Trying to decifer this message. Are they just saying it keeps memory of 2 levels for each mode (amp/pre) or is there more to it like the pre output is taken from an earlier stage than the headphone driver?
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Sabaj A10h Review (Headphone Amplifier)
- Thread starter amirm
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Trying to decifer this message. Are they just saying it keeps memory of 2 levels for each mode (amp/pre) or is there more to it like the pre output is taken from an earlier stage than the headphone driver?
47kOhm input impedance, @JohnYang1997, are you reading this?
Laughing Heart
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The switchable Preamp (Pr 1 - RCA out) or Headphones (Pr 0 headphones out) function is sadly not available on the higher end balanced Sabaj A20h, it only has XLR / RCA inputs, no line output option to take advantage of its relay volume control like the A10h.
I am interested in the complete A20 stack, Amp, DAC and Headamp, (once reviewed) My question is, could the 4 Pin "balanced" headphone out of the A20h be used as a line out, with an adapter cable, i.e. Neutrik 4 Pin XLR to Left / Right RCA or L / R 3 pin XLR to a pair of powered speakers, or a power amplifier, with the cable shield termination on the 3 pin XLR end, and left floating at the 4 Pin XLR A20h output.
What issues could this adaptation of using the headphones XLR output as a Line out create, and what would be the maximum Voltage output from the balance XLR output,
Maybe PeterWen could chime in ?
p.s. I've been a long time reader of this excellent website, the above question has forced my hand to register.
I am interested in the complete A20 stack, Amp, DAC and Headamp, (once reviewed) My question is, could the 4 Pin "balanced" headphone out of the A20h be used as a line out, with an adapter cable, i.e. Neutrik 4 Pin XLR to Left / Right RCA or L / R 3 pin XLR to a pair of powered speakers, or a power amplifier, with the cable shield termination on the 3 pin XLR end, and left floating at the 4 Pin XLR A20h output.
What issues could this adaptation of using the headphones XLR output as a Line out create, and what would be the maximum Voltage output from the balance XLR output,
Maybe PeterWen could chime in ?
p.s. I've been a long time reader of this excellent website, the above question has forced my hand to register.
Welcome to ASR @Laughing Heart
They need this because they also sell a class D amp which requires RCA input. Pr1 can reach 3 VRMS according to their site.
Is there an explanation for this? Has there been a big revelation in EE? Has there been a big discovery?
Wolf measured a DIY headphone amp that had SINAD of > 120 I think but the maker cannot be found easily and on QQ. (Someone called MBPhilips and doesn't look like he is selling this as well....).
Tks
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Yeah this thing is pretty sick, relay volume at this price with a screen? Goodness, and that beef AF power supply (no silly USB powered stuff). AND you get pre-outs at the end of it all?
SO basically the only problem with this device is the mystery of if your home setup will suffer from the floating ground setup.
How on Earth does someone make money making this at the end of the day? Amazing work sabaj
SO basically the only problem with this device is the mystery of if your home setup will suffer from the floating ground setup.
How on Earth does someone make money making this at the end of the day? Amazing work sabaj
For the 5th time I'll say it..lol. The eye cannot focus well on blue light. That's why it floats in the air and seems to not be where it is in the dark.
Maybe I can change it at next model.
Thanks
solderdude
Grand Contributor
Same gain 'issue' as L30.
The given power rating specs cannot be reached with most DACs that put out 2Vrms.
In 300 ohm there is no 500mW only 100mW
in 600 ohm there is no 250mW only 50mW
acc. to calculations based on the spec sheet and knowing TPA6120A2 run on their max. allowable +/-15V this means that the output voltage swing can be max +/-12.5V = 8.8Vrms giving the following specs at the knee of increased distortion.
In 300 ohm there is no 500mW only 250mW
in 600 ohm there is no 250mW only 125mW
so the manufacturer specs are incorrect or measured with > 10% distortion.
Using the A10D DAC with its 3V output this increases to 230mW in 300 ohm and 110mW in 600 ohm
The reason is the +9dB high gain setting.
To reach the calculated output levels you will need a DAC that reaches 3.2V.
All very similar (the same) as Topping L30.
The 15VDC is feeding internal DCDC converters. Inside there is +/- 15VDC.
The -15V converter power rating combined with the current limiter of 2 parallel TPA6120A2 output chips (0.26Arms) will define the max available output power.
Maybe, just like any other device can blow up when mistreated. It has had ESD testing to 8kV. The circuit and layout are not the same either. No idea why the device wasn't tested to 10kV/15kV and if the enclosure is connected to signal ground.
There is DC protection on the output. Hoping it is adequate under all circumstances.
Depending on the mode it is in (pre-amp or headphone amp) it stores/uses the last used volume level stored in its memory for each mode.
The line-out seems to come from a buffer (also used in headphone mode ?) with a 47 ohm resistor to the RCA.
I do too... gamers, for instance, might prefer the blue LED.
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Ha, that forum donation was potentially a bit dodgy, but this is one heck of a good headphone amplifier, well done Sabaj!
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General question about headamp reviews please @amirm . When you do the listening tests, are you always EQ the headphones ?
I know you are just listening to ensure good clean power rather than the impact the amp has on the sound , but perhaps new readers might think it’s the amp bringing the powerful bass etc etc .
I know you are just listening to ensure good clean power rather than the impact the amp has on the sound , but perhaps new readers might think it’s the amp bringing the powerful bass etc etc .
audio_tony
Addicted to Fun and Learning
Just regarding the ground loop discussion.
I don't think it is a ground loop as such. That looks like a switched mode PSU, which means there is probably a (small value) cap from the mains side to the negative of the PSU output, which is injecting 50/60Hz onto the DC output. This is in turn shows up as noise in the audio measurements.
Grounding the amp to mains ground provides a 'bleed' path for the abovementioned cap.
If this was powered from a linear PSU, this noise issue would not exist.
I don't think it is a ground loop as such. That looks like a switched mode PSU, which means there is probably a (small value) cap from the mains side to the negative of the PSU output, which is injecting 50/60Hz onto the DC output. This is in turn shows up as noise in the audio measurements.
Grounding the amp to mains ground provides a 'bleed' path for the abovementioned cap.
If this was powered from a linear PSU, this noise issue would not exist.
Isn't that what a ground loop really is anyway?
A ground loop is a ground current loop which is a "leakage current" loop ?
Genuine query - I've always been confused at the differences but someone told me they are all the same thing. Not sure if it's accurate or not
I feel that if they donate and produce a crappy product @amirm would for sure call them out on that
. Overall Sabaj seems to produce pretty decent stuff. There are some mediocre products from them that were reviewed on ASR, but those are older or had clear budgetary constraints.
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