audio-talk

Hey Steve - This amp plays classical as well ! I just rescued an LP from a stack of 'uninteresting' odds from a relative's house-clearance - been upstairs for ages : Beethoven Cello Sonatas ( Janigro/Demus ) on Vanguard budget label . Superb music, superb recording . Great stuff . Glad you like the...

Paul Barker wrote:
Just use a small resistor.

That's it Paul you've found the level

I'll give it a go.

It's easy enough to separate the two roles as I already have a decent series reg running on the amplifier right now. Only thing stopping me at the 'mo is the choke between the two stages. I have various power chokes but it is the winding for HF that is throwing me. I don't have the facilities or the...

Sorry Steve, but for me on paper it is a non starter. I don't do that much compromise. Hi James. Well usually as you know we don't think of everything at first, and in my case I often just build rather than write or talk, and adjust on test. We have to start somewhere some people on paper, me I see...

Cool :D Just humour me with this one I tried it with a 6336A and cos of the higher gain it does not need as much bias for the same current. http://dl.dropbox.com/u/7181882/srpppsu5.gif Using 3X75C1s I have managed to get the same currents through each half same bias. Probably will be a bit out in pr...

Hi James

I knew somebody, somewhere would have done something similar.

Well you could try it out Paul despite the resistor, are you really going to hear that single resistor in your psu

Hmm yeah you can't get the right bias with only 75V can you I was just going to post the very same after poring over curves myself. That's why I had the cathode of the bottom valve elevated that high. I remember now. I get nervous when questioned by people who know more than me these days. Never use...

Paul Barker wrote:YEs..

I am a little worried that there will ensue a run on 75C1's.

Fortunately I have mine.

There's always the QS75/60 loktal one.

Although it is credible to evaluate using a zenner ref. the audio ac signal passes right through it, and therefore the design in audiophile terms has to contain the VR tube as the reference. Zenners on cathodes sound nasty. Don't fret Paul I'm not about to fsck things up with Zeners It's just an ex...

OK so not as bad as I thought.

As I said earlier I'll try it with the Zeners first, then if it works and sounds promising
I can set it up with VR tubes.

I suppose the gist of the matter is that you can't just go around calling any old totem pole circuit an SRPP then?

Paul.....So what you are saying is that this totem pole regulator setup is going to introduce nasties into the sound of the amplifiers, because the PSU is part of the signal path. So taking it to its logical conclusion I'm in danger of turning a great amp; one that gave a sound through James' speake...

As you say Paul, a proper series reg, which I already have, followed by a shunt reg will probably perform better than the totem pole circuit but I just have to try it now.....one never knows. I'm going to have to be careful though that I don't alter too many things at once. I'll do the pair of regs ...

I think that your circuit would best be adapted to suit a single 75C1 on the cathode of the shunt section, and the position of the wiper on the voltage sense network altered. When you think about it the shunt half of the 6080 has only it's own current to worry about so it can handle more voltage. A...

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SteveTheShadow wrote: I have sockets for the Brit tubes as I was experimenting a while back with globe AC/Ps and AC/P1s with an 801A amp I built a couple of years ago now.

And here it is:

Took some finding but I dug a picture out for old times sake.