My friend has tried different tube types in his Io and ending up chosing smooth plate Teles. That said, if one is buying on Ebay, etc. the quality of the Tele 12ax7s is paramount. Some 12ax7s were obviously pulls and despite their readings, just sounded dead. But when he got some "real" new Teles, the Io really came to life.
I just replaced the (probably tired) Teles in mine with Siemens ECC83s I found in an ancient Scott mono preamp. Can you believe I've forgotten what 6922s are in there? Either Amperex or Mullard. The perils of geezer memory and too much tube rolling :-)
Whatever, it sounds great. Dave
Certain NOS tubes will make a big difference, but what surprises me is that you found the stock Sovtek's not bright enough? Just the opposite.
I also find it interesting, that as fine a preamp as this, which was Class A in Stereophile, is now overlooked. That is, until the latest review in Stereophile on it and the Signature version. Now, the used prices on the stock Calypso will rise. Uggggg, the fickleness and herd mentality of the audiophile masses.
Switched from Mullard CV4004's to smooth plate Telefunken 12AX7's bringing additional emphasis, smoothness and clarity to the mids & high's at the expense of sacrificing some bass response. Have been using white label Amperex/Phillips 6922 SQ's with good success for about a year or so.
For me RCA 5751 black plate triple mica's in place of 12AX7 are the answer with either Amperex 7308 Orange Globe (gold pin) or Telefunken 6922/6DJ8 (low noise) are the whip for my tastes. Buy'em once and they'll just about last ya a life time... so price is kind of a relative thing. My relatives are living about a hundred years, maybe several sets are in order...
Happy (roll'in) Listening!
As Sayles says above you need to make sure you get low noise tubes for the Calypso or lower the gain or you will hear the tube hiss thru your speakers. I have settled on the Sylvania black plate tripple micas with Amperex 6922. Nice thing about the Calypso is if you do not like the sound just change the 12ax7 tube out to something you like.
By the way tube rolling is addictive.
My experience with the Calypso over the years is not so much trying to reduce noise from tube choice as much as it is enjoying the music, and to a smaller degree in appreciating the outstanding performance/value of the way it integrates in the system.
One of the strong traits of the Calypso is it's ability to reveal even the most minute differences. If you're not up to the work, you may not deserve the rewards that come with it. The mere fact that the differences are evident, displays clearly how articulate the gear is, in my mind. There are easier pre-amps to satisfy and there are many that also do not produce near this level of satisfaction.
It's fun and enjoyable to roll and learn and listen.
I'm thinking of the Aesthethix Rhea, a bit concern about tube noise.
Is this something i should be concern about ?
I don't plan on changing the stock tubes if ever i go w/ the Rhea.
Thanks for the inputs.
when i had my calypso i tried several different brands of 12ax7 and liked the ge the best-from upscale. the preamp was very noisy even with new tubes which i hated
Both my Calypso and Rhea have been very quiet throughout the time I've owned them. No tube noise problems at all, that I can detect.
My Calypso is dead quiet from 6" away. No noise problems at all.
Having owned this preamp twice, my experience and that of many others has been that the Mullard 10M gold pin (12AX7) tube is the top of the top for this preamp. These are rather expensive tubes at about $600 per pair +. My second favorites where the Mullard Long Plate Square getters from the 50s. Just as a point of notation, Mullard did make the 10M gold plates for private label (even private labelled, they are still referenced as the 10M) which is a long lasting tube!
The 12AX7 rolling in the Calypso has much, much bigger impact than the 6922 tube rolling, so I would strongly recommend starting with the 12AX7s.
For a most complete review of Calypso tube reviews, see the posting/review by Agon user: Jadem6
As for tube noise with the stock tubes, I have never had this problem. I did speak with Jim at Aesthetix when buying my first one and was informed this happened over a very short period of time with some suspect tubes. Overall, the noise level of both of my Calypso have been very, very good (not silent), but very good.
My experience with NOStubestore was somewhat different. I ordered a pair of Philips 6X4's but they didn't even fit the sockets, and the lettering seemed painted on the glass. Emails to him went unanswered, and his site is now closed for 'inventory.'