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

Showing 6 responses by jsawhitlock

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.
Jolen1aub, Check out the Amperex US made PQ white lable 6922 E88cc tubes for the critical positions, a bit costly but have been my favorites. For a bit less cash the Mullard 6922/CV2493 low noise GT. Britain tubes are nice too.
Joel, I perfer the Amperex over the tele for the critical positions. The tele are nice but just a tad laid back for me. Tubemonger has always provided good stuff and I have never had any problems with his tubes. AA FAQ page has some good info you seek.
Joel, my favorite is the 6922 PQ white lable US then 6922 PQ white lable from Holland.
Egay,

LV2 and V2 are the most important positions and next is LV1 and V1 for the SFL 2, line 1, line 2 and line 3. Trim pots should be left alone. as the label says.