Bigbottle Phonostage Builders thread

Hi Vivan, thank you for your reply.
Yes, voltage measurements without tube installed.
Transformer is special order according specification (165v 2x9,5v), but actual voltages: 185v, 2x10,9v without tubes installed.
Tomorrow will install tubes and measure again.
Best regards.
Sasha.
 
Good afternoon Vivant,
I have installed tubes and measured voltage:
AC voltage - 182v,
V1 pin1 - 90v,
V2 pin2 - 130v,
V3 pin1 - 232v
Its working, will give a listen tomorrow.
Could you please confirm switch position?
LED is on when preamp in MC?
Thank you.
Best regards.
 
Good afternoon all.
I have a few questions about loading resistor.
My understanding in case of MM cart I can add loading capacitor?
In case of MC cart I can add loading resistor?
Could you please share your findings about best values?
Best regards.
Sasha.
 
Adding capacitance for MM is very dependent on the cart used, also depends on how much capacitance is in your tonearm wiring and connecting phono leads.
The board has 100pF fitted as standard.

Generally 100 ohms is a good all round load for a lot of MC carts.
 
Just looking at your photos again, R2P and R3P look as if they need more solder on one side.

The other side was fine but added some more for good measure. I switched out the zener now i am getting 7 volts at my heaters. I then plugged in the HT and got the following readings on my caps:

C4P - 243v
C5P - 134v
C7P - 133.7v
C8P - 133v

I was not getting any voltage between pins 1 and 6.
 
it's a long time since i built it, and am in the process of moving house, so as luck would have it the phonostage is 150 miles away, otherwise I could check R7L&R. From what I remember they are as per original BOM.

As for the LEDs, yellow seems to be what you should use according to post 863 in this thread, although when I built mine the BOM at the time said red or yellow, and I used red with no apparent issues.

Edit:
Just remembered I used multifet PCBs on my build, and R7L&R were replaced by wire links
 
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