Preamp Deal of the Century

Thanks for all your advice, and especially Ecclectique(i will get back with you on your offer). The reason is that someone in this thread prefers to use the stock tubes instead.

Happy Holidays

Hello Frankiealverti. Certainly, the nos sylvania 6F6gt will perform as well or better than any other 6f6 type for regulation duty in the Supratek's providing they test strong and are closely matched for gm. I am still using a pr of them in my Syrah. The regulator tubes can have an influence in the sound of the supratek's however, the difference's are rather subtle here.They are used in conjuction with the rectifier to smooth out the residual ripple of the rectifier in the power supply . Far greater rewards are gained by changing out the stock rectifier first for a strong testing nos gz34/5ar4 before even thinking about rolling out the regulator tubes. Without rolling out the stock rectifier first....changing the stock regulators for something else would just be an exercise. By the way: When I first recommended the 6F6g for regulation duty way way back near the beginning of this thread, it was more to inform people that the 6F6G [shoulder shaped glass types only] was a low cost alternative to the stock Sovtek 6L6/5881 that Mick was supplying at the time.Most Nos tubes in the 6L6 family are rather pricey to say the least and some in that family are hideously expensive [the genelex kt66, Western Electric 350's for example]. At the time, I was using a pair of Western Electric 350b's only because I had a few pairs laying around in my stash. I could not and would not recommend them in good conscience, the cost for a pair of them is far better invested in music or elsewhere in your rig. The high cost of nos 6L6 types are due to the demand by the Guitar amp crowd. There are a whole host of nos tubes that will work for regulation duty, many are less expensive to acquire than the new issue tubes in the 6L6 family.

Here are the tubes on my Syrah:
6SN7 Gtb ge
6GK5 gt pro/comm
6bg6 philips

What is your opinions on these tubes?
Thanks.

Hi Ecclectique, thank you so much for your comprehensive reply.
My used Syrah came with a pair of matched metal based 7029's ("made in U.S.A.", the reputed dealer here in Germany wipes out the branding and re-brands them with his own name), but Mick wrote me they could be inadequate for the Syrah, because they are not exactly equivalent with the 5881/6L6. That is why I am considering 6F6's.
Otoh a pair of Heathkit W-5M's I used to drive my original Quads with, prior to getting the Radford STA-25, sounds best with 7027's!
Ecclectique, speaking about rectifiers, could you please let me know something else? With the Syrah when I play my LPs using my ZYX Fuji (not with FM or CD; sounds great) there are funny noises coming out of one channel after ten to twenty minutes, sometimes earlier. The noises sound like tearing paper or like the noise between channels in a radio or sometimes like a muffled heartbeat!
My Syrah came with a brown based Mullard GZ-37 rectifier, which Mick says should be OK for the Syrah if in very good shape. I have changed the 5842 and 6GK5 phono tubes and the 7029's but the problem persists.
Once you wrote that phono play could be affected if the rectifier is not 100%, except if it is a GZ-34 which could be less with no problems. Do you think that getting a GZ-34 would solve this problem (apart from sounding better)?
Thank you so much. Best,
frankiealverti

Houstonreef. The Ge 6sn7gtb.... if it is the sidegetter version, it is the proverbial "over achiever" if there ever was one in the 6sn7 family. A great score for paltry sum these can be bought for and they fly way below the radar relative to the cost of the other nos tubes in the family. [for the time being anyway]and they sound very good in the Supratek's. Sonically speaking, they are very smooth with a well balanced tone from top to bottom, decent at resolving subtle detail and posses a very punchy bass line [one of the best of the nos 6sn7's in that regard] a robust and reliable tube that's generally free from microphony and low in noise.Certainly not as texturally layered and transparent sounding as the Kenrad blackglass or Tungsol roundplates but certainly not bad in that dep't either. [ then again, only a few others nos examples are] and they generally sell 5x the price. It has been mentioned in the thread that Mick has voiced his current preamps with the stock EH6sn7 and it is a large improvement over the sovtek 6sn7. I would certainly agree with the general concensus when compared with the sovtek however, I do not concur with the general consecus here when compared to many nos 6sn7/vt-231/5692 varieties. The GE 6sn7 sidegetter easily best it, the reasonably priced RCA grey glass versions literally stomp all over the stock EH 6sn7 in every dept. Move further up the family food chain.... to the Kenrad Black or the tungsol roundplate....well.... a whole nother stratosphere to experience. Comparing the two would be like comparing the Supratek Chenin to an old Conrad Johnson preamp employing tired tubes. The 6GK5's in the pro/comm box are probably a late production tube rebadged with their label. Most of the 6gk5's out there are late production tubes and probably all made at the same facility anyway and then rebadged with a Mullard logo or number of other company's name. The early nos examples all had factory date codes. I have a pair of old stock Amperex's with factory codes and bugle boy labels that are far better sounding than the later production examples without the codes. The US made RCA 6gk5's are the way to go here if you can't find the older tubes as they are generally low in noise and all sound consistent.I suppose it's a moot point here for those with the latest production Supratek preamps that are sporting the Covi designed phono stage however those with older Syrah's and cortese models that employ Micks version of the renowned Loesch design should go out of your way to dig up some old stock 6fq5's in place of the 6gk5....A major impact and a big surprise to be had here folks! Regarding the 6bg6???????? Houstonreef, are you positive they say that somewhere on the tube! I am surprised, no more than surprised they would even work in the Syrah, unless the previous owner had the tube socket rewired to accomodate a 6bg6. The 6bg6 is electrically very close to a 6L6 however,it is traditionally employed as an output tube in an ampifier but requires a top hat on the top of the tube to operate in any given circuit. Just "Mind Boggling" to me as to why anyone would go to the trouble of using that tube for regulation duty in the Syrah anyway.