Tube Preamp Pedals

[BrianJ]

Hi Everyone,


It's been ages since I last posted here.  Too much work, not enough DIY.  I made a couple of tube pedals recently and I wanted to share some pictures.  The first is an SLO100 style preamp:

http://imageshack.com/a/img543/7603/by8w.jpg
http://imageshack.com/a/img692/9371/myrl.jpg
http://imageshack.com/a/img545/8551/wyc7.jpg
http://imageshack.com/a/img59/2416/iaxh.jpg

Eventually I'll take it apart and paint it.  The pot shafts are all cut to the same length now, but no knobs just yet.  The circuit uses both channels so one switch goes between lead and "crunch", the other switch is true bypass.  The PS is linear using an electroharmonix transformer. The B+ is a little low for this circuit - around 275vDC at the first stage - It sounds cool but I'm not sure I love it yet.  Putting the whole thing together inside of the enclosure was quite an engineering challenge... but it all fits and the noise is low.   Elevated AC heaters by the way.

The second is a preamp only clone of the Orange Dark Terror.  I played the amp at GC and thought the tone was just great... but not $650 great if you know what I mean: 

http://imageshack.com/a/img407/6449/t2it.jpg
http://imageshack.com/a/img856/1440/sc07.jpg

This one I wanted to do all point-to-point.   Kind of an homage to the organic sound of the amp.  After I machined the box it took about 12 hours to wire up.  I worked from the schematic directly with no preplanned layout and - aside from forgetting 2 ground wires (one of which lead to high voltage guitar strings!!) - everything worked on the first go.  Absolutely love this one by the way, easily the best sounding tube anything I've made yet.  The PS of this one is a Nixie Clock SMPS from Ebay.  Definitely the way I'll be going on future low current tube projects from now on - Small package, low current (ie, a little safer), and DC heater compatible.  I also made a conscious effort to build everything and mount from the inside so I can loosen everything up and drop the rat's nest of wiring out with no de-soldering if I ever paint it.

I'd appreciate build feedback... I'll post clips if someone recommends an easy way to host some audio files.


Regards,
Brian

[peterg]

Brian. Really nice work! You are a man of patience from the looks of it! Do you have schematics?

[Morocotopo]

Nice builds Brian!

It always make me nervous seeing a tube right where a foot will go... will the tubes have protection bars or a cage or something?

Also, the first one, the power supply board, will it be protected from contact with the other board and/or the box? I mean, high tension... i believe you have thought about it...

For clips, use soundcloud or something like that and post a link.

[J0K3RX]

Brian, Excellent work!!! Very interested, keep it coming!  

[Bill Mountain]

Wow! These look great.  Id love to see links to the supply you used.

Oh and I'd love to see a video of you playing them.

[J0K3RX]

These are some I found on the Russian forums. I have the full schematics and layouts for them.. I wanted to convert them all to use nixie since I have built a couple tube pedals using them and they work great and a lot cheaper than transformers etc..  I also have mixed emotions about the tubes protruding from the top of the pedals... The two I have built have the tubes sticking out of the top but, makes me nervous!  The next ones I build will have them on a daughter board like these.

These are just some examples

[kingswayguitar]

holy wow
great stuff guys
makes my pedals look like hamburg

[BrianJ]

Posted by: peterg
Brian. Really nice work! You are a man of patience from the looks of it! Do you have schematics?

Thanks... I've never been described as patient before.  I always thought it came from darker, more neurotic place.  Thanks!

So the SLO100 is the stock schematic... like this:

http://www.prowessamplifiers.com/schematics/misc/Soldano_SLO100.html

The only differences are that I changes the bypass caps to lower values in places and the LDRs are replaced with switch contacts on the stomp.  The output comes straight off the volume pot... I keep it set REALLY low.

The ODT schematic I used is here:

http://www.freestompboxes.org/viewtopic.php?f=2&t=14588

I posted there too... the output is taken after the volume pot at the junction of R19 and R20.

[BrianJ]

Nice builds Brian!

It always make me nervous seeing a tube right where a foot will go... will the tubes have protection bars or a cage or something?

Also, the first one, the power supply board, will it be protected from contact with the other board and/or the box? I mean, high tension... i believe you have thought about it...

For clips, use soundcloud or something like that and post a link.

Ya, I'm stepping lightly around the living room for now.   I'm thinking of improvising a a tube guard on the DT pedal from a drawer pull.. like this:

http://www.homedepot.com/p/KOHLER-Purist-3-in-Polished-Chrome-Drawer-Pull-K-14485-CP/202554131#.UmKeFxZCbww

As for how to keep the boards from touching:  I modeled the whole this up in 3D before I started building - the tubes, the turrets, the caps, standoffs, everything but the resistors.  I found where there were interferences and made changes.  I did have to open it up and notch out part of the PS board the fit the jacks in the back but the whole thing fits like a glove. 

You know what?  I think I have a soundcloud account.

[BrianJ]

Wow! These look great.  Id love to see links to the supply you used.

Oh and I'd love to see a video of you playing them.

Ebay!  Here you go:  http://www.ebay.com/itm/111025155835

[BrianJ]

These are some I found on the Russian forums....

Ya, that's a tight build.  Looks like the SMPS is right on the main PCB and everything.  No shortage of knobs either!

[BrianJ]

Any thoughts on if I could pull off one of these for a larger enclosure?

http://www.diystompboxes.com/wpress/?p=207

I'm thinking of painting the Dark Terror black and having the plexi go from white to orange... To match the amp's color scheme.