Schiit Saga vs Freya

[zackthedog]

Correction. Regarding the 1970's GE 6SN7GTB tube (with top series filament wire) I referred to, I must say that after my initial fascination with its level of detail and transparency, after a while (in my system) it gets a bit tiring and bass is a bit less tight/well defined as with a 1960's GE 6SN7GTB tube.

 

In general it's quite interesting to experience how electrically similar but physically (slightly) different tubes can voice a preamplifier such that it makes me wonder how e.g. their respective resulting dB SPL spectra compare. I'm planning to do some measurements.

 

YUp, I agree. Now try the GE 6SN7GTA. ;-)

[zackthedog]

Do you think it may sound better than a GTB? I'm expecting a GE 5692 brown base.

 

Probably not, but you might try one. It's got more mid-range energy, a little more "excitement". I'm not crazy about the GE 5962. Throws a big image but very flat and a bit brittle on top. Let us know what you think.

[zackthedog]

So I tried a GE 6SN7GTA and I love the effortless, sophisticated sound! It may actually sound better than a GTB, especially the bass. I will listen to it for a couple of weeks and then switch back to GTB for comparison..

 

The GE 5692 (brown base) also arrived and it sounds more different from the GTA than from the GTB. (Currently) I prefer the GTA.

 

Good! Glad you like the GTA!

[zackthedog]

Yes I really do like it. One question. The GE 6SN7GTA has a side getter, but the tube I have also has two small deposits of getter flash material in the top, directly above the heaters (see picture):

 

[ATTACH=CONFIG]33682[/ATTACH]

 

As said, the tube sounds great (without noise) and everything else looks fine, but does this mean it has at one time been overheated and could this have audible consequences? To compare, I've another (NOS) GTA from Viva Tubes on the way that's rated 100+% and which doesn't have these top deposits (as per the picture on their website).

 

It just means the tube has been used, not necessarily abused. :-) If it measures strong and sounds good I wouldn't worry.

[zackthedog]

Interesting Abtr is your journey through NOS rolling. I so far have hesitated to order an GE (or any other) NOS tube yet. The seemingly hard-to-pin-down experience has me a bit weary (I am already confused as to which tube is which and how to specify exactly what one is ordering) . That, and I have so far been happy with the top to bottom sound of my Sophia Electric new production tube.

 

Now that I have more hours/cycles on it, I would say that it has not changed much. I would say that the bottom end might have extended a bit, but the top seems to be the same smooth/extended but non "harsh" I liked in the beginning.

 

I have also replaced the Emotiva a-100 with a Parasound A23, which is doing a better job gripping my (obviously somewhat difficult to drive) Legacy Studio HD's such that everything below 200hz sounds cleaner and all around more resolved. Sound stage now also has real depth instead of just width, and separation/resolution is more precise (not that the Emotiva was "bad" at these things, especially considering its price).

 

I agree that tube swapping can be exhausting. I recommended the GE 6SN7s to Abtr as a money-saver and a solid choice. I have heard the Sophias but I imagine they are lovely. I think you're well set-up with those and don't see any reason to wear out your ears or your pocketbook any further. Just my .02.

[zackthedog]

Well, I purchased a pair of GE 6SN7GTA from a seller on ebay for about $60. He claimed they were manufactured in the early 1950's, though I can neither confirm or deny this. The typeface on the boxes certainly look the part . I have had one in my system since yesterday. A bit more bass, particularly below 50hz than the Sophia. I am trying to decide if what I am hearing is simply "more", or if it is also a looser and less well defined. At this point I think it is a bit of both. A well recorded double bass sounds good, but just a bit too full and bloomy. I think the Sophia's bass might be the more accurate of the two. The mids sound pretty much the same to me, excepting a bit of coloration on certain recording/voices that the GE has. Can't seem to pin this down, except to say at this point it is just different - sometimes I prefer the Sophia and sometimes I prefer the GE. The treble is also very similar and well extended, but here I can say that I hear just a bit more sibilance sometimes out of the GE.

 

Overall, at this point I would say that the Sophia is probably the more even and "accurate" of the two tubes, but that on certain recordings the GE seems to bring out a bit of something extra that sounds nice. Given the price differential ($30 vs $100), the GE is in fact the better deal...

 

Interesting, thanks for the report! If you like the GE but feel the bass is a bit much you might try tuning some other things in the system, maybe a different interconnect or something. Upscale is certainly a reputable dealer, but his prices are high. If you're looking for guaranteed service on rare tube types, he certainly provides that.

 

I've never purchased from him, and my only complaint, if it can be that, is that he sells the Philips 5R4 rectifier as a *direct* substitute for a 5AR4. This is utterly baffling to me. Apart from the sharing the same filament voltage and current, these are completely different rectifier tubes and should never be viewed as direct substitutes for each other. I built a pair of monoblocks for a friend, and the power supply and circuit are designed for a 5AR4. He recently asked if he could use this Philips 5R4 sold by Upscale, and I told him under no circumstances would that rectifier work in the amps.

 

I'm truly puzzled by a reputable dealer recommending a 5R4 as a substitute for a 5AR4.

[zackthedog]

I stumbled on this while researching the Saga-Freya. I have a vintage, solid state integrated amp (Sansui AU-919). Why doesnt it make sense?

I've used tubed headphone amps as "pre" into my amp and its a good way to get a tube buffer into the solid state; it sounds really good, particularly with digital music. If I had the Saga/Freya I could "tube" my digital music and run my turntable into whichever I choose. But the biggest reason I'm considering...I dont have a remote at any point in my chain and having one would be great especially when listening to headphones through my amp (which is better than any dedicated headphone amp I've yet to hear). Bascially my setup is more standard "hifi" than computer based so it makes all the sense in the world to me.

 

Doesn't the Sansui have a power amp input separate from the preamp? Judging by photos it seems to.

[zackthedog]

Question for those with some tube knowledge: Is the Tube still in some way in the circuit when the Saga is in passive mode? Obviously the tube is still powered up (and you don't save tube life by using your Saga in passive mode).

 

I think this might be the case, or I have a bad case of expectation bias because when I swap tubes I swear I can hear the qualities of the whatever tube I have in in passive mode as well....??

 

I once spent a whole evening carefully comparing 12AX7s in the line section an old Scott preamp. I was really torn between which brand sounded better, until I realized that I was actually swapping tubes in the phono stage, which was switched out of the circuit. Which is not to say that all tubes sound the same, or that we *always* imagine differences between components, just that this kind of A-B-ing is unreliable.

 

I don't know the circuit, but assuming the active stages are bypassed in passive mode, I'm afraid you might be imagining things. But perhaps someone else knows the operation of the piece better than I and knows a way in which the sound might be affected.

[zackthedog]

3 hours ago, Abtr said:

Well, I made some changes in my system that appear to reduce (analogue) noise and significantly improve the overall dynamics and definition of the reproduced sound/music. Most notably, a Chang Lightspeed mains filter now cleans up HF mains noise and I use a pair of Dave Slagle autoformers (Slagleformers) in between the DAC's analogue output and the Saga. The Saga's volume control is set to maximum, so the Saga only functions as an impedance buffer (to the power amp). The Slagleformers are used for (passive) volume control. Note that this also eliminates the slight but audible 60Hz hum coming from the Saga, especially at lower volume settings.

 

Anyhow, the improved sound made me re-evaluate some tubes that I tried earlier in the Saga, and particularly the solid-state-like realism of the Sophia Electric 6SN7 now sounds great! Possibly better than any of my NOS tubes (I didn't try them all yet).. So, I must revoke my earlier opinion of the Sophia Electric 6SN7, it really is a very nice tube! The best sounding tube for the Saga may be system dependent..  

 

A friend of mine just yesterday wrote to say that the Sophias in his ModWright Oppo-105 also excelled the GEs.  Guess I need to try them.

[zackthedog]

8 hours ago, Abtr said:

 

Maybe something is wrong with my Saga.. I recently noticed that at minimum volume it produces an audible hum, even without any input device connected to it and whether or not it is connected to mains ground/earth. The hum gets less at higher volume and disappears at maximum volume setting which bypasses the volume control. Since this is a passive resistor based volume control, I'm at a loss as to what causes the 60Hz hum. It can't be a bad PS cap. And when I use the Slagleformers as a passive preamp without the Saga, then (without a source input signal) my (class D) poweramp is dead silent even at max volume..

 

Sounds like a faulty pot.  Does it occur when you remove the tube and use passive mode?

[zackthedog]

4 hours ago, Abtr said:

I did some research. The Saga uses 6.3V AC heater power. The 60Hz hum may then result from excessive heater-to-cathode leakage which reportedly can be a (gradually worsening) problem with the Sophias. Yet it remains hard to see how the use of autoformers could eliminate such leakage.
 

 

Basically, anything attached to the input grid of the tube, including the volume pot, can act like a big antenna.  By turning the volume pot down, you're "introducing it" into the circuit.  If the tube is faulty, it can pick up RF or grounding problems and amplify them.  It may be that under other circumstances the Sophia would be okay, but it may be very sensitive to whatever sort of circuitry is precedes the grid in this particular preamp.  For instance, if they don't employ a grid-stopper resistor, that could cause this sort of behavior.

 

Bypassing the pot and using the autoformers may just have eliminated something in the volume control circuit that the Sophia is sensitive to, I couldn't say.

 

I'm not explaining this very well, but suffice to say that it seems like the Sophia is a problem in this circuit, either due to a flaw or just the way it's constructed.  

 

I'm surprised that the Saga uses AC heating for the tube.  That seems like a risky ploy in a tube preamp.  

[zackthedog]

The grid-stopper should ideally be a 1/2 watt carbon-comp resistor, say 1K ohm, soldered as close to the input grid pin as possible.  Perhaps there is one already there, I don't know.  I *could* help reduce the noise issue.  Another possibility would be to raise the filament supply from ground if it is not already.  Tying it to the B+ supply might help, provided it is less than 100 volts.

 

I don't necessarily recommend modifying the unit, it's up to you. :-)  Nor do I know if either of these things would help, it may just be the tube.

[zackthedog]

58 minutes ago, Speed Racer said:

Don't necessarily recommend? Apparently Jason Stoddard doesn't know what he is doing......

 

Well, in "passive" mode the tube hum is still a problem, so there's a shortcut in there somewhere.  I'm not saying the designer doesn't know what he's doing, but it's a $350 preamp.  No doubt it could be improved.

[zackthedog]

58 minutes ago, Abtr said:

OK, I found out that (in my system) what I previously thought to be normal tube noise/hum may be produced by the Saga itself! In active as well as in passive mode without a tube inserted, it slightly hums. This hum is most audible at maximum volume (without a source signal playing) and close to a speaker. (Funny that my apparently defective Sophia tube hums loudest at minimum, and least at maximum volume..)

 

Anyway, my system is nearly dead silent when I use (Dave Slagle) autoformers as a passive preamp (without the Saga). I must say that I don't mind the slight noise/hum from the Saga, but can anyone please confirm that the Saga actually does hum as described above, or should I contact Schiit? Thanks. 

 

Interesting.  Sounds like a shielding issue, and that B-grade Sophia was especially sensitive to it.  I have found that when a pot increases hum when turned *down* there's an RF issue involving the combination of the pot and the tube's grid.  Pots can introduce stray capacitances into the circuit.  Moving it closer to a speaker would create some magnetic field noise as well.  The autoformers may avoid that, which is why they are quieter.  But I could be wrong.  I'd be interested to know if you find a better answer.

[zackthedog]

1 hour ago, Speed Racer said:

 

Saga and Freya have no potentiometers.

 

That's true, I see it's a micro-processor attentuator.

[zackthedog]

1 minute ago, zackthedog said:

 

That's true, I see it's a micro-processor attentuator.

 

...though I also see that the screen shot of the board on their web site clearly shows a either a potentiometer or stepped switch.

[zackthedog]

1 hour ago, Abtr said:

 

The potentiometer you see on the Saga board is used to control a microprocessor that in turn controls a relay switched resistor-based attenuator. The Schiit Sys passive preamp is a potentiometer-based volume control. I tried it with the Saga and the hum is the same as with the Saga's own volume control, so you may be right in that this hum seems to be related to resistive attenuators in general..

 

Btw, I ran the new Sophia for about 48 hours nonstop and the hum/noise level has dropped significantly, especially at the Saga's max volume setting. This is nice because that's how I bypass the Saga's volume control. The tube may or may not develop the same problem as my other Sophia: excessive hum at the Saga's lower volume settings. We'll see..   

 

I'm really just throwing ideas out there. :-)  I assume you tried the manual's suggestion of lifting the ground?