amirm
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This will be an assessment and step-by-step dimensions associated with Schiit Saga passive/tube pre-amplifier. It’s on sort loan from a known member who has got waiting literally months for their review! The Saga costs USD $349 from Schiit direct with stock tube plus delivery. The tube provided with this device was the Russian 68HC which can be their clone of 6N8S (dural triode).
The commercial design is typical of Schiit item but as always, with yet another switch procedure and looks:
For reasons too embarrassing to describe, I experienced to start the machine and here, we noticed the analog volume control (which gets changed into electronic), had a nice notch on it. I happened to be delighted these people were using such as that could prevent the volume control becoming loose, and then understand the set screw continues on the part that is round of shaft, perhaps not flat!
Anyhow, returning to the switches, the are microprocessor controlled and feel good. Click the input one in the left and also you turn between five various RCA inputs. The turn on the proper chooses perhaps the Saga is a straightforward pass-through with amount control, or through an active hybrid tube+solid state production stage pre-amplifier. The gain both in full instances is zero meaning whatever voltage you place in, is really what you can get away.
The quantity control is a attenuator that is stepped a handful of relays and resistors. Comparable pair of relays are acclimatized to find the input that is right.
Let us enter dimensions and determine just how each mode performs.
Dimensions This being a pipe amplifier, we thought I measure I measure its performance in active mode because it driven on to observe how it changes:
While you see, performance is extremely stable. There was a very small enhancement in one channel as much as about one minute but from then on, there’s absolutely no distinction also only at that magnification. This is a good thing while you do not wish to age the tubes any longer than you need to.
I will be often saturated in complaints about fables audiophiles think it. In cases like this, the above busted certainly one of my very own fables that pipe items require significant heat up to get at stable performance. @SIY had told me personally otherwise but needless to say, I didn’t pay attention.
With that from the means, let us consider our typical dashboard. To actually judge the performance for the Schiit Saga in passive mode, we thought we show the performance that is native of Audio Precision APx555 on it’s own before routing the production through the Saga:
We come across the tiniest quantity of distortion at 2 kHz (degree at -150 dB) and mains sound (degree at -145 dB). There clearly was some sound around our primary sign dress. I will be rid of that utilizing the electronic (DAC) mode associated with APx555 generator but then distortion increases. Anyhow, we now have a SINAD of 122 dB as of this 2 volt output.
Routing the sign through Schiit Saga at maximum amount in passive mode we have:
There is certainly some mains leakage which may be because of ground cycle or leakage for the power for the stage that is active Saga. In any event, this really is excellent performance with simply 2 to 3 dB of loss in comparison to APx555.
I became waiting on hold to my chair anticipate massive fall in performance once I started up the pipe:
Wow, this might be really respectable! I’ve calculated Schiit DACs with far lower performance. The offending distortion may be the harmonic that is second nearly -98 dB which sets the SINAD/THD+N. There are power related surges however they are at -108 dB and lower so do not come right into play.
Overall, it is one good showing up to now!
Let’s measure regularity reaction at maximum amount:
The mode that is pass-throughin blue) is ruler flat, showing the superlative performance of this APx555.
We went the stage that is active means: 1) with standard 100k Ohm input impedance regarding the analyzer (green) and 2) 600 Ohm load of this analyzer. We come across that there surely is some droop with 100k Ohm load beginning at 50 Hz and increasing to 2 dB at 10 Hz. This shows a capacitor production stage which will obviously have increasingly greater impedance as frequencies decrease. Switching to 600 Ohm load emphasizes this and magnifies the nagging issue significantly and artificially, offering us 16 dB of droop by 20 Hz.
The 600 Ohm impedance is basically the inverted form of our production impedance bend but let us run the measurement that is full obtain the certain values:
Searching all of the real option to the proper, the minimum impedance is 183 ohm. During the budget of 20 Hz, impedance climbs to 3,130 ohm. Utilizing the typical 10:1 guideline, your energy amplifier input impedance must certanly be at the very least Ohm that is 30k to regularity dependent/EQ changes. Place more merely, by using reduced input impedance energy amplifier after Saga in active mode, your frequencies that are low 500 Hz or more will attenuate. This might accentuate all of those other range you may like, or perhaps not.
The mode that is passive its very own issues right here. As yet on function the volume has been kept by me at maximum as to help keep the attenuator resistors taken care of. As soon as you turn straight down the amount, you will end up placing varying level of opposition in the production path and therefore, increase impedance. This is actually the production impedance bend in passive mode with amount around 20%:
The cursor reaches 144 Hz showing an impedance of 2,760 ohm. This really is as opposed to simply 21 ohm impedance at maximum amount showing the 20 ohm production impedance associated with the APx555 analyzer.
Plotting a points that are few the amount control gets us this:
So fundamentally, any amount degree not as much as 50% will probably boost the impedance significantly. Happily the attenuation just isn’t frequency dependent so that the effect just isn’t there as there is certainly with tube phase. Nevertheless then turning down the volume may change the frequency response if the input impedance of the power amp changes with frequency and is less than 30k Ohm. Perfection in noise and distortion has this cost.
Conclusions i have to state, we developed a fondness because of this small pre-amp. I’ve no concept why it myself as I would never use. It simply appears like a neat mixture of features in a fairly cost package that is low. If Single Muslim reviews you’re shopping for its features and generally are mindful of disadvantages pertaining to its varying production impedance, however do not see grounds not to get and play with it. You could utilize it as a nicely implemented switcher that is audio instance with all the amount control for fine tuning of max level.
Therefore, good task Schiit.
———— As always, questions, commentary, guidelines, etc. are welcome.