30-01-2018, 06:55 AM
Construction is terrible, but now I have it going the right way I'll tidy it up. I couldn't find any HF or VHF osc yesterday.
After some alteration's resulting in going backwards I got progress of sorts on the amp and got 8v RMS out of it (8 virtual watts) yesterday at 0.7% THD. However the OPT I have isn't optimal, I had to bung a 23 ohm load too bump the Z pri up to 11k to squeeze that out.
Also bunged a speaker on the other end, it sounds ok but didn't result in a silly grin. However there's no hum or hiss and scoping the anodes of the 2C34 and OP shows no nasties. I had to put the 10x magnifier on (0.001v/div) to find anything. This showed some spikes and 50hz but no HF of VHF osc.
My big PSU has some nasty spikes on it, but it is a triac controlled PSU. It makes some odd noises too. It bangs and clicks.
I think there's an impedance issue between CF's and OP valve, will have another go at it today, have a few ideas.
A.
After some alteration's resulting in going backwards I got progress of sorts on the amp and got 8v RMS out of it (8 virtual watts) yesterday at 0.7% THD. However the OPT I have isn't optimal, I had to bung a 23 ohm load too bump the Z pri up to 11k to squeeze that out.
Also bunged a speaker on the other end, it sounds ok but didn't result in a silly grin. However there's no hum or hiss and scoping the anodes of the 2C34 and OP shows no nasties. I had to put the 10x magnifier on (0.001v/div) to find anything. This showed some spikes and 50hz but no HF of VHF osc.
My big PSU has some nasty spikes on it, but it is a triac controlled PSU. It makes some odd noises too. It bangs and clicks.
I think there's an impedance issue between CF's and OP valve, will have another go at it today, have a few ideas.
A.
