The Rude Tube

[simonsez]

Ok, i made this one, but I have a few question :

1. why you change the anode resistor of the first tube (EF86) to 200k? what if i stay with 100k?
2. I found that LPF freq is not good, too much hi cut, is 0.22uf is right?

 

[bernbrue]

Hi,
excellent! Be careful with brandnames and manufactures on frontpanels. It´s a "Rude Tube", nothing else. The reason to change the anode resistor was to increase gain of the EF86. In fact you can stick to the values as used in the REDD47. Choose the HPF cap to your taste. Try different values.
regards
Bernd

 

[bernbrue]

Are the pcbs from Drask? They look self made. Do you like what it does?
regards
Bernd

 

[RATMNL]

Yeah, was wondering the same thing, doesn't look like the pcb...
Also wondering how the Squish ended up on the "function" rotary, If I can see correctly.

 

[simonsez]

Yes, i made my own PCB, squish mode is fixed, no pot. I like squish mode, "less hard" sound, pentode give the most aggresive sound.
The drive pot is very sensitive, i change it to 1M log pot, it's help.
I feel that it was design to be a distortion box, not somthing like tape saturator, to much distortion.

I found that when switch it to pentode mode, the freq respone  change (RMAA test), less bass...but not much, is it normal?

I made it for my self, i hope they don't mind with the front panel.

Btw, anyone run it without output trafo?

 

[bernbrue]

Hi,
you do as you like concerning the frontpanel. Just my opinion. Frequency response changes slightly in pentode mode, that´s  true. Bass response changes a bit. For subtle saturation effect you should try normal, triode mode with drive pot at around 9 o´clock, bias at 0,4 mA. Recover gain loss with output pot. The other day I mixed a drumbus with these settings and I really liked it very much. If you want it to sound a bit harsher use the same settings in pentode mode. Anyway, it´s meant to be a distortion box. I see you didn´t implement the peak modes and put the squish mode on the same rotary switch instead. Good idea. I wouldn´t run the unit without output transformer. When the output cap discharges it could damage your mixer. You even designed your own pcb. You must love it!
regards
Bernd

 

[simonsez]

Hi,
you do as you like concerning the frontpanel. Just my opinion. Frequency response changes slightly in pentode mode, that´s  true. Bass response changes a bit. For subtle saturation effect you should try normal, triode mode with drive pot at around 9 o´clock, bias at 0,4 mA. Recover gain loss with output pot. The other day I mixed a drumbus with these settings and I really liked it very much. If you want it to sound a bit harsher use the same settings in pentode mode. Anyway, it´s meant to be a distortion box. I see you didn´t implement the peak modes and put the squish mode on the same rotary switch instead. Good idea. I wouldn´t run the unit without output transformer. When the output cap discharges it could damage your mixer. You even designed your own pcb. You must love it!
regards
Bernd

Of course i love it,  when put it on the master bus, very subtle setting give the mix a nice character.
Nice project indeed !

Thank you Bernd..

Simon

 

[simonsez]

Any opinion about good 6AS6 tube choices? i'm using Zaerix NOS tube, but i found it's pretty microphonic.

Simon,

 

[RATMNL]

Jerome Adviced Sylvania NOS 6AS6, haven't been able to test them though, bought a few pretty cheap off ebay

 

[ilfungo]

Hi
I can not find a on-on-on switch  for overdrive ...
I can use a rotary switch?
how?
thanks

 

[bernbrue]

Hi,
yes, of course you can. Take a 3x4 Lorlin, have a look at the schematic and you´ll shurely find out how to connect it.
regards
Bernd

 

[ilfungo]

I'm tryng but i'm confused....
Why 3 pole 4 position switch?
Can you help me with a drawing?
Help please!!!
Thanks

 

[bernbrue]

Hi,
you can use either a 1x12, 2x6 or 3x4 Lorlin switch, but you have to set the stop at position 3. Here is your drawing.
regards
Bernd

 

[ilfungo]

thanks!!!
I do not know why, but seeing the other switch (on-on-on) seemed much more difficult!
Thanks

 

[bernbrue]

Well, it depends how you want to design your frontpanel. I had to think for more than a few hours how to implement the three position toggle switch. With a Lorlin it´s much easier.
regards
Bernd

 

[ilfungo]

HI bernbrue!!!
Thanks for your help!!!
I've just have some problems:
On DI input ( with guitar) there is no distorsion but only good clean sound
LPF which is the condenser that make the frequency cut? C6?
it's possible to use standard VU meter? What I Must change?
THANKS!!!

 

[bernbrue]

Hi,
yes, C6 is a low pass filter (i.e. high cut). The given value (0,22uF) seems to be a bit too high. Try smaller values (0,1 or 0,068 uF). There should be plenty of distortion with the DI in. Switch to pentode mode, bias at 0mA, crank up the drive pot, switch to overdrive and let the 6AS6 glow. The meters only show the current going through the 6AS6, so Vu meter do not make sense. The 6AS6 won´t work correctly (i.e. distort) without a 1mA meter, bias pot or function switch connected
regards
Bernd

 

[ilfungo]

hi
I've changed the vu meter with 1ma meter from hairball, but I've some strange problems:
when I change the bias pot the meter go down....
The output pot when go CW increase the distorsion...
for what is 1ma meter ( Level)?
When there isn't signal the meter must stay on the left or full right?
thanks

 

[bernbrue]

Hi,
the meters show the current going through the 6AS6. They have nothing to do with a VU meter. Turn the bias pot CCW and the meter goes down. Turn the bias pot CW and the meter goes up. Use the trimpot to set the meter to 1mA (full scale). The output of the Rude Tube is very hot. I´m shure it´s your mixer that starts to distort.
regards
Bernd

 

[bernbrue]

To get an idea how it behaves and what it does (though it´s different). The bias pot is wired the other way round.

http://www.youtube.com/watch?v=RfosiJZPqWQ

regards
Bernd