WD Pre III CF

[bob orbell]

Hi all, has anyone purchased the new Per III CF yet, it would be nice to hear any reports. Bob

[MarkL]

Hi Bob, I've just ordered mine from Matthew to do a conversion from my pre2. Will let you know how I get on!

[bob orbell]

Thank's Mark, there has been a lot of topics on here about CF's, I too had a Pre II, horrid thing, so converted to CF and very pleased, I then moved on to a Akidio CF in Pre III case and this is bloody good, please post some pictures as you proceed and let others know how you find it. Bob

[colin.hepburn]

Hi All
Yes I two have the CF, converted by BOB. At the time which I then purchased from him still working well with a Russian 6N1P. EV. in it sounds very good better than the 6922 in my system which is all single ended Amp 6SL7/KT66

Yes Mark, pleas post your build of the Pre III CF, for us all

PS. BOB. I would be interested in your views on the Akidio. CF comparing it with the WD CF. II. as I my look in to this one as well
Thanks
Colin

[bikerhifinut]

I use the John Broskie Aikido CF, built on his PCB and using the recommended resistor values for ECC82/12AU7. I think its a bloody good bit of kit, does what it says on the tin and i'd agree with JB in that the design of the circuit that uses each individaul valves non linearity against itself in a clever bit of correction, makes it pretty much immune to Valve variations. I've bunged a pair of no name Chinese 12AU7 in just recently after I swapped the mundane alps RK116 motorised pot for a RK127 "Blue" and they are every bit as good as the mullards and sylvanias I had in before, in fact better as they don't exhibit the odd rustle or other noise as I suspect the NOS valves probaby weren't.....................
This is what I want from a cathode follower, no coloration, no "added extras" just a nice well balanced sound from having a decent impedance match to power amps, a CF should be able to drive a transistor amp with input impedances of 10k or sometimes a bit less, and this one does.
As to any improvement over the standard "Bootstrapped" Cathode follower, I am not so sure. I think it would be very difficult to tell any difference.
I see the WD board has an option to use a CCS load which may or may not make a difference. There are reasons why an active load isn't always a good idea on a CF. Morgan Jones explains the issues well but it isnt quite so Black and white as is so often the case.
I use the ECC82 because as it draws a bit more current, and I hope I understood the theory here, which gives it a better drive especially into longer cables. They're also cheap as chips compared to the ECC88 and derivatives and I'm afraid I have an irrational bias against that Valve based on the fact its a VHF RF amplifying valve by design and I figure it could give HF instability issues if allowed to "sing". This could explain perhaps why some ECC88/6922 etc etc etc can sound very different to thers especially if the circuit design and layout can give rise to HF/RF oscillations.
I'd expect the WD CF to be just as good at the very least as the Aikido and it will have a well designed PCB that takes into account the instability potential noted earlier.
My take on it is that any properly designed CF circuit will be neutral sounding and simply just do its job of buffering an input without drama.

A.

[bikerhifinut]

Just a thought Colin, but the costs of JB's circuit boards and bits have increased of late due to a lot of factors and without actually knowing matthews prices, I'd hazard a guess that he'll be a lot cheaper for the official WD CF board and it'll be a virtual "Drop in" to the Pre2/3 case. And you can be sure that it will work "out of the box" so to speak.

A.

[bob orbell]

Colin, I think Andy has answered your question to me, for the record, I am using Mullard E88CC gold pin in mine, ( thank you JC ) and it really is a very good product, from memory, I paid about £78.00, I got hit by customs , but even at £100.00 it would be worth it, shame my hearing is now very poor . Bob

[colin.hepburn]

Originally Posted by bob orbell

Colin, I think Andy has answered your question to me, for the record, I am using Mullard E88CC gold pin in mine, ( thank you JC ) and it really is a very good product, from memory, I paid about £78.00, I got hit by customs , but even at £100.00 it would be worth it, shame my hearing is now very poor . Bob

Hi Andy/Bob
Yep thanks was just after a general view about the Aikido I have considered it before but still happy with the WAD CF but maybe could do with a bit more gain for the single ended amp

But first I think my plain is to upgrade the WAD PSU II with a voltage regulator supply?. And see if I can get a Phono III Case from Matthew for my Phono III PCB I forgot I had
Colin

[MarkL]

OK, weather has broken, so construction has started. Pre-op photo enclosed.
Pre2 always sounded quite nice to me. Was better with a Mullard valve and Black Gates. Circuit board was hard wired underneath as the tracks peeled off.

Other photo is the new board with the stand-offs fitted( just to make sure it did fit!)

[MarkL]

Here is the populated circuit board,(not sure how I feel about people seeing my soldering!)