Phono3 new build hum

[Steebo123]

Hi John, yes I did, but I am going to check all my earthing tonight.

Cheers

[Steebo123]

Plucked up the courage to plug my Gyro/Rega/Goldring in, in my listening room. No hum, just lovely music!

Thanks all, I think it was an issue with my old Thorens setup.

Now to listen properly.

Cheers

[bob orbell]

You don't need much courage to get good music, glad you are sorrted, what do you think of the phono then ?. BOB

[Steebo123]

Sounds pretty good Bob, a little bright, but I am sure it will settle down, I used the upgraded Soniq caps.

Really enjoyed the build, next is the pre, then the WD88 as a power amp.

[bob orbell]

Hi Steve, I do agree that the phono is a little bright, it dose change for the better with time, let it run for some time and settle. Do you have any better components in the PSU? better fast recovery diodes, evox capacitors and snubber capacitors on the choke all go a long way to making the phono sound cleaner and less bright and it will also help the PREIII if you go that way. The WA88 is very good and also benifits from the XL upgrade. If you need any advice, just ask. BOB

[Richard]

Steve,
1) if it is Phono 3S it has adjustable caps which may need setting,
2) it is very responsive to valve choice, you will find 5751 are warmer and more interesting than the supplied valves,
3) try the cathode bypass caps on the first stage valve as in the faq
I've played around with it lots and checked/set riaa for accuracy at each change (using a reverse riaa filter sig gen and scope) and my favourite is 5751 with the cathode caps. That set up is indeed warmer and bigger sounding than stock version.

[Steebo123]

Hi Thanks for the comments. I will give it a few days, and then reflect on the options above.

Cheers

[Steebo123]

Richard, how can I check the variable cap setting without a reverse RIAA/signal generator? They are set mid way; which way of turning makes the sounds less bright?

Thanks

[Richard]

Steve,

More cap will make it darker and less cap will make it brighter. It affects the 3.18uS corner which may or not be audible but also the 75uS corner frequency lower down which may be more audible. Have a turn from one extreme to the other and see if it is audible to you;

Looking down on the adjustable ceramic cap closely with a magnifier if needed you will see the ceramic body next to one leg has a flat on it.

Now see the brown disc with silver half circle and screwslot on it. When the silver halfcircle is aligned nearest the body flat (screwdriver slot at 90 degrees to the legs) the cap is at max value, 60-70pF.

When the halfcircle is furthest away the cap is at min value about 5pF.

When the screwdriver slot is running inline from leg to leg the cap is midway value.

The disc/slot can be rotated completely around either way without damage and will just increase/decrease etc.

Hence when set midway with slot aligned leg to leg it is about 30-40 pF added to the 180pF fixed cap giving about 220pF of the original Phono 2 design. More on tweaking that design here,
http://www.world-designs.co.uk/forum...read.php?t=145

[Steebo123]

Thanks Richard, I appreciate it.