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As I write this, I'm listening to the whoosh of my DT50-112. I should be hearing less of that, or nothing at all, I believe. And I'm ready to try some new tubes, even though I don't actually need them at the moment. From what I've seen here in this forum, the EH tubes from the factory are the culprits, but folks trying JJ tubes and other makes have experienced premature failure. There was a post from a Line 6 tech who said that the el84s <EDIT--he did not cite EL84s, I believe he was speaking only of EL34s, which go only in the DT50> MUST be the EH tubes due to narrow tolerances required by Bogner's design, and that EH was the only tube known to be in compliance with the stricter standards. <EDIT see below for the link to this quote> Further confusing to me is the lack of discussion about the EH tube choices in the el84. <EDIT--SHOULD BE EL34 FOR THE DT50> If you look at MF or Amazon, you'll see that they come in 3 flavors: soft, medium, and hard. Which ones do the DTs ship with from the factory? One poster opined that replacing the inverter tube and the other little guy (12ax7s if memory serves) helped with the noise floor. Does anyone else concur with this? Apparently any ole 12ax7 will work for these. Should I stick with EH or is another brand better? So what do you, oh community of DT players, have to say? Care to share? THANKS!
The Helix is designed for the user to set up a number of signal flow combinations. It allows for unique situations that would normally be extremely difficult to set up in real life. They can now be easily arranged within the unit. For further reading, make you also check out the Helix manual section on Serial vs. Parallel Routing and Moving Split & Merge Blocks. View the Helix manual here Having said that, you can also get some un desirable results if you're not careful with how you set up your routing. These can include phasing issues, volume drop, or noise floor increase. *Notes about Inputs and outputs Â· 1/4" Returns are unbalanced. Â· All Helix outputs (main outs and Sends) are impedance balanced, so you can plug a TRS cable and go to another device balanced input and profit from some common-mode noise cancellation. . When the Helix outputs are set to line level, they are +4dBU nominal with approximately 15dB of headroom. When set to instrument level, they -10bBu. Or more simply, they are 20Vpp max input/output. Noise floor increase due to the introduction of Sends and Returns When using the Helix sends and returns the noise floor can be increased. This is due to the number of A/D converters now used in the signal chain. Most of the increase is negligible. However, it can become more noticeable if the sends/returns are placed in front of a high gain amp model such as the PV Panama (Peavy 5150) due to its inherent high noise floor. This phenomenon occurs on the Pod HD series as well. . Potential latency issues due to the introduction of Sends and Returns This is another one that you won't notice in most situations, but could arise given certain circumstances. The tiny amount of latency introduced from another set of A/D converters is impossible to hear on it's own. An issue could occur if you merge that pathway back with another serial pathway that wasn't going through that send/return. The millisecond delay may cause some undesirable phasing. Below I have pictured a signal path that might yield poor results. If you move the merge block before the Send/Return, then it would eliminate any potential phasing issues. Using Helix Hardware as an interface to record When using the Helix as an interface with a DAW, the signal routing can get a little confusing and it might become difficult to balance levels for monitoring. The typical set up would be guitar into Helix, then Helix to computer via USB. You would then monitor from the headphones, 1/4" or XLR outputs. Given that setup, the guitar and the DAW's playback are sharing the same monitoring. If you have the guitar going into the DAW and then back out, you will hear your guitar twice. You can mute the DAW's return of the guitar track to avoid this. Also, in this case the volume knob will control the total output making it tougher to balance the sound of the guitar and the DAW's playback. Try setting the volume knob to only control the feed you're monitoring, and it will no longer control the USB feed to your computer. You can also try making the playback volume adjustment from the DAW. Using Helix Hardware as an interface to record with Helix Native The above signal flow still applies, but a new level of complexity is added. Since the hardware is no longer processing the guitar, you can't mute your guitar tracks return feed, because you'll want to hear it. What works best is the set up the Helix with a blank preset, and then change the output block to your desired USB output. That way, the only thing you're hearing from the Helix is your DAW's return. Auto Impedance Switching With the Helix family, the default setting for the guitar input is auto impedance. The impedance will be determined by the first block in the signal chain. Even if the first block is bypassed, the impedance setting from that effect block will determine the input signal level. This automatic impedance will change the input volume and tone, this is most apparent with guitars that have passive pickups and are directly connected to the guitar in of Helix. Distortion Pedal Volume Drop Sometimes when adding a distortion/fuzz pedal, your signal volume drops. Here's a link to a great article written by our sound designer Ben Adrian that can explain in detail what's occurring. Although the article is written to describe what happens in the analogue world, it's affect can be experienced within the Helix and it's digital models. Distortion Pedal Volume Drop (and how hard diode clipping works)
My DT50 212 has a prominent hum, even when no guitar is plugged in. It is not affected by the master volume level. It changes level slightly when using different voicings, but is quite loud in all of them. A tech listened to it and said that it is somewhat higher pitched than a 60 cycle hum. It has always hummed and been noisy, but it was not such a problem in a band setting. Now I would like to use it more for recording and it has become quite a problem, as the noise floor is very high. I have experimented with one or two different 12AX7 tubes in the past with not much difference that I could tell. I have not tried a Mesa SPAX7 as has been suggested in other posts. I have opened a support ticket, but any help/guidance/info from the forum would be greatly appreciated. Thanks so much!
After waiting 6 weeks I finally got my DT50-112 back, and it's just as noisy now as it was when I took it in. Being that my tech couldn't find any reason for the noise, and having heard similar complaints about the noise in these amps from other owners, I'd begun to wonder if playing at practice volume while hearing fizz and whoosh and buzz (and even before I plug in too) was just the way this amp was built. After all, it's a high-gain hybrid yadda yadda... Then I ran across a used DT25-112 at a local store, and found that this amp has about one-tenth the noise that mine does (and this would be in either LPM or regular mode). Even in voice III, which we all know is the noisiest, I practically had to stick my ear on the grill cloth in front of the cone to hear the noise. In other words, this amp has an appropriate level of noise (very unlike mine). At half the watts of a DT50, somewhat less noise is to be expected, but this is totally night and day, and my frustration level with my own amp is soaring. So before I ship this puppy back to Line 6 with angry letter, does anybody out there know if these 2 amps I've played are representative of their brethren? Are all DT50's noisy beasts while the DT25's are just fine? Or are some amps just plain noisier with no real explanation why? Or is my theory that something is wrong with my amp the best bet here? THANKS!