Salas DCG3 preamp (line & headphone)

[killie99]

I am using this for attenuation and source selection :

Arduino based LDR volume and source selection controller

Have you got a picture of your arduino build or a link to it? That's how I'd like to do my build.

 

[wineds]

Nice speakers. LDR adds some of its own THD also but many people seem to like LDR.

Thanks. I tend to alternate between low distortion and 2nd Harmonic philosophies. I am also building a Nutube line stage to swap in when I prefer a different "flavour".

 

[wineds]

Have you got a picture of your arduino build or a link to it? That's how I'd like to do my build.

You can see here : Arduino based LDR volume and source selection controller

I have since tidied it up inside and substituted on of Zdr's all in one boards. The reason for this is that the original design has some pops when switching inputs. This is fixable though by using an additional relay at the output.

FYI I don't think those all in one boards are still available. You could ask Zdr. He has a new design but please be aware that the new design is not open source at this stage. Whether or not that matters to you is for you to decide.

 

[Syl20m]

Hi All,

i never been to productive ;-) just finish last week my M2Clone, also a B1 buffer, which i currently use toggether, and this is quite nice! thanks Papa.

but now i have on my shelf the DCG3 waiting to be assembled .
a have a quite large box for it , and planning to put on the front panel
- volume control
- balance
- input selector
- power swith
so i need little bit free space on the front of the box.

what do you think guys about the imptantation of the componants, (few pics attached showing the possibilities i have been thinking ).

does the DCG3 power rectifier produce lot of heat ? better to put them over the vents?

what do you think about staking the 2 big transformers ? is that a problem ?

thanks in advance for your advises

 

[Syl20m]

Hello,
another possibility is to use this spare box without heatsink ?
more compact, more heat,
but would it be enough?

this box does not have any vents holes on the bottom (not yet at least ) but has some on the top !

thanks

 

[Salas]

Better not to use up your power-amp capable box to a pre-amp. Keep it for a power project. Use the spare one. Its vents on top will be helpful enough. The 38mm tall DCSTB radiators will go to 46C the middle ones and 42C the outer ones when in an open environment for 100mA bias and 20C room temperature to give you an idea. All the capacitors are 105C and the semiconductors are mildly driven so it should be trustworthy. Some had made and shown here more cramped examples than yours. Nothing stops you from drilling a few ventilation holes at the bottom plate anyway. To ensure enhanced air circulation.

 

[vgeorge]

No problem to stack the two transformers one on top of another.
I prefer it that way.

 

[Syl20m]

Thanks for your advises,
i found this heatsink in my trash drawer!
maybe not helping much, do you think the side plate would be enough?
or would you use the heatsink?

well, you will see that using the heatsink will need to adapt little bit the welding with a small piece of wire !, maybe does not worth it !!!!

 

[Salas]

Not worth it. Maybe just a 5mm thick Alu plate mounting interface would be welcome.

 

[Syl20m]

Ok for a piece of alu plate which fits the side plate I should find that, would you put little bit thermal compound in between?
Thanks

 

[Salas]

Ok for a piece of alu plate which fits the side plate I should find that, would you put little bit thermal compound in between?
Thanks

Yes, some thermal paste in between will do good.

 

[ivigueras]

Salas, please,

I've a +-15VDC bipolar BiB psu. Would these 15v be enough for the DGC3 or it's mandatory to reach 17v?

Thanks a lot!
Ignacio

 

[Salas]

It can run at +/-15V but you will have to short one out of the three LEDs that feed the output relay. It arguably sounds bit better at 17V than at 15V. But that's for you to judge.

 

[ivigueras]

It can run at +/-15V but you will have to short one out of the three LEDs that feed the output relay. It arguably sounds bit better at 17V than at 15V. But that's for you to judge.

Thanks!

 

[soldersober]

This is one of my builds of DCG3, running at 130mA. There are some big holes under the heatsink. The whole this is warm, but well within normal temperature range

 

[Salas]

With what gear they usually play with and how do you like them builds?

 

[soldersober]

With what gear they usually play with and how do you like them builds?

This one is for TV room. Plays into Aleph or AKG712's, for movies and occasional music listening. Funny thing is I hooked Aleph to "temporary" speakers, literally ones I got for free with some A/V gear purchase. I have still not completed the speakers I intended for this system, and those cheap boxes sound really really nice here. I heard the idea that cheap speakers with good amp is better than the other way around, now I get to hear it myself. Very happy with the setup

The other DCG3 is for main room, no TV, just music. Plays into F6 or Aleph 5's (all clones). Also sounds great, big and wide. Not on duty right now though as I've been playing with tubes recently

 

[Salas]

When some cheap speakers use full range or extended range drivers they can be coherent enough.

 

[soldersober]

The small build as in post #3735 has the main board mounted flat on 50mm tall heatsink, with FET's wrapped under the board. So I had to mount everything except the opamp on the reverse side. No problems at all

 

[troystg]

This is one of my builds of DCG3, running at 130mA. There are some big holes under the heatsink. The whole this is warm, but well within normal temperature range

What a beautiful(efficient) build! Not an inch of wasted space.