Tube Rolling questions from a recent addict:


I recently entered the wonderful world of vacuum tubes with a Cary SLI-80 integrated amp. WOW what a sound this thing produces! The Cary and its seductive little glowing crystals of joy has made the single most dramatic improvement to the sound of my system since I added my Infinity IRS Delta speakers. Now I understand why tube-heads go on about mysterious NOS finds and seemingly magical differences between certain tubes. I’m both happy, and sad, to say that I’m hooked!

 

Anyway, on to my questions: 

  • When tube rolling, what are some recommended strategies when comparing the sound quality of different tubes?

 

  • Is it OK to power your amp/preamp down, switch tubes, and then power right back on a couple minutes later? I know tubes don’t like to be power cycled like that. But how else can one compare the sound of different tubes?

 

  • Generally, is there a bigger sonic difference between rolling preamp tubes, or power output tubes? (I know, I know, YMMV.)

 

  • And my most technical question. The Cary SLI-80 uses a one 6SN7 tube per channel as a “phase inverter”. From the manual, “the phase inverter is a self-balancing split load configuration utilizing the 6SN7”. Is this “phase inverter” part of the audio signal path? Can I expect to hear differences in rolling different tubes in that spot?

 

Thanks in advance for any other Tube Rolling 101 advice!

 

(P.S. – Thanks to everyone on Audiogon that makes it, IMO, one of the best places anywhere for higher-end audio and music fans everywhere.)

 

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Thanks for everyone’s responses - I appreciate your feedback and guidance!

 

I found Brent Jessie’s site and Joe’s Tube Lore very informative, and Andy Bowman’s Vintage Tube Services site looks fascinating. I've been hanging out at Upscale Audio's website a lot too (they recently changed the format of the site and I prefer the old version).

 

Looks like the consensus here is that the preamp tubes tend to have a bigger effect on sound quality than the output tubes (generally). Popular opinion on the ‘net seems to agree. I like newbee’s suggestion of “start with power tubes and then fine tune the tone by changing small tubes”.

 

>> One follow-up question: <<

 

  • When breaking-in tubes, does a musical signal need to be playing through them in order to break them in? Or is simply having the amp powered on enough to break them in?

 

Mostly due to crappy room acoustics, my current system tends to be lean in the bass/mid-bass region, and is easily excitable in the mid-highs and highs. I’m learning that I kind of enjoy that classic “tubey” euphonic sound – warm, rich, lush harmonics, slightly full bass, extended but smooth highs, etc. I was reading about the classic Mullard NOS sound as being that way, and the reviewer described it as having a “tweedy harmonic overdrive”. Fascinating how that makes sense to me.


To think of all the time I've spent listening to solid state, even good solid state, and have been missing out on what it turns out I actually prefer in tube sound.

 

Thanks again for everyone’s 2 cents!

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Re your sonic preferences, perhaps a new production  power tube to consider would be the Tung-Sol 6550. It has a little extra bass tone. I use them in one of my Primaluna amps, and a Cayin Amp, quite happily.  The new production Genalex Gold Lion KT-88's get high(er) marks but are a bit more expensive. Deal sells both and has recommended both so you might contact him - he is well acquainted with your amp and could easily advise you what they might sound like in your unit. He used to sell that as well. 

Re break-in. Don't get too anal about that. Start listening right out of the box, just don't make any judgments re what they will sound like after 24 hours of play time. They will change. Often the sound of power tubes will be dark initially but they will open up considerably and continue for some time. LOL, I recently tried some popular tubes that sounded 'great' out of the box and 24 hours later  they were way too bright for my tender ears. Enjoy hearing the changes, its part of the 'learning' experience.


If you go the KT88 route I'd suggest considering Black Treasure KT88s, IMHO they are a step up over the Gold Lion's - have had both in my Ayon Spirit 2. BTs to my ears have more authority and richer sound
Congrats on the purchase, been there done that twice!  She is looker with all those tubes glowing and wanted very hard to make it work.  I had an F1 version and a regular version and no matter what NOS tubes I put into them, I could never achieve your desired sound.  Too modern sounding for my tastes and maybe yours.

I too love the that classic “tubey” euphonic sound – warm, rich, lush harmonics, slightly full bass, extended but smooth highs, etc.  I moved on to Quad IIs and Mac 30s which give me that tubey, euphoric sound in spades.

Maybe a change in speakers will get you closer to the sound you want if you are determined to keep the SLI-80.  Also adding a sub can cure the bottom end issues.  Since it's an integrated, you can take to the store and demo until you find a match.

Enjoy the ride!