Hello
Today I could buy some of this famous Toshiba 2SK389 / 2SJ109 double JFET's.
I will make a stripboard layout (with Lochmaster) for a JC-2 preamp (also usable for selected 2SK170 / 2SJ74) and publish here (or in a new thread).
Why?
My actual chinese JC-2 board does not allow balanced input. I will use a JC-2 circuit, allowing balanced input directly from the transformer (as in the original JC-2 circuit).
My best wishes for the new year!
Franz
Today I could buy some of this famous Toshiba 2SK389 / 2SJ109 double JFET's.
I will make a stripboard layout (with Lochmaster) for a JC-2 preamp (also usable for selected 2SK170 / 2SJ74) and publish here (or in a new thread).
Why?
My actual chinese JC-2 board does not allow balanced input. I will use a JC-2 circuit, allowing balanced input directly from the transformer (as in the original JC-2 circuit).
My best wishes for the new year!
Franz
Someone is using B1 buffer as output stage for this DAC
http://www.diyaudio.com/forums/pass-labs/152794-voltagedac-b1-output-buffer.html
http://www.diyaudio.com/forums/pass-labs/152794-voltagedac-b1-output-buffer.html
Hello
Maybe the Aleph-P or the B1 are better as the JC-2 in this place, as they are true buffers, e.g. gain=1
As I wrote earlier: my line level is too high now, I have to attenuate it more than other sources.
Franz
/Edit
I think, the JC-2 is very suitable for using transformers with a relation about 1:0.6 rather than 1:1
/second Edit
I also must tell you, that I am using a passive pre, e.g. a stepped attenuator between the DAC and the T-amps. Maybe, thats why I have a very big improvement using a buffer after the DAC's output trannies as I am avoiding damping by poor impedance matching within my audio chain.
Maybe the Aleph-P or the B1 are better as the JC-2 in this place, as they are true buffers, e.g. gain=1
As I wrote earlier: my line level is too high now, I have to attenuate it more than other sources.
Franz
/Edit
I think, the JC-2 is very suitable for using transformers with a relation about 1:0.6 rather than 1:1
/second Edit
I also must tell you, that I am using a passive pre, e.g. a stepped attenuator between the DAC and the T-amps. Maybe, thats why I have a very big improvement using a buffer after the DAC's output trannies as I am avoiding damping by poor impedance matching within my audio chain.
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Franz
May I ask something about this.
What if I have a passive pre like the LSA then using a buffer like B1 buffer, would that combination will improve the DAC with output transformer just like you have in your latest setup with the JC-2 output stage ?
Hi,
im interested in this dac-kit here (link)
im quite new here and didnt follow this thread before, can you maybe tell me what I have to change on this dac to make it sound very good? I dont feel like reading 167 pages
I already read before, that this dac may have problems with certain preamps, im planing on building a preamp with pga 2311 (lsqr 2.0, its from a german forum) as preamp, might this be a problem?
greetings,
Chris
im interested in this dac-kit here (link)
im quite new here and didnt follow this thread before, can you maybe tell me what I have to change on this dac to make it sound very good? I dont feel like reading 167 pages
I already read before, that this dac may have problems with certain preamps, im planing on building a preamp with pga 2311 (lsqr 2.0, its from a german forum) as preamp, might this be a problem?
greetings,
Chris
Chris
Try this DAC and don't use the analogue output section (the opamps). Attach a fine 1:1 line trannie directly to the CS4398's outputs.
For example a Lundahl LL1540.
Then relax and listen.
After that experience, you could add a passive low pass filter and/or, as I am experimenting actually, a fine buffer.
The best wishes for the new year
Franz
/Edit: there are no problems with "certain preamps"
Try this DAC and don't use the analogue output section (the opamps). Attach a fine 1:1 line trannie directly to the CS4398's outputs.
For example a Lundahl LL1540.
Then relax and listen.
After that experience, you could add a passive low pass filter and/or, as I am experimenting actually, a fine buffer.
The best wishes for the new year
Franz
/Edit: there are no problems with "certain preamps"
Hi Franz,
thx for your answer, i think i will try the line trannie option first. lets see what I can find about the lundahl.
is it the "best" one? or are there better ones? i think i dont want to buy such a line tracie for $500 when the dac itself only costs 110$ with shipping, that wouldnt make that much sense
lets say im searching for the best "bang for the buck", thats at least what the people at head-fi say
and of course: best wishes for the new year
edit: i just found out there are different versions of this lundahls from 23-111 over 23-112 and 23-113 and 23-131
which is the right one?
thx for your answer, i think i will try the line trannie option first. lets see what I can find about the lundahl.
is it the "best" one? or are there better ones? i think i dont want to buy such a line tracie for $500 when the dac itself only costs 110$ with shipping, that wouldnt make that much sense
lets say im searching for the best "bang for the buck", thats at least what the people at head-fi say
and of course: best wishes for the new year
edit: i just found out there are different versions of this lundahls from 23-111 over 23-112 and 23-113 and 23-131
which is the right one?
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i didnt mean that the lundahl you mentioned first would cost $500, just said that i dont want to buy such an expensive line transformator...
can you maybe tell me which toroid transformator i need?
edit:
i found this one here:
Print-Netz-Trafo prim 230 V
sek 1 = 8 V 1,6 VA sek 2 =13 V /8,6 VA
size L=50, B=42, H=34 mm.
Typ U 8311 1 St. 1,75 €
adress/shop(german)
can you maybe tell me which toroid transformator i need?
edit:
i found this one here:
Print-Netz-Trafo prim 230 V
sek 1 = 8 V 1,6 VA sek 2 =13 V /8,6 VA
size L=50, B=42, H=34 mm.
Typ U 8311 1 St. 1,75 €
adress/shop(german)
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@Chris
If you are using transformers instead of opamp outputs you don't need the power supply for them. 6-8VAC is enough to power the DAC, something like this (from the website you supplied):
Print Netz Trafo
prim 230 V,
sek1=8 V 15 VA
sek2=8 V 15 VA
Maße: L= 63 , B = 54, H= 54 mm.
Typ U 4062 1 St. 4,25 €
Of course you only need one 8V secondary, not two like this one, but it doesn't matter, no one forces you to connect the other one
And for the line transformers my suggestion are the UTC A-20, they go around 100$ on ebay and sound great.
Here is a pic of my DAC, changed almost everything, currently playing with LPF filters:
If you are using transformers instead of opamp outputs you don't need the power supply for them. 6-8VAC is enough to power the DAC, something like this (from the website you supplied):
Print Netz Trafo
prim 230 V,
sek1=8 V 15 VA
sek2=8 V 15 VA
Maße: L= 63 , B = 54, H= 54 mm.
Typ U 4062 1 St. 4,25 €
Of course you only need one 8V secondary, not two like this one, but it doesn't matter, no one forces you to connect the other one
And for the line transformers my suggestion are the UTC A-20, they go around 100$ on ebay and sound great.
Here is a pic of my DAC, changed almost everything, currently playing with LPF filters:
An externally hosted image should be here but it was not working when we last tested it.
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if i dont buy a transformator that can also deliver 13v i cant even test the dac, if i make changes and solder some stuff on this dac and then realize it doesnt work my warranty will be gone i dumped $110
so i need a transformator with 8v and 13v... this is not so good but i dont want to risk anything
hm well $100 is a bit too much for my taste. i think ill prefer to try cheaper ones first but thx for ur suggestions!
so i need a transformator with 8v and 13v... this is not so good but i dont want to risk anything
hm well $100 is a bit too much for my taste. i think ill prefer to try cheaper ones first but thx for ur suggestions!
Hey hey, confusion!
There is no need for I/V conversion outside of a CS4398. It's a voltage out DAC.
The redline in this thread is talking about using 1:1 trannies connected directly to the CS4398 instead of the analog opamp circuit.
When using 1:1 trannies, then you will have the full scale line level mentionned in the CS4398 datasheet (and about 1% loss).
Franz
There is no need for I/V conversion outside of a CS4398. It's a voltage out DAC.
The redline in this thread is talking about using 1:1 trannies connected directly to the CS4398 instead of the analog opamp circuit.
When using 1:1 trannies, then you will have the full scale line level mentionned in the CS4398 datasheet (and about 1% loss).
Franz