BBE - Green Screamer modification

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Re: BBE green screamer: more drive?Add GE diodes for Zen tone?

Postby nooneknows » 09 Dec 2008, 14:03

sidehatch wrote:I'm wondering if I can get more drive out of this thing now like keeley's "baked" mod?

Also, Is it possible to add the GE diodes to this to get those cool Zendrive like tones?

What would be cool is if I can keep the 3 way switch I now have and add another switch that kicks in GE diodes for the Zen thing.

Thanks!


you can increase the gain:
- with a bigger gain pot (500KA or 1MA for example)
- decreasing the value of R8 (in that case you have to modify C6 too to keep the same low frequency cut, f = 1 / (2*PI* R * C) )
- changing D3 and/or D4 with GE diode (you will notice a volume drop in that case).

I don't know exactly what you mean with "Zen thing", I guess you'd want to add a couple of ge diodes in series with D3 and D4: doing this thing only the gain will be decreased a bit beacuse the voltage swing could be wider, unless you put a bigger pot.
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Re: BBE - Green Screamer modification

Postby sidehatch » 10 Dec 2008, 01:37

I might try a higher ohm pot. The damn pots are board mounted so it may be a huge hassle. I found it very hard to solder on BBE's board.
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Re: BBE - Green Screamer modification

Postby indyguitarist » 15 Dec 2008, 20:22

sidehatch wrote:I was worried nobody would see my last question becasue the thread is so long.

Can anyone help me get more gain out of this pedal like keeleys bakes 3 times the gain mod?

Is it possible to add GE diodes to get in the realm of zen type tones?

Thanks!

c6: .22uf
r8: 1k
gain pot: 1m

Might be too much gain though without a buffer before it - maybe try 500k if you get oscillations with the 1m pot
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Re: BBE green screamer: more drive?Add GE diodes for Zen tone?

Postby nooneknows » 18 Dec 2008, 23:45

nooneknows wrote:I guess you'd want to add a couple of ge diodes in series with D3 and D4: doing this thing only the gain will be decreased a bit


ops, sorry! I wanted to write 'distortion' not 'gain'
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Re: BBE - Green Screamer modification

Postby sidehatch » 19 Dec 2008, 01:46

I picked up another BBE green screamer today.

I think Im going to do the same mods I did to the first one except make this one hardwired with the leds becasue thats what I will want on the higher gain. I'll also add
c6: .22uf
r8: 1k
gain pot: 500k
Ge diodes with d3 and d4

its a combo of both ideas. I bet it should be cool
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Re: BBE - Green Screamer modification

Postby sidehatch » 23 Dec 2008, 04:34

I got the other Green screamer going.

I did the same thing since I have another to use while doing the mod.


I subbed GE diodes in one of the 3 way positions -A trick I picked up from Keeleys SD1 mod.

This is pretty cool and makes it worth keeping both.

I did the cool swirl paint job on one and may do the other tonight.

Thanks to you guys and this board!

Merry christmas!

Shane
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Re: BBE - Green Screamer modification

Postby koji » 04 Feb 2011, 19:23

I'm thinking about buying one of these Green Screamers making the big change to pedals from my old GT-3. The mod installing the dpdt switch is one I'm defenitely going to try and all of the info is great. On the dpdt switch do you have to drill a hole to install it. On the two diodes they usually have a stripe on one end and you install them in opposite directions where on the stripe lines their just opposite from each other and don't line up. I'm not sure why you use led's. Do they light up to where you can see them or are they used to tap into a voltage and apply some resistance. Led's I think usually have two lead wires coming out of them. So if you are using two led's would you be soldering 4 leads to one of the positions on the dpdt. Do the dpdt's come in different sizes. If they do should you get the smallest one and would Radio Shack have all of these items. Led's and a dpdt switch. If they don't is there somewhere else to go that anybody would recommend. I'm new at this and don't have any expierence. But I've worked on electronic equipment in the office machine business for a long time and have good soldering equipment and do all of my own repairs and customizing on my guitars. I'd like to get an op amp socket also and am wondering if Radio Shack would have one of them. Thanks.
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Re: BBE - Green Screamer modification

Postby jimmyhaggard » 03 Mar 2011, 23:21

I know this thread is old, but I just ran across it and wanted to add a note.

My original BBE Green Screamer (not the airplane paint job version) always had a bit of a weird shrill edge to it. So, I decided to try a different opamp. After a lot of online research (including finding a place that had sound samples for comparison between ships used in TS-808 and TS9 pedals), I decided to try the Texas Instrument RC4558P chip. I ordered the chip from Digi-Key and it cost 46 cents plus $2.27 for tax and shipping - total $2.73 US.

The RC4558P chip is great in the BBE Green Screamer. The weird shrill edge is gone and the overdrive is full. I definitely recommend picking up a BBE Green Screamer for cheap and dropping a couple bucks to replace the opamp with a RC4558P chip.
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Re: BBE - Green Screamer modification

Postby TubeDude22 » 26 Mar 2011, 00:05

Guitar Denter seems to be blowing these out for $44 this month. So, yesterday I grabbed one. The box includes a 9 volt wall wart and a carbon battery. I liked the way chords sound on it using humbuckers in my Les Paul. Today, I socketed the chip and tried a bunch. Indeed a TI 4558 sounds superior to the stock TL072.

:applause:
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Re: BBE - Green Screamer modification

Postby garrobos » 02 Jan 2012, 23:06

In the schematic rev 1.1 traced by sugarinthegourd, R12 value should be 1K Ohm which is consistent with the manufacturer´s output impedance specification. Also R7 should read 21.5K Ohm.

Enrique
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Re: BBE - Green Screamer modification

Postby slaveunit » 15 Mar 2014, 17:51

For anyone that did the mods and added switches, where did you fit them on the enclosure?
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Re: BBE - Green Screamer modification

Postby sugarinthegourd » 15 Mar 2014, 21:40

I put them on the sides towards the bottom. As I recall there was lots of room.

slaveunit wrote:For anyone that did the mods and added switches, where did you fit them on the enclosure?
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Re: BBE - Green Screamer modification

Postby finom1 » 01 Feb 2017, 13:10

Does anyone have a working link to a good schematic?
Thank you.
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Re: BBE - Green Screamer modification

Postby sugarinthegourd » 01 Feb 2017, 14:44

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Re: BBE - Green Screamer modification

Postby EmmG » 12 Mar 2017, 09:47

I added a bass switch (C6) and LED Clipping switch (D3, D4) to one. They are SUB mini sized toggle switches because there wasn't much clearance due to PCB placement.

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