More tube questions

[bds9487]

I'm looking at the groove tube kt66's on musiciansfriend.com. Do any of you guys know the difference between the ratings?

* Low (1-3 GT Rating)
* Medium (4-7 GT Rating)
* High (8-10 GT Rating)

Thanks.

[kissfanps]

go to the groove tubes website

i dont suggest groove tubes. for the most part they just stamp their name on another brand and charge you for it.

[Dave W]

+1...I am not a fan of groove tubes, they are a re-labeler of tubes. Your money is paying in some part for the tubes be relabeled by Groove Tubes, you can find the same tubes for cheaper. They get their tubes from the same factories. There are lots of places where you can buy tubes without being re-labeled and they will match them correctly etc. I also recommend avoiding big places like the big online music stores for tubes because they are usually overpriced and you are really not dealing with anyone at those places who knows tubes. Just googgle tubes or a specific tube and you will have plenty of options with stores that deal in tubes specifically.

[MKB]

I think the ratings relate to the relative value of sensitivity of the tube to bias voltage; i.e. a higher number will need less bias voltage for a given bias current setting. They try to spin the number to mean something tonally, but I'd think this is a bit of a stretch. What it does buy you is consistency; you bias your amp for say a #5 set, when you retube you are supposed to be able to get another #5 set of the same tube type and install them without needing to rebias the amp.

That being said, I have had very good luck with Groove Tubes, and still buy them. I think they do a better job screening out bad tubes; I've had other sets from well known retailers that have failed quickly, but all the Groove Tube sets have worked very well and held their bias. I did have one Siemens EL34 in a Groove Tube quartet fail back in the mid-eighties, but they were quickly replaced. They are also easy to purchase in that many retail stores carry them (in case you need a set quickly). They are a bit expensive though.

[bds9487]

Thanks for the input, guys. As some of you might know, I bought a set of Tung Sol kt66's from musicians friend. I discoverd, via this forum, they're not compatible with my VM. So, I'm exchanging them and the only other brand MF carries is groove tube.

[bds9487]

I found it: