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By default, SA-1 is in low gain mode. If you need to drive headphones, it is recommended to use high gain mode. You may need to read the instructions. When we use the high gain mode on the decoder SDA6-PRO (4.6V RMS output) to balance the input and output, we can even push AKG K1000 headphones.
Oh dear! This is the 3rd post I have to reply implying I can't (or don't) read manuals.
I did switch it to high gain.
I have a low post count but I am not a noobie in this hobby....
I read you are the designer. Perhaps you can explain if it is realistic to expect the increase in volume with some usage that another poster mentioned.
I have my Gustard X16 connected both XLR and SE and when I listen to my Sundara HP, I do not hear any change in volume when I change inputs using the same SE output. I have not yet tried XLR in balanced out. Those gain changes are to keep the volume constant or at least so close that I really cannot tell the difference.
For comparison reference:
I just now tested my hardest to drive headphone the Dan Clark Aeon 2 Closed (Impedance: 13Ω, Sensitivity: 92dB) single ended on the SA-1 fed by Pegasus Musician with RCA (2.2V) on low gain with volume knob at 2 o'clock volume setting at very loud listening level (balanced headphone cable at 12 o'clock position) .
From what I can tell the OpAmp is only used on the single ended inputs to convert to balanced.
Looks like the balanced inputs go directly to the input select relay.
Perhaps your combination of input/output is lowering the overall gain Vs another Amp ?
See below for SA-1 headphone amplifier gains:
1. Single-ended input, single-ended output: low gain is 0db, high gain is 11db;
2. Single-ended input, balanced output: low gain is 6db, high gain is 17db;
3. Balanced input, single-ended output: low gain is -6db, high gain is 5db;
4. Balanced input, balanced output: low gain is 0db, high gain is 11db;
By the way, where did you find this information? I know it is not in the manual.
I have experimented a bit and cannot hear those differences. In essence switching from XLR to RCA inputs results in nochange that I could hear.
Perhaps the 6db difference in gain makes up for the voltage difference from your DAC's RCA/XLR output? Typically 2V from RCA vs 4V from XLR, so that the result is equal volume regardless of your input connection on the SA-1. Just a guess.
From earlier in this thread, according to the designer of the SA-1.
Perhaps the 6db difference in gain makes up for the voltage difference from your DAC's RCA/XLR output? Typically 2V from RCA vs 4V from XLR, so that the result is equal volume regardless of your input connection on the SA-1. Just a guess.
One more headphone to report: Neumann NDH20: 4 o'clock on the SA-1, 12 o'clock on the V200, both maxed out at 5 o'clock.
Sounds about the same on both. I prefer the Elegia.
From what I can tell the OpAmp is only used on the single ended inputs to convert to balanced.
Looks like the balanced inputs go directly to the input select relay.
How many hours you did use the SA-1 in total? The volume will improve after some hours of use, had the same effect with the SA-1 myself (never had this with any other amplifier before...)
I totally agree. I thought it just me. I'm not a real believer in burn in, BUT,
(flame suit on), its getting better over the first week. I'm using it in high gain mode now that Amir indicated no loss running in high gain. Improves head room. and volume knob range. Great amp. Replaced my A90 and I'm real happy. The A90 had lots if power and gain, but, I'm liking this SA1 in a big way. Its a keeper (especially at 539).
Buy one.
Received my SA-1 today, along with a Topping E30. My initial sound impression is that this combo sounds significantly better than my previous setup (iFi Zen DAC). My iFi Zen distorts on medium/high volume levels and have significant channel imbalance on low volume. The SA-1 does not have these problems and simply delivers clean signal to my headphones which sounds excellent regardless of volume level.
Regarding the volume/gain settings. E30 is at max volume, RCA out. SA-1 at low gain/default (all 4 switches on the left side) and going balanced (XLR) to my HD650 and I am at 10 o'clock on the pot for my preferred listening level. Around 1 to 2 o'clock is my limit where the volume becomes uncomfortably high for my ears, but still sounds clean even past this. I unfortunately don't have any instruments for objective measurements.
I can't say that I notice a big difference between Hi-Z and Low-Z on the HD650. I likely wouldn't be able to tell them apart in a blind test, though perhaps this is different on other headphones.
Received my SA-1 today, along with a Topping E30. My initial sound impression is that this combo sounds significantly better than my previous setup (iFi Zen DAC). My iFi Zen distorts on medium/high volume levels and have significant channel imbalance on low volume. The SA-1 does not have these problems and simply delivers clean signal to my headphones which sounds excellent regardless of volume level.
When I first turned amp on and used it, I felt the sound was a bit too sterile.
Over time , sound to my ears is a bolder, less sterile, A bit more balls.
It also appears to be playing A bit louder than when first used.
Btw, running high gain, mostly now. Range changed from about 5 o'clock at low to noon on high gain. D90 , SA1
Well, I did it! Ordered the SA-1 from Apos today, with price matching to $539 (with free shipping) via Drop. I bought my Monolith 887 from them and had a great experience, so saving the 60 bucks and sticking with Apos made it too good to resist.
My experience with SA-1 low gain (using sennheiser hd600, hd6xx and hd800):
1) xlr input (Gustard X16 - 4.1V)
- volume at 2 oclock using pop/rock music
2) rca input (Audio-GD R2R11 - 5V)
- volume at 10 oclock using pop/rock music
I must say that I'm enjoying more using rca with the r2r11 (variable dac mode) as the voltage coming into the SA-1 does indeed help in achieving more volume headroom for the amp even at low gain and really helps when I'm playing low volume classical music. I wonder if using Topping d70s xlr connection will provide more enjoyment volume headroom wise as the max xlr out is at 5V max if not mistaken
Mine is a version 2 SU-8, so a bit better than the early ones. The better DAC's since then have a bit better measurements, a few more features, and a few put out a higher voltage (which I have read a few folk saying is a good thing for the SA-1). As you suggest, however, that may well not be worth the upgrade.
