WD88VA noise

[Riggers]

Hi All,
I have recently completed my WD88VA xl version with single input and no volume control. I picked up a couple of dry solder joints (links on tag boards) during testing which were responsible for an obvious buzz or noise on one channel only. That sorted, I have plugged in the amp for some more long term listening. Firstly, let me say that it sounds superb. The only niggle I have now is that once the amp has warmed up, (say after 5-10 minutes) i can barely hear a slight "tick" noise occurring at a regular interval of 3 seconds or so. It is only detectable when you listen for it, (i.e. like a vinyl LP which is almost in perfect condition but with a slight amount of surface noise).

I have completed the build this week and was wondering if the weather in my part of the world (rain, mid 30's temps and 90%+ humidity) may be an influence, or would the recurring nature of the noise indicate a capacitor fault? If so , which one?

A minor niggle but I would appreciate your help.

Cheers

Phil.

[Riggers]

As a quick addendum, the tick noise is on the right channel only.

[Riggers]

After checking and resoldering a couple of joints, the noise is in fact both channels, sorry for confusion. It still takes around 5-10 minutes of the amp powered up for the noise to appear, a recurring tick noise every few seconds or so.

[bob orbell]

Hi Phil, 30 deg, , we are only at 5-8 deg, , I think your ticking noise may be something arcing, possibly in the HT, somewhere, the only test I can suggest is to remove all three small valves, switch on and see if the tick is there or not, if it is the problem is in the power valve area. I assume that you have done all the voltage tests and all are within spec. BOB

[John Caswell]

Hi Phil,
Check the the covers/cores of the three transformers, power and output, are all connected to chassis as we had problems of static build up earlier on.
You might even be able to see it flashover in the dark. It is NOT dangerous!

John

[bob orbell]

Yes, I remember now I had a similar problem with mine, I connected three leads from earth post to one bolt on each transformer using star washers to get a good connection, sorted. BOB

[Riggers]

Hi Bob,
That sounds like a plan. I'll give it a go in the morning and post back results.
Cheers
Phil.

[Riggers]

just a quick note, off topic. It's really cool how when I power off the amp, the voice speaking on the radio tuner fades gradually off into the distance. It takes me back 40 odd years and listening to my Grandfather's radiogram ;-)

[david]

Sounds like static from the transformer core //covers to me as others have said. My 300b clone started doing it recently, easily sorted by the aforementioned earth wires from tx covers to earth post!

[Riggers]

Hi All
An update. i have connected earth wires from one bolt of each optx to the chassis earth post. I did this internally David, (I'm not sure by your post if you were implying that you connected these wires externally from the top of each Tx under the cover from a corner bolt?? I also scraped a little of the coating from the tx where the cover rests on the tx and added a thin washer at that point. The mains tx already is connect to the earth post as per plans.

Result, the static faint "tick" occurs every 10 seconds now, not every 2-3 seconds. So I think that i am on the right track. I will try the scraping of coating from the top of the mains tx and fit a washer there under the cover in the bolt hole. i will also change all these earth wire washers to star washes.
i will update soon.
phil.