Will KT77 Tubes fit in 6v6 slot without Adapter

[burton4snow]

Doing a tube swap on an Egnator Tweaker

[WRGKMC]

They are Apples and Oranges that aren't even from the same tree. The two tubes are incompatible and require different amp circuits and components to run.

 

As far as adaptors go, you can find adaptors called Yellow Jackets, that allow lower wattage power tubes to run in a higher power amp.

 

No adaptor is going to provide the higher voltages to allow higher wattage tubes run in a lower powered amp.

 

The power transformer on a 6V6 amp produce maybe 400~460V max. The output of each 6V6 is only 15W max. A pair produce 30W.

 

A KT66 needs around 800V. KT77 can produce 35 W each and 70+ watts a pair and would easily smoke a 6V6 transformer.

 

All the surrounding circuitry in the amp chassis or the two amps are completely. The KT77 components are need to handle the higher voltages/currents for the higher powered tubes.

 

Think of the 6V6 as a 6 cylinder engine, and the KT77 as a 12 cylinder.

 

Other tubes can be 1 stroke, 2 stroke, 4 cylinder and 8 cylinder.

 

You can stick a smaller engine in a car. It may whine loudly and sound terrifying, but its essentially under powered for that car size. This is essentially what tube adaptors do. you're sticking smaller engines in larger cars to make a big noise, but its got no power or speed.

 

You can't stick a Mustang engine in a tiny VW without "Major" redesign and modification. Transmission, Wheels, Brakes, chassis, cooling, electrical system you name it would all need to be changed out as well to support that larger engine.

 

When you're done, none of the original Volks wagon parts will be left besides maybe the chassis (and even that may be too small) It may look like a VW on the outside but you essentially have a hand built Mustang that cost a mint to build.

 

It would have been cheaper and more reliable to just buy the Mustang in the first place if that's what you need.

[guitarcapo]

A KT77 will fit in the same OCTAL SOCKET slot as a 6V6. And Bill Egnater has stated that any octal power tube that will fit in the Egnater Tweaker, will work in an Egnater. BUT:

 

The biggest issue when swapping out a 6V6 for these larger power tubes is the heater current that a K77 consumes. About 1.4 amps per tube.

A 6V6 uses .45 amps per tube....Since there are two power tubes involved, we are talking about an increased work load on the power transformer of almost 2 WHOLE AMPS.

 

Bill Egnater says (indirectly.... assuming "any tube that will fit will work") that his Tweaker can take this.... but I'm a bit skeptical. I'm thinking he had more common octal power tubes like EL34, 6L6GB and 6L6GC etc in mind. KT77 tubes are a bit tall and I'm not sure they would fit inside a Tweaker's enclosure anyway. The "coke bottle" versions certainly won't. Too wide. I've tried. Bias isn't probably an issue at least because this amp is cathode biased.

 

And after all this, what would you gain? Well, in my opinion, Kinkless tetrode power tubes have a bit more "mid hump" to the sound. That thick swampy dull overdrive sound that better for heavy rock than sparkling cleans. But it's nothing you can't get from a cool pedal like a Snouse Marshall Bluesbreaker a lot easier, cheaper, and with less strain on your amp's power transformer.

 

That's not to say that I use 6V6 power tubes in my Egnater Tweaker. After a lot of tube swapping I ended up liking a pair of GE 6L6GB in mine. The sound is a bit more mid scooped and "bigger" on the cleans with a tighter bass than a 6V6 delivers. It's subtle but I love it going into a 12" speaker cab either with a Jensen C12N or P12N.

 

If you have a KT77 that fits, you might try it in your Tweaker for a short while to see I you like the sound....but I probably wouldn't recommend doing it for a long time....maybe just long enough to see what I'm saying about the sound not being worth it.