Found copy of article about Real McTube, if anyone's interested...

[liddokun]

I recently dug up a February 1999 issue of Electronics Now, which is the issue that contains the original article about Fred Nachbaur's (r.i.p.) Real McTube.
If anyone is interested in reading it, let me know, and I'll scan it and post it in this thread.

Cheers

[rousejeremy]

+1 I wouldn't mind seeing that.

[liddokun]

Alright, I'll scan it in tonight, or tomorrow morning. 

[kurtlives]

How did you find that article?

I am interested in seeing it as well btw.

[punkin]

  Oh...yes please.

[Ice-9]

Me too, I would like a read of that.

[liddokun]

How did you find that article?

I am interested in seeing it as well btw.

My former high school's engineering teacher has subscriptions to nuts and volts, electronics now, and various other magazines, that run back years and years.  He keeps them all  at school, and there's piles of them. I went in to visit the other day and while I was waiting for him to finish a test for his students, I dug through the pile and noticed the picture of the tube on one issue, so I grabbed it. And the teacher gave the issue to me. 

[liddokun]

Can't get access to a flatbed scanner until tomorrow, but I took a picture of the cover with my digital camera. I'll post the article tomorrow.

[compuwade]

Very cool, i'd like it too..

Thanks

[trevize]

can't wait to see the scans, thank you very much!

[liddokun]

Here ya go! Enjoi!

[jkokura]

that's awesome! It gives the schem and parts list, as well as giving a gut shot. That's a super find, and I'm glad you posted it. I want to build this eventually...

[liddokun]

There's an updated version on Tonepad, with pcb and everything. It's nice to have the original one for reference though, and see where changes were made.

[Thomeeque]

 Thanks for the scan, liddokun!

I'm not in condition to read it completely, could you (or somebody else ) tell me:

Is there somewhere explained why the volume pot R11 is 500k in parallel with R9=100k resistor? Why it's not 100k pot only (without R9), which would make it little bit "stronger" (less dependent on load resistance) signal source?

Thanks, T.

[caspercody]

Visit ampage.org for more information on this project. Looks like there are (2) articles on there.

[liddokun]

Thanks for the scan, liddokun!

I'm not in condition to read it completely, could you (or somebody else ) tell me:

Is there somewhere explained why the volume pot R11 is 500k in parallel with R9=100k resistor? Why it's not 100k pot only (without R9), which would make it little bit "stronger" (less dependent on load resistance) signal source?

Thanks, T.

Hey Tomas,

The article  states :

"the output of the second stage is routed through an attenuator consisting of R8, R9, and output control R11.  The accumulated gain after the second stage is so high that the absence of an attenuator would make it ridiculously difficult, if not impossible, to adjust the controls for varying degrees of overdrive." (pg 34, top right corner block of text)

hope this helps

[frank_p]

Thanks Nam-An, this was on my -to do- list and I had buyed all the parts to build it.  Some have posted about some safety issue about the "two power transformers in one" approach. Putted aside the project but appreciate your input.

Hey, hope your studies are going well Nam !

[Thomeeque]

...
Is there somewhere explained why the volume pot R11 is 500k in parallel with R9=100k resistor? Why it's not 100k pot only (without R9), which would make it little bit "stronger" (less dependent on load resistance) signal source?
...

Hey Tomas,

The article  states :

"the output of the second stage is routed through an attenuator consisting of R8, R9, and output control R11.  The accumulated gain after the second stage is so high that the absence of an attenuator would make it ridiculously difficult, if not impossible, to adjust the controls for varying degrees of overdrive." (pg 34, top right corner block of text)

hope this helps

OK, thanks, so there's nothing else about it? I understand the attenuation, but I don't think it's a good idea to use needlessly such a big value for R11 (Volume pot) in stompbox as it makes dialed volume level more influenced by actual load at stompobox output (which varies with configuration of following effects chain) - I would advice to use A100k pot for R11 and dump R9 or use R9=510k (to achieve exactly same output levels as the original circuit).

T.

[Ben N]

Does everyone get that Fred's site is still up, with all his unique projects, including  slightly revised version of this article and project?

[liddokun]

Yep, I'm well aware that Fred's site is still up, I was just over there the other day actually looking for a tube phono preamp.  I posted this article just because I figured some people on here would like to see the original article (which I don't think Fred's got on his site). The circuit has since then been revised and improved, and Francisco Pena has a pcb design and project for the revised one (McTube II) over at Tonepad.