JJ ECC83S Biasing conditions

[Zoran]

This value You have also on the jpeg pic.
Voltage drop @ 122K with Io=2.2mA current is 268.4V
+ 260V of Ua
+ 1.5V of Ug
= 536V cca of Vb, of the stage...
like on the pic too.
.
Dont get me wrong please Mashly
I think based on You posts, that Ypu dont have enough experience
in high voltage electronics and tubes.
PLESE dont get into konstructing and putting something.
Consult and ask someone else with experiance to build for You a device
or rearange present.
Take it seriously, because we talking here about high dangerous voltage.

 

[Mashly]

Don't worry Zoran. I am trained in using High Voltage, I worked for a high voltage power supply company recently testing there circuits.

This is exactly as I thought, I was just asking to make sure. I did not state it at the fear of getting it wrong and looking stupid, but it seems I have made myself look stupid by not stating the value.🙄

And how am I ever going to learn about valves without asking questions?

 

[Zoran]

Ok then You are familiar with measures and procedures with HV 🙂
For which purposes You need this gain stage?
hifi audio or performing music?
.
I am asking because it is important and not the same issue.
🙂

 

[Mashly]

I would like to use it for a hifi amplifier, I have these and some 6L6GC's by JJ as well. But to be honest this is my first valve amplifier so I will be happy with anything just to start the learning process.🙂
I have Morgan Jones's book and am working through that. I also have a couple of pdf's from the internet and now that pdf that was posted earlier.

 

[Zoran]

Ok that is for input tube or phase splitter if it is push/pull amp?
Maybe it is useful first set the things around output valve.
.
But in any case, SE or PP amp, ecc83 is not for the driver tube.
because of the higher Ri, internal resistance, leading to higher resistance of the stage generator to next stage. Which has capacitive loads...
You can use like input stage section tube, but followed with some catode follower tube stage driver for output tube section.
Also not so good choice for the phase splitter.
.
You have exactly the same topologies in numerous guitar amps,
where the ecc83 doing the job, but for home reproduction,
for my opinion is different.
🙂

 

[Mashly]

Have you any good links or documents detailing the difference between designing for guitar amplifiers and for Hi-Fi use?

My guess is that you want a very linear amp for Hi-Fi with as little distortion as possible, where as guitar amps you drive the tubes hard to create a colourful sound (sometimes anyway). This I perceive to be just the tip of the iceberg but any pointers you can give me would be much appreciated.

Thanks

 

[Palustris]

And how am I ever going to learn about valves without asking questions?

Valve Ampifiers by Morgan Jones
ISBN-10: 0080966403
ISBN-13: 978-0080966403

 

[Mashly]

Thanks Palustris, I am working my way through that book as we speak. It is a very good book so far.

 

[funk1980]

Have you any good links or documents detailing the difference between designing for guitar amplifiers and for Hi-Fi use?

My guess is that you want a very linear amp for Hi-Fi with as little distortion as possible, where as guitar amps you drive the tubes hard to create a colourful sound (sometimes anyway). This I perceive to be just the tip of the iceberg but any pointers you can give me would be much appreciated.

Thanks

Well..... that's pretty much it 😀.
There have been loads of 'design flaws' in early guitar amps that caused all kinds of distortion, but ultimately turned out to produce the distinctive 'tone' we all love.
Designing preamps for guitar and bass by Merlin Blencowe is an awesome read and is, as the title suggests, aimed at guitar and bass.