Hello,
Finally I got some recommended parts for 67SE and I almost there with my upgrade
Please find attached pictures that I took from PCB and chassis.
Can you guys give me some constructive advise, on what else will make grate sound improvement?
Not in the picture yet:
the OAMP, I will use Browndog with Burr Brown OPA627au
clock will be mounted on the right side of the chassis (looks like FLEA)
toroidal transformer 10VA will be installed above the power switch (on the main board) to supply 12V for clock.
Any important surface mount caps and resistors on the print side that you can recommend? I have seen some on the DAC area.
Any help, advice will be greatly appreciated.
Thanks.
Aram
Finally I got some recommended parts for 67SE and I almost there with my upgrade
Please find attached pictures that I took from PCB and chassis.
Can you guys give me some constructive advise, on what else will make grate sound improvement?
Not in the picture yet:
the OAMP, I will use Browndog with Burr Brown OPA627au
clock will be mounted on the right side of the chassis (looks like FLEA)
toroidal transformer 10VA will be installed above the power switch (on the main board) to supply 12V for clock.
Any important surface mount caps and resistors on the print side that you can recommend? I have seen some on the DAC area.
Any help, advice will be greatly appreciated.
Thanks.
Aram
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
stuck at the shaft i clean it up and apply some grease now silent already thanks for helping 
Hi Aramparonaram said:
There are lots of mods you can do to improve this machine.
What did you do already ?
Search this thread about removing output caps, removing HDAM, building dedicated psu´s for each chip and use sregs locally, building dedicated psu for analog opamps... dream about a DOS... etc.
Ricardo
Hello Ricardo,
Thanks for reply.
So far I upgraded the chassis, replaced all diodes, I added varistor and the missing filter in main psu.
I removed 4 output caps, replaced pretty much all caps and resistors around OPAMPS and OPAMPS themselves.
I added foil on the top of all chips. I also have a clock, and I tested (it was a diy kit).
And last but not least separate psu for clock. Well it's not a real psu, it's just a toroid 10VA transformer. 12v stabilizer is build on the clock.
Aram
Thanks for reply.
So far I upgraded the chassis, replaced all diodes, I added varistor and the missing filter in main psu.
I removed 4 output caps, replaced pretty much all caps and resistors around OPAMPS and OPAMPS themselves.
I added foil on the top of all chips. I also have a clock, and I tested (it was a diy kit).
And last but not least
separate psu for clock. Well it's not a real psu, it's just a toroid 10VA transformer. 12v stabilizer is build on the clock.Aram
Hi Aramparonaram said:Hello Ricardo,
Thanks for reply.
So far I upgraded the chassis, replaced all diodes, I added varistor and the missing filter in main psu.
I removed 4 output caps, replaced pretty much all caps and resistors around OPAMPS and OPAMPS themselves.
I added foil on the top of all chips. I also have a clock, and I tested (it was a diy kit).
And last but not least
Did you notice good improvements with the clock ?
Depending on what type of opamp you are using, people reported high gains bypassing the hdam circuit.
Put a sreg on the dac analog.
Replace stock +5v reg by something better.
Ricardo
Hi
I am now building sregs for a +-15v analog psu.
After reading a lot, I am wondering if I can use LM317 / 337 and replace R2 by leds (just like I did on the +5v sregs)
Can I use more than two leds ? (The combination I came up consists of two high brightness blue leds and three "normal" red leds, in order to reach 15v)
Is this ok or should I stick to the typical zener + diode ?
Hope this does not sound boring.
Regards
Ricardo
I am now building sregs for a +-15v analog psu.
After reading a lot, I am wondering if I can use LM317 / 337 and replace R2 by leds (just like I did on the +5v sregs)
Can I use more than two leds ? (The combination I came up consists of two high brightness blue leds and three "normal" red leds, in order to reach 15v)
Is this ok or should I stick to the typical zener + diode ?
Hope this does not sound boring.
Regards
Ricardo
RCruz said:
It may work with leds or a zener but it is not designed to nor, IMHO, will it work correctly.
The design is different and so is the method of operation.
It will output up to 35v anyway and the main criteria is that he I/O voltage difference is not exceeded.
Read the data sheet.
I have attached an extract.
Andy
Do try it - it's actually possible to pick up a few more dB of rejection, especially at higher voltages*
Rcruz - use a zener and pick R1 at about 120ohms so that 10mA flows through the zener. It will be a better reference than a chain of LEDs.
* like this: http://www.acoustica.org.uk/t/3pin_reg_notes1.html
There can be, yes; but by far the best way to do it is as a tracking pre-regulator (see the datasheet). That separates the tasks of line and load regulation (the reg powering the load ends up with constant voltage across it, a very good thing). Effectively, a 'cascode' voltage reg. You get a lot more ripple rejection. Cheap and effective where you want brute-force regulation for a load that draw plenty of current (up to 1.5A no problem of course)
Down sides are complexity, voltage overhead required, the fact that the output isn't actually any 'quieter' than a single 317; and its easy to make the whole thing oscillate if you pick the wrong caps for bypass purposes. I've got a page or two to write-up on all this...
Rather simpler is just a touch of RC filtering before a single reg; 1-10R + a small (preferably film) cap makes a very effective filter for HF noise riding on the raw supply.
Down sides are complexity, voltage overhead required, the fact that the output isn't actually any 'quieter' than a single 317; and its easy to make the whole thing oscillate if you pick the wrong caps for bypass purposes. I've got a page or two to write-up on all this...
Rather simpler is just a touch of RC filtering before a single reg; 1-10R + a small (preferably film) cap makes a very effective filter for HF noise riding on the raw supply.
Thank you All
It took a while but in the end my subject proved of some interest.
Reading this http://www.acoustica.org.uk/t/3pin_reg_notes1.html started it all because the autor informs that for a +5v reg, we get better results with two leds instead of the zeners and diode.
Nevertheless, I opted for the easiest option and used the zeners.
I will install this new +-15v regs on my preamp and report latter.
Ricardo
It took a while but in the end my subject proved of some interest.
Reading this http://www.acoustica.org.uk/t/3pin_reg_notes1.html started it all because the autor informs that for a +5v reg, we get better results with two leds instead of the zeners and diode.
Nevertheless, I opted for the easiest option and used the zeners.
I will install this new +-15v regs on my preamp and report latter.
Ricardo
Ricardo,
The clock upgrade was definitely very good improvement in player performance.
In OPAMPS I will be using Browndog OPA627AU, do you think I should bypass the HDAM circuit?
Replace stock +5v reg by something better - do you have anything in mind? The once that people talk about are pricey.
I am sure they are the best on the market, but still a little pricey
Aram
The clock upgrade was definitely very good improvement in player performance.
In OPAMPS I will be using Browndog OPA627AU, do you think I should bypass the HDAM circuit?
Replace stock +5v reg by something better - do you have anything in mind? The once that people talk about are pricey.
I am sure they are the best on the market, but still a little pricey
Aram
An externally hosted image should be here but it was not working when we last tested it.
