Tube Amp, Preamp upgrades -- what did you do that improved your units?

besides the caps, you may want to also consider MILLS wire wound or Dale wire wound resistors for the plate and cathode values. Much more detail and better resolution due to the lower noise floor offered by the wire wounds over the metal film or worse yet, metal oxide. 

Greetings! I've used the Odams in two SETs, a PP amp and a two stage DC coupled preamp as the output coupling caps so far (I still have them in the preamp as an alternative "flavor" to compliment a couple of amplifiers). They all have over 500 hours on them. With the exception of the preamp, I found that they sound congested in the lower midrange and upper bass even after burn in, but are very nicely extended on both extremes. The Miflex can sound forward in some circuits, and I've found sound best when there is only one coupling cap in the circuit (otherwise the upper registers tend to sound vague and lack focus). I recently ordered a dozen Miflex KFPM, which are copper coil and metalized poly and have been burning in a pair. They remind me of the Audyn True Copper, but with much better detail and extension and the same midrange body and texture. They present incredible delineation throughout the range, albeit I'm getting a little brightness on the top end which I'm hoping will smooth out with burn in time. Jeff at Sonic craft recommended these to me, and they are one of his bang for the buck favorites. In the end, not all components will produce the same results with the same upgrades and the overall system voicing will dictate what sounds best. Look at it as a chef's spices, and you'll realize not every recipe tastes good with the same blend. Best regards, Aric

@aricaudio 
Thanks for the comments on the Odams. I'm planning on just the preamp for them. Will likely avoid the Miflex.

In the end, not all components will produce the same results with the same upgrades and the overall system voicing will dictate what sounds best. Look at it as a chef's spices, and you'll realize not every recipe tastes good with the same blend.

So much (all?) in this hobby depends on the specifics involved, from source to room. It's all semi-guessing.

My premise is simple: try better parts that other owners of the same gear have found beneficial and reverse it if it doesn't work out.

@hilde45 - You're very welcome! I definitely wouldn't rule out the Miflex as there's many folks out there that really love them. I also wouldn't rule out Audyn True Copper, V-cap Odam, or many of the other fine capacitor upgrades that we have to choose from!

All the best in your endeavor, Aric

Wow. The Odams never sound congested in the over 20 units I placed them in. In audio it seems nothing is ever absolute. We get that. I know Jeff at Sonic Craft likes the Miflex. The Jupiter copper caps sound better, but he no longer sells them. He will push what he carries and that makes sense. He told me the Miflex sounded as good or better than the Jupiter copper foils for less money so I tried them. I just cannot agree. They are too forward sounding in the electronics and crossovers I placed them in. The Odams were the best of the lot. Just my opinion.

Some like that forward, front row perspective and that is a subjective preference for sure. This is why nothing is absolute. Builders have sonic preferences just like the rest of us.

The one thing I find strange however is the congested comment on the Odams. I have never heard it. No other comment I have heard or read suggests this either. This is an outlier opinion that has me scratching my head my a little 🤓. However, I greatly respect Aric and his builds.  He does great work and that is a fact!