AK4490 sings,but gain is a little high..

[Ryssen]

I will order some caps and try the BCF first before I ev,need to try:

Use a resistor attenuator at Vref to step down the 5 analog supply to, say 2.5V. Two 470 ohm resistors in series to ground, then a 1000uf cap decoupling the mid point which is taken to Vref and you have reduced gain, as well as a cleaner Vref.

The traces on that dac board are so thin... uhh

 

[Ryssen]

I woder if R1 and R4 should be as high as 100K as they are original ?
Or could I use say 1K instead?

 

[ljufa]

Bfc manual say they could be in range 10k-100k so you can leave bcf circuit as is now, just add cap and connect dac out directly to it and make sure previous two stages are disconnected from everything else.

Here is BCF1(slightly different from bcf2) user guide
http://glass-ware.com/User_Guides/BCF 9-Pin.pdf

 

[Ryssen]

Ok,just ordered the 2 extra caps..

 

[Ryssen]

I disconnected the first tubes and soldered the 2 newcaps and powered on.
And it works,the level is much better now.I´ll leave the input tubes in there (glowing) just for loocks.
Tomorrow I´ll do some tuberolling to se if anything sounds better than the
12BH7´s,6N6p or 6cg7 with adapter..

 

[Ryssen]

Been listening for couple of hours now and I think that 6N6P is a little to dark for my taste,I think that the 6CG7 is more neutral/ballanced I use RCA cleartop,I have some more brands I will listen to.But as I said it sound better than my ES9018 with unballancer.

 

[Ryssen]

What voltage should I use for The 6cg7 for best result, I am now using 260v,should I usel More?

 

[Ryssen]

The cleartop are the clearest sounding..

 

[swak]

Ryssen,

i was thinking of using the unbalancer 2 with the ak4490. Are you using the first balancer or the BCF?

S

 

[swak]

And one more question Ryssen, have you dropped the I/V resistors? I believe they are not necessary with this DAC.

 

[Ryssen]

I am using the BCF,and no I/V resistors.