Just received this innocuous lump from Hong Kong. Wonder what's inside?

lump is right - it is almost beaten into a sphere.

I agree, not a pretty sight.

The chassis made it across the pond ok though.

Good thing they double boxed it with an inch of hard foam around the inner box.

_{A case of case hardening?}

Before anyone asks - those are pain killers on the left, vitamins on the right.

Below is a pic of the rough layout.

The boards will have a gap between them, the left amp pcb shifted back so the overall tube footprint forms a rectangle.

The psu pcb will be stood off higher than the amp boards with about a half inch of overlap above the amp boards.

Still waiting on the heatsink delivery.

The new soldering station showed up on the doorstep yesterday along with a lighted gooseneck magnifying glass.

Started stuffing boards with resistors last night. Now it's time to find the ideal soldering temp, then go to town with Mr Kester.

Are you building it with the 1968 ccs?

Nope.

I would not build the BH if I had to deal with that.

I have some CCS that Nattonrice made.

See posts #9 and #11.

memory blanked out, sorry

I saw your pic of the old boards and thought, sure hope he has a stash of them

So, it's been a month since I posted on my necrofied thread.

Amp and PSU boards are stuffed, undergoing soldering.

The populated CCS boards are now mounted on the heatsinks, the chassis top-plate has been drilled swiss cheese style.

The bottom "drawer" has the trafos mounted along with the input & output jacks and IEC module.

Still waiting for my 50K Alpha Quad to arrive....

I'll post pics soon when I find my camera.

My daughters have a nasty habit of borrowing it and not bringing it back. Hmmm?

Edited September 25, 201213 yr by livewire

Most exiting follow your BH project.

My you tell why you choose ccs 10m90s and not the 1968 version?

#1) Lower cost. The 1968s are becoming rare and their price reflects that.

#2) Availability. If my CCS burns up in the future, hopefully the 10m90s wil be in abundant supply. The 1968s wont be.

#3) Reliability. I've heard of strings of 1968 transistors burning out. Not one, but a bunch of them.

#4) Ease of construction. Drilling, tapping and aligning (6) 4-40 holes into the heatsinks is much less work than the 30 required for the A1968s.

#5) HeadAmp uses them.

The current version of the BHSE uses a similar CCS. Seems to me to be a natural evolution in circuit design. And a good one at that.

Edited September 26, 201213 yr by livewire

Thanks for sharing your considerations about the CCS.

Livewire, just for knowledge what were the changes you had to make to the circuit to accomodate the use of the 10m90s in place of the 1968? I beleive that in the KGSShv the were some difference for both the resistor and diode values.

Edited September 26, 201213 yr by Victor Chew

Since the newer CCS circuit layout has not been published by the designers, I wont divulge the schematic without their consent.

Nattonrice did post some pictures of his KGBH build in the HC DIY forum. One can see which parts have been omitted on the amp boards.

Gone are the 1968s, the 500 ohm pull up resistors, the two series LEDs and the 400K resistor that connected to the bases of the 1968s.

I can be stupid when it comes to linking threads.

To see his pics, look in the 'DIY amp and such build gallery' thread, page 212 - post #4239

Edited September 27, 201213 yr by livewire

Update - This project is on hold until I have the mula to buy more sand.

I hate when stuff is lost.

I was going to take some in-progress pics after I found my "lost" camera.

Turns out my daughter borrowed the cam and lost the USB adapter cable.

Got the camera back but haven't been able to upload nuttin.

Recently I lost a bag of pricey $$$ sand I had bought from BDent for the KGBH.

No money in the budget to replace it at this time.

Prolly wont be until the end of Feb until I can scrape the funds together to replenish.

Hoping that I will be able to find the lost parts in the meantime.

Meanwhile, there's a few other DIY projects that i'm pursuing.

Currently building a 1974 vintage Mark-8 "minicompter".

There's also a 1971 Kenbak-1 in the works too. This design pre-dated microprocessor chips.

Still need to find a pcb or some gerbers for the Kenbak.

Failing that, perfboard with wirewrap is an option.

The necromancy continues...

 

After four months of searching in vain, I found my bag of lost BH sand.

It was shoved into a shopping bag of Home Depot door parts that was bought around the same time.

My daughter was cleaning the living room and rearranged all my stuff, and put it elsewhere.

Got lucky for waiting and saved ~$170. (repurchase cost)

 

Time to get this project back on track.

Almost done stuffing the boards, will post pics in a day or two.

Glad you found the stash.

Really look forward to see your build.

Did you have a hard time finding any of the sands? I assume some of them are EOL?

Congrat on your find, and best of luck with the BH.  Truly a wonderful amplifier.

Thanks Al. Can't wait to hear it sing!

Really look forward to see your build.

Did you have a hard time finding any of the sands? I assume some of them are EOL?

 

Wasn't hard to find when I bought them almost a year ago.

Yes, they are all EOL, I sourced them through B&D.

One of the transistors is no longer available at B&D, the only source is through a Chinese distributor on ebay.

Didn't want to go that route with all the fakes being sold these days.

Edited March 20, 201313 yr by livewire

Most of the sand for the original BH is either all gone or almost gone. 

True dat! Although we know that you got a stash! 

Well somebody has to keep some in stock for the apocalypse.  I also have some BH's to build...