New vacuum-tube preamp-project!

[Gost22]

Hi guys!
I make some preparations for the development of tube preamps with 6922 or 6n23p, ECC88, 6JD8 and etc,.
First, go to the schematics (see Figure1 and Figure2).
Which schematic is better in your opinion, so let's move on ...
Thank you for your cooperation, going on, ..

 

[Osvaldo de Banfield]

The second drawing has a mistake. The diode is useless and in fact rectifies signal causing distortion.

Also a resistor from arm of pote to ground is useless too.

Finally, I would wire them in DC and plate of first triode bootstrapped from cathode to augment gain and lower distortion. http://www.freewebs.com/valvewizard1/dccf.htm, last schematic.

 

[Gost22]

The second drawing has a mistake. The diode is useless and in fact rectifies signal causing distortion.

Also a resistor from arm of pote to ground is useless too.

Finally, I would wire them in DC and plate of first triode bootstrapped from cathode to augment gain and lower distortion. The Valve Wizard, last schematic.

Mr. Osvaldo already-known theoretical things first.
Diode is not too much!?
Question: why does she serve?
Please be specific with the answer of the question, ....
thank you!
P.S.
Here are the boxes that I prepare for this High-End tube/valve preamplifier!

 

[Osvaldo de Banfield]

Diode SS and diode grid cathode are in parallel and have no DC return. A small AC voltage positive going will be rectified charging coupling cap negative to the side of grid. So in few cycles second tube (Cathode follower) will go cutoff as negative voltage always increases and can't decrease., and first, severe audio distortion will be heard, and then completely no sound until the cap discharges in its own self leakage.(You must turn off power to let the cap discharge). The circuit is completely useless.

Salu2 de Argentina.

 

[Gost22]

Mr Osvaldo,
Somehow, English is not my better half, so please show the changes to the schematic and to talk a little more specifically, ...
thank you

 

[Osvaldo de Banfield]

I'll send you a PM in Spanish. Wait for me till tomorrow.

 

[Gost22]

I'll send you a PM in Spanish. Wait for me till tomorrow.

ha,..ha, OK!?
P.S.
Congratulations on all Catholics choice POPE.

 

[Vincent77]

Also a resistor from arm of pote to ground is useless too.

Not completely useless: it keeps the grid grounded if the pot wiper loses contact, thus protecting the tube. Mandatory with stepped attenuators.

 

[SY]

Hasn't this thread already appeared twice before with the exact same questions and the exact same schematics?

If you want to build something, put down the pencil and paper and go do it.

 

[DF96]

Didn't someone once say something about someone who keeps repeating the same action but expecting a different outcome?

 

[Gost22]

Hasn't this thread already appeared twice before with the exact same questions and the exact same schematics?

If you want to build something, put down the pencil and paper and go do it.

I took pensil and paper and I'm ready for a new proposal.
Sorry if you think that repeating thematic.
thank you

 

[SY]

Try a soldering iron and a voltmeter.

 

[Osvaldo de Banfield]

Not completely useless: it keeps the grid grounded if the pot wiper loses contact, thus protecting the tube. Mandatory with stepped attenuators.

OK, you are right. But in this case I believe to choice a higher value than a few Kohms.

 

[Gost22]

I'm just looking for opinions about improvements of this preamp, with no one to offend. All improvements and suggestions about the seeds will accept.
By that I create the schematics the preamp-first or the second?
Thank you!

 

[SY]

You don't have a preamp. You have a drawing. Build a preamp, take some measurements, decide from actual data what you want to improve, then it's worth asking questions.

 

[Gost22]

You don't have a preamp. You have a drawing. Build a preamp, take some measurements, decide from actual data what you want to improve, then it's worth asking questions.

I designed this schematics, therefore, I ask your opinion is everything wrong with the schemtic and seek assistance schematics is better.
I need to do some changes to the schematics or to all of them right, you understand ...?

 

[SY]

Yes, that was what your last identical thread was about. When you've soldered and measured, come on back and people will be happy to help.

 

[Osvaldo de Banfield]

I sent you a pm in Spanish. Read and make your answers or comments in our language to my PM or emails.

Good luck.