Salas DCG3 preamp (line & headphone)

[bambadoo]

Using an old good old HP workstation (Z220) with an asus essence stx pcie soundcard.
Also have a focusrite solo mk3 and a 12bit picoscope at hand, the latter for different kind of measurements.
Switching between REW and Sillasoft Visual Analyzer for software. They do their job for me.

 

[Salas]

That Asus soundcard with the characteristic Nichicon FG caps on board had very good specs and it was pricey for early 2010s, but I have not seen one in lab use before. Seems like it's doing a good job.

 

[minoas]

My DCG3 ,thanks salas

 

[minoas]

with Cretan olive wood

 

[Salas]

What a nice & different DCG3 build. Congratulations! Did you try it enough in your system already?

 

[myleftear]

Olive-wood! Almost as hard as steel…
And I especially like the selector’s v-belt!

 

[Salas]

Do I see Apogee or Analysis magnetostatic speakers in the mirror finished lid's reflections?

 

[minoas]

yes I have it Already about a month .it is the best I have made in pre-amp.I have put dact 20k (I had it) what better do you suggest?
thanks

 

[Salas]

DACT is alright. Clean and neutral. The EI transformers have flux bands around their bellies?

 

[minoas]

Do I see Apogee or Analysis magnetostatic speakers in the mirror finished lid's reflections?

you noticed correctly
is the Greek epsilon analysis

 

[Salas]

Very nice speakers. Magneto-static dipole makers are very few left in the world anymore. I liked their Omega model also.
By the way If you want to also try warm style volume pot, try TKD 2CP-2511.

 

[minoas]

DACT is alright. Clean and neutral. The EI transformers have flux bands around their bellies?

Yes the Transformers are shielded. used Transformers for Tube Amplifie came out a little over 80VA but I do not mind.
I also tried an alps black beauty
But I like the dact more

 

[Salas]

The preamp isn't cold itself although resolute so DACT or not won't be a matter of bottleneck attention, but more a matter of taste.

 

[pfarrell]

Superb build! Enjoy. I agree about the selector V belt... also love the tip-light toggle. Nice.

 

[savvas]

What kind of EI transformers are these ?

 

[pidesd]

i have a small question if i may:

Does the DCSTB supply allows flexibility for pass transistor? Like a mosfet like irfp240/9240 +adjusting the current resistor for bc550? Or even paralleling BJT pass transistor (for higher current)?

 

[Salas]

About MOSFETs possibly, I don't know offhand, have to check.

 

[Salas]

Looked into it, for IRFP pass elements R3 R4 should be 470R, also add 100R gate stoppers. Vin-Vout should be kept at no less than 5V else drop out will start there due to Vgs is high vs Vbe when normally using a BJT pass. But not >>5V either if used for high current loads because of dissipation & sinking concerns.

 

[pidesd]

thank you Salas..will give a shot

 

[merlin el mago]

Salas what's the input & output impedance?

TIA
Felipe