The Rude Tube

[mad.ax]

Oooops! How many decades will I keep doing the same ole mistake of confusing screen2 and G2? Silly, silly me! ;D

Your right of course, screen2, that is G3 is tied to the cathode.
Which gives us a cathode/G3, a grid, a screen grid, and a plate. So 4 electrodes, hence me calling it a tetrode.

Axel

 

[mikeyB]

Brilliant work Bernd ;D - do you get any loud popping when changing the triode/pentode settings? Have you experimented with seperating the 2 parts of the switch? - ie) Different lc settings in triode mode - if this is even  possible??

 

[bernbrue]

Hi,
there is only a plop when changing from triode to pentode mode. Changing between different PK modes doesn´t cause any plops. I´ll fix this with a single 4M7 resitor for triode/pentode switching. We need an MBB Lorlin (make before break) here to avoid plops, though. Different LC setting in triode mode should be possible. I still haven´t found a solution for the pentode 2 mode which gives you interesting gating effects. This mode is realized by significantly reducing H.T. and feeding G3 with a constant current (preferably +4V) But how to make it switchable? I´m working on the 2nd channel right now, but time is limited at the moment. Soundwise it´s really versatile, from fattening to brutal. You´ll like it. I´ll keep you updated.
regards
Bernd

 

[JayDubrek]

Hi...just have a couple of questions- I take it you've steered away from using the original REDD47 power supply being as your circuit operates from 290V? Earlier you referred to the DAOC supply- is this what you used? Also I've had another skim through the thread and can't find the resistor values used on SW1a?
Cheers
Jay

 

[bernbrue]

Hi Jay,
here is everything you need to build a REDD. And yes, my PSU is very similar to the D-AOC PSU.

http://www.groupdiy.com/index.php?topic=33424.0

Build the 6AS6 tube stage on veroboard and insert it before R8. There are a few changes and modification, but mainly concerning resistor values. You don´t need any resistors at SWa, they were just an idea to realize the squash modes. Leave them out.
regards
Bernd

 

[mikeyB]

Hi,
there is only a plop when changing from triode to pentode mode. Changing between different PK modes doesn´t cause any plops. I´ll fix this with a single 4M7 resitor for triode/pentode switching. We need an MBB Lorlin (make before break) here to avoid plops, though. Different LC setting in triode mode should be possible. I still haven´t found a solution for the pentode 2 mode which gives you interesting gating effects. This mode is realized by significantly reducing H.T. and feeding G3 with a constant current (preferably +4V) But how to make it switchable? I´m working on the 2nd channel right now, but time is limited at the moment. Soundwise it´s really versatile, from fattening to brutal. You´ll like it. I´ll keep you updated.
regards
Bernd

Bernd - where goes the 4M7 resistor? - is it from HT to switch pole?
Also - sketch me the modes you want and i'll come up with a solution
Mike
just been looking at the squish on the orange project - is this how you want to implement (with the 500k pot)or can you sketch how you'd do a constant current source?

 

[JayDubrek]

I'm already part way through building a PTP REDD47 using the original supply with OA2 tubes etc...thinking I may try a PTP version of your design once I've cleared a couple of projects up so thanks for the info...
Have you used the Guavatone PCB as a starting point with this then?
Jay

 

[bernbrue]

Bernd - where goes the 4M7 resistor? - is it from HT to switch pole?

Hi,
there is only a plop between Triode and Pentode Mode. Have a look at the attached schematic and then it gets clear where to put the 4M7 resistor. For my built I just wanted to realize Triode, Pentode and 4 Peak Modes. Since this project is open, it´s to everyone´s own which modes to imply. I´m happy about a vivid discussion. I use a self etched pcb of the REDD that was floating around here a few years ago. I got it from a friend who etched one off for me. The Orange 86 pcbs are the way to go here. I can imagine that Guavetone is already working on a pcb for the 6AS6 tube stage, though it is not that difficult to realize on veroboard.
regards
Bernd

 

[bernbrue]

updated schematic (see first post)
regards
Bernd

 

[JayDubrek]

Not had time to look at the Orange86 circuit yet but I do remember there's a 'squish' point on the PCB...does your circuit simply slot in here?
Jay

 

[bernbrue]

no, my circuit (only the 6AS6 stage) is just inserted before R8 of the Orange 86. The mic preamp valve stages are EF86 -> ECC88 whereas the Rude Tube valve stages are EF86 -> 6AS6 -> ECC88. You only have to change 3 resistor values from the Orange 86 build and drop in my 6AS6 stage. You don´t need the suggested Cinemag/Sowter/Edcor mic transformer here, since the Rude Tube only runs line levels. That´s it.
regards
Bernd

 

[JayDubrek]

I see! Thanks....I'll have a proper look at this early next week with a view to having a go at building it...
Jay

 

[bernbrue]

Hi,
I did some measurements with RMAA. Frequency response (from 40 Hz to 15 kHz), dB +1.44, -1.84, Noise level, dB (A) -93.1. Quite good for a prototype. I changed the output pot of the 2nd valve stage to 50K. Schematic updated.
regards
Bernd 

 

[bernbrue]

Someone wanted to hear distorted drums. The audio sample starts with different peak modes and ends with switching between some ridiculous distortion settings and bypass.
Enjoy it (link in the first post)
Bernd

 

[drask]

Hello,

I'm really interest for build one.
The rude tube work perfectly?

Thank you

 

[bernbrue]

Hi,
did you listen to the audio demos? When your ears liked what they´ve heard then build it.  ;D Yes, it works perfectly.
regards
Bernd

 

[drask]

Yes, good sound.
I try to build One so
Thank you

 

[bernbrue]

2nd channel works as well. I have to make the wiring neat. 
regards
Bernd

 

[bernbrue]

ready to rack.  (pictures in the first post)
regards
Bernd

 

[[silent:arts]]

congrats my friend!