Haigh Wobbulator is there sufficient interest for a PCB?

[Electronpusher0]

Originally Posted by vahakuja

Hello Peter,

Would it be possible to get one (or two) of PCB to Finland too?

Regards
Ake

Finland would be no problem, postage at cost.
At the moment I am only selling kits due to the difficulty in getting the coils.
I will add you to the list for a second batch if you like. I need to get the first board finished and tested and the current batch shipped first though.

Peter

[vahakuja]

Hello Peter,

Thanks for your message.
I am also interested in to buy one of your kits, so please add me onto your list.

Regards
Ake
**

[Electronpusher0]

OK Ake, I will do.
Looks like there will be sufficient interest for a second batch, after I have got the first one out of course.

Peter

[Electronpusher0]

The last components have now arrived. I was waiting for the Varicap diodes.

The first board is built and is being tested, the ramp generator is fully tested and working, now testing the rf section.

Meanwhile I have drawn an assembly drawing, I have tried to keep the look and feel of the original assembly drawing in the Haigh article.
The wires are drawn in Magenta, this makes it easy to see them if viewed or printed in colour but will still print clearly in B&W. see attached.

As soon as I have finished testing I will request payment and get the kits shipped. I don't want to take money until I am 100% confident there are no problems with the board.

Peter

[eddie_ce]

Hi Peter,

Happy New Year and thank you for all your time and effort put into this project.

I'm a bit late to the party, but if there is the chance of a second batch and you have spare capacity please consider me for a kit.

I will of course pay all additional postage costs to Germany.

[Max Power]

Excellent work

[Electronpusher0]

Sorry about the long delay in reporting progress.
It shows the value of testing the pcb before requesting money or shipping.

The rf section just would not oscillate, it was "squegging", it would start to oscillate but would swiftly decay to a flat line.
I was afraid that the problem was with the coils not providing enough feedback to sustain oscillation but after a lot of headscratching it turned out to a duff batch of 2n3819s!

I substituted a BF256 I had left over from the Minimod project and it burst into life.

I will be supplying BF256s in the kit. They work well but have a different pinout so a certain lead jiggling is required, see the attached photo.

The coils I sourced cover the required frequency ranges.

In the original Haigh article the secondary coils are connected in series with the primary to increase the inductance. In my pcb I have made the connection between the lower end of the primary and top end of the secondary a link to give maximum flexibility in the choice of coils.
If the link is not required the lower end of the Primary is linked on the track side of the board to the 0V track alongside. In the pcb I have just tested the 3 lower frequency coils do not require the secondary and the primary is linked to 0V, the top range coil works best with the secondary in series and the link is fitted to the top side of the board. See the picture.

Never fit the link and short the primary to 0V as this will short out the primary.
A certain amount of experimentation may be required.

I also managed to miss a short piece of track that links CN5 to C10 and C11, sorry about that but a short piece of tinned copper wire fixes the problem.
I will provide instructions in the kit.

That means that I am finally ready to request payment and can ship the kits when the FETs arrive which should be by the weekend.

Peter

[Sundog-]

Well done!
I seem to remember junction FETs of that era had big variations of pinch-off voltage.

[mole42uk]

Excellent work, I'm itching to get to grips with one....

[bc312]

Great stuff Peter - well done.

Mike

[cathoderay57]

Thanks Peter for your hard work. I'm thinking ahead to the enclosure and I have ordered one of these https://www.ebay.co.uk/itm/265409449440. My plan is to print the paper template for the control panel and mount it under a clear perspex sheet screwed to the top of the box. The box depth is 6cm which should be plenty for the board etc.I already had all the resistors and caps in stock, and ordered the remaining bits - a couple of pots, BNC sockets, knobs, mini SP switch and batteries from Bowood. They arrived very quickly, thanks to Will's prompt service. Jerry

[Electronpusher0]

The replacement FETs have arrived and I have posted all the kits!

I have included a print of the assembly drawing from Post #64 also some assembly notes (copy attached)

Please let me know they have arrived safely.

Peter

[ian_rodger]

Originally Posted by Electronpusher0

The replacement FETs have arrived and I have posted all the kits!

I have included a print of the assembly drawing from Post #64 also some assembly notes (copy attached)

Please let me know they have arrived safely.

Peter

Hi Peter,

I'm fairly sure that you don't have my address for posting, therefore I it looks like I have been left off your list (kit requested in post 43 of this thread). Hopefully not! Can you check please?

Thanks,

Ian

[Electronpusher0]

PM sent to Ian

Peter

[PaulR]

If I am not too late could I be added to the list for the second batch of kits please?

[Electronpusher0]

I may well do a second batch, if so I will correct the missing track.
I am also testing an add on to add a Z mod marker as the sweep passes the set mid frequency, if this is sucessful I will publish it. It comprises a dual op amp and some resistors. This can be assembled on vero board and connected to the current pcb to add the function.
Again if successful I will add the extra function to the pcb as a Mk2.

Watch this space as they say.

Peter

ps I have added Paul to the list for a possible 2nd batch

[mole42uk]

I would be very keen to add the Zmod marker.

[Freya]

received today with thanks

[mole42uk]

Kit received today, many thanks. It looks super, I'm impressed.

Richard

[Horris]

Received my kit today. Many thanks for all your hard work and professional presentation. Looking forward to building it.

Dave