(tl;drs: start reading from the beginning, and once you have read enough information to know what's up, that's what I'm looking for)
So I was just messing around with my little Tanchjim Space, comparing its clarity at 16 vs. 24 bit at various sample rates, when I got an idea:
"This would be a lot easier to discern with my 300 ohm headphones if I used a secondary amplifier!"
Since I don't have a 4.4mm to XLR cable (and probably never will), I found an old 1/8" to RCA cable lying around, plugged it into the little 14.8g DAC, and connected the RCA ends to my headphone amplifier: Topping L30 II.
There are 3 gain modes on the L30 II which [I believe] are:
-14, 0, and +16.5dB
Obviously 0 is no gain, so I set the gain to high and...
My HD650s have their 4.4mm end on them (obviously!)
To make things as quick and easy as I could with what was in my immediate vicinity and how it was already connected, RCA out on L30 II went into Topping A70 Pro RCA in. This allowed the 4.4mm cable to be used me not to look for the 1/4"
I was expecting for the setup to make it easier for me to hear the different ways the noise affected the signal, because it was louder. And in the beginning, that is what happened...
Say I turn up the volume of both the 30 and the 70 all the way, though. I get a LOT of hiss! I mean... a LOT of HISS.
WAYYY more than you'd think!
If I back down just the A70's gain from 0 to -3dB, what happens? Probably a 40dB reduction in hiss!
(yes, 40)
If, instead of shaving 3dB off of the 70's volume control, it comes off the 30? (from both at maximum) ?
That same reduction happens!
It's just, the weirdest phenomenon! I don't know where the noise is coming from! It's separate from the Tanchjim space, too, I'm pretty sure...
When I've got as much combined gain as can be enabled by both amps before this extra noise starts rising, the noise floor is still VERY low. At 24/44.1kHz, the hiss is near zero. When switching that to 16/44.1kHz, the audio gets notably more noisy. But that's not anything I don't expect and have experienced elsewhere with different also quite technically capable stuff.
The A70 has a dB meter as one of its options, analog style - the lowest number on the scale is -20dB. -15dB is the next notch up, and when silence is coming through the A70, the needle is pointing below -20dB, about 1/3 the distance between -20 and -15dB. What I'm getting at - the sound level needs to be preeetty high for this meter to register! When both the 30 and 70 are cranked to 100%, the needle moves one pixel towards towards -20dB!!!! I don't know what this signifies exactly, but we can make an informed Guess...
What can cause all this gain to just... Happen? And it's only of the noise! It's the strangest thing! The low level music coming in through the DAC goes from being like half of the signal (with the other half noise), to just ...gone. Gone? Yeah, gone! The hiss is probably +30dB of the attenuated music with noise! It's SO LOUD!!! Unbelievably loud... Consider this: the music was being normalized to about -65dB (so RMS is probably between -80 and -85dB), and the hiss was about half of that. Half!
And then the hiss explodes in amplitude to the point that the dB meter, which starts at -20dB, is affected!
The E30 II is 16.5dB, while the A70 pro is 19.9, so... 36.4dB? I think, for hiss to be this loud, 100dB gain would be needed
I know, it sounds like I'm being dramatic - it's so nobody underestimates JUST HOW LOUD the noise is!!
(remember it literally overtakes and then completely dwarfs the original signal)
This is already quite long, so I won't make things too much worse... I will say, though
I've never thought twice about doing something like this with receivers/other hi-fi components...
As far as I'm concerned, this is, and should be, no different than hooking up a Tanchjim Space to a stereo receiver's Aux input, enabled a graphic equalizer on Tape 2, and all the bands of the graphic equalizer set to their very non-standard +16.5dB maximums. Then adjusting the receiver's volume from there -
So what gives? Any ideas?
Or is something horribly, horribly wrong... No, don't tell me that!
So I was just messing around with my little Tanchjim Space, comparing its clarity at 16 vs. 24 bit at various sample rates, when I got an idea:
"This would be a lot easier to discern with my 300 ohm headphones if I used a secondary amplifier!"
Since I don't have a 4.4mm to XLR cable (and probably never will), I found an old 1/8" to RCA cable lying around, plugged it into the little 14.8g DAC, and connected the RCA ends to my headphone amplifier: Topping L30 II.
There are 3 gain modes on the L30 II which [I believe] are:
-14, 0, and +16.5dB
Obviously 0 is no gain, so I set the gain to high and...
My HD650s have their 4.4mm end on them (obviously!)
To make things as quick and easy as I could with what was in my immediate vicinity and how it was already connected, RCA out on L30 II went into Topping A70 Pro RCA in. This allowed the 4.4mm cable to be used me not to look for the 1/4"
I was expecting for the setup to make it easier for me to hear the different ways the noise affected the signal, because it was louder. And in the beginning, that is what happened...
Say I turn up the volume of both the 30 and the 70 all the way, though. I get a LOT of hiss! I mean... a LOT of HISS.
WAYYY more than you'd think!
If I back down just the A70's gain from 0 to -3dB, what happens? Probably a 40dB reduction in hiss!
(yes, 40)
If, instead of shaving 3dB off of the 70's volume control, it comes off the 30? (from both at maximum) ?
That same reduction happens!
It's just, the weirdest phenomenon! I don't know where the noise is coming from! It's separate from the Tanchjim space, too, I'm pretty sure...
When I've got as much combined gain as can be enabled by both amps before this extra noise starts rising, the noise floor is still VERY low. At 24/44.1kHz, the hiss is near zero. When switching that to 16/44.1kHz, the audio gets notably more noisy. But that's not anything I don't expect and have experienced elsewhere with different also quite technically capable stuff.
The A70 has a dB meter as one of its options, analog style - the lowest number on the scale is -20dB. -15dB is the next notch up, and when silence is coming through the A70, the needle is pointing below -20dB, about 1/3 the distance between -20 and -15dB. What I'm getting at - the sound level needs to be preeetty high for this meter to register! When both the 30 and 70 are cranked to 100%, the needle moves one pixel towards towards -20dB!!!! I don't know what this signifies exactly, but we can make an informed Guess...
What can cause all this gain to just... Happen? And it's only of the noise! It's the strangest thing! The low level music coming in through the DAC goes from being like half of the signal (with the other half noise), to just ...gone. Gone? Yeah, gone! The hiss is probably +30dB of the attenuated music with noise! It's SO LOUD!!! Unbelievably loud... Consider this: the music was being normalized to about -65dB (so RMS is probably between -80 and -85dB), and the hiss was about half of that. Half!
And then the hiss explodes in amplitude to the point that the dB meter, which starts at -20dB, is affected!
The E30 II is 16.5dB, while the A70 pro is 19.9, so... 36.4dB? I think, for hiss to be this loud, 100dB gain would be needed
I know, it sounds like I'm being dramatic - it's so nobody underestimates JUST HOW LOUD the noise is!!
(remember it literally overtakes and then completely dwarfs the original signal)
This is already quite long, so I won't make things too much worse... I will say, though
I've never thought twice about doing something like this with receivers/other hi-fi components...
As far as I'm concerned, this is, and should be, no different than hooking up a Tanchjim Space to a stereo receiver's Aux input, enabled a graphic equalizer on Tape 2, and all the bands of the graphic equalizer set to their very non-standard +16.5dB maximums. Then adjusting the receiver's volume from there -
So what gives? Any ideas?
Or is something horribly, horribly wrong... No, don't tell me that!
