The Birth of the BHK 250 Power Amplifier


#1

After the initial circuit design of the BHK 250, the ever talented Bob Stadtherr designed the first circuit board and heatsink for me to debug and make work. Having this on my lab bench for while convinced me that I had made a pretty big mistake on the output stage and had to change it. See 1.jpg. As can be seen, considerable additional components and rewiring had to be done to make it work the way I wanted. 2.jpg is a closer look at the situation. After this, I got the second heat sink going. Next the tube input stage and associated circuitry was made to work as a separate AC operated unit. This is shown in 3.jpg. Now I am starting to assemble the amp as shown in 4.jpg. Further assembly to getting ready to listen and in 5.jpg and 6.jpg. In to my listening room and OMG, what have I wrought, it sounds great!

As a matter of interest, I had loaned this amp to a good friend for the past year or two. He recently passed away and I and others have taken on the task of selling off his extensive sound system. I have put this amp up for sale in that effort and if anyone might want to have it as a working historical item, let me know.

BHK


#2

Hello Bascom, I am wondering if its just me doing something wrong, as I can not see the pictures you mention in your recent post above regarding the Amp?


#3

Not just you, I cannot see pictures either.


#4

Wow, someone already finding this! I have asked Paul about how to get the pics into it. I will get them as soon as I figure how.

BHK


#5

Thank you Bascom!
I look forward to seeing them when you have them posted on the site!

Actually Bascom its very easy to post the pictures.

If you know where they are located on your computer then all one needs to do is click on the little" Mountain scene" just above one’s own reply text and a drop down menu will ask if you want to import them from a ‘file’ which you do.
Then click on the ‘from file’ button and then select the picture or pictures you want to up load to the site and give it a few moments and all will be good!

Try it and you will be surprised how easy it is to do.

Good luck and I look forward to seeing your lovely pictures.
Cheers,
Ian


#6

Well Thank you Ian, I will pics here . . .


#7

Outstanding Bascom!
I suspected you might be able to do it especially with a little guidance to get you started.
I am pleased to be of assistance to you, and now we all are able to see your work in ‘picture-form’ .
Thank you for posting them.

Best regards,
Ian