Valve Itch phono

[Salas]

No extra need to use

 

[merlin el mago]

Thanks

 

[merlin el mago]

Salas can be Linn K9 need more gain, I listen very very low with attached schematic.

 

[stajo]

What value is the cap you have drawn at input?

 

[merlin el mago]

My fault there isn't input cap between the grid & ground.

 

[Salas]

The gain is more than good for a 4.5mV cartridge. Something else must be wrong. Measure Ohmic load on phono input with power off and DC mV with power on. No TT cables attached when measuring.

 

[merlin el mago]

Ooooops Salas output grounds wires not connected to RCA outputs grounds😱

 

[Salas]

OK, restore proper connections and let us know if signal got strong.

 

[merlin el mago]

A little bit more but I need to listen full volume up

Left 47K4 -0.028V
Right 47K9 -0.049V

 

[stajo]

Your bottom tube doesnt bias. You should have 0,7 something if theres a 1N4148 down there with current passing. Measure your voltages in different points like anodes of all tubes. Are the diodes the right way (cathode down)?

 

[merlin el mago]

Wait a moment I will take a pic

 

[stajo]

.

 

[merlin el mago]

Pic

 

[stajo]

The diodes are the right way. The rest scares me. Measure your voltages

 

[Salas]

Looks like the left hand 1N4148 maybe does not securely touch the base pin.

 

[merlin el mago]

B+ only 126.3V I will check the PSU

 

[merlin el mago]

I checked diodes and are OK.

 

[Salas]

That low B+ should be the key problem.

 

[merlin el mago]

PSU is giving 350VDC

 

[merlin el mago]

Just remembered that I used the SSHV2 inside the Itch for other use and forgot to set again 300VDC😱.

Now time to warm up and listen, in the middle I will have dinner.

Thanks for support guys.