Preamp Deal of the Century

Hello Ecclectique, thanks for sharing your vast experience and knowledge. During the last week I have read and saved many of your postings in this fine thread! Would you please let me know (according to your experience) if the plastic based, round plate Sylvania 6F6GTs will perform and sound as good as a good pair of NOS 6F6Gs on the Syrah?
Thanks so much and happy holidays,
frankiealverti

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