Schiit Freya Modes: Subjective vs Objective Differences

Welcome, happy you decided to post. 

The result: no difference. No difference as in truly zero difference between the passive and tube outputs.

Schiit must have measured this device when they built it, send then your graphs and get one of their engineers to reply to find out whats up. 

Interesting experiment! I have a regular Schiit Freya +, i.e. not the Noval, subjectively I can say there is for sure a difference between passive and tube mode. More obvious if you give the tubes about 30 minutes of warmup.
 

I would try the same measurements using REW and a calibrated mic, and spend some time learning how to interpret the graphs. It would be interesting to compare the higher order harmonics in the distortion graph to see how they differ, thinking the tube stage would add some second order harmonics, but I am not an expert. 

Let us know the results if you give it a try. 
 

Thanks for your replies, @kota1 and  ​​​​@zlone .

I haven't gone down the REW rabbit hole just yet but that would be the logical next step to try to measure the actual perceived differences I originally thought I heard through my equipment and from my listening position.

Do you know if REW only works with recordings you make within it, or if you can use its tools on audio files you create elsewhere in order to analyze harmonics and frequency response?

And yes, I did the test in two parts, the first time with the tubes warmed up for well over an hour, followed by the passive test, then for the second round I did the passive first so the tubes were cold...same result. This makes me less keen to roll tubes on this unit, which is perhaps a blessing in disguise.

I have a Fryea Plus and honestly when I use it, I use the passive mode rather than SS. 

I haven't gone down the REW rabbit hole just yet

Before you get REW consider getting a room correction device that measures and applies room correction, there are 3 I am aware of for less than $500. If you want more info just ask and I'll post. 

Do you know if REW only works with recordings you make within it, or if you can use its tools on audio files you create elsewhere in order to analyze harmonics and frequency response?

Pretty sure it only works with it's own test tone audio that sweeps the desired test frequency range.

For the record, I mainly used the SS buffer mode on my Freya +, passive is slightly anemic sounding, and while the tube sounds are nice for dedicated listening sessions, I don't like leaving it on in tube mode.

@zlone @jeffrey125 I also notice the SS buffer appears to have a little more oomph than the passive, but question if this would hold up under scrutiny given it is a few db quieter than the passive and again difficult to level match in real time (running all RCAs at the moment as my vintage Accuphase amp appears to invert phase for the XLR inputs).

@kota1 which room correction device do you like best?

Passive will have zero gain, hence no oomph. I prefer is has it has no coloration. My SPL Phonitor 2 Preamp is designed for studio use so it has little or no coloration and I have the dip switches all set a zero. It is an apples to oranges comparison. 

OP

The three that I prefer are:

1) The Martin Logan Unison, it uses ARC room correction and also has an RCA in for a CDP or a TT and an app so you can use it as a streamer. This unit does not have a sub out so if you are using a sub get one of these others instead.

2) The Dspeaker Anti-Mode X2 is automated and very flexible, it can calibrate your speakers and multiple subs if you want.

3) The Mini DSP has a steeper learning curve and you have to BUY a microphone.

The Dspeaker is the one I would get if I were using a sub. The ML Unison I would get if I wanted a streamer function and didn’t have a sub. I would get the Mini DSP if you want to manually adjust curves instead of having it automated like the other two.

Amazing, thanks @kota1 I hadn't heard of the first two and I'm going to research them further. No sub in my setup right this second but when I do use one I do REL high level so all good.

The Martin Logan Unison is amazing, it has both optical and RCA inputs and has an app you can use to stream pretty much any service. It does hirez too, here is the measurement from my main system using it (and its on sale):

@kota1 Very cool! Can you only use ARC with the analog outs/ML wireless speakers, or is it possible to use that feature in conjunction with an external DAC? I would think not but worth asking.

Yes, I use mine with an external DAC, it has an optical out too. See page 9 in the user manual:

https://www.martinlogan.com/uploads/documents/manuals/manual-unison.pdf

For anyone who has a system that is passive friendly, check out the Hattor. Audio offerings. Hard to beat when compared to other passive devices.

I own and love the Freya +, using some nice tubes that made a significant improvement to my ear.  I like passive mode and tube mode.  I hear a difference along the lines of what you describe.  I don't really care what a meter says I just go with my ears.  

Thanks, @ejlif , despite this test I, like you, just can’t shake these same subjective impressions while listening: passive feels sharp but lean, tube soft but full. I came across some NOS Tesla E88CCs that I threw on the right side and continue to have the same reaction after this swap.

If I feel inspired to dive back in one more time, it will be with a USB microphone from my listening position. I’d love to verify my observations, but I won’t lose sleep if I can’t. And I won’t stop using tube mode either.

If nothing else, Schiit should be commended for creating a gain-adding signal path with four Soviet light bulbs that is so true to the source. I would love if there were more obvious differences between the modes, but still admire this unique preamp and will continue to enjoy it.

@nixanthrope did you ever present Schitt with your findings and get a response? 

My apologies for dredging up an old thread but I have been interested in the Noval preamp due to the cheap price more than anything but the balanced connections are a plus as well. These tubed Freya's seem to get grand reviews but my concern has always been Does it really have tube attributes to its sound? Certainly no disrespect to anyone but due to the price I take it as a good entry piece and not sure how much experience with tube preamps do these rave reviewers have? 

Your objective findings was something I wondered about this unit..even before you did the testing. But your subjective findings hold weight also I feel. Hard to ignore what's going on between and out of the speakers.. especially if you are being critical and are aware of the bias and acoustical mind tricks that truly do happen. I have experienced something kinda similar to your testing in the form of speakers and crossover mods. Using REW and testing frequency response the before and after testing of loudspeakers with stock and "upgraded" parts  were the same. But the mod speaker was perceived as clearer with better separation between instruments. A darker background. 

Was that all in our heads though? Sure didn't seem like it. Measurements will say no difference..ears and brain says Oh it's there. 

Anyway, I was just curious if you ever presented Schitt with your findings? 

On a side note I have had good experiences with room correction as well. Plenty to choose from these days and a few were obviously already mentioned. 

Hi @mattw73 , no worries happy to provide an update.

I didn't end up pursuing my findings with Schiit, though I continue to be a happy camper using this preamp and would encourage you to pick one up if you can still get one, especially with the balanced options. It's a steal.

I learned shortly after my last post that my microphone was no longer compatible with my recording software so I put a pause on further recording and have just been enjoying the music.

However, I have a UMIK-1 in the mail right this second as I was interested in exploring convolution filters within Roon and HQPlayer so I might pick this back up and can let you know what I find.

Regarding my experiences in the subjective realm, I've tried out some additional NOS combinations, and I feel there are differences, but they are definitely subtle. Most notably, there seems to be less energy and dynamics whenever you deviate too much from the recommended 2.4A heater current total of the four tubes. Using 4x 6922s just feels too mellow for instance, but adding 2x 6N6Ps to the output side restores the excitement while letting some of the character of the 6922s come through, which with my Bugle Boys, I interpret to be a tiny bit of warmth, with a slightly wider and more holographic soundstage compared to the SS Buffer. As tempted as I am to spend $300+ on a pair of NOS Mullards, I just feel that this application wouldn't do them justice. Luckily 6N6Ps are plentiful and cheap though.

So in short, I think you're right to call this an entry point to tubes, but it's still worth it in my book given the range of features and strength of the solid state modes.

Thank you @nixanthrope , I truly appreciate the response and opinions you've shared.  I have an opportunity to get my hands on the Noval for a used price..and for the money & features it will be hard to pass up. Seems like it would be an easy resell down the road if I discounted the price a little bit. Thanks for your insight on the tube pairings. I actually have a few pairs of old well regarded 6922's I never had the chance to use. Some GE labelled Mullards, Phillips Holland Miniwatt SQ's and one pair of PQ's that I spent a decent amount on many years ago. So a pair of those and something with a little more power seems like the way to go...yet not going over the 2.4 mark. 

I'm glad to hear that you are still using the preamp and enjoying it. Awesome 👍

@mattw73 I think since you're already stocked up with options, it's a no brainer and you should go for it.

Buying second hand might break the warranty, so maybe have a look at some QC issues others have experienced here before pulling the trigger (I personally haven't had any, mine is a good unit):

https://www.head-fi.org/threads/schiit-freya-impressions-and-tube-rolling-thread.832177/page-210

And if you're stateside, ebay seller "kambremer" has US stock Russian 6N6Ps and 6N1Ps for good prices. For the latter, you can get a matched quad for cheap, which is better than what the Freya N ships with. I also recommend trying 4x NOS 6CG7s which will also give you the full 2.4A.

Good luck and Happy New Year!

@nixanthrope thanks for the heads up and link to some real user issues. Information sharing like this are what Forums should be all about. I'm glad I reached out and you were kind enough to spare a little time and share with me. 

Happy New Year!!