Wad kit88

[Fred Shaw]

Hi, a bit of a long shot, but has anyone converted a KIT88 from PCB to hard wired. I have a KIT88 I constructed in 2001 which is now in need of a refurbishment as a number of tracks have lifted and the amp has a hum which is proving difficult to cure. John Caswell has used his magic on it a couple of times, but the hum always returns after a few hours of home use. As a project I would like to remove the PCB and hard wire it. I can (mostly!) follow instructions and solder components, but no way would I be able to redesign the circuit layout to fit the existing chassis.

If anyone has converted the amp from PCB to hard wired, I will be keen to hear from them.

Fred.

[bob orbell]

Of course it is posible to compleatly hard wire the curcuit in to tag boards, but I think you have aswered your own question Fred, it will not be simple. Would it be posible for you to hard wire the broken tracks from poin to point ? this may be your best option if the PCB is single sided as you will not have to remove the PCB, however, if it is double sided then that involves more work, sorry I can't be more helpfull, best of luck. Bob

[Fred Shaw]

Hi Bob,
There are a number of wires already soldered point to point and, if my memory serves me correctly, the board is double sided. (It is over a year since I last did any work on it so I could be mistaken!). I don’t expect converting it to be easy but it would be a good project - albeit one with lots of help from the World Designs community. Do you think the layout of the WD88, ie tag strip positioning etc, would be close enough to the WAD KIT88 layout to be a good starting point for a redesign?

Fred.

[Greg.]

The WAD KiT/KaT88 amps had a double sided PCB.

Additional space can be created within the chassis by moving the toroidal mains transformer to the chassis top and fitting a suitable cover for aesthetics.

[bob orbell]

Hi Fred, the layout does not matter too much as long as it fits in neatly, the WA88 has one input tag board, two driver boards two boards for the output stage and two half size boards for HT and the heaters. You need to do some kind of simple drawing, IE, all valves will need to remain in the same place, this should be quite simple to fit valve bases to the chassis and work from the curcuit diagram in blocks. A scetch of the stages will help you sort the place for the tag boards. Please keep us posted if you proceed and good luck. Bob

[Fred Shaw]

Thanks Bob & Greg for your views & advice. I think it’s time to really consider my options before starting something I may not be able to finish!!

[Greg.]

Fred, if you think it helpful, I can send you a set of instructions and diagrams for a WAD kit that has a tag board construction. You could then use them to learn how a schematic is transposed into the physical tag board method to guide you drawing up a conversion for your KiT/ KaT88. PM me your email address if you would like this. If nothing else, it’ll confirm if you have the capability for the task required.

[Fred Shaw]

Greg, many thanks for the information on the KIT6550. The diagrams will be very useful in planning the KIT88 layout. I can see it taking me a while just to draw up the component positions!! The build instructions will also be extremely useful if and when I decide I can confidently go ahead.

[Phil Y]

This is something I have been considering as well, the PCB in my Kat88 is in a similar tired state(as I expect most of them are by now!). I have had a few dry joint related problems lately and so have been inside a few times. In the long run a solution will be needed I think.

Keep us updated Fred☺

Phil.

[Fred Shaw]

Phil,

At the moment I’m just trying to relate the KIT88 circuit to the WAD6550 circuit, and plan of the hard wiring, kindly sent to me by Greg. I sense it may be quite a while before I have anything resembling a practical KIT88 layout. I’ll keep you updated.

Fred.