Preamp Deal of the Century

A question for you guys.

I have just received a new Berning ZH270 with the wire upgrade. Haven't received the cryoed tubes yet, Allan will be sending these in the next few weeks. I have about 6-7 hours on the amp and it is improving each hour. I am still scraping my jaw off the floor. With more break-in and cryoed tubes, I can't wait to hear the full potential of this amp. Maybe the wire upgrade makes a big difference, but I can't imagine anyone thinking this amp sounds lean. Not as syrupy as the ASL 845 I had, but the dynamics kill the 845. The bass simply ratttles the walls. Tubes aren't suppose to have this kind of bass!

But here is my reason for posting.

Have you guys noticed how long it takes for your Supratek to bloom after start-up. Mick says it is up to full speed in an hour, but my experience is that it takes a minimum of 4 hours, usually 5 for the bloom to happen. It sounds good upon start-up, but when the tubes bloom the soundstage expands considerably and the 3D, holographic images are amazing.

What is the general consensus as to how long you Supratek takes after start-up to open up and take on that life-like quality?

Bwhite- this is new. I had used the Berning and the Joule with no problems. Then the Joule crapped out and went home to Jud for repairs. When I hooked it up upon return, BUZZZZ. Its from the amp, not the speakers. Swapped in a new (old) pre, dead quiet. Upon Jud's suggestion, I powered the Supratek via (gasp!!!!) an old extension cord from another circuit. A little buzz at the amp, but in playing around with home made noise detector (a length of old hose held up to the ear), I was able to track the predominant noise source to the power supply stage of the pre-amp!!! Further testing showed me that it is coming from inside the pwer supply, up through the vent (?) slots in front of the rectifier. NOt sure I want to fish around further in there with power on and high voltages, but does anyone who knows how these things work have any ideas?

Swampwalker,

I had the same problem. It was DC on the line. I fixed it with a combination of the 'Ah! AC Offset Killer' and an isolation transformer. The 'Ah! AC Offset Killer' seemed to be 90% of the cure.

Now there is just a teeny hum that you have to listen very carefully to hear. I mentioned this fix to Mick soon after I got my Supratek and he said he would look into it. Not sure what happened after that.

Fiddler - Thanks for the information, I'd like to know a bit more about your solution. Was your amp making a mechanical hum, or did you hear buzz from the speakers? What isolation transformer do you use?

Do you connect the system like:

A. AC Offset Killer --> Transformer --> Supratek
B. Transformer --> AC Offset Killer --> Supratek

Swampy. What rectifier are you using and does it test strong?