HQ-IV tube output balance DAC

[quanghao]

Dear Quanghao,
I have received today the 2 sets of PCB. They are excellent quality. Thank you.
Victor

Hi !
I'm happy . You got my pcb
Thanks

 

[jonwhitear]

Quanghao, do you have a drilling template for both boards please?

 

[quanghao]

Quanghao, do you have a drilling template for both boards please?

It is no hot

 

[adeveza]

Shunt HV Regulator

Quanghao,

The parts list is missing D5. What is diode D5?? specs??

Alex

 

[quanghao]

Quanghao,

The parts list is missing D5. What is diode D5?? specs??

Alex

D5= 1n4007 . thanks

 

[Ryssen]

Is it okay to use the 6N23p at 2,3mA/triod because on one side the trimpot reaches it´s endpoint and I can´t get any higher...

 

[quanghao]

Is it okay to use the 6N23p at 2,3mA/triod because on one side the trimpot reaches it´s endpoint and I can´t get any higher...

no, tube input need low current for best sound.

thanks

 

[jonwhitear]

2.3mA _is_ low isn't it? I have 12AU7 input tubes with 220V B+ and 47k anode resistors. By my calculations 110V across 47k gives me 2.3mA. Sounds good to me!

 

[quanghao]

2.3mA _is_ low isn't it? I have 12AU7 input tubes with 220V B+ and 47k anode resistors. By my calculations 110V across 47k gives me 2.3mA. Sounds good to me!

No low . 2 to 3ma . That is good sound .
You can go up max + 235 or 240 v.
Thanks

 

[jonwhitear]

So the anode resistors (R1 and R2) should be 470k then, rather than the 47k specified?

 

[quanghao]

So the anode resistors (R1 and R2) should be 470k then, rather than the 47k specified?

47k . Thanks

 

[jonwhitear]

Now I'm confused. Does that mean I should adjust the current so there's about 10V across those resistors? That would give me about 0.2mA.

 

[Ryssen]

I have about 95v across them.

 

[Ryssen]

The time before the relay starts is about 1,5 minute,is there a way to shorten this time?

 

[nick696]

Hi! Quanghao,

still have 1 x HQ-IV+ 2 x No.Shunt HV ?

Can I pair this HQ-IV with Buffalo IIIse?

 

[Ryssen]

The DAC is playing (AK4490) allthow the gain is a little to high...
But I must ask again the delay for the relay is waaay to long.....How long is it for you other that have built this?

 

[adeveza]

Delay

You can just disable the delay circuit. I did it on mine and its really not necessary, if you are careful. Just turn on your DAC before your amp, turn your amp last and you should be fine. Just manually do the delaying yourself.

Alex

 

[Ryssen]

Yes that is an option to remove the delay,just thought if it was as simple as to change an e-lyt to a smaller value.

 

[quanghao]

The DAC is playing (AK4490) allthow the gain is a little to high...
But I must ask again the delay for the relay is waaay to long.....How long is it for you other that have built this?

Hi!

C9 late on duty close to the relay, avoiding audible speaker.

Closing time lag depends on the capacitor C9.

470uF: closing delay of about $ 30.

680uF: closing delay of about $ 45.

very good time for most of the pre tube.

thank you

 

[quanghao]

Hi! Quanghao,

still have 1 x HQ-IV+ 2 x No.Shunt HV ?

Can I pair this HQ-IV with Buffalo IIIse?

yes, i only have only PCB for it

1 x HQ iv Ok
2 x no shunt ok

thanks

quanghao