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

[JCN1218]

Wow! July, glad to see this thread isn't as dead as I'd feared.

I bought this project second hand a while ago from the black market. Came with everything I needed save a few things. I played with it a bit initially and then got sidetracked, but now I'm back on it!

Anyway, I finally sorted out my power supply which is now spitting out 250VDC at B+. I have my heater wired directly to my power tx which is reading 6.3 VAC (red probe on positive terminal, black on negative terminal). I don't have the filaments jumpered for 12AX7 tubes. I'm also using a bias pot and ammeter in place of R15.

When I power up the unit with the motherboard attached to the PSU, my tube doesn't glow, and my ammeter doesn't move at all. I can trace the audio signal fine into the board when I feed a test signal, but I get no signal at the output. I'm a little nervous to probe around the board since it's so hard to get to.

My best guess at this point is that the tubes that came with the kit (of which I've tried both to no avail) are either defective, or maybe the wrong type for my configuration. Just trying to figure out what my next move should be, so any help at all would be immensely appreciated. If the tubes truly are the culprit here, maybe I should try to buy a known 6N2PEV to try out. Otherwise I think I'm stumped.

Thanks!

 

[bernbrue]

Sounds like a bad or wrong tube.
Cheers
Bernd

 

[JCN1218]

Sounds like a bad or wrong tube.
Cheers
Bernd

Thanks, Bernd!

I'll purchase some fresh tubes over the next couple of days and hopefully in the next update I'll have a working unit

 

[JCN1218]

So I got my new tubes a while ago and I put one into my channel one. Nothing. I figured maybe there's something wrong in channel one, so I hooked up channel two. Nothing there either. Despite correct voltages, my tubes still aren't glowing like they're supposed to. Any ideas?

 

[bernbrue]

There at two ways to connect the heater wires, depending on which tube you have used. 12AX7 or the Russian equivalent?
Bernd

 

[JCN1218]

I'm using the Russian equivalent

 

[bernbrue]

Just in case you haven’t seen that:
http://www.xaudia.com/xmanuals/PreliminaryDocs140614.pdf
Have a look at the schematic (last page). Otherwise check voltages, wiring, test another tube.
A picture might help as well.
Cheers
Bernd

 

[JCN1218]

The inside of my chassis is a hot mess of spaghetti wires, so I'm not sure of how much help it would be. Checking over the schematic, I noticed that it looks like pin3 of Input and Output are tied into ground. I checked those pins and they're definitely reading too high of a resistance.

Should both of those pins be tied directly to ground like the schematic is implying? I'm using the rotary switches, so if so, what would be the best way to do that?

 

[bernbrue]

I suppose you are referring to pin 3 of the XLR connector. Yes, pin 3 is tied to ground. Best place to do that is a wire bridge on the XLR in/out connector.  The stepped rotary pots are connected as shown in the schematic.
Cheers
Bernd

 

[museic]

I'm dusting this one off again. Wanted to report back I figured out my issue with the power supply putting out too high a b+. I had neglected to jumper over the HTTRIM. So simple fix and the power supply is working great!

Now to a puzzling question. The unit passes audio. But the only control that affects the sound is the output control. The input, drive and eq have no change on the sound. I'm using alpha pots. They are correct values and I've tried wiring the pins different combinations with no change. One strange thing I noticed is moving the wires to the pots they are very microphonic, except the output control wires. A clue maybe? Try different wire?

 

[bernbrue]

Grounding, psu and main board.
Bernd

 

[museic]

I found two dead pots. Must have been a bad batch? Waiting on some replacements.

 

[museic]

New pots in and I have a VERY clean tube pre !

Little more troubleshooting to do. I'm not getting any breakup with the drive control.  So it's clean all the way up. Actually just acts like a second output control. This is with a strat plugged straight in.

 

[bernbrue]

Great! A strat will certainly sound beautifully with this preamp, but the signal won’t be hot enough to overdrive the tube. A strong line signal will do so.
Bernd

 

[museic]

Ahhh ok that's what I was thinking! Sounds so good. Thanks for the project!

 

[madreza]

Hi guys.
Would tropical fish 400V be fine for the film caps ? Or it wouldn’t be enough ?

 

[redmojosteve]

Morning. It's quite a while since I have been on the forum as I've been building some other audio gear (very slowly) and some guitar effects pedals. I hope this thread is still running. I have got my Rude Tube Ivory about 90% complete and have started connecting the PCBs etc within the case and all seems fine so far. I am just a bit puzzled about the grounding arrangements on this. Normally I would connect the incoming earth  (from the IEC socket) to a star point on the case, which I have done, and connect this point to the boards as appropriate. I obviously need to ground the power supply board and there are a number of grounding points on the PCB e.g. there are ground connecting pads in the middle of the board and also the V+ ground near the V+ led.  Some of you have obviously got this up and running so I wondering how you have connected the ground wires?
One other point related to grounding; are the jack sockets on the front panel grounded to the case or do they need to be insulated from it? For example, I built a high power valve guitar amp which required the sockets to be insulated to prevent hum loops.
Thanks for a great forum and keep safe.
Cheers
Steve

 

[redmojosteve]

An update!
Well, I reread the thread a couple of times and I spotted one comment about grounding and also noticed that there was another about reversed controls. I thought I had lost concentration when I was connecting things up! I also had some Molex connectors that provided a very poor connection. I improved these and now all is quiet, when it should be of course, and running well.
Thanks
Steve

 

[dribro]

Hi

Got two units up and running with haufe out, cheap thomann high ratio DI  in (?). Managed to get almost the same level as the DI.
Only thing left is to do some waterslide on the frontpanel.

 

[grapyofire]

Hi guys,

I decide to go with 2 power transformers from mouser mentioned in a BOM. Do I need to use both for mono unit? Or just one? Also I think 12v relay would work with it, right? Or should I put 5v? I'm in US.

Best regards Anton.