UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Wireless World April 1969 Amplifier Kit. 2N3055 Transistors.

AndyAmp1970 · 24th Nov 2021, 11:40 am

Open and Honest Update: I managed to get the one channel working last night. I re-drilled the clearance holes in the heatsink (aluminium angle). so that it was isolated from the screw passing through it.

Well it worked for about 5 minutes, sounding crisp, powerful and concise, although not as loud as I would have liked when I cranked the source (mobile phone headphone output) up to full volume.

Current draw was about 1A at this point - on a single channel.

In the 6th minute I heard fizzle and a pop, then silence. I guess I have now cooked the 2N3055, due to insufficient heat sinking. I will order some replacement 2N3055's and a beefier finned heatsink.

How can I get more volume? I am using an 8ohm speaker. and running the Bench PSU at 24Vdc

24th Nov 2021, 11:40 am	#9
AndyAmp1970 Diode Join Date: Nov 2021 Location: Kessingland, Sufffolk, UK. Posts: 3	Re: Wireless World April 1969 Amplifier Kit. 2N3055 Transistors. Open and Honest Update: I managed to get the one channel working last night. I re-drilled the clearance holes in the heatsink (aluminium angle). so that it was isolated from the screw passing through it. Well it worked for about 5 minutes, sounding crisp, powerful and concise, although not as loud as I would have liked when I cranked the source (mobile phone headphone output) up to full volume. Current draw was about 1A at this point - on a single channel. In the 6th minute I heard fizzle and a pop, then silence. I guess I have now cooked the 2N3055, due to insufficient heat sinking. I will order some replacement 2N3055's and a beefier finned heatsink. How can I get more volume? I am using an 8ohm speaker. and running the Bench PSU at 24Vdc