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
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?
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.
Thank you fellow members for voicing out your experiences whch makes me feel better. I too don't really have a problem with this unit. I just thought I might try replacing my noisy tube and get them from
a reliable vendor/s for a change. BUT this particular vendor have been true to his words in the past with good recomendatons from fellow goners.

I was quite surprise and caught off-guard when he mentioned that Sonic Frontier preamps eat tubes by design (meaning they get noisy after a few months).
He did not even have any to sell BUT in the end of the conversation he mentioned to check back in 2 weeks. He recommended sticking to 7308s Siemens NOS tubes from germany which will cost around $200. for the pair (which I thought were within fair price).
Another source which I was looking into is Chris Johnson's "Parts Connexion".
Heck the price is also in that neighborhood. Don't mind spending that kind of money as long as I get a pair of QUIET, expected Sonics, and the reliability
these tubes were designed for.

Jea, I bought these previous pair of tubes from another well known vendor in
S. California (NOS Siemens CCA 7308) which performed fantastically for a few months then one side went "tube-rush" on me. No, I do not have a tube tester.
Tube testers are not cheap let alone choosing the right brand and model that does a good job checking the tubes.

I'll ask another favor- and this may already be on some thread here at Agon but since we're at the subject matter- Which vendor would any of you good folks recommend to buy these tubes from? Antique Electronic Supply?? Upscale Audio???, Parts Connexion??? Tubestore?? Tube Depot??? VTS?? Bio??
Vacuum tube valley??? Angela Insruments??? Tubemonger?? Decware???

I really like the Siemens CCA 7308s as they deliver the kind of PRAT I really enjoy. I've tried several 6DJ8s Elite gold but they got noisy after a few months (1-2 tube out of 6) & nowhere close to the Siemens Prat. Also tried BRAND NEW Sovteks 6922 (3 pairs)- which another vendor claimed I'll get great bottom end- Yes, but found out that was all it was good for (Weak top end but quiet). My sanity check is always swapping-in the original tubes which are dead quiet and good sonics (again but not as good as the 7308s).

Again THANK YOU ALL for your feedbacks- now if I can only find another
helpful vendor who can deliver reliable tubes without me second guessing and not be prompted to get a tube tester..:^)
Line 3SE owner for 5 years, only had to re-tube once last year and I had 6H23 in them before without ever noticing any tube noise thru out the 4 or 5 years of usage. Given the life span I got from the tubes, I would rate it as gentle on the tubes.

Yes, you can get better sound by putting in NOS. But I have been using cheap tubes (EH or NOS Sovtek) in buffer stage with good success.
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.