Problem with noise using a 65amps Ventura

[Trick]

Hi, I'm having a noise issue using a 65amps Ventura. When i use the fx loop this ground type noise becomes more amplified. I've demonstrated the noise in the video link. I've tried different pedals as well in the fx loop and same noise occurs. All tubes were swapped out and that didn't fix it.

Thanks for your assistance.
https://drive.google.com/file/d/0B7e...ew?usp=sharing

[g1]

Pedals are made to go in front of the amp. This is a passive FX loop and as far as I know, it is designed for line level effects. Does it talk about the loop in the owners manual?

[Trick]

Hi, yes, i have it hooked up correctly and am sending line level into the loop. It doesn't have this problem with the other passive fx loops i've tested in other amps, such as a fender deville and egnater tweaker.

[J M Fahey]

We don't know what you actually have hooked in the loop, and, frankly, I can clearly hear hum fading in at 0:15 and out between 0:21 and 0:24 , at 0:32 you pull the input plug "so we can hear it"..... pause and ... we do not ; "it's still there" .... it's not, then at 0:38 "pull the effects send".... we hear it barely in the background for a second ; at 0:40 you pull the effects return ... silence yet you claim "the noise is still there", at 0:50 : "I'll crank the master , you can still hear that" ... nothing , even when you zoom in towards the black speaker grill.

In a nutshell, noise can be clearly heard at the beginning, reappears weakly for a second and then nothing.

Hard to help you when the audio does not match what you say.

Not being there, we need consistency to check this, doubly so because no measurements are made.

Please put the camera or microphone in a fixed place, say 1 ft in front of the amp on a stool or taped to a microphone stand and leave it there all the time, then repeat the video.

Moving it around can make 20:1 volume variations,including noise and hum, which can not be attributed to amp but to "measurement" technique.

You also show around 1:00 that hum which you attribute to poor loop construction varies when you tweak input preamp volume which is a point well ahead of the loop insertion point.
And I still do not hear hum there, or at least it's 10X lower than what you showed at the beginning and never again.

Also, besides whatever you have in the loop (which you do not show or describe) , add this simple test:

* start with strong hum as found between 0:15 > 0:23 ,
* then unplug loop send but not at the amp itself (which injects hum in the cable same as if you unplugged a cable from the guitar) ,
* instead unplug the end at the effec input and show us what happens,
* then unplug Loop receive from outside effects,
* then unplug everything from send/receive,
* then plug a known good cable straight from send to receive.

All this without moving camera/microphone nor tweaking any knob.

This is the exact same sequence of tests I'd do if I had your setup in front of me, on stage.

At the Lab I'd add a Scope and an Audio Millivoltmeter at the amp out to see and measure what is going on.

Having only a home video to show the problem I'd at least demand consistency.

[Trick]

We don't know what you actually have hooked in the loop, and, frankly, I can clearly hear hum fading in at 0:15 and out between 0:21 and 0:24 , at 0:32 you pull the input plug "so we can hear it"..... pause and ... we do not ; "it's still there" .... it's not, then at 0:38 "pull the effects send".... we hear it barely in the background for a second ; at 0:40 you pull the effects return ... silence yet you claim "the noise is still there", at 0:50 : "I'll crank the master , you can still hear that" ... nothing , even when you zoom in towards the black speaker grill.

In a nutshell, noise can be clearly heard at the beginning, reappears weakly for a second and then nothing.

Hard to help you when the audio does not match what you say.

Not being there, we need consistency to check this, doubly so because no measurements are made.

Please put the camera or microphone in a fixed place, say 1 ft in front of the amp on a stool or taped to a microphone stand and leave it there all the time, then repeat the video.

Moving it around can make 20:1 volume variations,including noise and hum, which can not be attributed to amp but to "measurement" technique.

You also show around 1:00 that hum which you attribute to poor loop construction varies when you tweak input preamp volume which is a point well ahead of the loop insertion point.
And I still do not hear hum there, or at least it's 10X lower than what you showed at the beginning and never again.

Also, besides whatever you have in the loop (which you do not show or describe) , add this simple test:

* start with strong hum as found between 0:15 > 0:23 ,
* then unplug loop send but not at the amp itself (which injects hum in the cable same as if you unplugged a cable from the guitar) ,
* instead unplug the end at the effec input and show us what happens,
* then unplug Loop receive from outside effects,
* then unplug everything from send/receive,
* then plug a known good cable straight from send to receive.

All this without moving camera/microphone nor tweaking any knob.

This is the exact same sequence of tests I'd do if I had your setup in front of me, on stage.

At the Lab I'd add a Scope and an Audio Millivoltmeter at the amp out to see and measure what is going on.

Having only a home video to show the problem I'd at least demand consistency.

Hi Juan, sorry about the poor test quality. I did state at the beginning of video i'm using a pod hd with the 4 cable method. The noise is there with any pedal I've tried in the loop. I'll see if i can get the tools right to get an audio recording of the steps you have listed. Thanks for the help.

[g1]

It doesn't have this problem with the other passive fx loops i've tested in other amps, such as a fender deville and egnater tweaker.

Those amps don't use passive fx loops which is why I think it may be your problem. Have you contacted 65amps about the problem?

[Trick]

Here's is the track utilizing the steps you had listed: https://soundcloud.com/seanlehman/ve...x-loop/s-hLm13
Nothing plugged into input, preamp and tone at 12 o'clock. Fx loop has a line 6 verbzilla inserted. *I attenuated the parts where i unplugged the jacks*

thank you for the help

[Trick]

Those amps don't use passive fx loops which is why I think it may be your problem. Have you contacted 65amps about the problem?

It states in the manual it is a passive fx loop. I posted on the fans page on facebook where Dan usually does chime in.

I noticed that if I have something directly plugged into the return and nothing in the input and boost the preamp a smidge it does boost the volume as well. I thought that was weird. Once i raise it a little then no difference in volume after that.

[g1]

Yes it has a passive effects loop. The other amps you listed that do not give you the problem do not have passive effects loops.

[The Dude]

According to the website, the amp does use a passive effects loop. That still does not mean it is designed for instrument level pedals. Because it worked with some other amp and not this one, doesn't prove anything either. Amps are designed differently. Not all effects loops are equal. A few scenarios:

1) The amp's loop is not designed for instrument level pedals. Try a rack mount effect in the loop that is designed for line levels and see if you have the hum.
2) There is a problem with the pedals or pedal power. Try the pedals in front of the amp and see if you have the same problem. This will also help prove whether the loop is designed for line level ins and outs.
3) There is a problem with the effects loop of the amp that will require troubleshooting the amp. Try 1 & 2 first.

Going on what we have so far, I'm betting g-one is right and that there is a level and impedance mismatch.

Edit: I also have to ask: What is there to gain by running pedals that are clearly designed for instrument level in an effects loop anyway?

[Trick]

Yes it has a passive effects loop. The other amps you listed that do not give you the problem do not have passive effects loops.

ahhh i gotcha...damn, if that's the case it's sounds like this is normal then.

[Trick]

According to the website, the amp does use a passive effects loop. That still does not mean it is designed for instrument level pedals. Because it worked with some other amp and not this one, doesn't prove anything either. Amps are designed differently. Not all effects loops are equal. A few scenarios:

1) The amp's loop is not designed for instrument level pedals. Try a rack mount effect in the loop that is designed for line levels and see if you have the hum.
2) There is a problem with the pedals or pedal power. Try the pedals in front of the amp and see if you have the same problem. This will also help prove whether the loop is designed for line level ins and outs.
3) There is a problem with the effects loop of the amp that will require troubleshooting the amp. Try 1 & 2 first.

Going on what we have so far, I'm betting g-one is right and that there is a level and impedance mismatch.

Edit: I also have to ask: What is there to gain by running pedals that are clearly designed for instrument level in an effects loop anyway?

The Line 6 POD HD500x which i originally was using has a line level/stomp signal switch for the fx loop. I have in line level and putting to stomp increases noise more. I do have some rack fx i can try to verify.

[Trick]

Edit: I also have to ask: What is there to gain by running pedals that are clearly designed for instrument level in an effects loop anyway?

I'd like to use the POD so that the delays/verbs/looper,etc. come after the preamp. This way they do not have any extra gain added and keep it clean.

[The Dude]

Does this maybe help?

[Trick]

Does this maybe help?

Yes, this is how I'm hooking up the pedal. The reason i also did the test with another pedal was to show the noise isn't only coming from the pod. The signal to noise ratio isn't all that bad when I'm playing but the noise is there, so it's drving me a little crazy. I'm just upset that it makes the noise using this amp and not the deville, wish it was the other way around.