Preamp Deal of the Century

Fiddler has a point. Did some research on 6F6G and also found nothing saying that these could replace the 5881/KT-66/(...). Also the supratek "manual" does not mention the 6F6G as a possible substitute for the stock tubes (while other types are referred). As Fiddfler "I am foaming at the mouth to try the 6F6g. I just need a little reassurance that the tube will perform within acceptable operating points for the Supratek!" In the meantime, anyone asked Mich about this?

Fiddler,

Thanks for the toast! I am wondering why the views of this thread is stuck at 48. I know we were over 10,000 views. We must have broke something at Audiogon, or they got tired of keeping track. Be careful guys, when we hit 1,000 posts smoke may start pouring out of our computers.

Hat's off to you Slowhand. If it weren't for this thread I would't own this pre most likely. It has been a very pleasurable ride all the way.

Lisbon, I have an e-mail off to Mick to get the low down on this tube. I'll keep all posted.

Hello Gang. RE: The use of 6F6g as regulators. Fiddler and Lisbon,I can certainly understand your apprehension and anxiety here.Consulting tube substitution guides and doing net searches will give you imformation that is simply not applicable here regarding our application in the supratek. Firstly...The 5881, and the 6L6 tubes employed in the supratek are are actually output tubes[beam tetrodes]. They were never really designed for use as a regulator tube.These tubes were originally designed for amplification duty only, re: output stages for amplifiers,radios and TV's. Just like many other common output tube types such as the KT-66,el-34,kt-88,6550,kt-90 etc to name a few . When one referrs to any tube subsitution guide or manual,the manual will give you direct substitions for that one particular tube type that would have similiar voltage curves[among other parameters] for the tube being substitued."IE" for voltage,amperage,bias and output power[wattage]etc. These paramaters are really not applicable here as they are not employed as an output stage tube in the supratek.The duty of these tubes in the supratek were specifically designed and employed as regulator tubes, whereby their application in the supratek are specifically used to smooth the ripple of the rectifier, "not" as an output tube per say. A tube substitution guide will tell you absolutely nothing when referred to in this context. Consulting any tube substitution manual will only tell you what tube can be substituted as an output tube . Example: A typical substition for a 6L6 found in any given manual, would be a 5881,7581,5932,Kt-66,6L6G,6L6ga,6L6gb,6L6gc etc.In actual fact, there are many relatively common power tubes[power tetrodes,power pentodes,beam power tubes] that can be substituted for the 5881/6L6 in the supratek. The 6F6 is a small power pentode and is perfectly safe and suitable for use as regulation duty in the supratek. I personally use the western electric 350b in my supratek only because I've had a pair in my stash for many years.I have also tried nos 5881's, all of the 6L6 itterations, as well as 7581's,5932's,kt-66's,6v6g's and of the 6f6g's. The legendary WE 350b beamer is the "King of the Castle" for regulation duty in my rig and in my humble opinion, the 6F6g [round plate] is the next best thing to it.If I didn't have a pair of 350b's, than the 6f6g would be "THE" tube of choice. I ran a pair of these in my syrah for more than a month. Try em, they are terrific.

I've learnt a lot from this thread, and certainly appreciate the sharing of info re the 6F6. For what it's worth, I did ask Mick about this about a week ago. He simply said "No;" he would not recommend it. He did not elaborate. Mick's take is of course valuable, but it is not necessarily a trump card, and Ecclectique your experiences with it are a great contribution to this thread. Thank you.

Re the Ken-Rad VT-231 black glass, they made an immediate and noticeable improvement in my system (tube CDP, Chardonnay, SS amp, Hales speakers: a greater tube "bloom" and deeper bass; no unreasonable microphonics). Clearly, system dependency cannot be ignored.