Recent content by Xcalibur255

The 60hz hum will be your base background noise level from the transformer, no fixing that except to use tubes with the lowest gain possible so you're not amplifying it more than necessary. The "rattling" sound if I understand you correctly is probably thermionic noise coming from the output...

I would say it's not quite that simple. The early ones with the original transformer had enough headroom but it did make them run quite a bit hotter. More than one type of transformer was used over the years, however, and there's no guarantee the one in yours is up to the job unless you know...

A 12AT7 isn't necessarily a wrong driver to use in the amp, but with this type of design there is a trade-off being made between gain and noise which is why most people choose to stick with 6SN7 drivers. Glenn traditionally doesn't use much, if any, negative feedback in his designs which is...

Out of curiosity, why 12AT7? The increased gain over a 6SN7 or 12AU7 is going to exacerbate your noise issues. Have you tried running a 6SN7 and comparing noise levels yet?

It adds 20mA of plate current to the output tube bias. Beneficial for the 5998, pushes the 6080/6AS7 very hard (100% dissipation).

ALSO, hope everybody had happy holidays.

It might be pertinent at this point to get the first post of this thread updated with relevant info about the current state of things.

That's very interesting. I wouldn't have thought a metal can with a seal would hold vacuum integrity like that. I've read that vinylsavior post too and somehow forgot that. Getting old I guess.

There's still a glass tube inside of those metal cans. Might make for an interesting experiment to try to liberate a pair. I've done this with C3g, but the metal cans on those are technically two pieces. These might be harder to pry open without breaking what's inside but if I had a rusty...

Too much gain is the primary issue with using C3g in a Glenn OTL. Especially if the user likes 5998s. It's difficult to get a reasonable noise floor with that combo. In a bias circuit designed primarily for a 6SN7 a C3g will not perform any better than the 6SN7 does in terms of distortion...

I always meant to write more about my amp, but the funny thing about finally finding "the one" is that I really don't feel the need to to compare it to other things. More recently I also have weird power issues in my home that negatively affect the sound quality of anything I own that makes...

Always great to see a new member of the family. Congrats and enjoy @Ezumin ! These are forever amps and we're lucky to have them.

With each passing year I become more and more convinced that a significant chunk of the treble glare and treble harshness issues many people face are caused in large part by power noise issues, both at the line level and within the home with appliances and switching supplies/dimmers/LEDs...

Had bad luck with both G and GT. Beyond 6J5s even. Bit of a love hate relationship with ol' Kentucky Radio in general I would say.

There are two brands I've personally given up on because I've consistently had problems with them: the ST style Marconi L63 because they pop and develop shorts, and the Ken-Rads because they always have noise problems severe enough to make them unusable (usually the low pitch moooooooooaning...