audio-talk

would keep the EL84 if you dont have the 45’s. I looked at the driver stage for myself and the 6v6 was more distorted If I do push pull every stage would have to have very low 3rd h distortion. EL84 is a good one. In my own case though I found 2a3 most optimal driver, and thats what I would use ...

At last the bus came. In the kit bag two RCore OPT’s two 833’s one TY4-400. I couldn’t fit the RY81’s pair in. The 833’s have awakened fond memories!

Some of these items are on my bucket list!

Another change of direction then because you are right, too much heat.

Maybe 🤔 try find other R Cores and go back to 300b SE, 8 watts on this chassis. The push pull concept I thought up involves too much big iron.

So a bus ride to Flixton where lockup is. If I find the r cores Theyll go in my ...

A picture tells a thousand words.

OK Chatting to Victor at Victors Vintage on Falsgrave Rd Scarborough.

https://i.postimg.cc/9QWgXtvV/IMG-1692.jpg


It turns out that this valve line up is where I have returned. The whole push pull 300b idea gets me 20 watts. But so does an SE GM70.

With this simpler circuit the GM70 ...

I bought a d&r electronic mm phono stage. Broadcast quality for £75 on ebay. Best phono stage Ive ever auditioned at home. I had upgraded ear phono stage, the wad phono stage, some cheap ecc83 phono stages, and one fet phono stage oh and I built True Realism phono stages. Out of all those the only ...

The 2nd h at the 27 operating point is 1.5%.

So thats the line up per channel one 27 one 6J5 two 6b4g pp two 300b pp.(I have another Nightingale top plate punched so that may take all the signal stuff, but I dont know where its plinth is. But could get a plinth made. Though it may turn up.)
Have ...

So the 3rd harmonic of the 6b4g is 0.11

Not only have the 50k rule been neglected but perhaps many circuits are shortening the life of the valves through paracitic oscillation neglected.

I think you are tilting at windmills there. The minimum grid resistance will be in the case of fixed bias, and why would any oscillation due to ...

With a bias of 63v the PX4 or 6b4g on my investigations so far are optimal. 0.1 3rd h.

6J5 poor but mainly because the choke load Id be using was wound for el34.

I am happy I can use 6b4g. 10y wasnt quite as good and anyway wouldnt match the choke.

So My linup looks like 27 to 6j5 concertina to ...

That means in my case I have to check 3rd h at every stage, which is fortunately only the driver and the output stage. So the driver must operate in it’s sweet spot and not run into its dubious zone, so in PP that exceeding the bare minimum to keep driving the 3rd will get nasty. In short, more head ...

The 300b looks OK for 20 Watts class A1 push pull.

https://i.ibb.co/HVHwRj2/IMG-1818.png

I looked at the px4, 8 watts. I’ll not do that.


For Max searching out lowest PP distortion.

The operating point if the amp with 8k peak to peak transformers only stands if the loudspeakers are 8ohm. My ...

I like the way Marco explained the turns ratio of the OPT you might have wound yourself in those days.

https://i.ibb.co/7QsbV9w/IMG-1820.png

Both manufacturers recommend “automatic bias”

I have seen somewhere but cant find it, the max grid resistance for PX25 like WE.state for the 300b 50 k ...