WD88VA commissioning problems

[bikerhifinut]

Ok Guys I posted on the thread concerning my progress through the build.
However maybe this is the correct forum.
Basically the amp has 2 problems, which may be connected.
There appears to be a hiss and crackle on switch on which settles down after a while to warm up.
The 5687 Voltages are out, One is ok theother ain't.
Stop press: I just swopped 'em round and the fault replicates on the other channel, along with the marginal instability.................... BINGO! Can I have a new 5687 please Mr world designs?
Peter, would it be too much to ask that you test the valves prior to shipment of the kit? I appreciate that its a bit of a chore, but it would have made my satisfaction so complete at being able to listen to the ampafter the first fire up! There can't be anything fundamentally wrong with the instructions if the amp fires up and measures mostly ok on first switch on.
Now to trawl the net for 5687's to play with, they seem inexpensive valves.

Andy

[bikerhifinut]

Just a thought:-
is there any mileage in showing Voltage values at other points in the circuit?
I realise its such a simple circuit that the values shown will point pretty much the direction to chase a fault.
Just curious.

Andy

[bikerhifinut]

Did anybody who build a wd88va have problems fitting the LED lens in the front panel. Its just too big to fit the hole. Before i resort to drill surgery am I doing ssomething wrong? Is there a knack or have I just been sold a duff front panel or lens?

Andy.

[Dave the bass]

Hi Andy,

I just followed the instructions, the Lens seemed to fit fine on mine although I seem to remeber I put a tiny blob of Evostick on the holder to secure it.

We usually use a blob of clear silicone sealant on such constructions at work but I didn't have any to hand.

Sorry to hear of your Valve trouble. Thats rare in the WD88VA from what other builders have posted here.

Its a lovely amp.

DTB

[bikerhifinut]

Originally Posted by Dave the bass

Hi Andy,

I just followed the instructions, the Lens seemed to fit fine on mine although I seem to remeber I put a tiny blob of Evostick on the holder to secure it.

We usually use a blob of clear silicone sealant on such constructions at work but I didn't have any to hand.

Sorry to hear of your Valve trouble. Thats rare in the WD88VA from what other builders have posted here.

Its a lovely amp.

DTB

I measured the hole it was 2mm not 3mm. so I drilled it out to 3mm and the lens still didnt fit
so i shaved a bit off till it was a tight push fit. Works fine now.
Yeah the valve was a bummer its definitely off spec, even so tahe amp sounds quite nice, loadsa bass! but one channel definitely a bit down on whatever side i bung the dodgy 5687 in.
Also anyone noticed how the infrasonic bits off LP modulate the psu? Can see it on the LED flickering. I will need to make a filter I think to roll off the bass from LPs The old trick of a smaller coupling cap from the preamp might work.
otherwise so far theres a lot of potential in the amp. I'm prefferring it already fed from the active pre. The sound balance is warmer due to the 12B4 sonic signature. But The bass is still incredible i never realised Monitor Audio MA3's could go that low! And no doubt about it, vinyl sounds so much nicer a lovely rounded sound. Except I can hear more bad pressing faults than before, i thought that would have been more preamp than power amp but there it is.
Now all i need is my chrome knob, a new 5687, and a couple of other bits. oh the left channel is slightly noisy, and the right is completely silent. not enough to worry me though.
So now to knock up some interconnects with the remaining metre of soniqs ICT and a set with the blue silicone stuff i should have used instead of soniqs ICT inside the amp!
Andy