Tube Rolling Woes


I recently took delivery of my first tube preamp. Schiit Freya+. It came with new production Tung Sol 6SN7GTBs. I'm running fully balanced from my source components right through to the power amp. My first impression was wow! What an improved soundstage with width and a 3D quality that I've read about. What surprised me is how quiet the system is. I had expected tubes to be noisy. But the Freya+ running with the new Tung Sols is dead quiet. The openness and air in the presentation is tremendous. However, from a voicing perspective, the top end is bright, and the mids and bass are very thin. I have about 75 hours on the system. Ive read and listened to almost every review on this model and no one has complained about the tonal balance. I left an email with Schiit just to make sure that I haven't done something wrong, but haven't heard back yet. 

I thought I'd experiment with some NOS and used vintage tubes. I've purchased from established, well respected vendors as well as folks with excellent feedback ratings on eBay. Of the 8 tubes I've purchased - claimed as tested matched quads (1) or pairs (2) - all but 2 have been either prohibitively noisy, or just didn't pass a clean signal. From my (admittedly small) sample, there has been no quality differences between the well-respected companies selling NOS tubes vs. people selling used stuff on eBay. The good tubes I've received were used tubes (RCA) sold by an eBay vendor. 

So I'm running out of patience. If I go with new production tubes that a vendor will have tested, matched and stand behind the quality, how do I know what to buy? Note that this is a $900 preamp. So, there are limits to what is practical in terms of price point. I can't justify spending more than $200 on replacement tubes. My concern is that even if I spend this kind of money, how do I know what the results will be? 

Any advice is appreciated.

Glen 

128x128spacecadet65
I would not buy tubes on Ebay unless I received a strong recommendation from someone on this forum or another similar. I have purchased tubes from Andy at Vintage Tube Services and Upscale Audio with excellent results. Brent Jesse is also highly recommended. I have no experience with the Freya.   
Have purchased new production and NOS tubes from most of the well known vendors.  Best results have been from Brent Jessee Recording.  While a bit more expensive than most/all other vendors, the testing and matching service he provides is, I believe, the most extensive available.  
Nos, you are not hunting the holy grail with them.
Hit and miss but at least you will get the experience. A good vendor will always be helpful whatever the outcome. 
Something i always say is that modern equipment are designed with modern production tubes in mind, so if you like what you are hearing then go with same tube and if you have the itch for nos then go with older production ones but from same manufacturer.

G

Hello Glen -
I own the first gen Freya so am speaking from that experience. Hope it is relevant.

-Have you confirmed a proper impedance match between pre and amp?

-My next thought is be patient. 75 hours might be enough for the tubes but maybe not for the Freya to settle and "burn-in" (as recently controversial as burn-in time has become). Regardless that, my listening enjoyment benefits from allowing new gear adequate burn-in and settling time.

- It’s not unusual for installation of a new piece of gear to require "re-tuning the system" entailing (at least) adjustments to speaker placement. Knowing the rest of your gear and cabling would be helpful to members here. Maybe the Freya is just letting you hear a wider frequency range. Can you move speakers closer to the wall behind them? With some speaker types this can improve lower mid range and bass.

-I’m not sure there’s a way to accurately predict what impact tube rolling is going to have on your system sound to your ears. You might get some helpful advice from the likes of Jim McShane, Brent Jessee or Upscale Audio. Some vendors will allow returns on noisy tubes or if you just don’t like the overall sound (e.g., Brent Jessee but you’ll pay up front for the right to return, as I recall).

- I’ve run probably half a dozen different tube brands (NOS and new production) in the Freya. Some VERY inexpensive ($10/tube) Russian 6N8S that used to be a stock offering from Schiit did seem bright and harsh at the start but eventually settled down and warmed up tone-wise. Still not my favorites but did get better than they were out of the box.  (Right now listening with NOS RCAs in gain and current production Tung-Sols in driver).

-A bright top end (one that makes strings tough on the ears) is a personal bug a boo and something I battled for a long time given metal dome tweeters on the Totem Forests I have. This had nothing to do with the Freya.  Thin mids and bass, however, were never a problem even with brand new el-cheapo tubes.  Now, issues with high frequencies are all things of the past having made adjustments to speaker position, changes to cabling (including choices between upper vs lower binding posts vs which diagonal connection pattern) and installing an Aquarius power conditioner.

Hope this will give you some ideas to explore in addition to tube rolling.


That is the trade off, sometimes. Tone control through valves is tough and it takes someone that knows what they are doing. Tone control circuits were eliminated because of cost AND the noise they can add to the signal.

It is best if you plan to keep the unit, speak, listen and spend. Don't spend, speak and NOT listen.. I do the latter all the time.. Not so much anymore.. I find my pockets stay a little fuller and personally I stay a little calmer.. :-)

Talk the Brent Jesse and tell him that you have and what you want to do. SEE what it cost... That is what an OLD Mechanic would do...

Yes the little Freya + is a neat little unit. It is pretty transparent too. You are getting more than what you pay for MOST of the time. They are a good deal. NOT GREAT, NOT Perfect. But good and better than any at that price range... IMHO I like the look and weight too.. Heavy...
Ghosthouse nailed it. Audiophiles love to talk about expectation bias. Which is largely fake, by the way. Hardly anyone ever talks about recency bias, which seems to be hard-wired into our brains. You made a change, its not perfect, you assume all the imperfections are due to the change. It is equally likely to have had imperfections there all along, only you had a combination of components and setup that had kept you in the dark, so to speak. The new component in this case is not creating them but merely revealing them. What ghosthouse said is correct. 

That's what I think. Give it time. Tube rolling is not for fine tuning magic, not patching over shortcomings. 
First to everyone: THANK YOU for the great advice! Some have asked about what the rest of the system is:

Freya+
PS Audio Stellar S300 Power Amp
ifi NEO iDSD DAC
Denon Pro DN-500BD MKII DVD
APC H20 Power Conditioner
Bluejeans Cables throughout
Triangle BR03 speakers (waiting for Tekton Impact Monitors on order)

I completely get the risk of eBay. As usual, the cheap way doesn't work. 

Ghost: All great feedback. I'll try the patience thing - I'm going to put the OEM tubs back in and use them for a few weeks, leaving the pre on 24/7 and see how it goes. I listened to an Upscale Audio YouTube video and he was emphatic about all tubes - new or old need a minimum of 200 hrs. before evaluation is meaningful. I'll mess around with the speaker placement and see if that helps. I've played with the toe-in and it helped a bit. More work needs to be done there. 

OldHvyMec: Always good advice. So far, I did a lot of research, spent then listened... So I'm listening to you all now and appreciate the feedback. I'll let the OEM tubes settle in for a few hundred hours and see where I stand at that point. If the voicing issue is still there, Checking in with Brent, McShane, and Upscale and see what the options are. 

Miller: I've been lurking a bit and have always appreciated your comments. Thanks for affirming what others have said on this one. There's no doubt that my little system has all manner of flaws, and the Freya has likely uncovered some of them. With 2 kids in college, this is the budget I'm dealing with. It's a good reminder that tubes aren't effective tone controls.  As an aside, I have a pair of powered Tannoy nearfield studio monitors that I use in a small room system. While they are revealing, there is something in the upper midrange that goes right through me. So I purchased a Schiit Loki EQ (a very very poor man's Cello Audio Pallette) and learned that an EQ won't fix a speaker voicing that you hate...

Thanks All!
Are you experiencing similar issues (top end is bright, and the mids and bass are very thin) in the passive and/or buffer modes as you are in tube mode?
The voicing that was going right through you is most likely room treatment.. Un kind or bloated upper MIDS, mercy they can wear you out..
Not to mention blistering LOWER highs.  MC has a point too. 70 hours is pretty low hours for anything to get RIGHT.. Little room treatment, maybe change the placement a bit.. Settling, you getting use to it a bit..

Spend no more and collect some good data.. Seems like a good plan to me.. You'll get it.. Man oh man kids in collage. I just had one go BACK for the second time. God bless his learning mind.. Hope he fattens' his wallet at the same time along with a brain blessing.. LOL a Twofer..

Regards
Of the 8 tubes I've purchased - claimed as tested matched quads (1) or pairs (2) - all but 2 have been either prohibitively noisy, or just didn't pass a clean signal. From my (admittedly small) sample, there has been no quality differences between the well-respected companies selling NOS tubes vs. people selling used stuff on eBay.
Always request noise testing when purchasing NOS tubes. It's an extra step in the dealer's tube testing, but worth it. Brent charges $10 for this service. Andy tests every tube for noise and microphonics, so does Upscale.
Once your Freya is broken in with stock tubes, you'll have a better idea what sonic signature you're looking for from the many brands and tube types.



I only buy my NOS tubes from Vintage Tube Services (Andy Bowman).  Always have got a great tube from him and his prices are more reasonable than others.

6sn7 octals are well known to be quite prone to microphonics, so i can understand your struggles... furthermore there are really old ones out there, luscious sounding but not made very robustly, so even shipping them can make them noisy

have patience, perseverance, you have to go through quite a few to find ones that work really well and are dead quiet... worth it though, in my experience

the way good 6sl7/6sn7's flesh out a soundstage is very intoxicatingly lovely
Leave your preamp as is.  Your upcoming speaker change will probably address the concerns you have noted.
DJSpinner: Yes, the voicing seems to be similar but it's hard to tell. The soundstage collapses and the gain is so much different between the two modes that it's tough to tell. It's a good question because it would speak to the effects of the tubes...


One of the vendors who sold be noisy tubes said to clean the prongs. Would regular spray contact cleaner work?
Contact cleaner or Deoxit works, but you should do a final wipe down with alcohol. You don't want any residue getting in the tube sockets. 
recently swapping tubes on a 6SN7 based preamp, my first one.  i ran into some similar noise and quality issues and have learned some lessons.  
*the older tubes have had the most issues regardless of noise testing or where purchased.  the oldest tubes i buy now are late 50s.  
*brent jessee has a "bang it" procedure that is supposed to help by shaking loose internal debris.  it worked on one out of 4 tubes but might be worth trying,  the procedure is on his site.  
*always buy from someone with a clear return policy.  there are some very reputable sellers on ebay fyi that i have had great luck with.  


Noise testing is a must. I have many 1940’s WWII 6SN7GT/VT-231. These are cream of the crop tubes with no noise, they present a black background. They were purchased from Vintage Tube Services and from Brent Jessee.
Andy has told me he tests many tubes to find one that is quiet.

Thanks for the tips on the contact cleaner and alcohol. It's alway interesting to find that old technologies like WWII tubes have survived the test of time! I'll check out the Bang It method from Jessee and see how that works. I have nothing to lose from these noisy tubes at this point.

G
I also have a first gen Freya and a fave feature with this preamp (and the "+" version) is the fact than you can instantly check the "honesty" of your tubes...I often switch the thing to the passive or FET settings (adjusting for the large gain drop relative to the tube setting) to compare to the tube sound, which instantly tells me what I need to know. The micro detail, punch, and general tonal "rightness" of the tubes always wins, but if the tubes were funky somehow (microphonic, exploding, dead) or wearing out I'd hear it. Note I prefer NOS GEs but have Sylvania Chrome Domes, new Tung Sols, JJs,  and others in reserve. None are noisy.