6550 and KT88 differences?

If I were to investigate new KT88's I'd be interested in the new Gold Lion reissues. Minimal input yet, but from what there has been they 'sound' like they might be excellent. Don't read too much negative into my assessment of the SED KT88. Of all the tubes I tried in my Prologue 5 (including EL34's and 6L6's)and other brands of 6550's and KT88's it was my favorite. All tubes are agruably colored, depending on your speakers and amp, not to mention sonic preferences. Also, don't overlook the impact you can benefit from in further refinement by changing the small tubes.

With respect to its design, the KT-88 is the British variant of the 6550.

In use, they have proven less reliable than the 6550, particularly back in the 80's when their were some especially poor quality Chinese KT-88's that were more roman candle than output tube. VAC sells very good KT-88's.

It depends upon the use to which the tube is put and the production run, but in my experience, KT-88's tend to be a bit richer sounding than 6550's, while 6550's may be more accurate and linear.

and now for something completely different...

Try some KT66 toobs!
According to Primaluna these will also work in your integrated 8^)
The 6550's were softer in the top, and in the long run had a somewhat bloated bottom for my tastes.
The 66s on the other hand really spiced things up, it made the music more lively, a bit more forward, yet they offered the speed, detail, resolution, and transparency I wanted without sacrificing the sweetness and body I had grown to love.
additionally I have also rolled the small tubes in conjunction with them making an even bigger impact - the clear top 12au7 very smooth which compliments the 66s well. Along with some Brimar 12BH7s that added to the transparency sound scape .
thanks to the Kats @ the tubemonger for helping me match all the above.
cheers

The 6550's were softer in the top, and in the long run had a somewhat bloated bottom for my tastes.
The 66s on the other hand really spiced things up, it made the music more lively, a bit more forward, yet they offered the speed, detail, resolution, and transparency I wanted without sacrificing the sweetness and body I had grown to love.
additionally I have also rolled the small tubes in conjunction with them making an even bigger impact - the clear top 12au7 very smooth which compliments the 66s well. Along with some Brimar 12BH7s that added to the transparency sound scape.
thanks to the Kats @ the tubemonger for helping me match all the above.
cheers

I have ASL Hurricans which use KT 88's. Has anyone (or can this be) changes tubes to 6550's...and what was the differnence with the Hurricanes (sound).
Any good prices on KT88?

The SED 6550 had a very soft and rich midrange, almost mid hall sounding, not clinical sounding though. It made voices just a little too soft to let singers with an etched voice like Diana Krall sound natural in my system.

The SED KT88s much more dynamic and open sounding, yet still possessed a textured midrange. If you have a bright amp that is bothering you, you might like the SED 6550, if you want to open things up and be more front row center sounding, the KT88s will probably prove to be the best choice. The KT88 for me was the much better of the two choices in tubeds.