WAD v, WD

[david.rogers]

I'm hoping someone can lighten my darkness. My problem is that some of my equipment and components is at one house, and some at the other. Trying to sort out what I have here (here being near Oxford) I find some components for the WD Pre and a circuit board stamped as WADPre II. I have the circuit diagram for the WD Pre, which is quite different from the WAD, which appears to be a single valve (6922) design. Did WAD morph into WD? If so, what happened to the WAD designs? And can I use the WAD board (without significant deterioration in performance)?

Thanks
David

[Phil Y]

http://www.world-designs.co.uk/forum/showthread.php?t=2

[Richard]

Hi David, yes the morphing as Phil links to.

Phono2 and 3 were very similar and the first Phono3 used the Phono2.2 pcb.

Pre2 and 3 were very different in circuit, valves and OPTX so need to go together as a set.

The 2 series used the large Cliff umbilical connectors and the 3 used a smaller type who's name escapes me. Bob may know more as I only built the 3 but I think he had both

[bob orbell]

David, the II series used Cliff-con connectors and the III series uses Binder 678 series connectors available from Farnell , the two are not interchangeable, the holes in the case are very different in size, in my opinion the Pre II is bloody rubbish compared to the Pre III, although, I ask, do we need any gain at all to drive WAD or WD power amps, for this very reason, WD ( Matthew Snell, very nice chap ) now does a cathode follower Pre. If you need more history of WAD and WD go to the bottom of the page, on the right and click on World- Designs and follow through to history. I hope this helps you, by the way, the Pre II also needs two output transformers, these are very different from the III. Bob

[david.rogers]

Originally Posted by bob orbell

An update to Richards part no's 9906150005 Farnell no is now 2949826
and RS Components now stock them 5 pin no's 129-8523
129-8804
129-8753
129-8472
Bob

Thanks for your inputs, guys. I obviously didn't explain myself properly. What I have is the WAD II circuit board, which seems very similar to the layout of the WD3 Pre layout, except it uses a single 6922 valve, with both channels on the same board. I was just wondering if anyone has experience of this board and its performance.

David

[bob orbell]

David, if you are asking about the pre II board with the single 6922, my opinion it is rubbish, I had one many years ago, it was very bass light it coursed hum and the gain was massive, 12 dB, the III with two ECC 82 valve's is a different circuit with again different transformers and a choice of 6 or 12 dB gain. Bob

[Richard]

Hi David, It sounds like you have Pre2. If you PM me your direct email I can send Pre2 and Pre3 build sheets with circuits so you can sort it out.

[Richard]

Following Bob's comments David if you've not yet built yours, it's fair to say Pre2 was good for many builders and problems really only apply if it has too much gain for your power amp and/or your rack layout means it picks up hum from a nearbye mains TX.

If you've not seen it, Neal Gibbons wrote up a neat FAQ to easily convert it to a cathode follower in the style of the original WAD Line Pre (June 1993 for anyone with the Supplement Disc and Morgan Jones). He details an easy rewire along with removal of the OPTxs which leaves it without gain or hum using the original power supply,

http://www.world-designs.co.uk/forum...ead.php?t=7632

[david.rogers]

Thanks Richard. I'm

[Richard]

Thanks David, I removed your email address to save it from the spam bots.