Valve Itch phono

[merlin el mago]

I swapped the tubes but the situation doesn't changed....

 

[stajo]

Then I would first check so pin 3 (kathode) is to ground and measure voltage on pin 1 anode. If all ok then disconnect R5 from V3 pin 3 kathode and measure again.

 

[merlin el mago]

Oooooops stajo & Salas diode connected the negative side to V1 pin 3

I'm not justifiying but the strong light that I use caused my big mistake....

 

[stajo]

Thats a show(current)-stopper

But I checked some pages ago. Didnt you say channel was down also Before you put diodes there?

 

[merlin el mago]

Now both channels amplifies the signal, time to connect

 

[merlin el mago]

Thats a show(current)-stopper

But I checked some pages ago. Didnt you say channel was down also Before you put diodes there?

Thanks for support, the story it's a little bit long: this morning I discovered that grounded heaters was not well connected & tonight the reversed diode, I'm an electronic CRACK

 

[stajo]

So how does it sound Merlin?

 

[merlin el mago]

Thanks for your interest but still I don't know, I have a very busy day!!!!!!! I will let you know.

 

[merlin el mago]

So how does it sound Merlin?

First I used the same reversed diode but no sound left channel, chenged for a new diode and now both channels sounds OK, but my Denon DL103R needs more gain isn't enough Partrdige 977 1:6 so I have to change for a new MC step-up 1:10 or more....

 

[Salas]

Nice that you repaired it Merlin. Well done. Can you hear the rough supply's hum or buzz at all or the circuit rejects it enough?

 

[Salas]

BTW maybe 1N4148 diodes which are small current and very low capacitance can be best bet there for lifting the cathodes.

 

[merlin el mago]

Nice that you repaired it Merlin. Well done. Can you hear the rough supply's hum or buzz at all or the circuit rejects it enough?

As you said the circuit rejects it enough

 

[merlin el mago]

Salas if is not to ask too much could you suggest a 3rd stage to have moe gain, I'm very pleased with the SQ of Partridge 977 only that I need more gain.

 

[merlin el mago]

BTW maybe 1N4148 diodes which are small current and very low capacitance can be best bet there for lifting the cathodes.

Next Monday I will ask to my local supplier, thanks for the trick.

 

[Salas]

Salas if is not to ask too much could you suggest a 3rd stage to have moe gain, I'm very pleased with the SQ of Partridge 977 only that I need more gain.

Hmm it will reverse absolute polarity if its only one tube. If you will use an adapter for 6DJ8 / ECC88/ 6922/7308 in the second stage it will give +4dB over the 6SN7 without adding stages BTW.

 

[merlin el mago]

Itch 42dB + 4dB ECC88 = 46dB + 15,6dB Partrdige 977 = 61dB, can be enough for 0,25mV DL103R?

 

[Salas]

I used 61dB before for that cart with DCB1 and 30dB amp and it was alright on 90dB+ speakers. But its subjective also about what you and me feels "loud" enough.
What impedance line input you drive now with the Itch? Maybe you lose some signal on low impedance volume pot line preamp also that 6SN7 can't drive strongly?

 

[merlin el mago]

I use the Itch with:

-ECC81 mu-follower, 100k input pot (headphone amp for Sennhs HD600)
-#26 preamp, 100k input pot (lineamp)

 

[Salas]

No problem with loading the 6SN7 too much.

 

[merlin el mago]

How can loading much the 6SN7: changing the pot for another with more ohms?

Have I to change something or simply buy a couple of adapters 6SN7-ECC88?