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Helix/orange TH30/torpedo captor - help!

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Re: Helix/orange TH30/torpedo captor - help!

PostPosted: Sat Oct 27, 2018 6:39 pm
by BobTheDog
Here is the layout:

Image

I just tested the ground from power plug to input on the TH30 and got less than 0.1 ohm, so that looks good.

I tested from the cable ground sleeve entering the amp to the ground sleeve entering the guitar and got 2 ohms, is that a little high?

Re: Helix/orange TH30/torpedo captor - help!

PostPosted: Sat Oct 27, 2018 8:04 pm
by blinddrew
Which of the amp, helix and captor have proper grounds and which are type two devices?

Re: Helix/orange TH30/torpedo captor - help!

PostPosted: Sat Oct 27, 2018 8:15 pm
by BobTheDog
The Helix and amp have proper grounds.

The Captor is powered and grounded by the Speaker output from the amp.

Re: Helix/orange TH30/torpedo captor - help!

PostPosted: Sat Oct 27, 2018 8:21 pm
by BobTheDog
One thing I have been wondering is that there does seem to be hum from the amp, especially at 50hz and 100hz. These I find hard to hear through my monitors but when using the Cab the hum is there. This is just with guitar into amp.

Adding the helix seems to amplify these and add extra ones.

So could there be two issues, one with the amp and one with the helix?

Re: Helix/orange TH30/torpedo captor - help!

PostPosted: Sat Oct 27, 2018 8:39 pm
by BobTheDog
So this is the hum from the amp, via the captor into an Apollo, gain on Apollo at 0.

First, amp off so noise through interface:

Image

Then amp on, clean channel, volume at 0.

Image

Re: Helix/orange TH30/torpedo captor - help!

PostPosted: Sat Oct 27, 2018 8:44 pm
by BobTheDog
Raising the amp volume to full doesn't seem to change the 50/100 hum much, just generally raises the noise floor:

Dim plot is amp on full.

Image

Re: Helix/orange TH30/torpedo captor - help!

PostPosted: Mon Oct 29, 2018 2:06 pm
by CS70
Don't known the Helix, but if it works like a regular amp (which it should) the FX send is post-preamp? Does it send instrument or line level? The TH30 input is made for guitar, so it expects a relatively tiny instrument level voltage whereas you're sending line level. I would expect the in/out impedances may also not be right - is there an impedance control on the Helix?

Re: Helix/orange TH30/torpedo captor - help!

PostPosted: Mon Oct 29, 2018 2:33 pm
by BobTheDog
Hi,

Thanks for the reply.

The send/returns can be set to Instrument or Line, I have all of them set to instrument apart from the return from the Captor which is set to line.

I am now at the stage where I am trying to get to the bottom of the hum in the guitar amp that is there even when the Helix is not connected.

After a bit of reading I think it is the Phase Inverter tube that may be faulty so I am going to try replacing that...

Once I can get the Amp so that doesn't hum I will look at connecting the Helix again!

Re: Helix/orange TH30/torpedo captor - help!

PostPosted: Mon Oct 29, 2018 2:38 pm
by CS70
BobTheDog wrote:Hi,

Thanks for the reply.

The send/returns can be set to Instrument or Line, I have all of them set to instrument apart from the return from the Captor which is set to line.

I am now at the stage where I am trying to get to the bottom of the hum in the guitar amp that is there even when the Helix is not connected.

After a bit of reading I think it is the Phase Inverter tube that may be faulty so I am going to try replacing that...

Once I can get the Amp so that doesn't hum I will look at connecting the Helix again!

Ah-ah, yes if the Orange is noisy by itself of course it doesn't help. :-) Best of luck!

Re: Helix/orange TH30/torpedo captor - help!

PostPosted: Mon Oct 29, 2018 4:15 pm
by Wonks
The phase inverter valve may benefit from being replaced, but as ef37a pointed out to me, the two halves of the PI valve are almost certainly more closely matched than the bias resistors for the valve will be. I fitted a 'matched' valve in the PI position in one of my amps and it certainly reduced a lot of the hum, so maybe I'm lucky in having carefully selected bias resistors as well than could make use of the selection for equal gain. This is why some amps have an adjustable 'num balance' pot in series with one of the PI bias resistors (thats of a lower value than the other one) so you can set the bias of half the valve to match the other half for least hum.

But the hum may also be from one of the other pre-amp valves. You could simply try swapping preamp valves around (of the same type e.g. 12AX7) to see if one combination produces less hum than others.

Re: Helix/orange TH30/torpedo captor - help!

PostPosted: Mon Oct 29, 2018 5:02 pm
by Hewesy
Just a thought, you're coming into the Helix twice, once from the amp send then again from the Captor, but you are not mic'ing up the Orange cab?

As it's the send from the Orange adding noise, if you are not mic'ing the speaker presumably you could use the line level out from the Captor to feed the Helix as presumably the sound should be the same as the amp's FX send - from reading the Two Notes website the Captor needs their software to add in cab sims within a DAW so this should presumably be a "dry" output i.e. the unit itself is not trying to add any cab sim/EQ curves?

So you'd only need to feed the Orange FX return from the Helix if you wanted to use Helix preamp/Orange poweramp/Captor.

Shout if I have missed something blindingly obvious...!

Hewesy