You'll likely get some good arguments going. That seems to work well around here.
The remaining mods are, clocking and..er...yes..a linear power supply.
That's it!
oh. One more.
Heat sink on the on board regulators..and a 1/8th watt resistor across a certain set of pins on the Brown dog stand up adapters to bias all the OPA627's into 'class A'.
The remaining mods are, clocking and..er...yes..a linear power supply.
That's it!
oh. One more.
Heat sink on the on board regulators..and a 1/8th watt resistor across a certain set of pins on the Brown dog stand up adapters to bias all the OPA627's into 'class A'.
Deqx
Hi Jan
I have seen many posts from you regarding the DCX. I had looked at getting one of those modified a couple of years back but ended up with a couple of Deqx units for my 4-way Boulder amp driven Westlakes. Stunning to say the least. The dual Deqx system is daisy chained using the optional digital add-on boards. One Deqx controls the volume on both units (setup in the software) One deqx drives the low and mid bass amps (balanced outs) while routing the remaining signal out through the digital option board to the digital input on the second Deqx. The signal is then crossed over to the mid high and ultra high balanced outputs to the other amps. Damned expensive setup.....took months of tweaking to get it right. At 450 lbs each, it was impossible to move the Westies and use the auto analysis features of the Deqx to create correction filters. I used a stand alone RTA to tweak the system using notch filters built into the Deqx units. The system is so fricken dynamic it gives people goose bumps. The soundstage is extremely deep and wide. Not to mention very black between cuts. I have been in the recording industry and high end audio since the early seventies and have never heard anything like this. It is truly state of the art. FYI, I am not a rich man but have slowly put the system together over many years. The Boulder amps are simply the finest amps I have ever heard. I have 4 of them.
I just purchased a modified Deqx and am chomping at the bit to compare its performance to a stock Deqx. As far as describing and explaining the mods, I am not a circuit designer and can only say that all the opamps were changed along with many service mount components being replaced with higher quality through hole parts. I believe extensive buffering was done to all input output sections including the dac. Much of the power supply was upgraded as well.
KRK happens to be the fellow who modified this unit and could be far more technical if he chooses to add to my description.
I will definitely post my impressions once I receive the unit and try it out.
Respectfully,
Ken Pachkowsky
janneman said:I own a 2.6, unmodded. So far.
What are your mods?
Jan Didden
Hi Jan
I have seen many posts from you regarding the DCX. I had looked at getting one of those modified a couple of years back but ended up with a couple of Deqx units for my 4-way Boulder amp driven Westlakes. Stunning to say the least. The dual Deqx system is daisy chained using the optional digital add-on boards. One Deqx controls the volume on both units (setup in the software) One deqx drives the low and mid bass amps (balanced outs) while routing the remaining signal out through the digital option board to the digital input on the second Deqx. The signal is then crossed over to the mid high and ultra high balanced outputs to the other amps. Damned expensive setup.....took months of tweaking to get it right. At 450 lbs each, it was impossible to move the Westies and use the auto analysis features of the Deqx to create correction filters. I used a stand alone RTA to tweak the system using notch filters built into the Deqx units. The system is so fricken dynamic it gives people goose bumps. The soundstage is extremely deep and wide. Not to mention very black between cuts. I have been in the recording industry and high end audio since the early seventies and have never heard anything like this. It is truly state of the art. FYI, I am not a rich man but have slowly put the system together over many years. The Boulder amps are simply the finest amps I have ever heard. I have 4 of them.
I just purchased a modified Deqx and am chomping at the bit to compare its performance to a stock Deqx. As far as describing and explaining the mods, I am not a circuit designer and can only say that all the opamps were changed along with many service mount components being replaced with higher quality through hole parts. I believe extensive buffering was done to all input output sections including the dac. Much of the power supply was upgraded as well.
KRK happens to be the fellow who modified this unit and could be far more technical if he chooses to add to my description.
I will definitely post my impressions once I receive the unit and try it out.
Respectfully,
Ken Pachkowsky
Deqx
Just read the above over and wanted to mention I have the HRX 4 way active crossover specificly designed by Westlake for the HR1's. It was rebuilt and brought up to the latest version by Westlake tech's 3 years ago at a cost of 5 grand. It uses over 100 op amps per filter board combined with many different value polycarbonate caps to create the filters. Each board (2) has over 120 wima film de-coupling caps. It is an excellent crossover but lacks the performance of the dual Deqx system.
I will post some photos of the system if there is any interest.
Just read the above over and wanted to mention I have the HRX 4 way active crossover specificly designed by Westlake for the HR1's. It was rebuilt and brought up to the latest version by Westlake tech's 3 years ago at a cost of 5 grand. It uses over 100 op amps per filter board combined with many different value polycarbonate caps to create the filters. Each board (2) has over 120 wima film de-coupling caps. It is an excellent crossover but lacks the performance of the dual Deqx system.
I will post some photos of the system if there is any interest.
I have owned a DEQX PDC2.6 since 2002 from the first series, later in 2004 upgraded to the PDC2.6P preamp version and recently upgraded with the hardware upgrade offer from DEQX. As far as I know they have changed every opamp in the unit as well as every electrolytic cap.
This was a very worthwile upgrade. The unit has more air now and the slight sibilance in the heighs are almost completely gone now. It's just more easy on the ears now and the soundstage has improved a lot as well.
I still have the stock smps power supply and I think things can be improved here also. The new PDC3 unit uses a smps for the digital section and a linear supply for the analog section. I didn't want to upgrade to the PDC3 because I have allready spent enough money on it. I think it is possible to build a better power supply yourself and the next thing I would like to see is to change the electrolytic (Panasonic FM by now) in the highs output section with something better.
This was a very worthwile upgrade. The unit has more air now and the slight sibilance in the heighs are almost completely gone now. It's just more easy on the ears now and the soundstage has improved a lot as well.
I still have the stock smps power supply and I think things can be improved here also. The new PDC3 unit uses a smps for the digital section and a linear supply for the analog section. I didn't want to upgrade to the PDC3 because I have allready spent enough money on it. I think it is possible to build a better power supply yourself and the next thing I would like to see is to change the electrolytic (Panasonic FM by now) in the highs output section with something better.
He bought my DEQX that I had, er..relatively extensively modified. The usual. New opamps.
In this case, OPA627's on brown dog adapters, the stand up ones. Each op-amp board has polystyrene bypass caps. Each ceramic cap on the board was removed and electrolytics were added in.
I gave him all the parts required to finish off the one remaining stereo 'third channel' for a three way system. I was only using it for two way and had started the mods for that section, but stopped-as it was not in use.
The balanced input section needs to be modded, it is stock. I never used it, so no need to (for me). I gave him the parts to put in there as well.
The power supply is of the original digital type, and that might be upgradable to a linear supply, for a minimal sonic quality increase. I gave him some decent high pulse capacity non magnetic 20uf polypropylene caps to put between the PS and the main board, to possibly remove any hash that the digital PS might still have.
The digital/analog and clocking sections also have their capacitive mods to clean up their PS situations. All os-con sp type, right at the local ceramic buffer locations.
The entire Chassis is critically damped and the essential ground mod is in there as well, as the input/output signal ground is very remote from the actual PS level grounding point. I ran a wire across the ground pins of the RCA jacks and over to an unused screw mount post that is in the chassis. This brought the ground noise down to a much lower level.
In this case, OPA627's on brown dog adapters, the stand up ones. Each op-amp board has polystyrene bypass caps. Each ceramic cap on the board was removed and electrolytics were added in.
I gave him all the parts required to finish off the one remaining stereo 'third channel' for a three way system. I was only using it for two way and had started the mods for that section, but stopped-as it was not in use.
The balanced input section needs to be modded, it is stock. I never used it, so no need to (for me). I gave him the parts to put in there as well.
The power supply is of the original digital type, and that might be upgradable to a linear supply, for a minimal sonic quality increase. I gave him some decent high pulse capacity non magnetic 20uf polypropylene caps to put between the PS and the main board, to possibly remove any hash that the digital PS might still have.
The digital/analog and clocking sections also have their capacitive mods to clean up their PS situations. All os-con sp type, right at the local ceramic buffer locations.
The entire Chassis is critically damped and the essential ground mod is in there as well, as the input/output signal ground is very remote from the actual PS level grounding point. I ran a wire across the ground pins of the RCA jacks and over to an unused screw mount post that is in the chassis. This brought the ground noise down to a much lower level.
HRX Crossover
Charles
The HRX uses the 5234N and 1% tol Polycarbonate Caps and 1% tol TAS Metal film resistors for the filters and slopes.
I tried many 4-way active crossovers before paying the 5k to bring the HRX up to date. Nothing compared to the HRX so I bit the bullet. I wish I would have tried the Deqx first.
A friend of mine bought a Deqx and suggested I might like it. The only problem was I needed 2 to run the 4-way system.
The difference was not fully realized until a great deal of tweaking and experimentation was done.
The single greatest improvement is depth and dimension/width of the soundstage. If you have never heard Leonard Cohens, Ten New Songs cd, pick up a copy. Its a great cd for testing the above. The background vocals are lush and well placed throughout the cd. The Fir filters with steep slopes have a lot to do with this I suspect.
Although a fine xover, the HRX falls short in the above.
PS. I have a great deal of spare parts for the HRX crossover including a blank filter board if you know anyone looking for one. I was going to solder up a spare but never got round to it. The polycarbonate box caps are a fortune.
I will post some photos soon.
Ken
phase_accurate said:
Charles
The HRX uses the 5234N and 1% tol Polycarbonate Caps and 1% tol TAS Metal film resistors for the filters and slopes.
I tried many 4-way active crossovers before paying the 5k to bring the HRX up to date. Nothing compared to the HRX so I bit the bullet. I wish I would have tried the Deqx first.
A friend of mine bought a Deqx and suggested I might like it. The only problem was I needed 2 to run the 4-way system.
The difference was not fully realized until a great deal of tweaking and experimentation was done.
The single greatest improvement is depth and dimension/width of the soundstage. If you have never heard Leonard Cohens, Ten New Songs cd, pick up a copy. Its a great cd for testing the above. The background vocals are lush and well placed throughout the cd. The Fir filters with steep slopes have a lot to do with this I suspect.
Although a fine xover, the HRX falls short in the above.
PS. I have a great deal of spare parts for the HRX crossover including a blank filter board if you know anyone looking for one. I was going to solder up a spare but never got round to it. The polycarbonate box caps are a fortune.
I will post some photos soon.
Ken
Do you also have the circuit diagram of this x-over ? Not that I would want the exact circuit but I would like to know what priciple they use. Is it a conventional crossover consisting of low- and high- pass filters or is it a subtractive-delay crossover (i.e. subtracting a low pass from the delayed input signal) ?
Regards
Charles
phase_accurate said:
Charles
I am sorry to say I don't have a schematic. As far as the design principal, I have no idea. Its sold as a phase coherent design.
I can solder like a pro but don't understand much about actual circuit design.
I do have a complete parts list for the xover including the power supply. The crossover points are 250/1.2k/4.5k
Ken
Soekris DAC DAM1021 in DEQX PDC 2.6P
DEQX PDC 2.6P is nice.
Long time thought: using better dacs might even improve sound quality...
Well, this is the case.
I've just added 2 Soekris DAM1021 boards for channels 2 and 3, respectivelly.
Here how the PoC currently looks like
Hugh improvement.
DAM1021 are connected to the PDC-2.6 main board the same way as the digital out board is connected: a ribbon cable carries a supply voltage and all i2s signals needed to feed DAM1021:
Some wires to connect the ribbon cable to the respective DAM1021 input - that's all needed
https://hifiduino.wordpress.com/2015/03/16/soekris-dam-1021-r-2r-dac-users-guide/ will tell about the DAM1021 side.
The onboard buffer doesn't sound too well, as reported by friends I do trust. The r-2r raw output has 625 Ohm - a bit high in my case as my amps run with 3k at the input. My plan is to use SSB01 Sjöström Super Buffers directly behind r-2r raw output.
Feeding the DEQX with Arta generated 0dBFS gives just 200 mV at the r-2r raw out - to little for my gear.
DAM1021 is specified 1.4V at this output.
Closer look at the i2s signal reveals both, the reason and a possible solution:
Gain Adjust is set in my case not too many dBs below or above 0dB. In order to have +20dB head room, roughly the four MSB bits are off in this case (left side in the picture above). Gain Adjust set to +6dB gives another bit in the i2s signal (right side).
All fine so far - apart from not being able to use the Mute button anymore.
As DAM1021 muting is yet to be solved, the DEQX Mute will be on the list.
Happy ears
Ulli
DEQX PDC 2.6P is nice.
Long time thought: using better dacs might even improve sound quality...
Well, this is the case.
I've just added 2 Soekris DAM1021 boards for channels 2 and 3, respectivelly.
An externally hosted image should be here but it was not working when we last tested it.
Here how the PoC currently looks like
Hugh improvement.
DAM1021 are connected to the PDC-2.6 main board the same way as the digital out board is connected: a ribbon cable carries a supply voltage and all i2s signals needed to feed DAM1021:
Some wires to connect the ribbon cable to the respective DAM1021 input - that's all needed
https://hifiduino.wordpress.com/2015/03/16/soekris-dam-1021-r-2r-dac-users-guide/ will tell about the DAM1021 side.
The onboard buffer doesn't sound too well, as reported by friends I do trust. The r-2r raw output has 625 Ohm - a bit high in my case as my amps run with 3k at the input. My plan is to use SSB01 Sjöström Super Buffers directly behind r-2r raw output.
Feeding the DEQX with Arta generated 0dBFS gives just 200 mV at the r-2r raw out - to little for my gear.
DAM1021 is specified 1.4V at this output.
Closer look at the i2s signal reveals both, the reason and a possible solution:
Gain Adjust is set in my case not too many dBs below or above 0dB. In order to have +20dB head room, roughly the four MSB bits are off in this case (left side in the picture above). Gain Adjust set to +6dB gives another bit in the i2s signal (right side).
All fine so far - apart from not being able to use the Mute button anymore.
As DAM1021 muting is yet to be solved, the DEQX Mute will be on the list.
Happy ears
Ulli
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CS8420 used on the DigiOut board allows to mute the Output. Looks like this is done by some control communication which can be seen on the cable:
Might be a bit to complicated to emulate this...
In many cases i2s proved to be the better signal compared to either SPDIF or AES/EBU. Soekris claims to have implemented a very effectiv jitter reduction. If that's true, using DigiOut's SPDIF output might be the better connection to DAM1021.
Happy ears
Ulli
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