AKM 4393 vs. AKM 4396 why bother?

[nonsub]

I am not familiar with Jan's active output boards. This is a first time that I hear about differences in output. In my case that is OK, because I am using transformer coupled output with symmetrical jFet buffers. Quite honestly I didn't noticed any difference in that department. The only difference I found was the one described above, and that is something that is not influenced by output level, but by the character of the output signal. I do remember though, that Jan has made that conversion from 4393 to 4396 chip and I do not think that he expressed any concerns about output level with his boards. It was interesting that his and some other people's findings that made the conversion, were very similar to what I was experiencing and reporting.
In addition, manufacturer states that these two DAC chips are straight replacement for each other.

Hey AR2. Well manufacturer states that maybe but it's clearly in the docs that the output voltages are different... but I'm just a lamer trying to learn Now if I understand Jan's circuit correctly that 2.8v +, 2.8v - goes into a CS3318 and that should be fine/within spec. What I don't understand is what comes out... what my guess is is that the voltage coming out will be the same but the higher the voltage the greater the difference between attenuator "steps." I guess a lot depends on the amps and what they can handle for Vin? Thx!

 

[nonsub]

And continuing that thought if the max output voltage is by a big margin too high for the amp then only a few "steps" in volume setting will go from inaudible to clipping. Maybe I should leave this to people who know what they are talking about?

 

[nonsub]

And another thought. If I understand the datasheet, at unity gain, that controller has 96db of attenuation in 1/4db steps so that would seem to make it a non issue at the end of the day unless the display is calibrated to db otherwise its just a question of not using the lower 2/3rds of attenuation maybe?

 

[jan.didden]

Any suggestions on how to deal with the extra voltage if using JD's active output? Thx!

There's nothing to deal with. The output is 1.4V peak instead of 1.2V peak in the '93. And that's ONLY with full scale digital. No issue at all. My mod can handle about 5V peak input.
Anyway, since you will always set the volume to your liking, this slight increase (16% or 0.4db) is totally irrelevant. Just turn your level down a fraction.

jd

 

[jan.didden]

[snip] but the higher the voltage the greater the difference between attenuator "steps."[snip]!

No, 0.5dB is a ratio, and it stays 0.5dB whatever the voltage is. It changes in absolute value, but it always is a 6% step.

jd

 

[nonsub]

There's nothing to deal with. The output is 1.4V peak instead of 1.2V peak in the '93. And that's ONLY with full scale digital. No issue at all. My mod can handle about 5V peak input.
Anyway, since you will always set the volume to your liking, this slight increase (16% or 0.4db) is totally irrelevant. Just turn your level down a fraction.

jd

Hey Jan, per e-mail I'm not "worried" anymore but now it is a question of curiosity/learning so I'll ask more

How do you get a peak of 1.4V? What happens to the 5.6Vpp analog out from 4936 per datasheet?

 

[sendler]

The AK4396 sounds better and measures better

Reading through the specs these appear to be the same with the following:

a) 4396 can sample up to 192khz whereas 4393 is 96khz. In an application for example trying to mod a dcx with this chip, I believe supports only a max of 96khz anyway?

b) Potential problem is the 4396 output is 2.8v/5.6v whereas 4393 is 2.4v/4.8v

c) 4396 sports a linear 256 step digital attenutation, has anyone interfaced to this?

So the question is why bother modding and how are people claiming improved performance (other than louder due to voltage LOL)

The AK4396 sounds better and measures better. The AK4395 sounds better still.
.
http://www.diyaudio.com/forums/digital-line-level/137231-ak4395-vs-ak4396-listening-comparisons.html
.
Ultrasonic noise spectrum is better.
.
http://www.diyaudio.com/forums/digi...5-4396-ultrasonic-noise-spectrum-graphic.html

 

[nonsub]

The AK4396 sounds better and measures better. The AK4395 sounds better still.http://www.diyaudio.com/forums/digi...5-4396-ultrasonic-noise-spectrum-graphic.html

AK4395 sounding better = subjective. Also not pin compat.

 

[sendler]

pin compatible

AK4395 sounding better = subjective. Also not pin compat.

I use the AK4395 pin compatible in a Behringer DEQ or DCX2496 by lifting pin 2 in order to supply 5v. The AK4396 will drop in with no mods.
.
The AK4395 sounding better is subjective. If you want to base your decision on a spec sheet rather than the experience of some one who has actually tried it just stick with the 4393.

 

[nonsub]

The AK4395 sounding better is subjective. If you want to base your decision on a spec sheet rather than the experience of some one who has actually tried it just stick with the 4393.

Meh everyone is saying both are better than the 4393 but there are different opinions on 4395 vs 4396 some like one some like the other, apparantly different characteristics.

 

[fleximan5]

Removing the AC coupling caps

Hi Guys
Can you help a NOOB out?
I'd like to try these 96's on my digital recorder outs but I haven't a clue which cap/s are the AC coupling caps the literature says you can eliminate?

I've attached a schematic (blowup) around the chip for CH 1 & 2.
I would assume I could bypass C142/C141 and C144/C143?
I am curious what C146/C147 are there for?

If I remove C142/141 and C144/143, then the outs will go into ADA4627-1's (schematic also attached) - really like the sound of this op amp.

I was intending to leave the analog out circuit section alone and just upgrade the C414 to a Panasonic FM 100uf/25V (only cap that will fit 6.3mm dia space).

Do you see any issues doing that?

Thanks and Best
F5

 

[Jaimo]

Capacitor-less output circuit

Here's a link to a circuit I built for my DEQ after changing to a AK4396...

http://www.diyaudio.com/forums/digital-line-level/144166-ak4396-best-solution-output-stage-10.html#post2087716

Check out post #98

 

[fleximan5]

Wow!
Thanks Jaimo
I am just excited to see the same number of components!
Hello SMD world....here I come ...gulp!!!
How did you come up with those cap and resistor values? Is that Op Amp specific or do you think your values would work better than what's already on my circuit board (For ADA 4627-1)?
So if I read your circuit correctly, I can eliminate C414 and R417 after the Op Amp?
All the Best
F5

 

[fleximan5]

Funny enough, a buddy of mine is working on taking this -10db output to +4db via transformers (no clue when I'll see that though).
At this point I will take this -10 into a +4 daughter board that is sold as an extra for the recorder.
Sorry for the probably inane questions but I really don't know anything yet (head is still spinning from all the capacitor study I did! LOL)

 

[fleximan5]

Hey Jaimo
So I talked to my buddy and he recommends getting a bread board, O scope , variable resistors and such so I can check output with various input voltages of the original circuit. Then I need to tweak things with the new op amp/circuit to match that.
Do you agree?
Just curious, how did you pick the OPA2604 and did you do as described above?
Even if you go from FET to FET, BJT to BJT style op amps, do you still need to test as described?
I am dying to try and just drop a dual ada4627-1 into your circuit and be done but what do you say?

Thanks and Best
F5

 

[Jaimo]

Good regulated PSU's make good sounding op-amps!

Hey Jaimo
So I talked to my buddy and he recommends getting a bread board, O scope , variable resistors and such so I can check output with various input voltages of the original circuit. Then I need to tweak things with the new op amp/circuit to match that.
Do you agree?
Just curious, how did you pick the OPA2604 and did you do as described above?
Even if you go from FET to FET, BJT to BJT style op amps, do you still need to test as described?
I am dying to try and just drop a dual ada4627-1 into your circuit and be done but what do you say?

Thanks and Best
F5

Regarding Bread Board - I'm not a fan. IMO BB is okay for simple digital circuits but I have had several bad experiences with poor connections, stray capacitance etc. Instead, I use a proto-typing board and hard solder my connections and pay careful attention to wire routing and PSU arrangement, etc. A good electronics store will have a wide range of prototyping boards that allow you to build up and tweak a circuit that you can use as your final product. (saving you the need to get a printed circuit board made up)

I used an OPA2604 in a Kenwood KT7500 that I tweaked and loved it's sound quality. For my DEQ, I built up a cct on a prototyping board using the AK data-sheet design and tweaked the resistors until my output level was satisfactorily low. This was initially intended as a temporary fix until I found some good transformers but the sound quality was good enough for me to make this a permanent tweak.

Since the op-amp in your circuit comes highly rated, you would probably do better by building a better regulated psu before "rolling" op-amps. Take a look at the many threads on low impedance regulators in the diyaudio forums.

 

[fleximan5]

Ah. Thanks Jaimo
Then you concur with my buddy on the PSU thing! Although, he didn't put it quite the way you did.
Nice to know my insatiable desire for the best drove me out of control again! LOL

I've been practicing with SMD and feel quite comfortable. I might just have to try your 2604 circuit out on a channel though. If I do, I'll post what I qualitatively hear.

Not sure what to do with all these 4627-1s now...