KT88 vs KT90 the final showdown

could have placed this topic in tech  forum,,, but as  the amp page gets more attention and this has critical importance as to how our am will voice, thought we would share what we know about the KT90.

I plan to swap out these Svet 88 aka 6550, same thing (88 = 6550) for a  set of KT90's.

As you all know the 88  has a  much greater popularity as  power tube by popular demand.

Perhaps this has to do with the fact that the majority of audiophiles have xover low sens speakers which need as much full midrange as they poosibly can get , the best tube for the job is the 88.

But as I have FR speakers,, I dont need/want the 88  **bloomy** midrange.

I am hoping the 90 has a bit toned down mid section.


Now dont  in and claim ** just the oppostite, 90 has more forward mids..*

Again I don't  expect much of a sound dif, nuance, minisclue at best.

But a  miniscule is all I am hoping for.

Bass and highs not that much interested. 

can't find much of anything about the KT90 on the Inet/YT.

Its alllllllll about the 88. 

Its like the 90 has been thrown under the bus and then steamed rolled over.

btw the EI's did in fact have some issues, but the legend lives on. 

They  make music sound alive in my JOR but had a  steely/harsh  (distorted) top end) But not fatiguing in any degree. 

Now you are wanting to  know **harsh top end,,but not fatiguing..??? how is this possible..**, I find the fatigue factor has much more to do with the 120hz range,,, muddy, greyish,  resonances in the low end.

So in fact the EI90 has this super clean, live soundstage in most fq;'s, except some of the upper range, 

The EI was not a   long lasting tube as well.

Electro Harmonix has corrected the issues in the EI type.

In 3 months we will find out.



El 90s were and are a very good valve. New they are over 200.00 each if you can find them.

KT88 are NOT 6550s, period! Two entirely different valves.. In some cases they are NOT interchageable. The MC60 is an example, KT88s will work, but not like a 6550. different valve..

VTL voiced Wotans with EI KT90 valves. 1250 watt MB valve amps. Enough said!!

If you want to ask questions, ask. If your gonna do the soapbox thing after owning a pair of valves for 15 minutes, I’ll pass this time around..

Happy new year.