Modify behringer DEQ2496?

[3dit0r]

Hi,

If using the DEQ2496 digital in/digital out just as an EQ and not using the DAC/ADC are there any mods which will bring benefits? E.g. I don't know if modding the PSU, or re-clocking will make a difference in this mode... Is jitter an issue when using it this way?

Cheers,
James

[shanyau]

I want spdif (75 ohm) digital out from the DEQ2496,
how can I do that?

I have seen there is a little transformer before the AES socket, is it 75 ohm to 110 ohm transformer so I can just bypass the signal directly to the AES and has 75 ohm from the AES socket?

Please help.

[jakobsladderz]

Since the AES-EBU output is much higher voltage level than SPDIF, a simple resistive T-circuit will provide a good conversion, no need for transformers or anything. search for such a circuit on the net - there's a few around.

[stef1777]

Hi Folk!

I've built a new clock for the DEQ2496. I wrote a web page with some pictures if you want to have a look. Sorry, for the moment, the text is in French. It's the same principe, I've used in the v1 miniCLOCK but this time with a small low ppm SMD TCXO.

[ChuckT]

Originally posted by Ryssen
I changed opamps on the AUX out from JCR4580 to LM4562 yesterday.

I think it was a downgrade smaler sound stage life less etc.
So now I am locking for 3 JCR4580 to change back to.
please,they seems to be hard to find.
Thinking on the shipping etc.

That is very strange, since the lm4562 is the one of best sounding opamp IMO.
But the decoupling in the deq2496 is SO POOR that just changing opamp is not good enough. If you check the opamp supply pins, you will find only "ONE ceramic cap" decouple 4 opamps (at least that is what I found).

I think at the very least you should put a small film cap directly accross the +/- pins for each opamp before pulling those lm4562 out.
And if possible, add good e-cap for the +/- 15V entering into the output stage board.

[ChuckT]

Originally posted by shanyau
I want spdif (75 ohm) digital out from the DEQ2496,
how can I do that?

I have seen there is a little transformer before the AES socket, is it 75 ohm to 110 ohm transformer so I can just bypass the signal directly to the AES and has 75 ohm from the AES socket?

Please help.

If you check pins 15 & 16 for the ak4114, it gives spdif output. It is very possible that they go to the AES output. Check out the ak4114 datasheet.

I have bypass the AES input and directly use pin 44 for direct spdif input.
I add a BNC input with a digital tranny and a cap and then into pin 44.
Coax input deq2496

[ChuckT]

Originally posted by stef1777
Hi Folk!

I've built a new clock for the DEQ2496. I wrote a web page with some pictures if you want to have a look. Sorry, for the moment, the text is in French. It's the same principe, I've used in the v1 miniCLOCK but this time with a small low ppm SMD TCXO.

Hi stef1777, lots of good info on your web page. I am very tempted to try out your clock mod.

A note about the cap update. I found that adding a good cap across ak4393 pin 17&18 and the ground of c32 ceramic cap improves the sound a lot. You might want to try that, I found the decoupling of the dac is poor ( pin 17 & 18 should be separately decoupled).
I use Oscon sepc grade with good result.

[stef1777]

Originally posted by ChuckT


Hi stef1777, lots of good info on your web page. I am very tempted to try out your clock mod.

A note about the cap update. I found that adding a good cap across ak4393 pin 17&18 and the ground of c32 ceramic cap improves the sound a lot. You might want to try that, I found the decoupling of the dac is poor ( pin 17 & 18 should be separately decoupled).
I use Oscon sepc grade with good result.

Hi!

I've also done that. The caps is missing if we compare the DEQ design with the AK4393 datasheet. Look on my web page (http://www.awdiy.com/index.php?page=...-deq-caps-mods). Myself, I placed the caps on C33.



Concerning, the op-amp on the Analog board. Add 10uF caps on IC11 and IC12 is fine too. But don't use LM4562 at DAC output. Bad sound (too metallic and analytic).

For the clock, I've ordered 30 pcb. They will be available in 2/3 weeks. The beta clock seems to works fine in my own DEQ. I will also try it inside a DCX. The final version will also have a 10uH at + input.

Stef...

[ChuckT]

Hi Stef,

I thought c33 decouples the ak4524 (although it shares the same 5V as ak4393).
I think it might be better to put a cap as close to the ak4393 as possible.

Also for the opamps output, only 2 of the opamps will be used if you don't use the "higher db output" button.

[ChuckT]

One more note about changing caps.
It might not be a good idea to put ultra low esr caps like Oscon immediately after those 3 pins regulators like 7805 or lm317 as they might oscillate.
Good info below.
http://www.tnt-audio.com/clinica/reg..._noise1_e.html