[Supremevegbeef]

By the way. Can I ask what the "Mic" connector on front does? @sajunky

The informational picture of the listing shows the volume knob as "headphone jack", both headphone and optical output as "optical output", and rear optical as "Copper tube", so it's very confusing...

I'm imagining it has digital and USB input? Toslink, headphone 3.5mm, headphone 6.5mm output?

 

[sajunky]

Maybe it was a misunderstanding, I meant the product you linked is not well known to Head-Fi users - certainly i could not find much about it on head-fi. I can see it has a better following on diyaudio.

I will explain-

I have read the datasheet for TDA1387 and I was curious if it was so good, why it is not more well known, even if it's all old stock. There are few sellers for TDA1387 by itself, one seller is offering 20pcs for under $2 with free shipping!

I have to wonder if they are fake, and if not, if they are leftovers that did not pass QC long ago? And if they are fake, could they be delta sigma TSOP-8 DAC in disguise?

I just find it hard to believe if it's actually non- delta sigma, that the chips would be available for so little money.

I couldn't find out anything about Continuous Calibration besides links to a few other old Philips data sheets. Maybe it was their term for R2R? i don't know.

I also couldn't understand why I saw some TDA1387 DACs on Aliexpress with 4x TDA1387 and some with 8x. Though, it seems that one can use a single TDA1387 or run many of them in parallel.

For what its' worth, this is the cheapest price i can find - $36.99 free shipping
https://www.ebay.com/itm/L1387USB-8...HiFi-Headphone-Amplifier-DTS-AC3/323438251474

I believe you at your word and have been finding nice low prices like $30 with shipping for the TDA1387 DAC you linked. I don't think you are trying to raise my interest in a bad product. I can't understand why such a good DAC chip would be available for so little money, and from so few vendors, unless the chip is still unknown to Hi-Fi non-DIY community.

.LOL.

It is obvious I have no reason to cheat and/or promote a wrong product. I need to answer few questions.

Technology has improved over couple decades, so I think China is able to manufacture fake TDA1387 chips. They can make very good as well, but is it worth for 10c, really? It is why I believe that chips are original from the recycling facilities. Do you remember Sound Blaster AWE sound cards? You will find one TDA1387 chip on every AWE card. Implementation was hammered by using sensless DSP processing, but it was manufactured in millions around the world.

Nope, definitely these are not obscured DS chips. There is a real R2R sound coming through, no DSP processing, no oversampling. Such cheat would be easily detected, as DS converters require such processing.

Continuous calibration is a continuation of a dynamic element matching concept used in a famous TDA1541 chip. A difference is that R2R ladder was entirely replaced by the 16 constant current sources, each one giving a half of the juice. So in effect it is not R2R anymore, but rather I2I design. A six(?) MSB current sources are continuously calibrated. Philips did not fully reveal details of the continuous calibration, in result it was an initial distrust to the new design. However switching to current sources was a good move, giving more output power and implementation was easier using a single power supply. In the same time a multibit DS converters started to gain popularity replacing a pure bitstream DS design, so Philips decided to stop development.

It is four or eight chips in parallel. I will explain benefits later.

I would not recommend saving few bucks. We know that every Nobsound DAC has a different set of I/V resistors and the value exceed a maximum given in a datasheet. It means that during production they do measure eficiency of the bank of chips and adjust I/V resitors to get maximum output without clipping. It means Nobsound is trying to do it well. I don't know about others,

 

[sajunky]

By the way. Can I ask what the "Mic" connector on front does? @sajunky

The informational picture of the listing shows the volume knob as "headphone jack", both headphone and optical output as "optical output", and rear optical as "Copper tube", so it's very confusing...

I'm imagining it has digital and USB input? Toslink, headphone 3.5mm, headphone 6.5mm output?

There is one USB power/data port, 6.35mm headphone jack driven by TDA1308 MOS amp, 2x RCA output sockets, this is what I need.

There are also two S/PDIF outputs, RCA and optical (it can be confused with inputs!), and one 3.5mm microphone input. Note that microphone is just an extra USB reverse direction endpoint. Why so strange? It is perhaps because that they use Cmedia CM108 chip. It is a complete Delta Sigma ADC/DAC/interface combo that conforms with a driverless UAC1 specification. A DAC portion is bypassed, only the interface portion is used in this device.

When DAC is plugged to the PC, it shows a new recording device, a microphone can be used for Skype, etc. I can only speculate that S/PDIF outputs can be used for recording music from a streaming service, I see no other reason for bypassing TDA1387 DAC.

The output power is not great, 60mV on 32 Ohms. Very good pairing with 19 Ohm Sennheiser HD 4.50BTNC, lot of power, for HD600 is just barely adequate. Sound is balanced and very relaxing, hights are smooth. Not very detailed, but sufficient to hear lot of microdynamics and reverbations on a decay which I miss in DS converters.

While HPA is just OK, sound is very good on the RCA outputs. I am very confident it will beat many DACs in the price range below $150. It is because a DAC is not using cheap opamp buffers, but a passive I/F conversion. It is why there is not just one, but eight TDA1387 chips in parallel. It increase output power to the required level and no additional amplification is required. The other benefit of paralleling DAC chips is a lower noise and distortions. It is a known fact, mathematically proven and high-end equipment is paralleling DACs. Here chips cost so little, that it can be done in a $42 DAC.

A passive output has many advantages, but it needs pairing with amplifiers. A voltage is fine, but a power amp may have non-flat (frequency dependent) impedance. Examples of variable impedance are IcePower or Hypex modules. A proper pre-amp with a linear 8kOhm impedance or higher is required. A standard is 47kOhms, so there is no big deal.

 

[magicalmouse]

seems to be going off topic?

 

[sajunky]

seems to be going off topic?

Tell us please, why do you think so?

 

[IEManiac]

Dragonfly Cobalt sounds great if your OK at 24/96 + MQA as max.

If really on a budget give a BTR5 a try wired and primarly used as a BT DAC/AMP.

I've had all and now just keep the BTR5 for wired and BT use.

Not wanting a Mojo ? For my use I'd not pick a Mojo now over my BTR5 or DFC.

Yeap, unless you need more power than the 80mW at 32 Ohms provided by the Fiio BTR5, there's no need to buy anything more expensive or bigger.

 

[labrat]

HI i am looking for a dac/amp that is usb powered and is as good as or better than mojo, i only havesingle ended headphones so do not need or want balanced output.

Any ideas?

thanks

d

The Mojo is not USB powered.
If you want something small, powered (rechargeable) , amplifier only, look for a Ray Samuels P-51 mustang.
It is as nice sounding as a Mojo!
Smaller!
The Predator is good too, a bit "drier" in sound, with a DAC.
If you can find, and is good without a DAC, find a Xin SuperMacro3, the best headphone amplifier sound there is!

 

[magicalmouse]

Thank you for all the responses but i was looking for something currently available in the uk - either new or easily available on the s/h market

d

 

[m-i-c-k-e-y]

https://www.head-fi.org/threads/fs-lh-labs-go2a.918818/

USB powered (they say better than Mojo). 32/384Khz and up to DSD128 DOP. Has balanced output.