Tubes 101


I'm very new to tubes. Is there a sonic signature to different tubes? For instance, do Kt-88's have more highs and bass? Do 6550's have better midrange?

It seems like KT-88's, 6550's, EL-34's are the most common, or at least those are the ones that I keep seeing pop up.

I can use KT-88, 6550, KT-90, EL-34, 6L6GC, 7581A, KT66...

In terms of sound, I want it all, and why save $100-$200 on tubes when I'm already this deep in the rabbit hole?

To further complicate things, which brands are better? I'm thinking a matched quad set of Cyro'ed Gold Lion Kt-88's might look pretty sitting in my PrimaLuna Prologue 5....
128x128b_limo
Ei KT90 Type II is wonderful. However, I advise you to avoid Type III which is unreliable junk that may destroy your amp, start a house fire, etc.
Jburidan - Per Jim McShane (one of two local tube sellers) the type 3 is a wonderful tube as long as you didn't get the last from the factory. The last ones had mis-aligned heaters which caused the anodes to get cherry red (typically in a few hrs) before arcing over resulting in premature failures. Probably not many left. I have 2 quads of type3 and 3 quads of type2. Except for the type3's being slightly lighter (thinner glass) and the lack of spot welds on the anodes they sound the same to me.

So I do agree there may be a handful of bad type3's still out there there are a lot more good ones left. The type1's were the worst by far.
Thank you! I will research them today, as I am snowed in and listening to some music.

Any oppinions on input tubes?

Btw, I'm still absolutely loving this switch. It has resparked my interest in audio equipment, but more importantly, my interest in music. The combination of this amp and my current speakers that use seas excel drivers has been enlightening. What a revelation when the music starts to make more sense because of the nuances, timing and dynamic swings that are present now.
B_limo don't get too ahead of yourself swapping tubes. For any advice to be meaningful you need to know what you want to change the sound to with your current tubes. Looks like the PL5 comes with Gold Lion KT88's for outputs. But what brand are the 12ax7's and 12au7's? Also the PL5 is autobiasing so another word of caution before swapping output tubes. You want to get matched quads. Unlike manual biasing the autobias has a tighter window for biasing.

Where are you that you are snowed in?
I bought my prima luna used. It came with svetlanna 6550's, Electroharmonix KT-88's (my preference), stock prima luna input tubes, and a different set of input tubes (one pair says "usa" the other pair says "ge".

I figure if Electroharmonix KT-88's get slightly poor reviews, that it might be good to swap them out for something else...

I do agree though that itsbest to listen to new piece of equipment to become familiar with its sonic signature before you start tweaking things, so you can tell the difference and whether its an improvement or not.

I live in Colorado. It's been snowing here like crazy, and a bmw m3 on coilovers with michelin pilot super sports isn't exactly a snow mobile, lol.