As I've mentioned above, the Cary SLI-100 with the Klipsch Cornwall IV is a magical combination. Everything sounds massively enjoyable, even poorer recordings. I'll admit, though, that I'm suffering from tube anxiety.
- When will they start to sound crappy? This happens very gradually, so when is it not good enough?
- Is it time to check the bias? I've read that a monthly check is best, which seems ludicrous.
- Will a failing tube cause damage in the amplifier, requiring a trip to the shop?
Some here on the forum have indicated that I won't have to change tubes for many years, if not decades. The Cary manual says that the power tubes (KT150) should last 3-4 years. Paul McGowan from PS Audio changes his tubes every year.
The four KT150 tubes would cost CAD$800. The six input and driver tubes would be another $200-400, depending on what I buy.
I originally bought the Cary, because the seller was local and could bring it by for an audition in my house with my speakers. Most here said the amp was overkill for my needs, but I've been ecstatic with the results.
One of the other amps I had considered was the PrimaLuna EVO 100, but it was two hours drive from here, so not as easy to audition. Well lo and behold, a PrimaLuna EVO 400 (the top of the line) appeared nearby. One of its features is adaptive auto bias, which not only adjusts the bias, it supposedly continues to do so while music is playing. The auto bias also drives the tubes easier somehow, so purportedly extends tube life by 3-4 times. If a tube fails, it automatically puts the amp into safe mode, and indicates the bad tube with an LED. That would go a long way to ameliorating my tube anxiety.
It also does a cool parlor trick: it can switch between "Ultra Linear" (Class AB) and "Triode" (Single Ended Class A) with the push of a button on the remote. It's like two amps in one!
I arranged with the fellow to bring it over last night. The cost of the PrimaLuna is almost the same as the Cary, so I had high hopes that it would sound as good, while adding the tube maintenance features.
We sampled a few tracks with the Cary, to set a benchmark. Then we switched over to the PrimaLuna. I was rather surprised that it took a few minutes to go through its startup process, before we were able to play music. The seller also indicated that it took 30-45 minutes to really wake up. (FYI, the Cary sounds great within a couple of minutes, so this was already a negative for the PrimaLuna.) So, we started to play music, with me reserving judgement until full warm-up finished.
I should add that the amp is just two years old, and the seller replaced the two inner input tubes with expensive Mullards, which should boost things.
Out of the box I was underwhelmed. All of the dynamics that I loved were gone. The bass was deeper, but exaggerated and flabby. There was no sparkle in the presentation. The seller felt that the PL sounded less colored, but I've never perceived the Cary as sounding colored. It was still early, though, so I patiently waited for the magic to happen.
...And it never happened!
It improved a bit, but we shut things down at the 30 minute mark. Completely uninvolving! It was clearly no match for the Cary. And this lack of engagement was even worse at lower volumes. It was also nowhere as good as my Avondale SE230 and Neurochrome Modulus-686 transistor amps. Overall, a big failure.
In retrospect, if I had tried the lesser PrimaLuna EVO 100, I would have sworn that tubes were awful.
I hooked the Cary back up after they left, and was relieved to hear the magic return. It made me grateful for my luck with encountering it first. So much of this hobby is trial and error, chasing that special presentation that makes your spine
tingle and your heart
melt.
It reinforces the message that reviews are great, but only personal experience will tell you whether you're going to like something.
