audio-talk

Good to know.

OK so back on the 300b amp. I was uncomfortable with the 6j5 lack of load and rather larger ri caused by the lack of bypass cap. I also decided it was worth trying the 6em7 stage at higher than usual voltage but drop the current to 35 mA. That means I dont need to drop the b+ voltage. The 6j5 I ...

Well to be honest the 801a amp sounded pants compared to the EL38 triode connected SE amp. It had the hammond interstage transformers. That proves nothing but makes one aware of something.

So I went forward using srppcl and cant prove anything but it sounds bloody marvellous. The C’s are Siemans ...

My mate subscribes to the trade magazine "Osteopath Monthly".

He has a lot of back issues.

Nick wrote: Wed Dec 11, 2024 9:20 pm So remove the center tapped choke and use to resistors. Ok, standard PP driver stage. Not sure where the CCS's come into it?

At the b+ end two ccs one for each pole.

Ok that makes sense Nick. So is that where the ccs comes in you were talking about to Dave was it?

Max yes secondary left open.

Nick, so actually I could use a two power resistors of the value required and b+ to centre tap? Or just use the ccs and have a horizontal. Loadline?

Not that Im goingto ...

But in deciding the driver the 2a3 or px4 were outright winners. The 45 probably has other sound qualities to mitigated its distortion. But its ability to drive the grid of 300b may be insufficient for full output aswell. Its either Sukuma concept and use another 4 300b’s or use 2a3 types. My ...

I was about to build pp 300b but the 8 valves, I would have used 6b4g driver and the biggish pp opt’s used as ct choke for drivers, add to that the big Sowter opt’s. It was as big a boat anchor as an se GM70 SE. So changed my mind.

The bee in my bonnet is you guys all building pp amps full of ...

At one time Russian capacitors were highly thought of.

I have a pair of 4uf 630V PIO (although in this case the P in PIO is not paper).

They are almost identical to the Ebay listing below but mine are +/- 5%

If suitable for your needs I would donate them to your project. :)

https://www.ebay ...

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 ...