DCB1 Build

[spirovious]

But I am still trying to identify the issue of crackling of the voice in high pitch voices which sometimes show up in some of the songs but not all songs.

It can be due to dry solder.Also I think that analog wires you used looks thicker in size than needed.Try color coded flat cables which sounds better to me.

http://www.daburn.com/images/products/detail/Picture0551823.jpg

 

[manniraj]

It can be due to dry solder.Also I think that analog wires you used looks thicker in size than needed.Try color coded flat cables which sounds better to me.

http://www.daburn.com/images/products/detail/Picture0551823.jpg

I do not think analog wires is the issue as it is the same cables that were being used earlier with the B1 which I have not experienced this kind of crackling of high pitch voices in same songs. I think the analog wires are the same size as the ethernet cable single strands. But as Om suggested I will have a re-look at the ground wire connections between different sources.

 

[jls001]

Yes, please concentrate on correcting the ground wires first. A floating ground will pick up moise, and perhaps behave in unpredictable ways.

 

[omishra]

Opamp works fine on 10V

 

[manniraj]

Update from my system, I replaced the 49990 to the stock opamp on the SSP and voila the harshness is gone. The 49990 are still on the CNC which still does not induce any shrill voices on high pitch voices. So not sure whether the 49990 on the SSP was the culprit. I am running on the same voltage as Om suggested with +/-10v for the DCB1/CNC/SSP and 15,0v for SS. I am happy with the outcome :clapping:

 

[manniraj]

That regulators may go to thermal shutdown or reduced life. Also Hi temperature has raised noise - figure beyond recognition of ears but measurable on scope.

LM317/337 can deliver 1.5A with proper dissipation of heat. But here we can kill it within 20mA (.02A) only. Reducing gap between input and output voltage is the key with small piece of Aluminum L shape attached to it. Look like cobra shape staring at front.

Hi Om, need some pictures on how to replace these parts on the PS. I procured the resistances/small aluminium l shaped heat sinks. Once I replace the parts should I be changing any output voltages as at present I am outputting +/-10v and 15,0v for DCB1,CNC,SSP and SS respectively.

Thanks

 

[sann]

Hi Guys,
While changing R1-R3, I also changed my PS caps to Panasonic which Sachin sent me to try, and it brought a very significant upgrade to the sound, the music started to sound more enjoyable, I was reaching out for record after record, even the FM was sounding clearer than ever.
It was a very happy listening session tonight.
Regards,
-sann'

 

[sachu888]

Hi Maniraj
You will need to replace 3 big 1r 2w resisters on power supply board to 220r resisters I sent you. 3 heatsinks for 3 regulators lm317/337.

Regards
Sachin

 

[jls001]

Hi Guys,
While changing R1-R3, I also changed my PS caps to Panasonic which Sachin sent me to try, and it brought a very significant upgrade to the sound, the music started to sound more enjoyable

I also swapped out all five Samwha 4700 uF caps in the OPS of my DCB1 to similar value of Rubycon. Will reserve judgement for later after some hours of burn in. Had too much music going into my ear today. Need to reset But on first few notes I could hear weightier bass. Will revert to my regular IC for better judgement.

I will also swap out the 100 uF caps in the DCB1 board for either 330 or 470 uF Keltrons I bought. Plus swap out the dual Samwha 4700 uF in the DCB1 power rails to either Rubycon or Keltron. I'll do this one at a time to understand which change is beneficial and which isn't.

 

[spirovious]

Thanks Jls001 for so many trials and successful changes.Hoping next batch of DCB1 will be with updated parts and easy for others to get best sound quality.

 

[tnvijay]

The cost of the kit?

 

[shanindia]

Sachin, Om,

Can the source selector board for B1 be used along with the remote control circuit as described by Quad (http://www.hifivision.com/diy/53964-dcb1-build-5.html#post617930), along with rotary selector?

 

[jls001]

The cost of the kit?

About Rs 2000.

Do add costs of power supply kit, R-Core transformer, RCA sockets for the input and output, cabinet, IEC socket, front panel power switch.

 

[omishra]

Sachin, Om,

Can the source selector board for B1 be used along with the remote control circuit as described by Quad (http://www.hifivision.com/diy/53964-dcb1-build-5.html#post617930), along with rotary selector?

Yes, quad has already explained.

 

[shanindia]

Cool, thanks for confirming. Was not sure if Quad had same selector board. Will try to make one myself.

 

[jls001]

I'll do this one at a time to understand which change is beneficial and which isn't.

I lied

Opening the cabinet again and again, desoldering some connections to be able to desolder the components from the board, using the desoldering suction, etc was too much work, so I resumed with all the planned changes in a second sitting, instead of doing it in phases. The 100uF caps in the DCB1 board are now replaced with Keltron 470 uF caps (as advised by Om) and the Samwha power rail caps have been replaced with Rubycons of the same value (4700uF). The initial impression (more bass weight) still stays the same.

PS: I also got 100uF and 330 uF caps in case I don't like the sound of the 470uF caps.

 

[omishra]

Cool, thanks for confirming. Was not sure if Quad had same selector board. Will try to make one myself.

Main idea is - in order to select any source by switching specific relay on. For that you have six wires going to rotary switch. One is supply other 5 are selected input logic to relay 1-5. In place of rotary switch you can have any of the logic at front face which could handle triggering one relay on at a time. There is example of such a circuit consist 4017 chip, same applies to other relay based circuit.

 

[avesbilal]

Hi All,

Is this board available for purchase? I saw a post from jls001 that it will cost Rs:2000. Please do let me know if it is available.

Regards

 

[spirovious]

Hi All,

Is this board available for purchase? I saw a post from jls001 that it will cost Rs:2000. Please do let me know if it is available.

Regards

PM to Sacchu/Sachin.He will supply the one.

 

[jls001]

Input 2-source selection wiring diagram:

A small guideline for those who may want to use the DPDT switch shown in the above picture - the switch chassis is made of rather soft plastic, and the plastic can melt when the leads are being soldered. To avoid this, insert the connecting wires into the small hole which is present at the tip of all 6 leads of the DPDT, fold the wire over, use fine tipped nose plier to press the foldover tightly on the lead to maintain electrical contact, then solder the folded ends of the wire, without heating it too much. Just apply enough solder to grip the wire and to fill the lead hole. Do not put pressure on the switch leads with hot solder tip, as pressure plus heat can misalign the lead easily, and jam the internal moving mechanism.

I have always found the lead of the DBDT quite difficult to solder right. It needs lots of heat for the wire to stick, but the heat can easily destroy the plastic.

I lost my right channel yesterday and after eliminating everything else in the audio chain, I found the DCB1 to be the culprit. On further troubleshooting, I found one input worked fine. Finally the trouble was isolated to the DPDT switch. I replaced it and also tidied up the internal wiring. The faulty switch had jammed inside when I was switching inputs.