Is it possible to adapt kt88 to a 6A3 single ended

Don't even think about it :-) The KT88 and 6A3 are completely different animals, electrically as well as mechanically.

Regards,
-- Al

Have you tried one?or just a wild guess.

I would never try any such substitution, for fear of damaging the amplifier, including the possibilities of damaging both its output transformers and its power transformer.

A 6A3 is a very low power 4-pin directly heated triode. It has 3 elements -- a filament/cathode, a control grid, and a plate.

A KT88 is a much higher powered indirectly heated beam power tube. It has 8 pins, providing connections to a filament, a separate cathode, a control grid, a screen grid, beam forming elements, and a plate.

The two tubes have numerous electrical parameters that are highly dissimilar. There are so many differences that I would see no point in taking the time to analyze their consequences. And in any event a schematic and other design information for the specific amplifier being used would be necessary to properly do so.

IMO substituting a KT88 for a 6A3 would at best, if you're very lucky, result in poor sonics. At worst it would result in smoke and fire. My guess is that the result would be somewhere in between, probably a damaged amp.

Rleff, thanks :-)

Regards,
-- Al

10-20-15: Charles1dad
A word to the wise is sufficient.

One would think so, Charles, but evidently not in this case.

Realdeal, in addition to the architectural differences I cited between the two tubes, with one being a directly heated triode and the other being an indirectly heated beam power tetrode (sometimes referred to as a beam power pentode), you might examine and compare the numbers in the datasheets for the two tubes. Which I did before posting.

You might consider, for example, the numbers for filament current, transconductance, plate resistance, and typical operating voltages and currents for the plates and grid(s) of each tube, among other numbers. As well as the graphs that will be included in a comprehensive datasheet.

Wild guesses? Yes, I did make a couple. In addition to guessing that the result of the substitution would likely be worse than poor sonics, I optimistically made a wild guess that depending on the design of the specific amplifier the result may very well NOT be smoke and fire.

Good luck.
-- Al

Thanks, Ghosthouse. Perhaps in addition to clarifying who OV is, Realdeal can provide a link to detailed information about that amplifier. I find it hard to imagine, to put it mildly, that a practical audio power amplifier using a single-ended 6A3 as its output tube could be implemented as an OTL (i.e., without an output transformer).

Charles, Rleff, Onhwy61, thanks also :-)

Best regards,
-- Al

Speaking of Ralph, here is his response to Realdeal's statement that was quoted in the post by Ghosthouse above.

Regards,
-- Al

Great post, Larry, as always! And I think that your "can guppies live in milk" analogy captures the essence of this discussion perfectly.

Mapman, thanks also. And thanks to Bill (Brownsfan) as well, for the best chuckle of the day :-)

I'm wondering, though, whether there may be more to this thread than initially meets the eye. I note that the OP has chosen not to answer any of the four questions that have been presented to him in the thread thus far. Including who OV may be, whom he nominated in the "Designer Hall of Fame" thread, and who allegedly designed an amp utilizing a single-ended 6A3 as its output tube in an OTL configuration (which cannot possibly work in a reasonable manner in conjunction with a speaker load that is even remotely conventional, as can be shown via some simple calculations), and into which a KT88 can allegedly be directly substituted via a socket adapter.

In that regard, and given the lack of clarification about that amp and its designer, I can't help but also wonder about the fact that among the many positive feedback comments RealDeal has received for sales he has conducted here, there are several in which it can be seen that his first name begins with the letter "O."

Best regards,
-- Al