Difference 300B / KT88 ?

[Dr. Flicker]

Hi Dr Flicker,

May I draw your attention to this, which you seem to have missed:

Quote:
What's your first name and where are you from?

Oh...I didn't miss it...I'm not blind, shy nor unfriendly. Being an admin, I just assumed you checked the "welcome" section, where following forum instructions, I made my first post giving my name, location, equipment, etc.

But it's Kevin...from Toronto.

[anthonyTD]

Oh...I didn't miss it...I'm not blind, shy nor unfriendly. Being an admin, I just assumed you checked the "welcome" section, where following forum instructions, I made my first post giving my name, location, equipment, etc.

But it's Kevin...from Toronto.

thats told him!!!
welcome kevin.
anthony,TD...

[Marco]

LOL. Very good, Kevin!

Do you expect me to memorise everyone's name or something?

That's why it needs to go into your signature so that it appears under all your posts. So please add "Kevin" to that, and "Toronto" to your profile.

Cheers!

Marco.

[Dr. Flicker]

Do you expect me to memorise everyone's name or something?

Uh....yea?

But what's the point of being Dr. Flicker, anonymous internet chat forum audio fool, if you know my real name (but don't really unless it accompanies every post I make)?


Ok...so let's get back to 300B vs KT88.

The 300B is a triode and the KT88 is a pentode

A pentode can be run as a triode, but a triode cannot be run as a pentode

Triodes are generally used for single ended and pentodes are generally used for push-pull, although there's nothing stopping you from doing either with either tube. Either can also be used in parallel single ended or parallel push pull.

The KT88 run as a single ended triode will give you 5 watts pure class A, and the 300B run as a single ended triode will give you about 7 1/2 - 9 watts pure class A. I think most people would agree the 300B sounds better, as well as having the power advantage.

You can run the KT88 as a single-ended pentode for about 15 watts of pure class A, but again, not going to sound like the 300B. As a matter of fact, it is debatable whether running a pentode in triode mode is even a great idea at all.

You can run the 300B and KT88 in push pull, and the resulting advantage is more power, but now you lose any advantages of single ended and pure class A sound (if you indeed consider those advantages in the first place). More output tubes also mean more cost.

A lot of people believe that the 300B does its "magic" in SET configuration, and using it any other way takes away from that. The KT88 can be used quite successfully in many ways, as it doesn't seem (to me anyway) to be that special as a SET, making it quite equally adaptable for more power, and hence able to drive many types of speakers.

The 300B sounds best as a SET, but suffers the problem of low power output, making it limited in speaker choice because of efficiency and loads. But, this problem can be overcome by simply being very careful with speaker choice. The push pull amps solve the problem of low power, but cannot sound like a SET.

What this boils down to I guess is not which tube...but SET vs push pull. For SET, my vote goes to the 300B. For push pull...not sure...let's call it a tie?