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OLD THREAD DAC End by Andrea Ciuffoli

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As this dac definately seems a keeper... i have just ordered a ncie front panel.

An externally hosted image should be here but it was not working when we last tested it.

Good idea adamus, I'll find out where it can be done here locally.

I replaced all interconnect cables yesterday and I have done new ones with RG59 solid core copper as I don't believe many b**sh*it cables on the market. Further detail improvement.
4-500$ cables IMO can only improve 2-5% the sound so I never spend that money in cables like that. However a simple RG59 can be better than many good looking cables on shelve.
I prefer spending money in more efficient way in other parts of the amplifier.
If anyone wants good interconnect cables I can make now for $399 each 1 metre. :0) HAHA **Just kidding**.
 
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Dac End - End

After replacing E182CC with Philips Jan 5687 I had to deal with power dissipation on heater power supply section. The bridge rectifier gets really hot so I added a custom made heatsink.

The best sound I achieved with Sprague HyperQ PIO 1uF 300V. The details are better then any MKP I have and with the natural sound of PIO.

I will also try Adamus LED mod Let's see.
 

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After replacing E182CC with Philips Jan 5687 I had to deal with power dissipation on heater power supply section. The bridge rectifier gets really hot so I added a custom made heatsink.



won't this could be dangerous...or bad to the bridge rectifier ?

And since changing R8 & R9 from 2.2R to 1R is there any excessive heat problem anymore?

I have a lot of ceramic 1R 10W with me like this ..

An externally hosted image should be here but it was not working when we last tested it.


IRC / TT ELECTRONICS|CVW101R00JLF|Power Resistor

The leads is short to lift the resistor for clearance from the pcb....would this be suitable ?
 
won't this could be dangerous...or bad to the bridge rectifier ?

And since changing R8 & R9 from 2.2R to 1R is there any excessive heat problem anymore?

I have a lot of ceramic 1R 10W with me like this ..

An externally hosted image should be here but it was not working when we last tested it.


IRC / TT ELECTRONICS|CVW101R00JLF|Power Resistor

The leads is short to lift the resistor for clearance from the pcb....would this be suitable ?


It is ok for the bridge to be hot but needs to have heatsink. If you use 5687 you must use heatsink or will get extremely hot, probably still works but you will have dry sold joints down in the future.

By replacing 2.2R to 1R you push more power dispersion to the regulator. I think is better run 2.2 resistors hot then the regulator more hot.

For reliability, don't allow solder joint to go over 80C.

I like those resistors they have larger surface area then others but I could not use them because the legs are too short.
 
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It is ok for the bridge to be hot but needs to have heatsink. If you use 5687 you must use heatsink or will get extremely hot, probably still works but you will have dry sold joints down in the future.

By replacing 2.2R to 1R you push more power dispersion to the regulator. I think is better run 2.2 resistors hot then the regulator more hot.

For reliability, don't allow solder joint to go over 80C.

I like those resistors they have larger surface area then others but I could not use them because the legs are too short.

Maybe if I reduce the rating from 3A to 1.5A could reduce the heat problem in the heater section since 6h6P heater needs 750mA±70. Is this correct ?

Secondly running 2.2R instead 1R....how about chattering problem ????
 
Maybe if I reduce the rating from 3A to 1.5A could reduce the heat problem in the heater section since 6h6P heater needs 750mA±70. Is this correct ?

Secondly running 2.2R instead 1R....how about chattering problem ????

Using 6n6P you save some power dispersion but not much.

I had chattering problem with 2.2R yes, but I resolved by replacing the LM338 regulator with LT1085 which has lower dropout voltage. I still have 2.2R in place with AC 9.3V input.

Because you cannot change transformer voltage output you can only change the regulator first and if not enough then you have no choice but changing 2.2R to lower value.
 
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Using 6n6P you save some power dispersion but not much.

I had chattering problem with 2.2R yes, but I resolved by replacing the LM338 regulator with LT1085 which has lower dropout voltage. I still have 2.2R in place with AC 9.3V input.

Because you cannot change transformer voltage output you can only change the regulator first and if not enough then you have no choice but changing 2.2R to lower value.


Why tranny in the heater section is 9.3V or something, not 9V....??? Is this matters so much or just you happens to have that value....???

One more thing is should I change the trimmer from 220R to 200R....??? or just follow the original value..

My solder melts at 170°C. I'm bit worried it might couse a problems to the heat....
 
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After replacing E182CC with Philips Jan 5687 I had to deal with power dissipation on heater power supply section. The bridge rectifier gets really hot so I added a custom made heatsink.

The best sound I achieved with Sprague HyperQ PIO 1uF 300V. The details are better then any MKP I have and with the natural sound of PIO.

I will also try Adamus LED mod Let's see.

it is very nice. you work very well, congratulations!
of course it will be very hot, because the filament of 5687 need 1.8A total!

I always remind you is the most difficult as the filament 5687.
all very easy to complete except for the filament 5687
 
ok then....

gabanyayaya ,
I forgot to mention that you need to replace R11. Put 560R instead of 1K or you will not be able to adjust the voltage down to 6.3V

8.7, 9, 9.3V AC all good. You need to make sure is working after the regulator. Relay chattering means no smooth DC so as I said you need to put LT1085 regulator in any case and juggle with 2.2R or 1R.
 
it is very nice. you work very well, congratulations!
of course it will be very hot, because the filament of 5687 need 1.8A total!

I always remind you is the most difficult as the filament 5687.
all very easy to complete except for the filament 5687

Thanks quanghao.
Yes 5687 heater is difficult because the power supply is very compact so the power dissipation is in very small area.
 
Hi Quanghao.
Cangratulations for the interesting project.
I have some question for you.

1.Is it really necessary to supply pin 18 (M2) to a dedicated regulator(VD4)?
If so, why don't you connect also pin 24 (M1) to VD4 instead of VD3?

2.How hot are the mosfet on Salas Regolator?
Is it safe to run it without heatsink?

Thanks and regards.
Atok
 
Hi Quanghao.
Cangratulations for the interesting project.
I have some question for you.

1.Is it really necessary to supply pin 18 (M2) to a dedicated regulator(VD4)?
If so, why don't you connect also pin 24 (M1) to VD4 instead of VD3?

in this question, im sorry , I do not answer! ( there are on member ask me that)

2.How hot are the mosfet on Salas Regolator?
Is it safe to run it without heatsink?

yes, no hot ! No need heatsink, but i want safe for IRFP and beautiful, you need use it

thank
 
gabanyayaya ,
I forgot to mention that you need to replace R11. Put 560R instead of 1K or you will not be able to adjust the voltage down to 6.3V

8.7, 9, 9.3V AC all good. You need to make sure is working after the regulator. Relay chattering means no smooth DC so as I said you need to put LT1085 regulator in any case and juggle with 2.2R or 1R.

thanks for the reminder....that means I need a set of 2.2R and 1R and 220 and 200R trimmer for this project....going shopping and broke again...
 
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