Groove Tubes Rating System +Boogie Amp

[dmt]

I am looking at a Quartet of GT-KT66 HP tubs that are rated "10" on the GT Scale. What does this translate to the Boogie Ratings?

I spoke to Mike B. and he recommended that I use "cooler" tubes in the outside pair, so that the tubes won't burn up in Class A.

Are these tubes usable in my amp? These tubes are supposedly the Saratov KT66 tubes, but I want to make sure that they will work well in my amp. I have been using new production Sovtek KT-66's but I would like to try some better tubes, but NOS tubes are too expensive, and I don't trust the Chinese replicas.

 

[Rocky]

Those are completely out of the boogie range. I wouldnt recommend using them.

The 'boogie range' for Groove Tubes is 4 to 7. 1-3 and 8-10 are way out of the Mesa bias range.

 

[MusicManJP6]

Rocky nailed it...

 

[dodger916]

The higher the Groove Tube number the later the breakup, thus providing more headroom:

http://www.guitaramplifierblueprinting.com/Rating.html

 

[dmt]

The higher the Groove Tube number the later the breakup, thus providing more headroom:

http://www.guitaramplifierblueprinting.com/Rating.html

Yeah I saw that too, I'm not sure what it means tho. According to that page, a "10" simply means more head room, while Mike B. recommended Mesa "Red" or "Yellow" for the Class A pair. Those convert to "4" on the GT scale.

I don't mind more clean room, but I want to make sure that they work in the amp.

 

[JOEY B.]

The higher the Groove Tube number the later the breakup, thus providing more headroom:

http://www.guitaramplifierblueprinting.com/Rating.html

Yeah I saw that too, I'm not sure what it means tho. According to that page, a "10" simply means more head room, while Mike B. recommended Mesa "Red" or "Yellow" for the Class A pair. Those convert to "4" on the GT scale.

I don't mind more clean room, but I want to make sure that they work in the amp.

Listen to Mike Bendinelli, as this has to do more with idle current draw than clean headroom. 8)

 

[dmt]

I bought some GT-KT66-HP's that are marked "7" and some marked "5", so those should work fine. The "5"'s ill put in the Class A sockets and the "7"'s I'll put in the middle. Any reason against this?

 

[domct203]

I bought some GT-KT66-HP's that are marked "7" and some marked "5", so those should work fine. The "5"'s ill put in the Class A sockets and the "7"'s I'll put in the middle. Any reason against this?

You should be ok. You should consider a bias probe. They are real easy to use, and it's good to know what your idle current is, especially if you ever try non-Mesa tubes.

Just because you can't adjust the bias doesn't mean you can't check it.

Dom

 

[dmt]

Yea, I've been thinking about that as well as a tube tester. I'm not sure of what to get in the way of a tube tester. I want something inexpensive that will provide me enough data to know some basic information about what tubes I have and or buy.

On the note about these particular tubes, I am having the Mesa store take a look at the amp and make sure that the tubes are within spec. No reason that they shouldn't be, but I have requested that they check the amp out and make sure the tubes I provide them are within the range of the amps capabilities. I want the amp to work well and last a long time, no use if I melt tubes or components.

 

[dmt]

I tested the tubes today, just to get an idea of whether or not the tubes would work in the middle two slots and I found that 2 of the 4 tubes began to redplate almost immediately. The other two tubes are fine and did not redplate in the middle two sockets. Looks like I am going to swap the two tubes that are out of spec for another pair. These 4 tubes are rate "7". The other quartet that I ordered should be here in a few days and is rated "5", so that may work better for the outer pair, and hopefully those can withstand running in class A.