Valve Itch phono

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Salas

Salas

diyAudio Chief Moderator
Joined 2002
Paid Member
Fran, there is a 22K to 47uF RC dropper/filter on the rail towards first stage in Rev1 CCT. Was what we had. Have you got any 4.7u-10u 400V PP to try there? Since the filtering is enough anyway, maybe it can bring a detectable thing or not. I checked my DVM against a dedicated RLC bridge also, and the real value of the 15n 5% nominal caps could very well be 15n+ as yours are 15n3 tested by Vgeorge and seem OK tonally. My DVM shows a bit minus from real.
 
Salas

Salas

diyAudio Chief Moderator
Joined 2002
Paid Member
With 22k they still make a good time constant for filtering. If you had say a 4.7 or 10uF SCR would be stronger a filter of course. The main reason for that RC being there is to drop around 30V for correct bias and voltage staggering on the input totem. There is the SSHV and the PSRR of the stage to take care of ripple, so give it a try to see. 350V DC is the lowest you could use.
 
W

woodturner-fran

Member
Joined 2006
I added in the mgbo caps today. I wish I had used something more familiar as test before and after - I had a new stan getz album on the deck......

Anyway... Bass seems more snappy and tight - and it was no slouch in that dept before. I think there's also a little more detail in there too.

Now I have to figure out how I'm going to fit the new caps in the case!

I wonder if someone else would try this and report back? It's not a huge change but still audible.

Fran
 
W

woodturner-fran

Member
Joined 2006
Sorry cross posting there....

Heres the cap:

mouser cap


I recorded the same bit of music as before (saeta from sketches of spain). unfortunately its a bit louder recording - hard to set recording levels - so you will need to adjust down your volume between tracks, but I think the difference is clear to be heard. File is uploading slooooowwwwlyy to rapidshare.... links shortly.


Fran
 
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