Ampeg - Sub Blaster  [schematic]

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Re: Ampeg - Sub Blaster

Postby chicago_mike » 13 May 2010, 05:48

CD4013 :

Pins 9,11,4,6 go to ground.

make sure on your layouts / transfers that pin 4 goes to ground. It should not be floating.

So I get it to create the lower octave, but my dry signal is not clean, not full swing. Have to double check some soldering. :scratch:
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Re: Ampeg - Sub Blaster

Postby chicago_mike » 15 May 2010, 02:39

SUCCESS!!!!

99% anyways! :lol:

Okay I need help here. I have the octve signal, and everything else is great.

I do NOT have a J175.

I DO have though

J201
J111
2N3820
2N3819

I noticed the J201 is used in the Boss Octaver...Could I just use that and see what happens?
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Re: Ampeg - Sub Blaster

Postby chicago_mike » 15 May 2010, 02:49

OKay so swapping in a J201 Almost works.

In the Boss schematic, theres a couple extra parts to do, an extra resistor tying one of the pins back to Vref.

But I do get a pre octve, Octave and post octave signal ( of some sort ). :D
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Re: Ampeg - Sub Blaster

Postby chicago_mike » 15 May 2010, 02:56

So in theory, on paper. :lol:

Tie the Drain to a 100k to Vref.

Tie 1meg to gnd to the gate After the 100K resistor coming out of the CD4013.

Change the 100K to a 1MEg.

All I did so far was the 100K vref mod.

Going to try the others right quick and see what I can see.

Fuck if this works!!!! :horsey: :mrgreen: :applause: :popcorn: :horsey:
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Re: Ampeg - Sub Blaster

Postby chicago_mike » 15 May 2010, 05:24

Now, to clean it up and see if theres any way to clean up the tracking. If not thats fine.

But, its working. :applause: :horsey:
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Re: Ampeg - Sub Blaster

Postby chicago_mike » 17 May 2010, 21:30

Adding a little gain make up stage after the passive Big Muff style tone control.

Changing the 100K resistor coming off the cd4013 to a 330K...this value is in the EBS, the DOD and a couple other octave pedals. All using an N Fet.

Might put in a switch to change out the .22 in the Octave filter and switch between that and a .1 or a .06 as I have a drawer full of .064's. :roll: :lol:

Octave pedal is still working though. So I can confirm with a couple mods that yes its a verified build.
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Re: Ampeg - Sub Blaster

Postby audioguy » 23 May 2010, 15:31

cool man... cant wait to build one myself
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Re: Ampeg - Sub Blaster

Postby chicago_mike » 24 May 2010, 07:15

IM gone for a month on tour and she is going on my pedal board. 8)
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Re: Ampeg - Sub Blaster

Postby audioguy » 24 May 2010, 13:56

Right on!!
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Re: Ampeg - Sub Blaster

Postby seele » 19 Sep 2010, 21:37

Bump 8)
Found the thread today, good work mike :thumbsup
Is there an chance to get the final schematic?
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Re: Ampeg - Sub Blaster

Postby mictester » 14 Nov 2010, 11:32

chicago_mike wrote:LADIES AND GERMS!!!!!!

the previous schematics have some incorrect areas.


MODS!!

I had issues with poor tracking of the sub octave. A huge improvement was achieved by making U4a a clipper (like a TS clipper with a pair of diodes around the output to the inverting input). I then did an active low pass filter (-18 dB/octave) with a bit of gain (to recover the loss due to the clipper) and a turn over point at about 1.4 kHz. It really tracks well now!
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Re: Ampeg - Sub Blaster

Postby DavidRavenMoon » 16 Nov 2010, 17:20

mictester wrote:
chicago_mike wrote:LADIES AND GERMS!!!!!!

the previous schematics have some incorrect areas.


MODS!!

I had issues with poor tracking of the sub octave. A huge improvement was achieved by making U4a a clipper (like a TS clipper with a pair of diodes around the output to the inverting input). I then did an active low pass filter (-18 dB/octave) with a bit of gain (to recover the loss due to the clipper) and a turn over point at about 1.4 kHz. It really tracks well now!

Please post a schematic!
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Re: Ampeg - Sub Blaster

Postby audioguy » 16 Jan 2011, 18:29

Any progress on a final schem and layout?
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Re: Ampeg - Sub Blaster

Postby seele » 18 Apr 2011, 20:49

mictester wrote: I then did an active low pass filter (-18 dB/octave) with a bit of gain (to recover the loss due to the clipper) and a turn over point at about 1.4 kHz. It really tracks well now!


Does it track correct when playing chords? I heard the EBS octaver could do that - looking at the EBS schematic I assume it depends on the filter design in front of the frequency detection.
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Re: Ampeg - Sub Blaster

Postby audioguy » 03 Jun 2011, 11:41

I lost track of this thread a while ago... would still love to see this box finished.
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Re: Ampeg - Sub Blaster

Postby Barcode » 03 Jun 2011, 16:54

Me too, I've been itching for another octave pedal.
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Re: Ampeg - Sub Blaster

Postby chicago_mike » 21 Jun 2012, 12:56

Food for thought

This is a very popular octave pedal for bass. Its red in color. the schema is the service schematic. So I have nothing else for it.

Perhaps we can add the tone controls to the ampeg unit?
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Re: Ampeg - Sub Blaster

Postby served » 21 Aug 2012, 13:20

Hi.

How is this going?
Is the final schematic verifyed?

Need to build this monster!
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Re: Ampeg - Sub Blaster

Postby teebe » 23 Jan 2013, 18:24

Are the potts confirmed 100k logaritmic, and what kind of pot, coal??
Need to repair my sub-blaster orgin, the octave pot only works after 75%
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Re: Ampeg - Sub Blaster

Postby chicago_mike » 24 Jan 2013, 01:26

The official schematic was published earlier. :)

It was from Ampeg themselves. In the DIY layout there is a missing connection from the CD4013.

I would trace your signal before the 4103..the gain structure feeding it, just to see of those opamps are working correctly. :)

For Octave pedals...its a simple circuit.
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