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Sonic Frontiers preamps tube eaters??

Just wanted to find out from member owners of Sonic frontiers preamps if they experienced frequently replacing tubes (within months) due to noise (tube rush noise).

The reason I asked is I was told recently by a reputable tube vendor (no need to mention names here)that Sonic Frontiers preamps (SFL and Line series) tend to develop noise even after being replace with NOS tubes. In addition, that by design the unit runs the tubes (6DJ8, 6922, 7308 etc) to their max limits which is the reason for their short life.

He even claims that there are a lot of post on the web about this. I've tried the AA and Agon to look for such specific threads but found not enough evidence pointing to this problem. He claims that the original tubes that came with these preamps were really Russian 6N1P which are very hard to find (re-labeled as 6922)????

Have had mine (Line 2 SE)since 2003 and yes I've gotten tube rush noise (very faint on one side). But this problem can be move to the other side when that tube is moved. Thus the reason for shopping on NOS tubes. The unit performs flawlessly with the exception of the very faint tube-rush noise on ONE side.

Hope to hear from SF preamp owners and Thanks in advance.

jojass402
radman707
29 posts
 
I don't know about the Line series, but I had an SFL-1 and now have an SFL-2. They are both very quiet and easy on tubes. I have used new and NOS tubes and had no problems whatsoever.
chadnliz
3,736 posts
 
I have an SFL 1 and have had same tube in it for a year, and it is on 24/7 unless I am out of town, swapping wires or power goes out............if anything I am surprised this tubes has lasted so long, I am using a NOS Valvo Amprex tube from Holland.
lissnr
365 posts
 
I also have a Line 3SE and have had no premature tube failures, in fact I have been using the orig. NOS tubes for several years with very quiet operation. I've had the occasional low level tube rush but nothing note-able from more than a few inches away. This is a great sounding and very reliable unit. You only need the really good NOS tubes in 4 locations... all else can be simply good/reasonably priced.
jea48
4,425 posts
 
I have the line one, I haven't experienced any problems with the pre eating tubes.

Jojass402, when you say NOS do you actually mean new, or used? Do you have a tube tester? Do you test the tubes when you receive them?

If used, how much life is really left in the used tubes you are buying?
jsawhitlock
302 posts
 
I own a SFL2 and wouldn't consider it a tube eater. It does run them a tiny bit harder but nothing to worry about. Don't get freaked out about this as a set of tubes are going to last many many years. As mentioned above there are critical locations where you want your best tubes. I get a little his but I can only hear it a few inches away from the speaker and it doesn't bother me.
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