MrEleventy
Headphoneus Supremus
- Joined
- Oct 24, 2012
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You also won't be using the tube plugging in via the rca ins. it bypasses the tube buffer so you'll just be using the ss amp.
I really wonder what the hell it is that makes 6AQ8's not friendly to the T1, it certainly isn't the heater as the T1 is rated up to 3A...
The gain is likely too high (57 vs 33 for 6DJ8), resulting in clipping.
I'm not that well-versed in tubes, but AQ has a Va (anode voltage?) specified at 250V while the DJ is 90V. Running the AQ at 90V may be sub-par as it only uses part of its full range.
Just guessing. Here are the data sheets...
http://www.r-type.org/pdfs/ecc85.pdf
http://www.r-type.org/pdfs/ecc88.pdf
Figured out two things over the past few days related to two separate problems.
This info might help some of you guys out, so please read carefully if you experience any of the two issues I experienced.
1) The sound would suddenly start to become muddy, even nasal-sounding, with a lot of distortion and static. Powering off the T1 and powering it back on would temporarily bypass the issue which would creep back up a few minutes later. For the record, I'm using an Amperex Orange Globe tube which emitting tons of heat. I couldn't leave my fingers on the tube for more than 1-2 secs. On a hunch, I bought a USB fan and pointed it towards the tube. Haven't had the issue since. It confirms what I was thinking following my experiment with seeing temperatures exceeding 140 degrees F with a BBQ thermometer. Not sure if this is considered to be a defect, but there you have it. In case anybody's interested, I bought a Thermaltake USB fan, although any USB fan blowing enough air will cool the tube enough to prevent this problem from occurring in the first place.
2) Secondly, I was hearing tons of electromagnetic interference (EMI) noise from my speakers that was originating from my PC. Every time the hard drive would be accessed or I would be scrolling through a website, I would hear static. There would be a constant squealing as well. Following advice I got from another forum, I bought myself an Olymex USB isolator (https://www.olimex.com/Products/USB-Modules/USB-ISO) that I plugged the wire originating from my PC into before connecting the USB isolator into my T1. Solved my issue instantly and I now have a perfectly quiet noise floor. Absolutely zero noise when no music is played and the music is therefore also clean-sounding, now.
Hopefully, this will help whoever has these issues.
That's the thing though, the tube worked perfectly for over half a year, no gain issues or clipping, not only that the issue it has is only with the right channel, the left still sounds great.
any1 here use GE 6AQ8 ECC85 for hip hop, dubstep songs ? I recently purchased that tube to replace Electro Harmonix6922EH. With GE, acoustic and instrument are sure sound warm and decent sound staging but electric beat give me some jittering and kind of distortion. more obvious at high level.
I used foobar and all equalizers are off. any thoughts ?
Is the distortion only for certain frequencies? Try setting your computer volume to 100 and lower the gain on the T1, if the noise is still present, try setting the T1 to maximum volume and gain while setting the computer to lower volume, worth exploring all options at this point.
I had a GE ECC85 that I found to be a perfect match for my DT990s, it worked perfectly for all of 8 or so months before I started getting bass distortion on the right channel.
Distortion is rather common with 6AQ8/ECC85 tubes and the T1, at this point it seems that getting a compatable tube is a matter of luck, thus why I'm trying to test mine by buying a 3rd 6AQ8 tube in the hopes of finding a good one.
I'd like to add on that before buying a USB Isolator, if you have a desktop then I would suggest trying to plug into the USB ports on the back of your computer, often times it's the front USB ports that plug into headers that have all the noise, while the rear ones that are directly on the motherboard I've found to be clean most of the time. This largely varies on your computer though and if you have this issue with a laptop you're going to need that isolator.