[BUILD] The Rude Tube IVORY ====== Official build & support thread

[bernbrue]

Hi,
yes, your transformer will work fine. The 12AX7 tube is very forgiving and performs very well even with lower B+ voltages. 6,3VAC is fine as well, but you should neatly twist the heater wires in order to avoid hum.
regards
Bernd

 

[tsv]

Ok cool

i'll omit the parts on the Heater PSU then. I'll save some money on those big caps  .

So back to my original question what size fuse do you think I need?

Thanks

 

[bernbrue]

Oh yes, almost forgot: 1A slow blow fuse should be fine.
regards
Bernd

 

[tsv]

Great thanks!

 

[tsv]

Hi Bernd

Out of curiosity what transformer are you using?

Thanks

 

[tsv]

So I talked to Antek and they have the 230V 100VA coming in in the next couple days.

http://www.antekinc.com/as-1t230-100va-230v-transformer/

I can return the 200V for this one.

I know you said the 12AX7 is not too picky on B+ but I want to build this correctly. Is it worth exchanging it then?

Thanks!

 

[bernbrue]

Hi,
100VA is a bit overkill for 2 tubes. I would keep your 200V transformer. B+ voltage might be a bit lower, but you won´t hear any difference at all. I´m using a 70VA transformer with Sec.: 250V/9V/48V that I´ve got from a forum member. The transformer was meant to be used in a tube mic pre. I just didn´t stuff the third rail of the psu.
regards
Bernd

 

[tsv]

Hi Bernd

Thanks for the info. I'll just keep the 200V then!

 

[tsv]

I receive all the parts from Mouser yesterday so I will be getting started on this soon!

 

[tsv]

So I have the B+ portion on the power supply built and one channel finished. Just waiting on the 100K 3W resistors I forgot to order to arrive.

Fantastic layout! The PCB is a real work of art.

I had a few ideas / questions:

1. Adding a front panel bias control. I assume making R12 or R15 variable would accomplish this. Any thoughts?

2. Adding a blend control for wet dry mix. There's some mention of series or parallel wiring for the relay pcb.

3. Input and output transformers. Any idea yet what some good values would be. I'd probably be looking at the Edcor's.

Any help would be greatly appreciated.

Thanks!!!

 

[bernbrue]

Hi,
build it stock and test it before applying any modifications. Sorry, cant answer  in detail (lost my mother last sunday).
 
Bernd

 

[tsv]

Hi Bernd

So sorry to hear that. Take care and best wishes to you and your family.

Thanks for taking the time to respond. I will build the unit as stock before undertaking any mods.

 

[bernbrue]

Hi,
updated the 2nd post (transformer hookup).
regards
Bernd

 

[tsv]

Thanks!!!

 

[bernbrue]

1. Adding a front panel bias control. I assume making R12 or R15 variable would accomplish this. Any thoughts?

Hi,
you can imply a front panel bias control if you like. Replace R15 with a 2k or 1k5 pot and test it. You can even insert an amperemeter (1mA) as I did in my first Rude tube (check original thread, you´ll find the schematic there). I wouldn´t touch R12, the effect will be more pronounced in the second triode stage (R15).
regards
Bernd

 

[tsv]

Great! I'll give it a try thanks.

 

[tsv]

Hi

I got it up and running yesterday on the first power up. Sounds great!

Bernd did you build yours with the stepped pot board? I think jumper pin 1 on the stepped switch board and the main audio board are opposite. I swapped 1 and 3 on one side and now the controls work as expected and not backwards.

I' still trying to sort out something with the bass switch it's not behaving quite right.

Anyway great project thanks!

 

[tsv]

Main Board

 

[tsv]

Switch side.

 

[bernbrue]

Hey, that looks great!
A few things to consider: The bass pot is more or less a bass cut. So fully clockwise it is almost linear. It´s almost the same thing with the mid pot. The high pot really boosts the high freqencies. Some interesting stuff to read:

http://pickroar.com/1003/the-tone-stack-explained-in-english-for-humans/

In addition to that you should download "tonestack calculator", a very useful programm that simulates various tonestack configuration (Fender, Marshall, etc.).

http://www.duncanamps.com/tsc/download.html

You might get in trouble with the wires from mainboard to Lorlin board when putting the boards in a 1HE enclose. You led them around the boards. Tony and I had a direct connection in mind. In other words, just take a ready made molex connector on one side and solder the open wires on the other side directly to the mainboard or vice versa.

I´m glad that you posted pictures of your boards for other builders to learn from!
Excellent!
Bernd