Author Topic: STM800 (BoobTube Twin)  (Read 11484 times)

juansolo

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STM800 (BoobTube Twin)
« on: April 02, 2012, 11:52:52 AM »
This is, to all intents and purposes, a Marshall in a box. Quite literally. It's the front end of a JCM800 amp scaled down and stuck in a stomp with the valves running starved plate. Power is from a Schmitt trigger based charge pump getting us up to 60v on the plates for this one.

Works well as a stomp, works incredibly well as a pre-amp plugged straight into the return of effects loops. Which I suppose is exactly what it is.

The Baby Boob Tube (coming soon) works better as a stomp box to be fair. We just wanted to see if we could make a dual tube pedal work right ;)



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eldanko

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Re: STM800 (BoobTube Twin)
« Reply #1 on: April 02, 2012, 12:44:26 PM »
droooooooooooooooooool
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gtr2

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Re: STM800 (BoobTube Twin)
« Reply #2 on: April 02, 2012, 12:48:13 PM »
lovely!

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midwayfair

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Re: STM800 (BoobTube Twin)
« Reply #3 on: April 02, 2012, 01:38:33 PM »
oh man. I think I need a mop.
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nzCdog

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Re: STM800 (BoobTube Twin)
« Reply #4 on: April 02, 2012, 01:43:44 PM »
 :o :o :o
You did it!  Nice job, looks absolutely sick!  8)
Dang!  Thats a friggin great lookin pedal... I want to build a valve preamp myself soon... love to have a peek at your schemo ;)

marauder

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Re: STM800 (BoobTube Twin)
« Reply #5 on: April 02, 2012, 02:21:30 PM »


Everything from the input to the master volume, excluding the low gain input.  Didn't bother scaling any values in the tone stack as it's driven by the cathode follower just like the real thing.  The 10K 2W resistors have also been removed the the plate power line.

Through the front of an amp it was a bit too bright, so the Klon buffer has been modded.  The 560R resistor is now a 10K with a 2.2nf to ground, then another 10K and 2.2nf.  Filters a little of the high end out, but still sounds great through the loop.

I've got an idea for a 2 channel, 2 tube pedal.  It's one I've never seen before in a stomp, and much different to the Marshall preamp.  I wonder what that can be?  Have a guess, and win a prize (or not!)   ;)
« Last Edit: April 02, 2012, 02:28:06 PM by marauder »

juansolo

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Re: STM800 (BoobTube Twin)
« Reply #6 on: April 02, 2012, 02:34:52 PM »
Just dawned on me that we actually did the schem for this... Would have been handy building it today!

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marauder

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Re: STM800 (BoobTube Twin)
« Reply #7 on: April 02, 2012, 02:38:23 PM »
The 10K/2.2nf filters are now on the Klon buffer.
That would have been handy though.

You don't win a prize by guessing the 2 channel pedal.

juansolo

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Re: STM800 (BoobTube Twin)
« Reply #8 on: April 02, 2012, 02:49:03 PM »
You don't win a prize by guessing the 2 channel pedal.

Damnit!  >:(
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night-B

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Re: STM800 (BoobTube Twin)
« Reply #9 on: April 02, 2012, 03:55:50 PM »
Pure madness  :o

Diamond

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Re: STM800 (BoobTube Twin)
« Reply #10 on: April 03, 2012, 02:42:04 AM »
Because two boobs are ALWAYS better than one! ;) Great job man! I can't wait for some sound clips.

Ettore_M

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Re: STM800 (BoobTube Twin)
« Reply #11 on: April 03, 2012, 03:55:25 AM »
Damn! You made it happen! And what a great result! Well done! I've been following the Boobtube thread all this time, and seen it evolving.. Now the time came for the BIG evolution, and the Boobtube twin! Guess there will be a whole new thread, as popular as the last..

Hector
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juansolo

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Re: STM800 (BoobTube Twin)
« Reply #12 on: April 03, 2012, 10:23:54 AM »
Still not sure the Twin is as useful a project as the original BT. Still it was fun to do and I'm really curious as to how Cleggy's mystery dual tube pedal will turn out.

However we've just built the Baby BT today and that most certainly is useful, very. Sadly it's in bits again as we need to do the enclosure. But a totally successful test. really liking it. It offers something different to the BT. To the point I might have have to have another crack at Eagle and see if a board can be done for it. It's a simple circuit (ridiculously so when you see it all sat on the back of a tube socket). It's just with the power and buffer requirements also, it'd be nice to have it on a neat/compact pcb.
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jkokura

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Re: STM800 (BoobTube Twin)
« Reply #13 on: April 03, 2012, 10:31:06 AM »
I'd love to see either the Tweed Bassman or Blackface Princeton end up done like this. I'd use it as a preamp for recording purposes if I had something like that.

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juansolo

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Re: STM800 (BoobTube Twin)
« Reply #14 on: April 03, 2012, 10:33:29 AM »
I know what Mr C is planning for his dual pedal and it's certainly going to be more Fenderish than mine, but not a Fender...
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