Borbely EB-1198/116 FET Amplifier build @ Courtiestown

[Richard Lines]

Good Afternoon All,

This will be a slow burn project but I fancied building one of Erno Borbely FET designs so I've started accumulating bits. JFET's aren't getting any easier to find.

Regards

Richard

 

[Richard Lines]

Good Evening All,

The above parts were sourced from Taiwan. I have to say they were ordered accepting it was something of a 'gamble' but the PCB's are of a reasonable quality and the JFET's are matched so all is well.

I have one lot of capacitors sourced from a German eBay supplier and several more incoming from Banzai. I also have some Roederstein Resista Mk.3 resistors coming from another Taiwanese supplier. Courtesy of another PFM member I'm trying to source some Caddock MK132 resistors from a Californian based supplier. I've bought some JFET's via Donberg and some more from B + D.

If only the parts could all be sourced from the one place...........

Regards

Richard

 

[davidsrsb]

The chances that the jfets are anything like the 170/74 in characteristics are not very good.
The NOS stocks are more or less exhausted now

 

[Richard Lines]

The NOS stocks are more or less exhausted now

Indeed as are the other components specified in the above list.

Regards

Richard

 

[Richard Lines]

Good Evening All,

Just down to finding the Caddocks really now - it has been a way more expensive exercise than I was expecting...........

The amount of time spent locating items is ridiculous - it is fortunate that the nature of my work provides me more than its fair share of 'dead time'.............

Regards

Richard

 

[davidjt]

I can understand a wish to stick as closely as possible to the original BOM, but in 20yrs might not Vishay or Bourns have caught up sufficiently, and for a much smaller outlay? (OK, I'm a cheapskate. But a few caps and resistors from HFC still cost an arm and a leg!)

 

[Richard Lines]

@davidjt - I understand where you're coming from about the cost of some parts.

The Charcrofts in my SE boards cost £13.26 each and the 300uF wet tantalums cost £14.40 each.................

The 'genuine' 2SJ148's I have sourced cost £6.50 a piece and the 2SJ79's cost £9.10 a piece........

Regards

Richard

 

[Richard Lines]

Good Morning All,

The 2SJ148's have arrived:-

Tested:-

I did try to edit my post from yesterday but there appear to have been some changes on the site in recent days???? The actual cost of these devices is actually £8.74 each rather than the £6.50 quoted yesterday.

The 2SK982's tested OK as well:-

Ended up sourcing trimmers from RS as the Copal RJ5W devices don't seem to be stocked by anybody:-

Regards

Richard

 

[Richard Lines]

Good Evening All,

That's more components arrived today, all the FET devices test OK. The resistors are Roederstein Resista Mk.3's:-

There are still more to come from LittleDiode and some via a very kind American member facilitating a purchase in the USA.

Regards

Richard

 

[Richard Lines]

Good Afternoon All,

That's a package with a few more components arrived from the USA today:-

Will need to look at making a start at some point - works intervenes again and I'll be away tomorrow morning.

Regards

Richard

 

[Richard Lines]

Good afternoon all,

that's me making a start on building the PCB's - close examination of the PCB/ component listing shows this isn't exactly the same as the Erno Borbely original!!!!!!!

On the one hand I have a PCB and on the other the correct components for the original schematic........

I suspect finding original PCB's might be a challenge - will have to see if I can find an original article and create a new PCB..........

The larger, very red, PCB in the background is my Doug Self 2012 Elektor 5532 Pre-amplifier project - I'll start a separate thread for this.

Regards

Richard