I finally fired up the preamplifier this weekend after a 48 hours burn in and I must say that I'm really impressed by the SQ!! I always use passives and the LDR3x from Tortuga is really transparent, DCB1 is also very good but not as transparent but the DCG3 is more in the LDR3x league but also add meat on the bone. Sound stage is as good as on my LDR3x so this I like to hear it doesn't subtracts anything on that side. Separation is quite excellent and under a torture test of complex passages in a few songs I've played, it passed with flying colors.
I'm a Cello fan and on one of Jorane's song ("Le Chant Du Cygne" from the second CD of the album "Dix"), the cello gave me some crazy goose bumps. It was really emotional and this is what I'm looking for.
I'm going to run a few more tests before I pack everything in an enclosure but a big THANK YOU Salas!
Do
I'm a Cello fan and on one of Jorane's song ("Le Chant Du Cygne" from the second CD of the album "Dix"), the cello gave me some crazy goose bumps. It was really emotional and this is what I'm looking for.
I'm going to run a few more tests before I pack everything in an enclosure but a big THANK YOU Salas!
Do
Yes, I actually have both in hand so I will most definitely test this before boxing it up.
Thanks
Do
It will be nice to tell us the outcome of your final configuration since some builders have been asking about plausible differences vs cost in selecting a good attenuator solution for this preamp.
Dominic, please, could you describe the sound differences between your JC80 and DCG3 modules?
Thanks!
Do,
Good to know that you are also enjoying the Salas DCG3.
What amps have you paired with it?
I have tested it with a few amplifiers so far, FC-100, USSA 5 and FirstOne 1.4, all with excellent results.
I will most definitely test and report my findings here.
Wow! Last I used my JC-80 was 3 years ago so I really don't remember very well the sound signature. I will have to connect it and test. This could be interesting but as I remember (and this is vague) the soundstage was a little closed up compared to the DCG3, DCB1 and LDR3x. I could be mistaking with something else though, so I will definitely give it a spin and listen.
Thanks
Do
It will be handy info since we already have excellent reports from users combining high grade attenuators right from the start like a good swithcer or microcontroller LDR but no users reports with details in upgrade results who made the change after simply starting with an Alps Blue.
Hi Salas, I did not see current spec of i-Select NEC relay coils, but assume CAT 6e cable with 8x23AWG wires should be thick enough to handle connection between board and input selector. Right? It is shielded too and I'm going to connect its shield to enclosure Earth GND.
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Connect the shield to the enclosure.
If the return signal uses the shield, then connect it to the signal return terminal at both ends.
In general the enclosure is NOT connected to the signal return. That means that the shield of a coaxial cable is NOT connected to the enclosure, unless the schematic requires that for the circuit to work.
When the shield is separate from the two signal cores, then the shield is NOT connected to Signal Return, instead the separate shield is connected to the enclosure.
The Safety Earth is a separate issue. Don't confuse that issue by trying to attach audio thinking to it.
If the return signal uses the shield, then connect it to the signal return terminal at both ends.
In general the enclosure is NOT connected to the signal return. That means that the shield of a coaxial cable is NOT connected to the enclosure, unless the schematic requires that for the circuit to work.
When the shield is separate from the two signal cores, then the shield is NOT connected to Signal Return, instead the separate shield is connected to the enclosure.
The Safety Earth is a separate issue. Don't confuse that issue by trying to attach audio thinking to it.
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The selector switch passes about 12 mA of DC current for operating just one relay coil at any input select position so almost any gauge no matter if thin will do.
Hi Andrew, (and it is mostly for new members) I learn from you guys quite long time ago that Rod's Elliot signal ground elevation method is the way to go for me. All my signal "returns" are insulated from chassis. Safety Earth or to call it Earth Ground is connect to chassis near IEC. "0" of PSU is connected to the same point via 10r//0.1uF//2-reversed to each other diodes.
Salas, thank you for that info. I found in my junk 8 wires shielded cable (it is like CAT6e) and I'll use it for input selector.
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Salas, thank you for that info. I found in my junk 8 wires shielded cable (it is like CAT6e) and I'll use it for input selector.
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Hi all
one question about power supply...
In BOM it state that transformer should be ;
2x18+18V 50VA
so is it like 18V with 0.7A x 4
or is it like 18V 1.4A x 4
Do I need 50VA for two channels
or I need 100VA for two channels
I think I see, some pictures, in this tread that some one uses 2x30VA ?
My headphones are GRADO PS500 32 Ohm
can I use like 2x20VA ?
one question about power supply...
In BOM it state that transformer should be ;
2x18+18V 50VA
so is it like 18V with 0.7A x 4
or is it like 18V 1.4A x 4
Do I need 50VA for two channels
or I need 100VA for two channels
I think I see, some pictures, in this tread that some one uses 2x30VA ?
My headphones are GRADO PS500 32 Ohm
can I use like 2x20VA ?
Thanks Marra
Jea, I know I see someone is useing 30VA
But I didn't read the post, just was looking at the pictures...
pfff...
so, 50VA is...will have to see, what can fit inside my case...
Thanks Salas
I just recive parts from TeaBag (thanks for GB Tea
)
So I have some more questions
In the package I didn't recive 150R but 220R (I think for R3) ? Is it ok to use 220R in that position ?
For bias of 150mA I will use some small 7.5R (he will not burn ? Looks a little small)
And for the gain of 2X (as Salas advise) I should use 500R (I recive 1K but will found some 500R some place around)
Before I solder everything I have some matched SK170 x 4;
would thay work/sound better than what's in kit ?
If thay will/do sound better, should I make some other adjustment to the circuit ? Replace some resistors value ?
As I understand thay are matched in groups 4x8mA, 4x9mA and 4x10mA
( I have 3 x matched quads )
ups...looks there's something wrong with photobuckit...will try to fix it...but pictures are not important...
I just recive parts from TeaBag (thanks for GB Tea
)So I have some more questions
In the package I didn't recive 150R but 220R (I think for R3) ? Is it ok to use 220R in that position ?
For bias of 150mA I will use some small 7.5R (he will not burn ? Looks a little small
)And for the gain of 2X (as Salas advise) I should use 500R (I recive 1K but will found some 500R some place around
)Before I solder everything
I have some matched SK170 x 4;would thay work/sound better than what's in kit ?
If thay will/do sound better, should I make some other adjustment to the circuit ? Replace some resistors value ?
As I understand thay are matched in groups 4x8mA, 4x9mA and 4x10mA
( I have 3 x matched quads )
ups...looks there's something wrong with photobuckit...will try to fix it...but pictures are not important...
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yoke, R3 for J3 was adjusted based on the current I was getting out of the semiconductors I stock. So Salas and I discussed that long ago, and I filter the supply of JFets to meet the 221R sizing.
7.5R has worked fine for me for many months. It will not burn.
500R gives less gain.
I am not certain of any mods for 2SK170BL's. I dont think so, but will let Salas address that.
7.5R has worked fine for me for many months. It will not burn.
500R gives less gain.
I am not certain of any mods for 2SK170BL's. I dont think so, but will let Salas address that.