wouldn't need a buffer. If it's high impedance, then I would. 

 

I don't have any 25ft cables to try so I removed the buffer from my board and ran my entire board in the DT-25's effects loop with all of the pedals off. There was a significant loss of high end so I'm thinking a buffer is more than likely going to be required  :(, although, it's not a perfect test and the loss may be less with a single cable than a bunch of smaller patches and TB pedals.


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#6 spaceatl

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Posted 20 September 2013 - 09:34 AM

What are your pedals exactly? Are you sure that you don't have some pedal in there with a 300 ohm input impedance? That would do it...


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#7 ghostrider25

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Posted 20 September 2013 - 10:26 AM

What are your pedals exactly? Are you sure that you don't have some pedal in there with a 300 ohm input impedance? That would do it...

 

Good question. I don't know what any of the input impedance ratings are (it's hard enough to find out how much current each pedal draws!), but this is what I'm trying to achieve...

 

Guitar -> Empress Buffer+ -> Bearfoot HBOD -> Timmy -> Rockett Blue Note -> Flashback X4 (in buffered bypass mode) -> Carbon Copy -> Empress Buffer+ -> Amp

 

Effects Send -> MXR Smart Gate -> Neunaber Wet (do not yet have) -> Ditto Looper -> Effects Return

 

 

For my above test, I did this...

 

#1. I plugged the guitar straight into the amp (3ft cable) and used a 6 inch cable to patch the Effect Send with Effect Return (no pedals). 

 

#2. I plugged the guitar straight into the amp (3ft cable), I removed the buffer loop from the chain, patched the two loops together and ran the following pedals in the effects loop with all of the pedals off...

 

Effects Send -> 6ft cable -> Bearfoot HBOD -> Timmy -> Rockett Blue Note -> Flashback X4 (in buffered bypass mode) -> Carbon Copy -> MXR Smart Gate -> Ditto Looper - 6ft cable -> Effects Return

 

 

There was definitely a very substantial difference in high end between the two.


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#8 spaceatl

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Posted 20 September 2013 - 09:04 PM

My first guess would be the HBOD...The little I know about those is they are really designed to be out front and might have some drag compensation for a passive guitar...I know the MXR is 1M input...So I would say start with the MXR alone and start adding pedals in until you find the culprit.


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