Preamp Deal of the Century

Hi, Slipknot1. Thanks much for your insights!

My speaker placement has been stable throughout all of my equipment upgrades to this point, not by neglect or stubbornness, but because there hasn't been any need to change. Leads me to think that the decreased imaging/focus has something to do with the Chenin with its stock tubes.

I will probably give a try to adjusting speaker placement if no other logical options present themselves, but from my previous experience with the sonic effects of changing tubes, it just seemed to me that tubes might be the starting point.

Make no mistake...I am totally thrilled with the dramatic improvement in sonic performance of the Supratek Chenin! Like most, I'm just hoping to 'get it all.'

Hoping for others with helpful experience to chime in!

Two other questions ('cause I'm not an electrical engineer):

1. I know the 6922 is part of the phono stage. Is that just the only one pair? Put another way, which are in the line stage?

2. Just what does the rectifier tube do to the rest of the system sonically??

Best regards, John

Hi John,

Check your manual! It outlines the tube for the phono section. My Chenin have the 6922 and 6C4 tubes for the phono.

The linestage tubes are the 6SN7's (or liestage output tubes). The 5881/6L6 are the regulators. The 5AR4 is the rectifier.

The way I understand it, what the 5AR4 does is to convert the AC voltage (from the wall) to DC voltage to provide the rail voltages needed (B+, B-) by the preamp base on the design criterion. The regulators as the name implies regulates the voltage level so that any sag of the rectified voltage will not produce a ripple on the DC voltage affecting the performance (bias etc. ) of the tubes.

regards

Ikkyu, See my post dated 31-May-06 & Amadarae post dtd. 14-May-06. For very little money you can have a significant improvement with the Sovetek KT66 tubes. These are the same tubes Mike sent as stock for the Six Moons review.

Thanks Amandarae and Dilly. I will look into the Sovtek KT66. At under $50 bucks there's not much risk.

Best, John

Hi John. Firstly, congrats on your new addition: amazing eh. Amandarae...a very good description regarding the duty of the rectifier and regulation. John, are you experiencing this image wander artifact with the phono stage only.... or is it noticeable with cd playback as well? The supratek preamps exhibit the most focused and stable imaging out there, and to this day the best yours truly has ever heard in that regard. I would hazard to guess this image wandering to be a tube related issue as opposed to speaker placement. The rectifier being the usual suspect here and the common denominator. It would be a good idea to test your rectifier,making sure it test's strong and matched on both sides.... a weak or an unbalanced rectifier will surely exhibit some image shift or wander. For example: the sovtek 5ar4's are notorius for image shift and wander in many high rez tube circuits. I wasn't aware that Mick is now supplying nos Mullard rectifiers as a stock tube with his preamps, kudos to Mick. The nos Mullard 5ar4/gz34 will traditionally last for many many years however, being that they are a full wave rectifier... I have seen more than a few with unbalanced halves. Further more: mismatched regultors can also exhibit this artifact.