ECL86 preamp?

[Elkaid]

Hi everyone !

Removing the cap will cause some degenerative feedback, this in turn will linearise it at the expense of a reduction in gain and an increase in output impedance.

What are the consequences of increasing output impedance ? More subject to catch noise ?

Regards,

 

[fdegrove]

Zo.

Hi,

What are the consequences of increasing output impedance ?

In order to transmit properly from one stage to another output and input impedance need to be low at the sender end and high at the receiver end.
Often a ratio of 1/10 is prefered, say a 10K Zo source driving a 100K Zin.

Disrecpecting this rule will inevatibly result in loss of fidelity.

Basically you best drive a high input impedance witjh a low output impedance.

Other factors play a role too, I just want to get the basics across.

Cheers,

 

[Elkaid]

Ooops, shame on me

Since I began to tweak using you suggestions, I was looking for the cause why my preamp was "so powerful". I finally found out that my supply was providing 325Volts instead of 285Volts which is a bit over the nominal maximal voltage. (300 Volts under normal use).

Well, I guess from now on I'll look for a new tube design ?
I'm looking for a ridiciously simple preamp. I've seen the 6sn7gtb preamp and I'm looking for similar schematics... Any ideas ?

Thanks !

Regards,

 

[paulb]

resurrecting this thread

Here is a TubeCad blog with a 6BQ5 headphone amp:
http://www.tubecad.com/2006/11/blog0086.htm

 

[tiefbassuebertr]

If you have any troubles reading French, maybe you should try Altavista's Babelfish

BabelFish


and then enter the following URL

http://dan.bellity.online.fr/haute-fidelite/DIY/LED-mu-follower/DIY-mu-follower.html

I hope this will give you an idea of what the article means.

Regards

URL
http-"dan.bellity.online.fr/haute-fidelite/DIY/LED-mu-follower/DIY-mu-follower.html"
is death in the meantime. also webarchive in the Moment due Service and maintenance.
Who can upload the shoot-screen of this describtion ?
I want to have a unity gain line amp either as cascode-follower with resistor current source or as normal follower and active current source according this:
the Power Folllower
thanks also for additional hints resp. advices.
The aim is getting lowest possible output impedance