HQ-IV tube output balance DAC

[quanghao]

Now All PCB ready for shipping to you

A. HQ-IV tube output stage for balanced DAC chips
Sizes: 160 mm X 180 mm
Material: double layer glass phip 2mm thickness
Surface plating: gold standard
The PCB is available for $35USD

B. No.shunt HV Regulator + Heater supply
The PCB is available for $20USD
Sizes: 95 mm X 185 mm
Material: double layer glass phip 2mm thickness
Surface plating: gold standard
The PCB is available for $20 USD
The shipping costs is 15 USD ( for all with 1- 2 PCB )
The shipping costs is 20 USD ( for all with 3- 4 PCB )
The shipping costs is 30 USD ( for all with 5 - 6 PCB )

C. Total: A+B+ship = 70
The payment you help me please:
Accepting USD PayPal only: quanghao168@yahoo.com.vn

Here is the list of registered and paid
1. adeveza : 1 x HQ-IV+ 1 x No.Shunt HV - paid
2. apnneto :1 x HQ-IV+ 1 x No.Shunt HV - paid
3. goldkenn: 3 x HQ-IV+ 3 x No.Shunt HV - paid
4. AR2: 2 x HQ-IV+ 2 x No.Shunt HV
5. Brooksl2: 1 x HQ-IV+ 1 x No.Shunt HV
6. mvictor69: 1 x HQ-IV+ 1 x No.Shunt HV
7. jonwhitear: 1 x HQ-IV+ 1 x No.Shunt HV - paid
8. rredline : 1 x HQ-IV+ 1 x No.Shunt HV
9. aradan : 2 x HQ-IV+ 2 x No.Shunt HV
10. vasillis 2 x HQ-IV+ 2 x No.Shunt HV
11. Ardahan: 1 x HQ-IV+ 1 x No.Shunt HV - paid
12. frankwilker: 1 x HQ-IV+ 1 x No.Shunt HV
13. passive420: 1 x HQ-IV+ 1 x No.Shunt HV - paid
14. mvictor69 :2 x HQ-IV+ 2 x No.Shunt HV - paid
15. mvictor: 2 x HQ-IV+ 2 x No.Shunt HV
16. maciejmo: 1 x HQ-IV+ 1 x No.Shunt HV - paid

All you have to register on the list, please pay me.

To day i will ship the PCB to you !

 

[quanghao]

Hello friends!

Help me please.

Would you please send me the complete information as follows: ( please PM to me )

Nick diyaudio:
E-mail:
Phone number:

It is very important. Without it, I can not ship to your PCB.

Special thanks !

 

[quanghao]

Information shiping for GR HQ-IV stage+ No. HV shunt

Hi all, today I ship all PCB to you

GR HQ-IV stage+ No. HV shunt
Shiping by: B?u ?i?n Vi?t Nam - VNPost

BPBĐ - Registered"

1 adeveza 1 1 RR105819925VN
2 maciejmo 1 1 RR105819965VN
3 passive420 1 1 RR105819948VN
4 mvictor69 2 2 RR105819917VN
5 micha8a 1 1 RR105819996VN
6 goldkenn 3 3 RR105819934VN
7 AR2 1 1 RR105819982VN
8 apnneto 1 1 RR105819951VN
9 jonwhitear 1 1 RR105819979VN
10 jean-paul 1 1 RR105820005VN

Can you check all tracking follow this image.
Now you can check follow:
Go to the web: B?u ?i?n Vi?t Nam - VNPost
And at number , ex: RR105820005VN
and choise :BPBĐ - Registered - and enter,
so you can see all information about your PCB.

thank you very much!
quanghao

 

[apnneto]

Thanks ....

 

[jonwhitear]

Thanks. Any recommendations for a DAC kit to match up with this I/V?

 

[passive420]

Thanks. Any recommendations for a DAC kit to match up with this I/V?

The Buffalo 2 is perfect so try to find one here or get one from their shop before they disappear for ever (look in bargain bin section). Also consider their COD and opus DAC's which also have balanced outputs

Or a Soekeris DAM1021 DAC.

Or a Chinese DAC (DIYINHK)

 

[passive420]

The Buffalo 2 is perfect so try to find one here or get one from their shop before they disappear for ever (look in bargain bin section). Also consider their COD and opus DAC's which also have balanced outputs

Or a Chinese DAC (DIYINHK)

Sorry, the DAM1021 has I/V already

 

[quanghao]

Thanks. Any recommendations for a DAC kit to match up with this I/V?

in my dac ES9018 with V-out.
I not use R i/V. and I connect DAC direct to Amplify. The sound I like!

So,

You can use R Iv from 47R to 100R .

thanks

 

[jonwhitear]

The Buffalo 2 is perfect so try to find one here or get one from their shop before they disappear for ever (look in bargain bin section). Also consider their COD and opus DAC's which also have balanced outputs

Or a Soekeris DAM1021 DAC.

Or a Chinese DAC (DIYINHK)

Thanks for the tips. The Buffalo 2 looks good.

On a different note, does anyone have part numbers for a suitable transformer, assuming I'm using 12AU7/6DJ8?

Cheers,

Jon

 

[passive420]

Thanks for the tips. The Buffalo 2 looks good.

On a different note, does anyone have part numbers for a suitable transformer, assuming I'm using 12AU7/6DJ8?

Cheers,

Jon

Hi Jon I'm hoping I got this right myself - you will need two transformers or a custom transformer with two secondary windings. The HV supply board has two power rails.

One transformer will need to be 6 - 9V AC secondary to provide 6.3VDC for the filament heater. The VA can be small around 10-15VA.

The other transformer will need to provide the +B supply which in your case (12AU7/6DJ8) according to the details in the schematic posted on page one, will need to be 220VDC. The I/V stage only draws 100mA.

So a quick and cheap way to work out this is to divide 220 by 1.414 to find the required secondary voltage before rectification - 220/1.414 = 155.5

So a secondary of around 155V AC is required for your +B voltage supply.

This is the spec of a transformer I may have custom made by Canterbury Windings, one of the finest toroid makers in the country:

Continuous power rating: 41VA
Primary: 0-240V @ 50Hz
Electrostatic screen
Secondary 1: 158V @ 0.2A rms
Secondary 2: 7V @ 1.4A rms
GOSS band

The correct formula I was shown to calculate transformer output (Numbers are relative to us) -

220VDC + 2VDC diode drops + 1.8VDC (5%) ripple) / √2 (1.414) ≈ 158.2V AC

And don't forget the supply for the DAC itself.

 

[passive420]

Boards have arrived Quanghau, thank you.

Excellent quality, I have never seen so many holes in a pcb, they are very well ventilated!

Just looking at the board now - why did you choose a 4 pin connector for the input when only 3 are needed? One pin is wasted. There is a trace that comes to a dead end by the ground pin ( something I have never seen on a circuit)

 

[quanghao]

Boards have arrived Quanghau, thank you.

Excellent quality, I have never seen so many holes in a pcb, they are very well ventilated!

Just looking at the board now - why did you choose a 4 pin connector for the input when only 3 are needed? One pin is wasted. There is a trace that comes to a dead end by the ground pin ( something I have never seen on a circuit)

good!

but need me sent all for built it!

thanks all!

 

[passive420]

Quanghau, can you tell me what C3/R11 and C6/R26 do in the circuit? I cannot see them in the schematic posted. Just wanted to choose the right components for the job.

It looks like they decouple the diff amplifier stage from the output stage?

 

[passive420]

Also Quanghau - R26/R28/R30 are not on listed the BOM - does this mean the BOM is missing components?

Should we add R26 = 100K / R28 = 1.5K / R30 = 100K?

Can I check that for 12AU7 / 6DJ8 we use 1.5K for R14 + R28

Do we jumper 'T12V' and T6V' for both pairs of tubes? What is 'RT' jumper point by the output?

 

[passive420]

I see now: RT is DC coupled output.

 

[quanghao]

Hi passive420!

check it again

thanks

 

[quanghao]

HI!

R3, R4, R11, R13, R18, R19, R26, R28 = 100K

Tube oput:
1. Use tube 12au7 , R5, R14, R20, R29 = 1.5K to 1.8K

2. Use tube 6DJ8 , R5, R14, R20, R29 = 470 Ohm

All filament need 12 V so the jum connect :

1. Tube 6.3v use jum: T6V ( ex: tube 6Dj8
2.Tube 12V use jum: T12V (EX: 12Au7)

 

[quanghao]

I see now: RT is DC coupled output.

No use it. Thanks

 

[passive420]

Thank you Quanghau. Sorry for the questions. First time with tubes.

I may have calculated my transformer supply incorrect:

Do I need 0-12VAC for the filament supply and 158-0-158VAC for the HV supply? (to get 220VDC)

 

[passive420]

OK read through the thread and I'll be fine with 6.3V filament supply as I wont be using 12V tubes. The HV rail does need a centre tap.