Mark V Effects loop impedance matching.

[Mrjason]

Anyone happen to know the values of send and return impedances on the Mark V's effects loop?

I'm playing around trying to make my TC Electronics G system as transparent as possible. For those interested I am running the G in a 4 cable configuration.
Guitar>G system input(1M Ohm) >Insert Send (200 Ohms)>Amp Input (1M Ohm)>Amp Effect Send (? Ohm)>G system Insert Return (24k Ohm)>G System out(? Ohm)> Amp Effect Return (? Ohm)

I been reading about impedance matching and wondering if and where a buffer may help. My tone flattens out a little bit in the front end of the G. Is it the G or effects loop impedance that is doing this? I figure first step is to find out the impedance of my configuration and then look at options to try.

Any help would be appreciated!

Thanks in advance!

 

[Masterof1angel]

That's a good question!

 

[Mrjason]

Well I have an answer! I called Boogie and asked today. I was told that the effects send is about 25k ohm and the return is about 50k ohm.

I also discovered that the G system sounds more natural when hooked up through loop 4 rather than the insert loop. Impedance really makes the difference as the insert send is 200 ohms and insert return is 24k. Loop 1 send is 100 ohm and return is 91k. I'm going to take my questions over to the G system forums as this is more of a g system thing now. Buffers and line drivers I dont know much about ... yet~!

 

[screamingdaisy]

Hmm.. That's interesting to hear as I've been using the insert loop. I don't expect anything to be transparent, but I haven't had any noticeable degradation using my G-Sysem. For myself, I've been running it with the "brain" on top of the amp. I figure using a series of 1ft patch cables is probably better than running four 20ft lengths.

 

[Mrjason]

Yeah I also use mine just sitting on top of my head with short 3 foot cables. No noise issues.
I also should add .. that I thought I was loosing tone from the front end of the G but it turned out it was the back end while hooked up through the insert loop. I cranked the amp on channel three .. bypass the front end of the G. No reverb or nothing. Just the sound of the channel with and without the signel going through the G. Toggle the effects loop on and off using the mesa footswitch while playing. I personally notice a big difference while the G system is cabled up in the insert loop. Using Loop 4 made it sound better no doubt. More noticable in the higher gain channel than the clean channel. After figuring that out .. i notice little difference when I run through the G system front end. I just went through all my presets to enable loop four in every darn patch!

 

[screamingdaisy]

Cool. I haven't really noticed a big change when I added the G-System, but I've made it a point to stop comparing things when I can avoid it. It's made me a much happier person.

Still, now that it's been pointed out to me I can't exactly ignore it, so I'll give it a try tomorrow when I get home for work.

Fortunately I only have 5 presets, so it's not a big deal.

 

[screamingdaisy]

Out of curiosity, did you set the maximum boost to 0dB?

If you didn't it'll cut the signal leaving the G-System. The idea is that the G-System creates an artificial boost by attenuating the G-System's output for your unboosted signal, then removing the attenuation when boosting up to the G-Sytem's max output. I could see that a 4dB or 6dB signal cut causing issues if you were to cycle the FX loop on and off with the footswitch. I suspect that using Loop 4 probably bypasses the attenuation, which may be why it sounds better than the insert loop.

When you set the max boost to 0dB, you disable the G-Sytems boost feature and the G-System will always output at the maximum volume with zero attenuation, which improves signal to noise and a few other things. I've since reprogrammed my "Boost" switch to trigger the relay for the Mark V's built in boost.

 

[Mrjason]

I initially set the boost to 0 and locked it that way. My global settings at first had the input gain at 8 and the output at -8. No volume change when bypassing the front and switching the effects loop on and off. I tried the boost at 4db and noticed a tone difference but at the same time i liked the 4db boost along with the amps solo boost with the band as i dont have a volume pedal atm. I eventually decided to raise my output from -8 to -5 and attenuate the other 3 with the boost set to 3db. I split the difference now with volume and output level.

The pedal loops and insert loop are basically the same other than impedance. And the fact you can lock the insert loop on or off in one setting. Boost is down the line after the post gain fx in the back end so it works in the loop 4 configuration too.

Globals now are
input gain 8
loop level 3db
headroom 2db
volume -3
output level -2
Boost 3db