Recently I bought a Blackstar Series One 10 AE tube amp. I was trying to connect the amp's speaker emulated output to the input of my Focusrite 2i2 (1st gen), which goes to FL Studio 20 as a track that I want to record. But there's no sound coming into the interface. The green ring around the gain knob of the interface doesn't light up. I've made sure both the guitar and amp are sending adequate volume. But if I connect my Audio Technica M50x headphone (38 ohm) to the emulated output, then I can hear the sound properly. I've also checked the lead wire that connects the emulated output to interface, and it's working fine. Moreover, if I connect my guitar directly to the interface, it works as it's supposed to.

Any input is appreciated, as I need this feature to record my compositions using FL Studio. I've gone though the amp's manual which can be found here, but couldn't find anything useful. I'm tabulating all relevant specs below:

  • Laptop: Dell Inspiron 5370
  • OS: Windows 10 (v1903)
  • Interface: Focusrite Scarlett 2i2 [1st gen]
    • Driver:
  • Amp: Blackstar Series One 10 AE
  • The emulated output is an unbalanced stereo output on a TRS jack. The Scarlett probably has balanced mono inputs for TRS jacks. You'll have to get a Y-cable to split the emulated output into two cables and connect them to the two inputs on the Scarlett. Or some sort of balanced-to-unbalanced mono cable. Commented Jun 17, 2019 at 20:30
  • Thank you. I've one confusion though. The headphone cable also has a 3-conductor TRS jack, and I can get the sound through that one, when connected to the emulated output. So, shouldn't the other cable also work? I'm confused.
    – Bitswazsky
    Commented Jun 18, 2019 at 2:49
  • @YourUncleBob I found out this thread, which says focusrite uses balanced input: gearslutz.com/board/…
    – Bitswazsky
    Commented Jun 18, 2019 at 2:59

1 Answer 1


The emulated output on the Blackstar amp is a line-level unbalanced stereo output. That means the audio signal for the one channel is on the Tip, and the audio signal for the other channel is on the Ring of the TRS jack. (I assume the audio will be mono anyway, so the signal on both channels will be the same.)

The inputs on the Focusrite Scarlett 2i2 are balanced mono TRS jacks (if set to line-level, which is necessary for the amp output), which means that it expects the audio signal on the Tip and the inverted audio signal on the Ring of the TRS jack. If you connect the amp with a cable with TRS jacks, you get the same signal on both Tip and Ring, and when the signal on the Ring is inverted, they cancel each other out; that's why you're getting no signal.

There are a couple of ways to connect the amp to the Scarlett 2i2. First, you could use a mono cable. This should work, but may not give the lowest background noise. You could also use a Y-split cable, with a TRS on one end and two TS jacks on the other, and connect one or both inputs, which would be better. The best solution is probably to buy or make a pseudo-balanced cable.

  • Thank you for the detailed explanation. It all makes sense now. Out of the 3 options you mentioned, the Y-split cable might be the best choice for me, as I neither have the tools nor the patience to make a pseudo-balanced cable. I couldn't find it online as well, here in India. One naive question though, would a DI box work in this case?
    – Bitswazsky
    Commented Jun 18, 2019 at 4:45
  • 1
    @Bitswazsky According to the article I linked to, a DI box would work, but they also mention drawbacks. Commented Jun 18, 2019 at 4:58
  • Oh, sorry I overlooked that part. Looks like Y-split cable it is, unless I can manage to find a pseudo-balanced cable online.
    – Bitswazsky
    Commented Jun 18, 2019 at 5:10
  • @Bitswazsky It appears that most cables sold online as pseudo-balanced are the basic variety, without the resistor and capacitor, so you could as well make your own. Commented Jun 18, 2019 at 5:53

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