Singxer SA-1 Review (Balanced Headphone Amp)

[nobody]

Well the hum on unbalanced out is no go for me I have Topping A90 and when I've tried it with my unbalanced Nakamichi PA5 as preamp, it makes really bad background noise, not only 50Hz hum but also high frequency noise SMSL SP400 is better, but still worse than my recently acquired Mark Levinson ML380 preamp from 90's... Yet with XLR out A90 and SP400 are quieter with NC500 Hypexes than the ML380.
It's really pity, that Armin doesn't properly test the preamp section of those devices and also the crosstalk on pre-outs. I understand, that these are primary headphone amps (and really fantastic!), but you can expect nasty surprises in other use cases. Another problem with A90 is crosstalk between inputs and mechanical high pitch noise from switching power supply (but I think that this was developed over time).

 

[Highvolt60]

I just received one of these on Monday.
Connected thru Balanced inputs from Oppo UDP-205 and the 1/4 output.
This is my headphone setup and its totally separate from the HiFi system on the other side of the room.

No hum and no noise of any kind can be heard at any volume !
The headphones used (name withheld to protect the innocent) are both fairly sensitive low Z phones.
Going to convert one of my headphones to 4 pin XLR balanced as well to see what can be gained (if anything) ?
Sure it measures great but hands down the best sounding headphone amp I have ever had or heard.

I have the Volume pot at about 3:00 position (low gain) and measured .25dB channel imbalance.
My unit does have a DC offset on the 1/4 output plug (with HP load) that is -7mv DC ?
Does not matter what volume level. Have not checked if the same is on balanced output.

The Oppo source is AC coupled so I'm thinking of doing the DC input jumpers I have heard about.
Anyone know where there is some more detailed info on this before I pop off the cover ?

Thanks
HV

 

[H-713]

Toggle switches in general do not wipe the contacts during make/break, so any corrosion doesn't get dislodged by the action of the switch. Rotary and slide switches have wiping contacts which are better in this regard. Personally I've never witnessed a problem with a toggle becoming intermittent, but I take pretty good care of my gear and keep it away from corrosive air.

Gold contacts are better, but can still get coated by crud from cigarette smoke or salt air from being by the ocean. For low level audio switching, sealed inert gas filled relays are best.

The only reason I bring it up is that I've replaced quite a few toggle switches in outboard gear and custom lab equipment. The lab equipment is about 25 years old, but it's also spent its entire life in a tightly climate-controlled facility and treated perfectly. Sometimes contact cleaner fixes it, but sometimes things get too far gone.

Almost without fail, analog mixing consoles that don't use gold-plated switches (and instead use something less expensive) will have issues within about 10 years. Going through and dealing with it is a massive pain. By contrast, I've got desks that use good-quality switches with gold-plated contacts, and they're fine even after 30 years. The few mixing consoles that have used toggle switches for pad switches or bus assign switches inevitably have problems.

Sealed relays are great, but unfortunately take up quite a bit of space.

 

[bloodshoteyed]

Not a single one certification, no CE-label nor it is mentioned in the review like before. This one won't be allowed to be imported into EU nor to be sold here.

i wonder how many products with CE stickers were actually certified so far (not to bash China specifically, but you know what i mean...) ...

 

[solderdude]

Wow really class A power? I think I found my next amp. I was waiting for Emotiva to release their class A balanced amp but that looks to be in limbo. The price is also very attractive.

Looks like it's class-A up to 80mA or so.
Stays in class-A for 100ohm and up imp headphones at full output power.

 

[JohnYang1997]

Looks like it's class-A up to 80mA or so.
Stays in class-A for 100ohm and up imp headphones at full output power.

It's about 30ma iirc shared on a Chinese forum.

EDIT: http://www.erji.net/forum.php?mod=redirect&goto=findpost&ptid=2207750&pid=33389002

 

[raif71]

Looks like it's class-A up to 80mA or so.
Stays in class-A for 100ohm and up imp headphones at full output power.

full output power, meaning in high gain?

 

[H-713]

We're going bananas wondering where that power amp at tho :}



As for this amp, I could forgive the odd SE performance drop and the switches on the bottom for gain settings. If only they provided a R2R volume control. Hate channel imbalance, and hate pots going scratchy.

As long as they kept DC off of the pot (and I can't imagine they managed to screw that up), those conductive plastic RK27 pots almost never go scratchy.

 

[Quomz]

I was thinking the usual XLR in, 6.35mm out for almost all the tests. They omitted the half branch of the XLR when using 6.35mm out, similar to Magnius essentially. And when loaded the performance also degrades a lot with 6.35mm out. View attachment 129593View attachment 129594
Usually a differential amplifier is needed to do the summing which adds a bit of noise.

I thought that the first picture showed a measurement similar to the „50mV“ (100mW in this case) and therefore the drop in performance. But that would look different right? No new spikes would appear, but the noise floor raise? What exactly is the setup in the first picture?

 

[H-713]

i wonder how many products with CE stickers were actually certified so far (not to bash China specifically, but you know what i mean...) ...

I know I've seen a fair number of things with UL "certification" that wouldn't have a snowball's chance in hell of getting one, though this particular amp is built well enough that I wouldn't be too concerned about its safety. It's got an all-in-one IEC socket with a fuse holder and is using off-the-shelf Meanwell DC-DC converters, and the photos of the inside suggest that they've done things right.

The lack of an electrical safety rating is still something that should be considered further, however.

 

[JohnYang1997]

I thought that the first picture showed a measurement similar to the „50mV“ (100mW in this case) and therefore the drop in performance. But that would look different right? No new spikes would appear, but the noise floor raise? What exactly is the setup in the first picture?

That's distortion rising under load of 32ohm at 100mW.

 

[Nango]

i wonder how many products with CE stickers were actually certified so far (not to bash China specifically, but you know what i mean...) ...

It is enough that they are banned from participating in Hi-End Shows Munich or Zurich, imagine them side by side with Marantz and Piega. Ohh no!!!

 

[solderdude]

full output power, meaning in high gain?

gain and idle current is not related.

It's about 30ma iirc shared on a Chinese forum.

EDIT: http://www.erji.net/forum.php?mod=redirect&goto=findpost&ptid=2207750&pid=33389002

I'm having difficulties reading Chinese writing
Quite possible, so really only partly class A.
Judging from the typical rise of distortion it looks like the 'switching point' where it leaves class A and goes to AB is around 80mA.
Of course it will be 40mA from the negative and 40mA from the positive half so the idle current could well be around 40mA.

At least at normal to loud listening levels it will be full class A for nearly all headphones.

 

[xema]

It was a pathetically bad attempt to make a joke. If they sourced some parts from other than their native China, then maybe some came from the USA. But the USA makes almost no consumer electronic parts. We buy them from somewhere other than here. Its a sore spot for some people that 'nothing' is totally made in the US. Like Philco televisions in the 1950s in which every screw and capacitor was made in the USA.

See the logic? I'll draw you a diagram is you wish.

The potentiometer and some capacitors are very likely made in japan, so you are right

 

[Eldgrim]

Not a single one certification, no CE-label nor it is mentioned in the review like before. This one won't be allowed to be imported into EU nor to be sold here.

It has been available for purchase in EU for a while now, from Audiophonics.

 

[Atrox]

Not a single one certification, no CE-label nor it is mentioned in the review like before. This one won't be allowed to be imported into EU nor to be sold here.

I have imported a Flux Labs FA-12S, which doesn't have any CE markings on it, and it went fine.

 

[Nango]

It has been available for purchase in EU for a while now, from Audiophonics.

Yes, in case it fires up your home and your insurance rejects the coverage you may ask them for a help ;-) .....

 

[amirm]

Yes, in case it fires up your home and your insurance rejects the coverage you may ask them for a help ;-) .....

There is no such exclusion in insurance policies. You could negligently set your house on fire and they still cover it. If you got hurt you could sue the equipment maker. That is why they need to get certification.

 

[JohnYang1997]

gain and idle current is not related.



I'm having difficulties reading Chinese writing
Quite possible, so really only partly class A.
Judging from the typical rise of distortion it looks like the 'switching point' where it leaves class A and goes to AB is around 80mA.
Of course it will be 40mA from the negative and 40mA from the positive half so the idle current could well be around 40mA.

At least at normal to loud listening levels it will be full class A for nearly all headphones.

It's 30mA per channel. So 60mA when depletion in either branch. And someone asked if it's more like a high quiescent class AB, he said there's a few hundred mW class A power.

 

[raif71]

It is enough that they are banned from participating in Hi-End Shows Munich or Zurich, imagine them side by side with Marantz and Piega. Ohh no!!!

Singxer reminds me of an old sewing machine that my family used to have. The brand was Singer

The manual sewing machine looked like above. Singer doesn't only make sewing machines but other stuff too.