AZ1 PSU

[euro21]

choke input PSU

Felipe, try this.

 

[merlin el mago]

Bela your schematic is for one AZ1 and two transformers right?

 

[merlin el mago]

> Manufacturer specs:
> Regulation 0.5%

This is unlikely, and a typo. The regulation is 5% at full load.

Because you bought a 100W transformer for a 5W-10W load, indeed you may have 0.5% regulation at your load.

If you indeed have 14 Ohm resistors and 10 Ohm choke (again very oversize), then the raw output of the power supply should be 180V at 30mA load (6K dummy).

> can't get 150Vout from SSHV2

This has a 20V dropout. 180V-150V is 30V difference. It should work.

The SSHV2 instructions say to set SSHV2 current 20mA higher than load current. What *total* current are you setting?

What do you actually get at the INput of the SSHV2?

To power 26 preamp = 10mA for two tubes @ 150V

 

[euro21]

Bela your schematic is for one AZ1 and two transformers right?

Yes.
Waste of transformers, waste of chokes, but working.

IMHO 150V for B+ just in case enough for #26 if you use IT loading (about 130V, 5mA, -9V op. point).


If you use CCS or gyrator, the #26 preamp B+ would be significantly greater than 150V.
150V, 5mA as operating point at -11.5V heater bias bias is good, but then anode voltage is 150+11.5= 161.5V!
The CCS or gyrator requiring -at least- 30..40V, so B+ at about 200V.

Is use 220V B+ for my CCS loaded @26 preamp (250V before SSHV2).
http://www.diyaudio.com/forums/tubes-valves/190857-4p1l-dht-line-stage-128.html
#1280 post.

A better way to use 220...260 V /440...480V CT/ (for example 240-0-240) 60mA capable transformer and omit SS diodes.

 

[merlin el mago]

You are right waste of power transformers and chokes.

My 26 preamp is loaded with LL1660 Alt S 4:4.5

The 125VAC or two for 250VAC are not the best for AZ1 or SS for 26 preamp so I have other transformers can suit better:

Salvaged Audio Note DAC 1 or 2, 240VAC nominal = PSUDII 244V 209.6 ohms

Lundahl LL1683 attached data sheet

 

[merlin el mago]

IMHO 150V for B+ just in case enough for #26 if you use IT loading (about 130V, 5mA, -9V op. point).

Yes I use IT LL1660 Alt S 4:4.5 loading.

For 26 preamp now I use the attached schematic, but I'm not sure about voltage at 26 plate because the voltage in attached pic is for Alt Q 4.5:1 with a DCR of 1K but I don't know what's the DCR of Alt S, sould I measure with a tester?

 

[merlin el mago]

Attached forgotten schematic pic

 

[euro21]

If you want to use SSHV2 at 150V output, probably must increase trimmer pot parallel resistor ( -R12- 1k) to 2k2. It depends of 2SK117 Idss current.

 

[merlin el mago]

Thanks Bela, what about the PSU?

I don't understand why R7 33K to the other channel?

R3 39R is the same R3 220R than in SSHV2, have I to change 220R for 39R?

 

[euro21]

why R7 33K to the other channel?

This represents the another channel's load (4.5mA). The correct SSHV2 dissipation calculation requires this load.

The PSU -maybe- the #12 post schematic, or either 180V-250V raw supply PSU. The greater input voltage generates greater dissipation in SSHV2 (on the CCS FET).

 

[merlin el mago]

I have several SK117GR Idss values:

3.47

5.00
5.18
5.37
5.42
5.43
5.45
5.46
5.47
5.62
5.66
5.73
5.75
5.94

6.07
6.08
6.12
6.15

 

[merlin el mago]

SK117BL

2.93
3.04
3.41
3.50

 

[euro21]

R3 39R is the same R3 220R than in SSHV2, have I to change 220R for 39R?

The SSHV2 CCS bias is 500R pot // 220-330R resistor. The CCS current settings is done by trimmer.

This resistor in my schematic only represents 30mA CCS current is the simulation, this value can be ignored.

 

[merlin el mago]

OK now I understand these values are only for simulation pourposes.

 

[euro21]

If you can set 150V (at 9-10mA load: 15k 5-10W resistor), nothing to do.

 

[merlin el mago]

Bela I can set the CCS to 30mA R5 is 1 ohm but SSHV" Vout can't reach more than 41VDC, Vin no load 363VDC.

 

[Salas]

Is your dummy 15k?

 

[merlin el mago]

4K7

 

[merlin el mago]

Salas could I try Bela suggestion:

"If you want to use SSHV2 at 150V output, probably must increase trimmer pot parallel resistor ( -R12- 1k) to 2k2. It depends of 2SK117 Idss current."

 

[merlin el mago]

One KSA1381 gone, CCS OK 30mA, now can reach 143.8VDC but needs 150V with 4K7 dummy load, any suggestion?