Spaceman Saturn V.

[digi2t]

Many thanks to Duff Man for lending me this little jewel. Not that I have a ton of experience with boosters, but this is the best one I've tried so far. Can be as transparent or dirty as necessary. Plays nice with any amp channel.

The vero and related info can be found here;

http://www.aronnelson.com/gallery/main.php/v/digi2t/veros/Spaceman+Saturn+V/

Also many thanks to the forum for nudging me in the right direction in figuring this sucker out. Enjoy!

[digi2t]

After some more breadboard experimentation, I found that some other depletion mode MOSFET's can be used as well, so I've uploaded an alternate vero project here;

http://www.aronnelson.com/gallery/main.php/v/digi2t/veros/Spaceman+Saturn+V/Alternate+Q2+version/

Of course the alternates can be used in either Q1 or Q2 position, and fixed resistor values can be used instead of a trimmer and/or diodes. I've only gone with the alternates in the Q2 slot, opting to stay with the LND150 in Q1. The different models I listed I've tested, and I find that each one imparts different sonic qualities to the circuit. Depending on the model and bias voltage you decide to run at, some can grind, while others can deliver more harmonic content. With some experimentation, you can try different MOSFETS, at different bias voltages, and discover your own magic. All in all, just a fun platform to mess with.

[BetterOffShred]

Am I correct in thinking that it looks like it has a built in Millenium bypass LED illumination circuit using the 2n7000? Tone Mojo!   Looks cool though, Mouser has the original Depletion Fet's for 50 cents USD   

Thanks for sharing Dino!

[digi2t]

10-4 on the Mill bypass. That's standard fare for Spaceman, and I always include it on my veros. You can also use a BS170 in place of the 2N7000, but you have to flip it around for the pinout to match.

Enjoy!

[BetterOffShred]

Well that's cool!  I have a big pile of 2N7000 I acquired somehow.  Imagine I'll build all these spaceman builds at some point.

[vortex]

Big thx for your fine work!

Two questions if I may ask:

I am never quite sure which Ferrite Beads to order for projects like this. Any recommendations on specific parts or specs to narrow things down?

On the Saturn schem there are two resistors in series from the +supply to the drains (3K?1K?). Is that part of the Spaceman biasing procedure? ( dial in the drain voltage and relace with a resistor...)
Maybe you implied this already...

[BetterOffShred]

I think the ferrite beads are just for minimizing rf noise. I bought a bag of the fair-rite ones that look like diodes. Work great

[vortex]

I think the ferrite beads are just for minimizing rf noise. I bought a bag of the fair-rite ones that look like diodes. Work great

So are they 43's, 73's I am seeing FB's with 25Mhz/100Mhz specs and wondering what's a good candidate for the job. I am genuinely interested if you've found something that 'works great'.

I searched this site and there are a few threads about Ferrite Beads that seem to lead to proposals of other solutions instead of FB's. Just curious...

[PMowdes]

Big thx for your fine work!

Two questions if I may ask:

I am never quite sure which Ferrite Beads to order for projects like this. Any recommendations on specific parts or specs to narrow things down?

On the Saturn schem there are two resistors in series from the +supply to the drains (3K?1K?). Is that part of the Spaceman biasing procedure? ( dial in the drain voltage and relace with a resistor...)
Maybe you implied this already...

The resistors in series are just something weird Spaceman do, I don't think there is anything to it other than pcb asthetics (and to annoy DIYers.

[digi2t]

I remember the first Spaceman pedal I traced out was the Gemini III. I got the same blow back about some of the resistor values in that circuit. Lots of comments regarding my vision, or whether I was color blind in regards to the stated values of some of the resistors.

Alas... the more I dug into these units, it dawned on me that this was just part of the deal with Spaceman. Having a 3.011K resistor in there isn't necessarily about the actual resistance, as it might be about the aesthetics of the resistor itself. Looking at a Spaceman circuit, any 120pF cap will do the job, but one has to admit, the 120pF MIAL cap carries so much more visual "mojo", that the eyes MUST be fooling the ears into believing that the sound is better. Right?

[vortex]

2 resistors instead of one for aesthetic reasons, perhaps layout reasons, fair enough. Thanks for clarifying.

Spaceman guts are certainly impressive to behold.

I googled Saturn V and found a thread on TGP where a couple of guys were looking for suggestions about using their pedal with out scuffing the finish on their pristine units... The irony of a stompbox too precious to touch with your foot...

[BetterOffShred]

That F&T Capacitor ..  Mojo? 

As for the 4 transistors.. As we were talking about at the start of the thread, it has a Millenium bypass built in, which after looking at Dino's traced schematic, is using a BS170 and a 2N3904.    The other two are the LND150N3 Depletion MOSFETs. 

Also, I looked at my ferrite beads that "work great" in the few things I've used them in, and they are the Gold variety of Ferronics Z-max chokes.   

[vortex]

That F&T Capacitor ..  Mojo? 

As for the 4 transistors.. As we were talking about at the start of the thread, it has a Millenium bypass built in, which after looking at Dino's traced schematic, is using a BS170 and a 2N3904.    The other two are the LND150N3 Depletion MOSFETs. 

Also, I looked at my ferrite beads that "work great" in the few things I've used them in, and they are the Gold variety of Ferronics Z-max chokes.   

Sorry, I am not firing on all cylnders today. I'm down with the flu and apparently challenged with the basics. Sincere apologies. It's been a while since I used a Millenium bypass and my flu brain was thinking 'one Jfet'....

Thanks for the info on the Ferrite Beads, I will check them out.

[BetterOffShred]

Oh for sure Man! I've been there recently.  I ended up with a sever sinus infection and was totally out of it, still managed to play a little though! 

I'd go with the cheaper fair-rite variety beads if you're even worried about it.  I put the gold Z-max on the tester and it's extremely low resistance (0.02R) and the spec says 10Mhz to 100Mhz off the data sheet.  I think they were used for aesthetics.

[blackieNYC]

Hey - I only see the depletion version schematic.  Any circuit changes needed when using plain old BS170 or 2N7000?

[BetterOffShred]

The effect requires depletion FETs.  I believe the other version just uses a different depletion fet.  The 2n7000 or bs170 is for the millennium bypass not the effect itself. 

[digi2t]

The effect requires depletion FETs.  I believe the other version just uses a different depletion fet.  The 2n7000 or bs170 is for the millennium bypass not the effect itself.

Correct, on both counts.

I've breadboarded both versions, and the only one that works with source diodes is with LND150's in Q1 and Q2. Also, using different diodes varies the Drain voltage, due to the vF tolerance of whatever diode you're using, so if you're trying to hit the reported voltages bang on, you'll have to audition a bunch of different diodes. I was lucky, the 1N4148 I used for Q1 gave me bang on numbers, but I had to try a few different BAT diodes to get Q2 to spec's. Don't sweat it though, I'm only talking about a 0.3v difference here, so it's just me nit-picking. Really no audible difference between 3.7v and 4.0v. Using the other D-MOSFET's requires trimmers.

To date, I only tried four other models of D-MOSFET's in the Q2 slot (ones listed on the alternate schematic), and I found that a couple sounded OK, while others sounded very harsh. Can probably be tamed with added/different cap values in the surrounding topology (but then it wouldn't be a Saturn V anymore, would it). The best sound was with the LND150's, but I listed the others simply as alternates if folks want to experiment. Circuits, as with everything in life, are set in very soft concrete.

[BetterOffShred]

I'm just going to order some LND150's from Mouser next time I make an order, they are like 50 cents USD each, so that's a no brainer, particularly if you say they sound the best.  (read "the best") 

Unfortunately for me (fortunately for me) I have 2 of Your circuit boards sitting here waiting for me to put them together, and I'm not quite done with the Skyripper yet, so the Saturn V will have to wait a few weeks at least! 

Thanks again for the layout Dino!
-Brett

[digi2t]

You might want to hold off making a vero board for this. PMowdes has already drawn up a PCB for it, which will become available in the near future.

[digi2t]

Sharp eyed rocket man Cristiano (intripped) pointed out that I left out a cap on the schematic. My sincerest apologies. Not major, it just got lost in the transfer from my hand drawing to the computer. It's a 100pF cap from Boost pot lug 3 to ground. Here's the updated schematic;




The original version schematic and vero in the gallery is updated. The alternate schematic is updated the alternate vero version will be updated soon.