Preamp Deal of the Century

Tubegroover, It turns out that I may be in Florida this weekend with my wife for some R&R. Is there any chance that I could come for a listen to the zh-270 and the Syrah? I guess it depends where in Florida you are!! I would love to hear the combo before ordering them!! Talk about a great long weekend!!

Tube Rolling Update: The replacement set of NOS tubes arrived last friday. After about 20 minutes of listening with the stock tubes (at a set volume level) I decided to go ahead and replace all the tubes all at once just to be sure all the tubes are working and that they light up properly - and they did.

The replacement tubes I receive:

1. 5Z4 Type - 5AR4/GZ34 Mullard standard-base.
2. 6L6 Type - Tung Sol KT66/7581 (matched pair).
3. 6SN7 Type - KenRad VT231 black-glass (matched pair, rectangular plate - not round plates).

First impressions: not much of a difference I'm afraid. I was expecting a more immediate and easily discernable change to the sonic characteristics of my system; but that was not the case at all, not like the time when I replaced a set of unknown Chinese KT88s tubes with Valve Art KT88s on my Air-Tight ATM-2 power amp. The KT88 experience was immediate; it felt as if the power had doubled on my amp. So in comparison, my first real tube rolling experience was a bit of a let down. Also, this was my first experience with “microphonics”. With the Kenrads plugged in, even a mild tap on the preamp knobs will generate loud humms through the speakers.

But now that I’ve had these tubes for a few days in my system, I feel the sound has warmed up appreciably, the music has more “air” and the bass is definitely more defined. I think some of the characteristics discussed throughout this thread are slowly beginning to appear in the system.

Late last night my wife and I returned home from a birthday party and instead of going right off to bed, I decided to play with the system a bit more. So I took out the Kenrads VT231s and put the stock 6SN7s back to see what changes are, if any. I could be wrong as I was quite tired and slightly intoxicated - I thought the stock 6SN7s sounded better with the rest of the NOS tubes in place than the kenrads vt231s. As I said, I’m not a 100% sure however I will check this out tonight as soon as I get home and report back soon.

Jewel I tend to agree that there is less difference between the 6SN7's and 5881 tubes. I've tried 5 different types of these tubes including National Union, Ken Rad, Sylvania, RCA and the stock tubes. There are differences but they tend to be rather subtle. I find the rectifier the same having tried several of the recommended ones. I am currently using a BEL which is a manufactured in India and was a supplier to among others Mullard.

I agree with Fiddler. Where I have noted the most significant changes and improvements in the Syrah's performance is in the regulator position. The 6L6 type seems to open up the dynamics on the pre to a greater degree than the 5881's, greater plate voltage maybe? And for the most significant improvement to date per Ecclectique (thank you David for this great recommendation) you must try the 6F6g. Relatively cheap NOS, less than 50.00 bought me a pair of Brimars and I was stunned at the enhanced dynamics and the bass, oh the bass. Everyone must try this tube. They are readily available and can be purchased used at considerably less than 50.00 for the pair.

Hi Tubegroover: You know what, initially I too was looking for some NOS 6F6g based on Ecclectique's recommendation but the fella (Mike) at www.vacuumtubes.com was telling me that he didn't think 6F6g's could be direct replacements for 6L6 application. I decided not to take the chance - oh well! In fact at the vacuumtubes.com's website they list 6F6gs at $20 new and $10 used without mentioning any brand names etc. But it's cool, I really didn't mind the process as I've been wanting to try this for a while. And really, it's all been quite fun so far. Just the process of tube hunting and then waiting in anticipation was fun & and educational in itself. Now I'm going to set my focus on getting damping material and possibly some DH cones; oh yes and some 6F6g tubes.

Jewel, Glad you're having fun! Finding good 6SN7's is actually quite difficult because most are microphonic in the Syrah. I estimate that 1 out of 10 6SN7's you'll find will be troublesome.