audio-talk

I think that the anode ccs’s don’t keep the cathode current constant because signal current flows through the load?
If you have a single shared cathode resistor then the current through that might be constant?

I was using the same load for all valves, so there is the reason for more distortion from the 45, it requires a higher impedance load. But when I was measuring distortion its was for a specific opt as a choke load. So to get realistic comparrison I cant change the load. So unless you buy a IT ...

Thanks for wading in, all input is useful :D
I don't actually have much to add except that I think a good cap can sound better than a bad transformer - apologies for stating the obvious.....


Yes. I would add to that, even if you have a decent transformer, it might not be the right place for ...

Did I miss the thread on the humane mouse trap in everyone’s projects

DOHHH! Ignore the above - I must have missed that post in Nothing in Particular….

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 ...

andrew Ivimey wrote: Tue Dec 10, 2024 8:07 pm I went back to 45s. And this is where lundhal 1660 ( offered the Amity/Karna) came in; simple single triode input through 1660 to 45push pull output- it was more than enough - glorious ( but I doubt its remembered at Owston )

I remember it well….very shoddy!

What does the phase look like?

One possibility would be monolith magnetics, either IT-02, ITA-02 or ITX-02
Tell them you are going parafeed so you will need access to four terminals on the primary. Also four terminals on the secondary if you want to bias the output tubes separately?
Also discuss if you want a gap - probably gap ...

Paul Barker wrote: Sat Dec 07, 2024 9:09 am Stephie started balanced and output tube was single ended. 845. What am I saying? The blend can go either way.

Good point. Avoids the phase splitter. Do you have a link to that Stephie amp?

A third option is to parafeed the Llundall’s I bought before Mark warned me against them. But maybe parafeed worth experimenting.


I may have made this up in my head, but I seem to remember Lundahls being a bit of a mixed bag (and I think this was interstage as well as output). But they released ...

I realized the solution was to have a power amp that just added power to the signal with as little as possible error, and then add that magic with a DAC and phono stage with a valve output that added a little of that magic with far less added problems.


Another option could be push-pull amps ...

Good news that it’s treatable Ray, and I’m full of admiration for your PMA. We’re thinking of you.

I'll wade in. Possibly a foolish idea.

Caps are odd things. I dislike them as coupling devices. If I have to have them, personal choice would be film and foil, not metalised. I have one amplification coupling cap.

However I'm not averse to electrolytics in power supplies for differential ...

That really does finish it off nicely!

Cressy Snr wrote: Thu Dec 05, 2024 3:28 pm Just put a Fender jewel light on the front of the HPA. That's better
I can't have a valve amp without a Fender jewel glowing away on the front panel; it's just not cricket!

We need a picture!