High Pitched Squeal on Tonelab

[rnegtr]

I bought a used/demo Tonelab and noticed that on certain higher gain amp models (UK90, UK Mod, US High Gain, etc.), if I have the VR gain and gain turned up fairly high and/or use an OD or boost with them, the unit produces a high pitched squeal in my headphones or output. Is this a defect in the unit? Tube issue? Internal feedback? I don't use these super high gain amp models too often but I want to be sure there is nothing wrong with the Tonelab. (I looked over the sight here and did not see any similar posting but maybe someone has seen this before). It is not affected by turning down the treble or presence. I can kill it off by dialing way down the gain or VR gain.

I bought this demo unit for a very low price knowing I might need to tweak it a bit or change a tube). Please advise. Thanks.

[Nik]

Does it do this with the guitar volume down?

Might be that the valve is microphonic. Change it. It's a good idea to carry a spare anyway.

[rnegtr]

As I recall, it happens even with the volume off on the guitar but I'll double check. (I ran it thru a bunch of different settings to see what was happening but I just don't recall if turning the guitar down all the way stopped it). Anyway, the tube sounds like a good idea. I thought I saw a posting somewhere about how to change to the tube so I'll look for that too. Thanks

[Nik]

Did you try it with the guitar volume down?

[cmac54]

Problem with my Tonelab SE: I purchased it new about a year ago and it's been great until last night at a gig. Set it up as usual, powered up and I got primarily a "white noise" sound with a very low distorted guitar sound buried in the background. Sounded somewhat like an open ground but with lots of static. I did all the troubleshooting I could on stage, changed guitars and cables, changed power sources, eliminated wireless and other external devices, changed SE patches, adjusted SE output level but no change. Any thoughts?

[cmac54]

Problem with my Tonelab SE: I purchased it new about a year ago and it's been great until last night at a gig. Set it up as usual, powered up and I got primarily a "white noise" sound with a very low distorted guitar sound buried in the background. Sounded somewhat like an open ground but with lots of static. I did all the troubleshooting I could on stage, changed guitars and cables, changed power sources, eliminated wireless and other external devices, changed SE patches, adjusted SE output level but no change. Any thoughts?

[rnegtr]

Well, I got this one started a while back and just haven't had the time to dive into it until now. Part of this was inspired by the posting of the wonderful amp model spreadsheet on the Vox site. I realized what may be at the heart of this (see what follows). So here's the analysis on my Tonelab:

The high pitched squeal is not a feedback type sound. It is higher pitched than that. When it occurs, it will NOT happen when the volume on my guitar is off, but even the slightest volume will set the squeal off. It as far as I can see it is directly related to the VR gain control. And it only occurs on the higher gain amp settings (UK-80, UK-90, UK Mod, Recto, US Hi Gain and Botique OD). I saw in the TLSE Amp model link that these are the amps where the VR control is essentially a Master Volume (as opposed to the others where having it on maximum is the accurate model setting). So, if I just turn the VR down to about 12:00 or below, I can avoid the squeal. The other parameter that effects it is the stompbox setting. If I increase the gain on a overdrive or distortion pedal, the squeal will set in at a lower VR level. The overall volume of the Tonelab does not effect the squeal (it happens at low overall levels -- again, just being tied to the VR setting).

That's it. I can't say that this is a correct behavior of the Tonelab but that's what happens. Has anyone else encountered this? And can anyone else offer any explanation for it? I put in a new tube and it did not correc the problem. It's as if there is some internal looping that amplifies the high pitch tones into the squeal at these high gain, high level settings.

And having said all that, the Tonlabs are still the best sounding modelers out there....

Thanks all, Robert

[Voxman]

Sounds as if your pick-ups might be the problem, not the TL - they've possibly gone microphonic. Can be particularly problematic with single-coils that aren't potted.

Rich

[firebrand]

If you are using both a high gain amp model and a high gain setting on a distortion pedal model this is bound to happen. They gave the ToneLab enough gain in both the amps and the pedals to please most musicians. Combining the 2 gives you more gain than ManOWar would know what to do with.

My Traynor amp will do the same thing. If I set the lead channel master, lead channel gain and the boost gain all higher than 9 o'clock it squeals. Just too much gain causing an undesirable feedback. The fun thing is I can change the pitch by turning knobs...

[rnegtr]

That might just be it. I was just wondering if other Tonelab users had actually encountered the same issue. Do you have a Tonelab and can you duplicate the problem? Just like you described, depending on the pickup or settings, the pitch will vary. Voxman mentioned microphonics but that's not what's happening. Most of my guitars (even the Strat style ones) actually have humbuckers and I've tested this on them and the squeal is still there. If I run the Tonelab into my DA-5 and have the amp volume so low it's barely audible, the squeal still occurs if the Tonelab settings are as I've described. So again, what you've said makes sense, I'd just like to confirm this with outher Tonelab owners. Thanks.