Sonic atributes ultralinear vs tetrode vs pentode


What are the sonic attributes of and amp running in Ultralinear vs tetrode vs Pentode. Looking to get a new amp, but live in a rural area can't audition them all. I don't like what I have heard from Ultralinear amps, too hard sounding for me. A lot of new pentode amps on the market, can't audition any. Why pick one over the other?
Thanks
Mike
128x128brm1
Mike, so often, it's the loudspeakers that are the culprit in an amplifier coming across as hard. However, that's an argument for another time and place, so let's continue to focus on the amplifier.

In today's world, there are scant few examples of true tetrode/pentode amplification. You have to look long and hard to find them. What makes things all the more confusing is so many amps labeled "pentode" are actually ultralinear. As I said, UL rules the day, and has since the 1950s.

That said, given the case you laid out in initiating this thread, I think you would would find more happiness with UL than pentode operation, the latter sounds more forward, open, and to use your term, hard. Pentode would steer you more in the direction you're trying to get away from. So, I think UL might be getting a bad rap if you think it sounds hard.

Here are three characteristics that can "soften" an amplifier:
1) Triode operation
2) Cathode (or self), as opposed to fixed, bias. To put this in a more understandable way, though it doesn't hold up all the time, look for an amp where the tubes are "plug and play", and need no adjustment of bias on the part of the user. The label "fixed bias" is counter-intuitive to most folks
3) Tube rectification

I wouldn't exclude a product based on having having only one or two of these features, as I can name some amps with only one of these three that sound quite warm and lush. But again, generally, these three take things toward where you mentioned wanting to end up.
Trelja,
Thanks for the responses'. Never having opportunity to hear a Pentode amp I feared that might be how it would sound. Definitely not what I am looking for. Honestly I have heard a Eastern Electric 520 amp that does Pentode/UL. I did not like that amp in Pentode, so I listened to it mostly in UL which did not sound like UL in other amps that I have heard, so I did not really want to take that experience as "true to like". Jolida,Cary, and other amps of that ilk did not sound like that in UL, they sounded "Hard"
Thanks
Mike
"What first needs to be recognized is that 0 is not one of the endpoints for a comparison between triode (20 wpc for the example at hand) and pentode (60 wpc). UL (40 wpc) is exactly midway (IOW, 50% not 66.67%) between the two. As such, the word "most" can never be used in such a context."

Speaking of "fatally flawed" analysis, would you try to argue that 10000 wpc does not retain "most" of the power of 10001 vs. 9999? After all, 10000 is exactly halfway between 9999 and 10001. I've only been following this dialogue between you and Ralph for a while, but it seems to me that your zeal to show him up outweighs your interest in contributing to this forum. I could just dismiss you as a troll, but you actually seem to know quite a bit when you are not trying to bait him. I'm enough of a noob to be ignorant of whatever has pulled your chain, but I don't think that you are making much of a contribution by making it unpleasant for Ralph to respond to this forum.
Thank you, Mike.

Jolidas are fixed (adjustable) bias. Some of the Cary offerings are cathode bias like the AES Superamp, and are considered to fall more on the lush and full-bodied side of things; some of their other products can be more forward.

Mcpherson, "would you try to argue that 10000 wpc does not retain "most" of the power of 10001 vs. 9999? After all, 10000 is exactly halfway between 9999 and 10001."

I'm not really sure how we do such a good job at falling so flat on our faces here. You've answered the question in stating that 10000 lies exactly between the two other values provided. However, in the attempt at wit, you also seem to suffer the failure to understand the lower endpoint you chose as having the same relevance as the upper. Again, this is simple mathematics

While the two endpoints of triode and pentode are distinct from one another in an obvious sonic way, those you chose in this example would be impossible to distinguish from one another by anything outside of a machine. In practical matters, the question is more of perception, and our ability (or inability) to resolve the differences, but the fact remains that in both cases, we are dealing with the midpoint.