Any recommendations for a new (budget) USB audio interface (+ USB filter?) and a pair of monitors

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bgravato
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Re: Any recommendations for a new (budget) USB audio interface (+ USB filter?) and a pair of monitors

Post by bgravato » Tue Jun 01, 2021 10:25 am

Just a follow up...

I got that FiiO D03K DAC yesterday. I must confess I'm a bit disappointed... But I guess I set my expectations too high for a 30 euros device.

It's definitely an improvement over the TV's poor internal DAC, but still miles away from the Presonus BT internal DAC.

Paul2
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Re: Any recommendations for a new (budget) USB audio interface (+ USB filter?) and a pair of monitors

Post by Paul2 » Tue Jun 01, 2021 12:45 pm

Some of those cheaper DACs are quite sensitive to load impedance.

What have you got it feeding into ?

Some simple things you can try:

1) Put a shunt resistor (to common) on each output of the DAC (left and right).
Try values between 560 ohm to about 3K3.
Some DAC output stages need a DC load to common.
Most audio equipment has AC couple inputs.

2) Put a series resistor on each output, between the DAC and the next stage, audio amp I'm assuming.
If you find the DAC lacks a bit of high-end, you can make a simple passive pre-emphasis filter like such (only 1 channel shown):
Screen Shot 2021-06-01 at 2.49.45 PM.png
Screen Shot 2021-06-01 at 2.49.45 PM.png (22.73 KiB) Viewed 1165 times
Experiment with the values, you want the pre-emphasis to gently roll in from about 4Khz and up.
You will get some gain reduction, but you can make it up with the amplifier's volume.
Resistor R2, may not be required.

If on the other hand the audio is too boomy/muddy, then you can experiment by using shunt capacitors to reduce
some of the low-end.

Of course, nothing stopping you from doing all of the above and changing the fixed resistors to variable ones,
to give you more control.
Screen Shot 2021-06-01 at 3.06.26 PM.png
Screen Shot 2021-06-01 at 3.06.26 PM.png (29.34 KiB) Viewed 1165 times
R1, C1 and VR1 control the high end.
C2, VR2, C3, VR3 and R1 control the low end.

Note that since it's purely a passive circuit, there will be some interaction between all of them.

I will leave the formulae and working out the values, up to you. :D

kozikowski
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Re: Any recommendations for a new (budget) USB audio interface (+ USB filter?) and a pair of monitors

Post by kozikowski » Tue Jun 01, 2021 4:20 pm

Where are you getting your parts from? The Radio Shack® that I used to walk to seems to be a Hair and Nail Saloon now.

Koz

Paul2
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Re: Any recommendations for a new (budget) USB audio interface (+ USB filter?) and a pair of monitors

Post by Paul2 » Tue Jun 01, 2021 4:29 pm

The Radio Shack® that I used to walk to seems to be a Hair and Nail Saloon now.
Radio Shack/Tandy went belly up a while ago.
Maybe the hair saloon still have some old parts in the back, next to the hair curlers.
You can get pampered while they scratch around looking for them. :D

In the U.S. you can get from several places, here are three of them:

https://www.digikey.com/en/products

https://www2.mouser.com/Electronic-Components/

https://www.jameco.com/

Their sites have a good inventory search option and they will ship anywhere in the U.S.
Some will even ship world-wide.

Another option, do you have a local TV repair shop?
They will probably have the parts laying about as the values of the resistors and capacitors are not that critical.

bgravato
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Re: Any recommendations for a new (budget) USB audio interface (+ USB filter?) and a pair of monitors

Post by bgravato » Tue Jun 08, 2021 7:08 pm

Thank you for the suggestions Paul.

I'm connecting the FiiO DAC between the TV's optical out to the RCA input on a pair of Edifier R1280T speakers.

But for a true comparison of all the DACs available I also did some tests with the Presonus E3.5 BT.

So basically the 3 testing scenarios using the Presonus were:
  1. TV line out -> Presonus RCA input
  2. TV optical digital out -> FiiO DAC -> Presonus RCA input
  3. Smartphone -> Bluetooth -> Presonus
Source was some youtube music videos (ranging different genres, from jazz to classical to folk, rock, indie, blues, etc)

Results for each test:
  • 1. sound is kind of "dull"
  • 2. has more detail than 1., event though it's not a _huge_ difference, it's still a very noticeable improvement over 1.
  • 3. has even better detail, better separation between instruments and is "cleaner" and "crisper" (in a good way)
For the end purpose (connecting the TV to the Edifier speakers), I think the FiiO DAC does a decent job and I'm happy with it for now. I think it's not worth investing any more time on it now, but I'll save your interesting suggestions for the future.


Koz, not sure how they work in the US, but Farnell is usually also a good place for online shopping of electronic components... The prices may not the best, but they have a lot of stuff in stock and fast delivery.

steve
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Re: Any recommendations for a new (budget) USB audio interface (+ USB filter?) and a pair of monitors

Post by steve » Tue Jun 08, 2021 7:12 pm

bgravato wrote:
Tue Jun 08, 2021 7:08 pm
Koz, not sure how they work in the US, but Farnell is usually also a good place for online shopping of electronic components..
Over here we have Farnell which deals mostly with trade accounts and bulk purchase, and CPC (Farnell) that deals with domestic purchases including small quantities.
9/10 questions are answered in the FREQUENTLY ASKED QUESTIONS (FAQ)

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