just for all practical purposes, l lets leave out the 66,77.
OK, so now, lets imagine we are testing the 5 power tubes listed about witha pure neutral colorless amp (just for all things being equal, pre tubes all equal, pure colorless) We are comparing these tubes based on each tubes ~~Unique ~~Individual~~ Charatcer , regardless of lab make. New production only, as NOS are not found in any quantities , nor at reasonable price points.
I would say the most important quality to be discussed is midrange.
For bass, its quite simple to add a sub amp/woofer,,and highs,,well maybe a new high tech Neo Beryllium woill solve that issue.
Although it is true we need to add footnotes on bass/high fq response.
Most importnatly, is how does each tube resolve
1) Voice
2) separation of instruments
3) purity of midrange fq resolution
4) low mids/upper mids response
5) openess/sound stage, = low distortion at higher levels of complex music, say a full orchestra.
Please add other characteristics which should be brought into the comparison.
Many of you have years , decades of experience with each power tube in many dif famous power amps, , your imput will be greatly appreciated by all of us newbies in this grey area of which power tube suits our needs best concerning the music we listen to.
Based on my very limited experience with power tubes, so far I have found the 88 to be my ideal tube,,however,,,seems i may have overlooked the ~~6550~~, based ona short YT vid, of some chinese lute/female voice,,shootout 88 VS 6550,,2 minute vid,,I may have to change my opinion of recent posting ** The KT88 is the best and finest power tube ever made**,,That opinion , may have to be adjusted, to say *2d best*, as i await a purchase and testing of the 6550, in 2 weeks time.
My hunch based ona 2 minute compressed YT upload then further compressed to my comp and $10 comp speakers,, i surmise it is the 6550 which is my ideal power tube.
Which would make the 6550, IMHO the finest power tube ever designed.
I am hearing things i heard on my JOR with the famous EI KT90's. = life like vocals, ,,but with the added bonus of tingling, sparkly highs.
As I say I could be wrong,,but my hunch and intution says i am spot on.
here is the 2 minute clip on which i base my daring ~hunch~~.
The 6550 and 88 look very close in construction,,but that might be where it ends,,looks is one thing, performance can be quite another.
Take the 12AX7,, Not any 2 sound alike,, all have shades of dif voicing.
(I'm a solid fan of Tele, and no others)
I had assumed a power tube is a ,,,power tube,,= we are talking power , less about nuances.
Could not be more wrong.
Although I hear the tele AX as set apart from all other AX's...in power tubes,,the voicing is perhaps even greater than in pre tubes..where as pre tubes adds a nuance here, alittle there,,, power tubes vary significantly from each others voicing,,but wait,,that could be wrong,,as i recall, the 90, was very close in voicing as the 88, the 88 offered more openess.
I sold off my 9-0's, so can not follow up on that shootout.
in fact to be fair to the 150,,i heard this magnificent constructed tube, with the old Jadis caps, and the 88's with the new M caps... so all things were not equal.. However,,I have the hunch,,the 150's would still retain that ~~blob like, mushed meal mids/rolled off high mids~~ with the new M caps. This is what i am getting at.
We need to bring up our experiences of the fundamental character of the power tube, regardless of quality caps, quality of amp.
Almsot like trying to hear the power tube itself apart from the components involved.
The EL34 I hear as a bit weak, limp vs the 88. So I give more pointsb to the 88.
The 90, as i say,,was very nice,,but not as full, rich, open as the 88.
again 88 remains as champ,,I have not herad the 120,,but based on my experience, rather limited of the 150,,I'd guessing the 2 are cousins, and thus , lacks the mid clarity i am looking for. The 150 packs low bass,, makes a great tube fora bass guirat amp,,not for rich mid range which is required for clasical, human voice, jazz.
Bigger is not alays better, and in this case very ture.
Once the 6550's arrive, i will quickly upload a YT vid,, which will give me further substance , evidence to my hunches.
Here is the shottout twix the very popular 88 and the rather not mentioned as often the 6550
**all power tubes have their respectful qualities~~ I ain't buying,
WE are searching for ~~The best of the best~~ in power tubes,, Only 1 tube can be left standing at this shootout, No survivors. Only 1 tube has the fastest gun in this power tube shootout.
There is no topic anywhere on the Inet where you can see a fair , honest, and based on bonifide experience, ofa shootout twix these long standing popular power tubes.
I am looking for 1 gun standing alive in this wild west town.
One power tube will be given the crown as ~~King of all Power Tubes~~
My biased vote is already in, all money riding on The 6550.,,as best gun in the west.
https://www.youtube.com/watch?v=oC1AVIsqoB8&t=3s