Big trouble with Pre Phono 2

[LSfarzo]

Hello...
it's a lot of time I do not write on the forum. Hope you all are doing fine!

I'm in big trouble with my (old) WAD Pre Phono 2. The Pre has 2 sowter 9570 step-up, PIO and jensen caps, as can be seen in the photo.

It souded really great (but really !) coupled with a Benz Ace L.
I also matched the load for this cartridge.

Some time ago the sound chnaged suddenly. It is like there is a sort of "cut" to some mid and low frequencies. It has suddenly turned harsh and bad, like if the cartridge is not able to track the LPs. The sound is definitely "packed" and unpleasant... it is bad, like something is not working anymore.

I sent the cartiridge for a complete check and it was cleaned and tested by a very well kown and good cartridge master (i do not write the name to avoid unwanted advertisitng...).

The cartridge has come back and the things are getting only very slightly better.

I think that the problem is with the phono preamp.
The WAD Pre works fine.

Now the point is: do someone has some smart idea about what I could do? I do not want to start changing things .. I could end up losing a lot of time and money !

The strangest thing is that this behavior affect both channels !

Every idea is very very well welcomed !

Regards
Luca
Italy

[Richard]

Hi Luca,


First thing is to check the HT voltage and the Heater voltage coming in to Phono2 and, if not correct, back in PSU2.

[bob orbell]

Yes, I would agree with Richard, it could be a HT voltage problem, now I know I am going to sound a bit aggressive here but, the build construction looks appalling, pictures of the PSU may help. Bob

[Greg.]

Originally Posted by bob orbell

Yes, I would agree with Richard, it could be a HT voltage problem, now I know I am going to sound a bit aggressive here but, the build construction looks appalling, pictures of the PSU may help. Bob

Clearly Luca’s Phono II has worked satisfactorily for a long time. You, like Richard, is of the view this is likely to be a PSU II issue. Is a derogatory comment on Phono II build quality necessary?

Luca, is the poor sound quality on vinyl replay only or is there also poor sound on line level sources straight into Pre II, such as CDP, Tuner etc?

[bob orbell]

Is a derogatory comment on Phono II build quality necessary? In a word Greg, YES, of course, I will help Luca all I can with his problem, the comment was made because this hobby can be very dangerous to a novice builder, and this construction looks dangerous and very poor to me, also, how do you think other potential would be customers thinking of buying a kit from Matthew would react if this is what his finished kit is going to look like ? , I rest my case, if the moderators think my comments are inappropriate, them please remove. Bob

[Richard]

If the HT and Heater voltages are correct go on to check the circuit running voltages around the valves using the build instructions.

When it's powered off, check around for dry/poor solder joints and bad earth connections. Check the umbilical lead connections.

Then change valves etc, but now we are into an area which is more likely to affect just one channel.