DCB1 Build

[sachu888]

Joshua, I have started using RG174 for signal which you sent me. I have used it on my recent few builds. I found it very good and easy to work.

Regards
Sachin

 

[jls001]

Yes, the RG-174 is very flexible, thin and well shielded. I think I will try that or Gotham GAC-2 in future.

 

[manniraj]

@ Sachin/Joshua

I have completed my DCB1 build and also did the polishing of the front face plate. It looks nice and cool now, but I wanted to incorporate the source indicator lights that few of you people have done with your cabinets. Let me know where to procure them and also the wiring diagram for the same.

Thanks

 

[hifiramr]

Those Kits are already available from Indian website please check I used to buy from them very good quality products

Microcontroller Based Modules

 

[spirovious]

The next one is for $120 fully assembled at door steps.
.

This must be 5.1 ch like this-
http://www.hifivision.com/what-shou...dding-cheap-5-1preamp-will-help-whichone.html

 

[sachu888]

Dcb1 is a unity gain buffer(gain of 1). You can try it with any preamp.

Regards
Sachin

 

[jls001]

Most sources have enough voltage to not need further amplification at preamplifier stage. So one can easily drive the DCB1 from most sources, and then plug it to power amp. DCB1 provides volume control. If source is non-standard one can try double decker DCB1 as done by some members on this very thread.

 

[omishra]

Just connected DCB1 with 20K volume pot (actually looking 25K linear pot), with single buffer on output. What a difference! its clean and instrument separation is more. So now I use single buffer at the output and 20K linear volume pot, stepper one from *Bay. Best results so far.

BTW when we were listening to difference in 2 different DCB1, we connected signal source of from 1KHz till 1MHz. With sine wave and square wave we did not notice any waveform change between input and output. Also no harmonics boosted, added or removed. Still audible difference was there. How? I don't have answer. We were looking on dedicated 100MHz Digital scope.

 

[jls001]

Om, how do you find the bass with 20K linear pot? I understand that's what Salas recommends (20-25K linear). When I tried 20K linear, I found bass suffered. I reverted to 50K log and bass sounded better in my setup.

 

[omishra]

Om, how do you find the bass with 20K linear pot? I understand that's what Salas recommends (20-25K linear). When I tried 20K linear, I found bass suffered. I reverted to 50K log and bass sounded better in my setup.

I did not find any degradation across full bandwidth. But yes BASS is optimal now. Actually HF became little prominent and thus given impression of less bass. Carefully listening it for 3 days with different sources I found bass guitar and drums are sounding tight and to the point. Still air decay of drum skin, HF metal instrument and guitar strings are more separable.

 

[Ankur604]

That's it! This is the last time I'm using CAT6 wires for internal wiring. I had been hearing crackling noise from my speakers and sometimes one channel goes off completely. I suspected all sorts of things and eliminated them one by one, but in the end reflowing solder on all internal wiring of the DCB1 did the trick. Next time I will stick to multi strand wires:sad:

+1 to that. I have been using Cat5 cables, not at all easy to work with, a little bend and it breaks. Very irritating!
Do let me know which multi strand wires you are gonna use.

 

[omishra]

Single core has problems, not in handling but subsequent usage and vibrations also break it. So its really untrustworthy.

Take a cut from colored patch cable, it is multistranded. I used up broken wires, it generally broken in connectors. So remaining wire is okay and 99.9% OFC.

 

[jls001]

+1 to that. I have been using Cat5 cables, not at all easy to work with, a little bend and it breaks. Very irritating!
Do let me know which multi strand wires you are gonna use.

I rewired the DCB1 with multi stranded wire taken from a Helusound balanced pro audio cable (Helukabel part # 400031). Soldering is much easier and I don't face dry solders anymore. You can use any multi stranded OFC copper wire of 22 to 24 AWG of reasonable quality (thicker gauge not recommended as it may not fit in PCB holes). Sachin has used RG 174 cable for cabinet wiring and he reported good results. If you can get it, pure silver wire in Teflon sheath is supposed to be very good, but they're usually available as single core wires.

 

[quad]

An interesting layout here - George also a buffer design by Pass
for use with LDR volume controls -

Another B1 buffer PCB design question - diyAudio

 

[omishra]

I saw it that time. But still impedance is defined by 2LDRs. Its same. Only difference is dual PS and single channel pot.

 

[jls001]

Small update: changed CITEC 50K log pot to an ALPS Blue Velvet 50K log. I hear improved bass.

 

[keith_correa]

Try the smd resistor based stepped attenuators available on ebay for ~$12. People have reported that they sound better than the Blue Velvets ?

 

[jls001]

Try the smd resistor based stepped attenuators available on ebay for ~$12. People have reported that they sound better than the Blue Velvets ?

Any link, please?

 

[sachu888]

Any link, please?

http://m.ebay.com/itm/201231759625?nav=SEARCH
As per some Diy audio members this sounds better than Alps Blue Valvate. Fm, Sann, Omishra are using same and have confirmed better than LSA.

Regards
Sachin

 

[quad]

A few of many such - available in different ohm values -

Hi End New Dact Type 21 Stepping Progressive Potentiometer 20K for DIY | eBay
Dact Type SMD Stepped Attenuator 21 Step | eBay
SMT Resistor 20K Step Attenuator Volume Control Alps | eBay