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Schiit Saga vs Freya


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Hi Zackthedog. As you know, the electrical characteristics of a vacuum tube are commonly described by three variables: voltage gain (Mu), transconductance (Gm) and plate resistance (Rp). In the case of triodes these are related: Mu = Gm x Rp. Mu and Rp are most important, where Rp directly affects output impedance. However, I understand that Mu and Rp are very difficult to measure and most/all vendors measure only Gm. With two triodes matched only for Gm (Mu/Rp), there is no assurance whatsoever that Mu and Rp will match. It seems to me this practice of matching tubes (triodes) is questionable and largely a marketing ploy..

 

I think you have a point, though I don't agree that matching sections is a "ploy". In a phase-splitter, a poorly-matched dual triode is going to affect the signal balance. The very least you can do is match the halves for Gm, even if further testing would involve more time and effort. In a cathode-follower, which I assume is being used here, it's probably less critical, but I'd still want to know that the two sections were performing somewhat equally.

 

ETA: Here's a good overview of the "matching" issue that sums up the issue pretty well. It addresses your concerns about the limits of tube matching.

 

http://tubesound.com/2010/10/27/tube-matching-with-a-tube-tester/

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I think you have a point, though I don't agree that matching sections is a "ploy". In a phase-splitter, a poorly-matched dual triode is going to affect the signal balance. The very least you can do is match the halves for Gm, even if further testing would involve more time and effort. In a cathode-follower, which I assume is being used here, it's probably less critical, but I'd still want to know that the two sections were performing somewhat equally.

 

ETA: Here's a good overview of the "matching" issue that sums up the issue pretty well. It addresses your concerns about the limits of tube matching.

 

TubeSound » Blog Archive » Tube Matching with a Tube Tester

Thanks for the link. Do you think matching Gm of the two sections of a *single* dual triode tube is more likely to indicate matched Mu and Rp, than would matching Gm of a *pair* of tubes?

 

BTW, As of yet I didn't receive the G.E. 6SN7GTB (1960s vintage). Should be here by Monday. I did try a new Shuguang Treasure CV181-Z in the Saga and it sounds different from its cousin, the Psvane CV181-T mkII. A bit more lush perhaps. I like it. :)

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Thanks for the link. Do you think matching Gm of the two sections of a *single* dual triode tube is more likely to indicate matched Mu and Rp, than would matching Gm of a *pair* of tubes?

 

BTW, As of yet I didn't receive the G.E. 6SN7GTB (1960s vintage). Should be here by Monday. I did try a new Shuguang Treasure CV181-Z in the Saga and it sounds different from its cousin, the Psvane CV181-T mkII. A bit more lush perhaps. I like it. :)

Well, that's an interesting question. The original Williamson amplfier design used four 6J5s instead of two 6SN7s. (the 6J5 is equal to one half of a 6SN7). I'm not sure of the reason for this, but one advantage would be that you could carefully select four matching 6J5s rather than search through batches of 6SN7s for well-matched halves, if you see what I mean. So, for instance, if the Saga used two 6J5s instead of one 6SN7, you could select your 6J5s for a better match. :-)

 

Which raises another interesting point: You *could* replace the single 6SN7 with a dual 6J5 adapter (you can get these on eBay) and use two 6J5s--a lovely tube, BTW. You'd probably need a socket extender (also available on eBay) because of the recessed socket. Just another tube-swapping option to drive you nuts. :-)

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Well, that's an interesting question. The original Williamson amplfier design used four 6J5s instead of two 6SN7s. (the 6J5 is equal to one half of a 6SN7). I'm not sure of the reason for this, but one advantage would be that you could carefully select four matching 6J5s rather than search through batches of 6SN7s for well-matched halves, if you see what I mean. So, for instance, if the Saga used two 6J5s instead of one 6SN7, you could select your 6J5s for a better match. :-)

 

Which raises another interesting point: You *could* replace the single 6SN7 with a dual 6J5 adapter (you can get these on eBay) and use two 6J5s--a lovely tube, BTW. You'd probably need a socket extender (also available on eBay) because of the recessed socket. Just another tube-swapping option to drive you nuts. :-)

Well, I was thinking that because the dual triodes of (e.g.) a single 6SN7 tube are obviously of the same make/series/date, matching Gm may yield a relatively high probability that other variables (Mu and Pd) are also matched, whereas selecting two different tubes for matching Gm may have a lower probability of being matched for Mu and Pd (where Gm = Mu/Pd).. Just a thought..

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Well, I was thinking that because the dual triodes of (e.g.) a single 6SN7 tube are obviously of the same make/series/date, matching Gm may yield a relatively high probability that other variables (Mu and Pd) are also matched, whereas selecting two different tubes for matching Gm may have a lower probability of being matched for Mu and Pd (where Gm = Mu/Pd).. Just a thought..

 

That might well be, yes.

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Thanks! I ordered an early 1960s G.E. 6SN7GTB for the Saga. Should be here this week. :)
I hope you like it. :-) Let us know what you think.

Sorry for the (slight) delay. I received the GE 6SN7GTB (1962 vintage) tube for the Saga. To be precise: a GE 6SN7GTB (EC33) red label, like this one:

 

.........................................GE6SN7GTB Red Label.png

 

Gm = 2400 (a dimensionless number) for each triode section, and in my current system it's the best tube I've tried; better than the Psvane and Shuguang.

 

Here's my personal (preliminary) Saga tube review:

 

- Sovtek 6SN7GT (factory 1970-80 vintage): Nice but relatively dull

- Tung-sol 6SN7GTB (new): Relatively harsh but quite open sounding

- Psvane CV181-T mkII (new): Well-balanced/coherent, open and dynamical

- Shuguang Treasure CV181-Z (new): Like the Psvane, well-balanced/coherent, open and dynamical, but a bit more lush sounding

- GE 6SN7GTB red label (1962 vintage): Best I tried so far, very dynamical, very well-balanced, very coherent, very good bass and mids and smooth highs :)

 

The GE tube really rocks, and I don't think this is an artifact of my system (although it does seem to tame the KEF's highs a bit). It sounds very natural and authoritative in every frequency range and genre. Also, of the tubes I tried, it sounds the most different from the Saga's 'passive mode'. Wow!

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Sorry for the (slight) delay. I received the GE 6SN7GTB (1962 vintage) tube for the Saga. To be precise: a GE 6SN7GTB (EC33) red label, like this one:

 

.........................................[ATTACH=CONFIG]33173[/ATTACH]

 

Gm = 2400 (a dimensionless number) for each triode section, and in my current system it's the best tube I've tried; better than the Psvane and Shuguang.

 

Here's my personal (preliminary) Saga tube review:

 

- Sovtek 6SN7GT (factory 1970-80 vintage): Nice but relatively dull

- Tung-sol 6SN7GTB (new): Relatively harsh but quite open sounding

- Psvane CV181-T mkII (new): Well-balanced/coherent, open and dynamical

- Shuguang Treasure CV181-Z (new): Like the Psvane, well-balanced/coherent, open and dynamical, but a bit more lush sounding

- GE 6SN7GTB red label (1962 vintage): Best I tried so far, very dynamical, very well-balanced, very coherent, very good bass and mids and smooth highs :)

 

The GE tube really rocks, and I don't think this is an artifact of my system (although it does seem to tame the KEF's highs a bit). It sounds very natural and authoritative in every frequency range and genre. Also, of the tubes I tried, it sounds the most different from the Saga's 'passive mode'. Wow!

 

Told ya! ;-)

 

Seriously, I'm glad you like it. I find that they convey a lot of energy without sacrificing balance across the range. That 2400 sounds like a Hickok measurement and is a solid NOS reading. Should last you a long time.

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Told ya! ;-)

 

Seriously, I'm glad you like it. I find that they convey a lot of energy without sacrificing balance across the range. That 2400 sounds like a Hickok measurement and is a solid NOS reading. Should last you a long time.

A really amazing tube! I highly recommend it for the Schiit Saga. The Saga with this tube sounds better than anything I've tried in terms of pre-amplification (passive or solid state or other tubes) in my current (and previous) system(s) so far. There may exist better triodes, but the performance of this GE takes my current system to a level of realism in sound reproduction that I actually didn't think was possible. Thanks again! ;)

 

On the other hand, this result makes me wonder whether solid state (pre)amplifier designs are somehow fundamentally 'flawed', and if so, and if (currently) the best audio tubes are NOS tubes, then there may be a supply problem in the (near) future!? I'm interested to hear experiences from Freya users who compared the JFETT buffer to (NOS) tubes..

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.........................................[ATTACH=CONFIG]33173[/ATTACH]

 

 

The GE tube really rocks, and I don't think this is an artifact of my system (although it does seem to tame the KEF's highs a bit). It sounds very natural and authoritative in every frequency range and genre. Also, of the tubes I tried, it sounds the most different from the Saga's 'passive mode'. Wow!

 

Where did you buy them?

Main listening (small home office):

Main setup: Surge protector +>Isol-8 Mini sub Axis Power Strip/Isolation>QuietPC Low Noise Server>Roon (Audiolense DRC)>Stack Audio Link II>Kii Control>Kii Three (on their own electric circuit) >GIK Room Treatments.

Secondary Path: Server with Audiolense RC>RPi4 or analog>Cayin iDAC6 MKII (tube mode) (XLR)>Kii Three .

Bedroom: SBTouch to Cambridge Soundworks Desktop Setup.
Living Room/Kitchen: Ropieee (RPi3b+ with touchscreen) + Schiit Modi3E to a pair of Morel Hogtalare. 

All absolute statements about audio are false :)

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A really amazing tube! I highly recommend it for the Schiit Saga. The Saga with this tube sounds better than anything I've tried in terms of pre-amplification (passive or solid state or other tubes) in my current (and previous) system(s) so far. There may exist better triodes, but the performance of this GE takes my current system to a level of realism in sound reproduction that I actually didn't think was possible. Thanks again! ;)

 

On the other hand, this result makes me wonder whether solid state (pre)amplifier designs are somehow fundamentally 'flawed', and if so, and if (currently) the best audio tubes are NOS tubes, then there may be a supply problem in the (near) future!? I'm interested to hear experiences from Freya users who compared the JFETT buffer to (NOS) tubes..

 

They don't make 'em like they used to--not that there aren't some good new production tubes, but still. The GEs are pretty plentiful, but it wouldn't hurt to buy a few spares. :-) I doubt they're run very hard in the Saga, so they ought to last a few years.

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Looks like you started a run. :-) But seriously, you can get them on eBay from well-rated dealers. I like Viva Tubes, myself. His tubes are always as advertised. Tube World also has them.

 

ETA: They were also rebranded as Westinghouse and Motorola.

The GE 6SN7GTB 1960s tubes come in slightly different models. The two I have are the same as called "NOS NIB GE 6SN7GTB Gray Flat-Aligned Plate O Get" by Viva Tubes and have an O shaped (getter?) structure between the sections like visible here (right tube):

 

................................GE6SN7GTBOGet.png

 

Do you think these differences matter soundwise? And if so, do you have a preference for a specific model?

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Do you think these differences matter soundwise? And if so, do you have a preference for a specific model?

 

Depending on the transparency of the preamp you will find that every tube version sounds a bit different. Sometimes wildly so even within the same model and there are a lot of different versions of 6SN7. This is why tube rolling is so popular. You can dial in the sound to your own liking and to balance/harmonize with your other components and cables.

 

The 6SN7 tubes I like best are Kenrad VT-231 and Tungsol Roundplate(TSRP). These tubes are getting more scarce and their reputation has driven the prices way up. Another option, if it will fit, would be to get some 7N7 to 6SN7 adapters and try some 7N7s. They are still cheap, electrically identical to 6SN7's, and rival them for sound quality.

 

BTW. I have found Viva Tubes to be a good vendor.


"Don't Believe Everything You Think"

System

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The Saga is a passive resistor-based volume control + an active tube buffer..

 

the Freya is tube driven

Main listening (small home office):

Main setup: Surge protector +>Isol-8 Mini sub Axis Power Strip/Isolation>QuietPC Low Noise Server>Roon (Audiolense DRC)>Stack Audio Link II>Kii Control>Kii Three (on their own electric circuit) >GIK Room Treatments.

Secondary Path: Server with Audiolense RC>RPi4 or analog>Cayin iDAC6 MKII (tube mode) (XLR)>Kii Three .

Bedroom: SBTouch to Cambridge Soundworks Desktop Setup.
Living Room/Kitchen: Ropieee (RPi3b+ with touchscreen) + Schiit Modi3E to a pair of Morel Hogtalare. 

All absolute statements about audio are false :)

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The GE 6SN7GTB 1960s tubes come in slightly different models. The two I have are the same as called "NOS NIB GE 6SN7GTB Gray Flat-Aligned Plate O Get" by Viva Tubes and have an O shaped (getter?) structure between the sections like visible here (right tube):

 

................................[ATTACH=CONFIG]33236[/ATTACH]

 

Do you think these differences matter soundwise? And if so, do you have a preference for a specific model?

 

I haven't found a big difference between the slight variations aomng the GEs. IMO, it's the plate structure that accounts for the biggest difference, and that is consistent across the GE models.

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Are you sure? I'm just asking, because "tube-driven" would indicate, to me, that the tube is an active gain stage, as opposed to a cathode-follower buffer stage. It would make a difference.

 

Freya description on product page: "Switch between passive, active JFET buffer, and tube gain modes".

 

Other Schitt quotes: "or choose the tube gain stage—a serious gain stage running on 300V rails. "; "employ highly linear 6SN7-type tubes on 200 or 300V rails in the active stages"

 

Schiit Freya Impressions and Tube Rolling Thread

Main listening (small home office):

Main setup: Surge protector +>Isol-8 Mini sub Axis Power Strip/Isolation>QuietPC Low Noise Server>Roon (Audiolense DRC)>Stack Audio Link II>Kii Control>Kii Three (on their own electric circuit) >GIK Room Treatments.

Secondary Path: Server with Audiolense RC>RPi4 or analog>Cayin iDAC6 MKII (tube mode) (XLR)>Kii Three .

Bedroom: SBTouch to Cambridge Soundworks Desktop Setup.
Living Room/Kitchen: Ropieee (RPi3b+ with touchscreen) + Schiit Modi3E to a pair of Morel Hogtalare. 

All absolute statements about audio are false :)

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I have no experience with a Tube preamp. Do preamp tubes need bias adjustments like a tube power amp?

 

Generally, no.

Forrest:

Win10 i9 9900KS/GTX1060 HQPlayer4>Win10 NAA

DSD>Pavel's DSC2.6>Bent Audio TAP>

Parasound JC1>"Naked" Quad ESL63/Tannoy PS350B subs<100Hz

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Are you sure? I'm just asking, because "tube-driven" would indicate, to me, that the tube is an active gain stage, as opposed to a cathode-follower buffer stage. It would make a difference.

 

I agree that it would make a difference, but I do not see how "tube driven" would imply a gain stage over a buffer.

Forrest:

Win10 i9 9900KS/GTX1060 HQPlayer4>Win10 NAA

DSD>Pavel's DSC2.6>Bent Audio TAP>

Parasound JC1>"Naked" Quad ESL63/Tannoy PS350B subs<100Hz

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