ryssen said:
Not realy but it's not difficult.
First build a small 15V PSU using LM317 and LM337. I use a 2x15V 15VA toroid. Fix it a the best place depending of the PSU size. Be sure to isolate the LMxxx and the PCB from the DEQ box. You will not need a large cooler for the LMxxx.
On the power cable cut the first RED cable (+15V), the second black cable (-15V), the fourth black cable (analog GND). Connect the + and - 15V from the DSP board to the new PSU. Connect the new PSU GND to the GND cable coming from the old PSU and the GND cable going to the DSP board.
That's all.
With the new PSU, you reduce the noice by x10, have less heat on the old PSU, and more power for the analog and digital circuits.
The last tweak.
New op-amps for the DEQ2496.
Input: 3 x BB OPA2134 (on the left).
Output: first I/V stage from AKM using four BB OP627 soldered on home made adapter and final stage using two BB OP2604.
The small adapters are only 5 millimetres tall.
The coupling caps have also be replaced with Blackgate PK serie.
Great mod. No more noise and great sound.
New op-amps for the DEQ2496.
Input: 3 x BB OPA2134 (on the left).
Output: first I/V stage from AKM using four BB OP627 soldered on home made adapter and final stage using two BB OP2604.
The small adapters are only 5 millimetres tall.
The coupling caps have also be replaced with Blackgate PK serie.
Great mod. No more noise and great sound.
Only slightly related... a list of OpAmp scope traces.
http://www.fixup.net/products/macro/squarewvtest/index.htm
AD829
AD829-A
AD744
AD744-A
NE5534AP
NE5534AP-A
JRC5534D-A
AD797
OPA604
AD8610
OPA627A
OPA637B
AD825
OPA227
OPA134
LM6171
http://www.fixup.net/products/macro/squarewvtest/index.htm
AD829
AD829-A
AD744
AD744-A
NE5534AP
NE5534AP-A
JRC5534D-A
AD797
OPA604
AD8610
OPA627A
OPA637B
AD825
OPA227
OPA134
LM6171
I opened up my DEQ2496 just to look. I am surprised to see a DSP board that doesn't have a ground plane. The decoupling on this PCB is terrible. I wondered why I had an occasional lockup where I had to power off and back on. Now I know!
I had some tantalum caps laying around and I soldered them near the SHARC chips. Right on top of the small ceramic caps.
I may add some more capacitance in the power supply cable instead of modding in a new power supply. (I'm using digital in and out, not the analog outs)
I had some tantalum caps laying around and I soldered them near the SHARC chips. Right on top of the small ceramic caps.
I may add some more capacitance in the power supply cable instead of modding in a new power supply. (I'm using digital in and out, not the analog outs)
rossl said:
Your power problem comes from a bad contact on the power connector (quality of the contact inside). I add the same problem. Check the 5V pins first.
Coupling caps are ok on the DSP board but I you want to tweak, you can unsolder the curent 10UF on the board and replace them with Elna RJH or OSCON.
I seccond that!!!!!!
Remove the glue dot off the connector en wiglle it.
That wil solve ít.
I had the DEQ for 3 days and it started switching on-off.
When removing the power supply, in search for bad kontakts, the problem was fixed.
I never have had a power failure again.
But I also agree on the bad PCB layout.
I only took a closer look on the analog part and i think that can be done much better.
Regards Simon
Remote Volume Control
Hi,
has anyone ever thought of putting a remote volume control into the DEQ?
As any needed voltage is available, this with a new output stage would be a interesting feature, eliminating the pre-amp. Would the power supply deliver enough current to drive the additional units?
Thanks
Stephan
Hi,
has anyone ever thought of putting a remote volume control into the DEQ?
As any needed voltage is available, this with a new output stage would be a interesting feature, eliminating the pre-amp. Would the power supply deliver enough current to drive the additional units?
Thanks
Stephan
I'm thinking of turning my UC into a preamp.
it should be simple.
There are 3 different inputs and i want to expand them with some relais.
Ofcource there has to be a motorpot at the analog outputs.
The thing is that with midi you can completely controll all functions so with a couple of buttons and a controller it would be easy to load a memory preset and switsh some relais.
Right now I use all 3 inputs with 2 different corrections.
2 (cd comes in optically and the pc by spdif on the xlr) have the same room correction.
For surround i use the analog inputs to adjust the center and subwoofer channels of my processor.
I was very dissapointed by the sound of both the center and the subwoofer but after roomcorrection they fit much better with my other speakers. (even though they are not corrected anymore)
I'm so pleased with it that i'm thinking to sell my processor (rotel rsp 1066) and buy me a extra deq2496 and a dvd player with multi outputs and make a multichannel preamp myself with the DEQs.
The thing is that the deq2496 has more potentials to be a good pre amp than all the **** you can buy below 2000$.
When it comes to signal handeling that is. I don't need the video switching!
The motorpot i can rip out of an old sony surround processor ESD type (its six channels). The relais will be the Nais TQ2 they are very good and can even handle the digital signals! maybe even video!
It should be easy
.
If this plan becomes more concrete i'll post it ofcource!
But the plan has just started.
Regards Simon
it should be simple.
There are 3 different inputs and i want to expand them with some relais.
Ofcource there has to be a motorpot at the analog outputs.
The thing is that with midi you can completely controll all functions so with a couple of buttons and a controller it would be easy to load a memory preset and switsh some relais.
Right now I use all 3 inputs with 2 different corrections.
2 (cd comes in optically and the pc by spdif on the xlr) have the same room correction.
For surround i use the analog inputs to adjust the center and subwoofer channels of my processor.
I was very dissapointed by the sound of both the center and the subwoofer but after roomcorrection they fit much better with my other speakers. (even though they are not corrected anymore)
I'm so pleased with it that i'm thinking to sell my processor (rotel rsp 1066) and buy me a extra deq2496 and a dvd player with multi outputs and make a multichannel preamp myself with the DEQs.
The thing is that the deq2496 has more potentials to be a good pre amp than all the **** you can buy below 2000$.
When it comes to signal handeling that is. I don't need the video switching!
The motorpot i can rip out of an old sony surround processor ESD type (its six channels). The relais will be the Nais TQ2 they are very good and can even handle the digital signals! maybe even video!
It should be easy
.If this plan becomes more concrete i'll post it ofcource!
But the plan has just started.
Regards Simon
i was just wondering about output transformers, instead of the $200 dac output transformers that were linked to two pages ago couldent you use these sowter transformers and still get a balanced line out?
http://www.sowter.co.uk/specs/3603.htm
http://www.sowter.co.uk/specs/3603.htm