Hi,
My friend gave me a load of spare parts because he married a beautiful girl and spends more timeto that girl.
I desided to use those parts and build a amplifire like K 8060 because I’ve build already six of these.
So I toke a pice of pertinax for PCB and enlarged the drawing (schematic) from the manual of one K 8060.
I placed all the parts on theright place and drilled with 1 mm. the holes in the PCB and connected these parts point to point.I had already an oversized heatsink and everything seamed to go wel.
While I was soldering the pars Iooked on the drawing and thought how can it be that only resistor 12 (1 K 5 ) and cap.
10 (100 u/ 50v.) are positioned between + 40v. and the L.S. terminal.
And yes after connecting all the parts on the right place (After testing with the Bulb 60W. Led glows) i messuered about 34 volts between L.S.Terminal + and ground. Nothing became hot, no humble from transformer, led stays on and over zener 9v. Bias was not posible to adjust.
I realise that it is not fair to build like an onofficial way , but I wanted to try.
My question is : Is the drawing right or is it totaly not posible to build like point to point.
You may burn me down , but please try to explain wat’s wrong.
Grtz: ferdiL
After rebuilding the amplifire I reduced the voltage on the L.S. terminals till 0,156 V.
But still the bias is not adjustable.
I checked every solderconnection and it seemes wel.
I decided not to worry and I’ll go on trying to get the thing playing like I wish.
One thing I learned : The best is to use excact the right parts and forget to try it with parts witch are look a like.
TILL LATER : FerdiL
Yes, the amplifire is working correctly ; there was one transistor not like we are used to have.
Some one changed basis and emitter. I’ve replaced it for a Philips tor and wonder on wonder : nothing had damaged and the bias was adjustable very wel. I adjusted the bias on 10,5 mv. and connected a big loudspeaker of Philips wich they don’t make anymore (Shame). What a beautiful sound I got.
So if you dont find an answer for your problems, please take some more time and an universal-meter and take every part to meassure.
I must say that even the diagram makes it posible to make an amplfire without hums or not wanted other noices.
Think wel before you start to build an amp like point to point : it’s not cheaper than buy a complete kit.
You dont have to think about twisting wires and where to place the tip’s and so on.
I stil have to build 5 other amps, so I think to buy 5 kit’s
Keep in touch: FerdiL
Hi Ferdil
I just saw your post. Are you going to try to install more than one amp in a single chassis? If so you may want to check out my posts. There appear to be grounding limitations if you install more than one. It seems like they need to be completely isolated, which seems a challenge especially if you are trying to manage mains hum.