A Few Pix From My BGW 103 Build...

[Loud & Clear]

I had a bunch of pictures, but here are a few. This is a BGW 103 studio preamp. There are a few pictures before & After. Thought I would post them just for the heck of it...

The preamp sound "Great". It was a lot of work!

[tcorrea]

Wow... I always wanted to see pics of the production version of the 103 Preamp. I am glad to here you like it. I am the original designer of this preamp from 1977. I did this design when I was twenty four, back in the late 70's. I still have the original prototype of this preamp and it still works fine. It is interesting to see how the design was modified since I left BGW shortly after this was designed. My original prototype has round push buttons instead of the rectangular ones used with the Model 203. My tone control knobs are the same size as the balance and volume control knobs. At the time LEDs that were colors, other then red, were very expensive, so were not used. This preamp was supposed to be a less expensive version of the 203 preamp, which I also have and still use. Looking at the PC board...It is interesting what was changed.. the phono stage is rotated 90 degrees.. the relay that connected the preamp output to the external amp with a delay has been removed... the power supply section is a bit different... My toroid transformer is incapsulated not left almost bare... the adjustable input capacitance for the phone stage was added.. You might notice that the layout of each section is basically a mirror image. Left channel is a mirror of the right channel. The other thing I was trying to do was to eliminate "wires". On my proto, the toroid connects the the board right at the transformer.. the headphone jack wired in right next to the jack. I have no long wires. The hardest part were the jacks on the back. I would have preferred the way the IO's are done on the 203, but that is more expensive. You may also notice this is a single sided board and not multi-layer. More cost savings. I layed out the original board by hand with tape, no computers doing that then. The interesting thing was... the measured preformance on the bench was better then the BGW model 203, although the tone control and filter section are from the 203. The phono stage was new and better as was the line out amp section. I wish you had taken a photo of the back side of the board. I had labels added to identify the various sections as well as where the inputs and outputs were on the circuit etch..... I bet they even removed my initials from the board....haha...

Anyway I am glad it has made it through the last 35 years..... OH one other thing... might be a coicidence.... I also built my own speaker cabnets, back in my college days, which I still used today.... the just happen to use the JBL slot tweeter, the 375 driver with the same potatoe masher slant plate and the 2215 15" woofer... but with active crossover instead of passive..

Thanks for posting the picks..

[nigelwright7557]

I think I would have soft wired the RCA sockets.
If the unit is moved around those solid wires might start to crack with any movement in the chassis.

[tcorrea]

True.... but at the time, my mandate was to keep costs down also. I believe there was a PC mounted jack style that was right angle to the board, but these we more expensive. If you see a picture of the Model 203 preamp, the jacks are mounted directly to the PC board with no wires at all. This works but makes the chassis fab more intricate, thus increasing costs again. I had other ideas, but I left about that time.

[theremin]

Hello everyone, I'm a newbie here. I have a BGW 203 preamp and a couple of BGW 410 amps and while they are clean and powerful, I'd like them to be more musical. I know this is a tough thing to quantify but my Mcintosh gear, all SS, has a musicality the BGW stuff is missing. Any suggestions for upgrades? I understand the power supply on the amps isn't the best. Is this true?

Thanks
Steve

[vancao]

Originally Posted by tcorrea

Wow... I always wanted to see pics of the production version of the 103 Preamp. I am glad to here you like it. I am the original designer of this preamp from 1977. I did this design when I was twenty four, back in the late 70's. I still have the original prototype of this preamp and it still works fine. .

Tcorrea
great to know that you were a member of the BGW design team. I recently got a 85D amp but could not find any single tech info of this model. Do you have any piece of docs of the one. Thanks for sharing, in advance.