EF14 RFT + Sockets Lets see?

[Papa Tango Charly]

Hi everybody Long time no seen.
Look what i have found on Aliexpress is it a dream?

Would it be reasonable to buy that RFT EF14


https://fr.aliexpress.com/item/1005...!sea!FR!1650395965&curPageLogUid=RNqWJgRvTqpC


https://fr.aliexpress.com/item/3223...!sea!FR!1650395965&curPageLogUid=RHWR1bUbFBqS




Have anbody tried RFT EF14 tried it?
Best

 

[kingkorg]

Crazy stuff, but i wouldn't trust them with this. Also i have managed to score these for less money from reputable sellers on Ebay. I have both RFT and Telefunken, both sound and work equally good to me.

 

[Papa Tango Charly]

Thank You Kingkorg!
Do you have somebody on Ebay That you could recommend?
Is the EF14 a quiet tube?
Woud you recommend This Olivier Archut Schematic to build U47 with the EF14?

 

[kingkorg]

Thank You Kingkorg!
Do you have somebody on Ebay That you could recommend?
Is the EF14 a quiet tube?
Woud you recommend This Olivier Archut Schematic to build U47 with the EF14?

The guy i bought from doesn't have any left. I had no noise issues with mine. That schematic is good but it needs different filament filtering than our usual chinese PSU. It will have a lot of 50hz hum with stock PSU. So either rework the psu, or change wiring of cathode/filament which will change the sound according to some. I haven't tested this claim.

Also i wouldn't use 1G resistors, that is supposedly too much for a tube, go for traditional u47 values.

 

[Spencerleehorton]

so are we saying these EF14 tubes are pretty close to the VF14?
is this a better choice than the EF80/800 tube to get U47 approximation?

 

[rock soderstrom]

so are we saying these EF16 tubes are pretty close to the VF14 or EF14?
is this a better choice than the EF80/800 tube to get U47 approximation?

There is no EF16 tube. You are confusing something here...

 

[Papa Tango Charly]

The guy i bought from doesn't have any left. I had no noise issues with mine. That schematic is good but it needs different filament filtering than our usual chinese PSU. It will have a lot of 50hz hum with stock PSU. So either rework the psu, or change wiring of cathode/filament which will change the sound according to some. I haven't tested this claim.

Also i wouldn't use 1G resistors, that is supposedly too much for a tube, go for traditional u47 values.

My question is it possible to rewok the filtering on the existing Tbone chinese PSU circuit ?
If yes How can i drop down the B+ to 105V and H+ to 5,05V?
Thank you

 

[rock soderstrom]

My question is it possible to rewok the filtering on the existing Tbone chinese PSU circuit ?
If yes How can i drop down the B+ to 105V and H+ to 5,05V?
Thank you

Which chinese PSU circuit? There are different ones. Schematic?

 

[Spencerleehorton]

Sorry I meant the EF14

 

[kingkorg]

so are we saying these EF14 tubes are pretty close to the VF14?
is this a better choice than the EF80/800 tube to get U47 approximation?

There is a never-ending debate on this, but imho and according to Milan's journey whom i respect very much Journey into the Legend of the U47 (There are 3 pages to go through)
EF14 is the closest one, the only difference being filament voltage. Some will still argue this is not true, but cant seem to prove it empirically.

EF80/800 lack specific microphonics characteristics of VF/EF tubes. Thanks again for confirming VF14 is actually quite microphonic Thomas.

https://groupdiy.com/threads/microphonics-in-vf14-and-u47.82644/

 

[Spencerleehorton]

A very interesting read that journey into the legend of the u47




It’s seems the EF13 would be the better option with some tweaks

Be nice if Milan could do the tests with the other EF800 and EF80 tubes as that is what initially I’ll be using

 

[Spencerleehorton]

Papa tango charlie

Check out my thread

https://groupdiy.com/threads/u47ef-oliver-archut-version.84508/
Maybe some stuff that could help in there

 

[Drosselmeier]

It’s seems the EF13 would be the better option with some tweaks

Yes, I think so, too

 

[Papa Tango Charly]

Thank you Drosselmeier​

Is your EF13 tube quiet
I can see a trimmer on the microphone but i don't see it on your schematic?

Thank you I have add the Pin out of the Ef13

 

[rock soderstrom]

It’s seems the EF13 would be the better option with some tweaks

The EF13 is a fine tube, very low noise according to the data sheet. But it is a control pentode, aren't characteristic curves a bit crooked in the range where it is operated in a microphone? Maybe that's what makes this tube sound really good...

Very interesting price-wise!

 

[Drosselmeier]

Thank you Drosselmeier​

Is your EF13 tube quiet
I can see a trimmer on the microphone but i don't see it on your schematic?

Thank you I have add the Pin out of the Ef13

View attachment 111549

this one

 

[rock soderstrom]

Looks good! Wav file doesnt work here...Which cathode resistor did you finally end up with the potentiometer? 1.8k? Is the tube underheated?

 

[Drosselmeier]

sorry, I can't say for sure anymore
microphone sold in spring
somewhere around 1.2 - 1.8 K

Song

 

[Papa Tango Charly]

Thank you
Nice sound!
I have made a Advanced Audio project with a Tbone 2000
Should i use my Tbone PSU Sct 2000
It is exactly the same votage 6V heater and i drop down the voltage of B+ to 120V with a 58V and 62V
Thank you

 

[Murdock]

Interested in your finds concerning the EF13.
I tried it once in my U47 build where I had an EF800 before and didn't like the results... But I did not play much with the components. Just swapped the tube. And I see drosselmeier even had a whole different circuit.