BBE - Green Screamer modification

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BBE - Green Screamer modification

Postby sidehatch » 15 Nov 2008, 21:13

Hi,

Im new to this forum and really like it. Im wondering if anyone has worked on the bbe green screamer? It sounds very good stock and better than any screamer Ive ever had but I'd like to add a switch that cuts the gain and makes it more of a boost and one that does clay jones or landgraff mods. I have also heard that the eternity pedal is a TS derivitive.

About me: I can solder and have modded pedals, guitars and amps before however a schematic alone wont do anything for me. I need to be told replace C2 etc.

I have plenty of nice OD's but specifically bought the BBE to fiddle with.

Any help will be much appreciated. I cant photo the curcuit board if needed but havent had any luck finding a schematic.

Thanks!
Shane
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sidehatch » 15 Nov 2008, 21:15

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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby IvIark » 15 Nov 2008, 21:35

Get a DPDT toggle switch, 3 position with a centre off. The layout of the terminals will be something like:

1 4
2 5
3 6

Take out D3 and D4 diodes and replace one of them with two wires. Take one of the wires to 2 and the other one to 5. Solder the diodes back in between 3 and 6 making sure there is one in each direction - you could add an extra diode so there is one in one direction and two in the other. Then get a couple of LEDs and solder them between 1 and 4, one in each direction.

This will give you symmetric clipping in the top position with the LEDs, assymmetric clipping in the bottom position with the diodes (symmetric if you just put the two diodes back in) and remove the clipping components in the centre off position which will be your clean boost setting.
"If anyone is a 'genius' for putting jacks in such a pedal in the only spot where they could physically fit, then I assume I too am a genius for correctly inserting my legs into my pants this morning." - candletears7 - TGP
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sidehatch » 16 Nov 2008, 22:33

Thanks a lot for your help. I have the dpdt switch and need to find the LEd's. Do you know which one to get?

I am almost visualizing this.Please see if I have it right:

So I remove d3 and d4 and run a wire from each end of D3. One goes to 2 and the other goes to 5. Then I solder the removed diodes in parallel between 3&6 but make sure the diodes are facing oppisite directions. Do I have it right so far?

If so then I solder the new led's in parallel but again opposite in between 1 & 4. Is this right?

What do I do with the hole on the board where d4 was? Do I have this all wrong?
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sugarinthegourd » 17 Nov 2008, 21:47

What do I do with the hole on the board where d4 was?


You can leave those holes open. D3 was in parallel with D4 and you've replaced D3 with 2 new LEDs in parallel -- to the circuit, it still looks the same.

I would have suggested a 2-way on/on switch, but I like the idea of the on/off/on which gives you the diode-less middle option -- very clever!

I think I may do the same mod, but may also replace the TL072 so I can try some other chips. Curious what a BB OPA2134 would sound like in there.
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby IvIark » 17 Nov 2008, 22:06

I haven't swapped opamps out with the Green Screamer, but I did with a Blue Boy Deluxe which is a Tubescreamer clone that comes with the more usual JRC4558D. I tried an RC4558P, TL072, NE5532, LF353 and an LM1458. I much preferred all of them over the stock JRC4558D (particularly at higher gain settings) with the exception of the LM1458 which sounded fizzy with my main amp. The TL072 sounded great and a lot more raw than the standard opamp, it actually sounded not too dissimilar to an OCD to me. My favourite by far though was the NE5532 which was much smoother and just sounded more musical to my ears.
"If anyone is a 'genius' for putting jacks in such a pedal in the only spot where they could physically fit, then I assume I too am a genius for correctly inserting my legs into my pants this morning." - candletears7 - TGP
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby IvIark » 17 Nov 2008, 22:11

sidehatch wrote:Thanks a lot for your help. I have the dpdt switch and need to find the LEd's. Do you know which one to get?

I am almost visualizing this.Please see if I have it right:

So I remove d3 and d4 and run a wire from each end of D3. One goes to 2 and the other goes to 5. Then I solder the removed diodes in parallel between 3&6 but make sure the diodes are facing oppisite directions. Do I have it right so far?

If so then I solder the new led's in parallel but again opposite in between 1 & 4. Is this right?


Yes everything you said is spot on and as sugarinthegourd said you can just ignore the D4 holes. You can just experiment with LED types as some people claim they are audible differences between them, I just used 5mm red ones I think.
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sugarinthegourd » 17 Nov 2008, 22:19

Are these boards pretty easy to work on, ie, non-SMT components and a bit of working room?
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby tunghaichuan » 18 Nov 2008, 01:25

sugarinthegourd wrote:Are these boards pretty easy to work on, ie, non-SMT components and a bit of working room?


I opened mine up right away when I got it last week and was surprised: no SMDs. The board is fairly small, but it looks like it will be pretty easy to work on. The board only takes up have of the case.

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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sidehatch » 18 Nov 2008, 03:15

I started to do it a few mins ago and the switch i have is an on/on switch with 6 lugs not on/off/on.

I went to radio shack and of course they dont have the right switch. Besides the 6 lug switch I aslo have 2 more switches but both are 3 lug on/on .

Do I need to just order the right switch or can I still do anything cool with my switches? What I'd really like to have is the clean boost and the best full on lead tone I can get.

I also switched out the op amp for a socketed one and tried many differnt op amps. The one I liked best is an old TI rc4558. I like it better than the 072 .

Thanks

Shane
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sugarinthegourd » 18 Nov 2008, 03:22

sidehatch wrote:I started to do it a few mins ago and the switch i have is an on/on switch with 6 lugs not on/off/on.


You can use that per the instructions above, you just won't have that 3rd option of bypassing the diodes completely for a clean boost. Not sure what it would sound like without the diodes, but you can find out by playing it a bit after you snip them out. If you find it's a tone you like and want to get again, you'll want to track down a DPDT (6 lugs) on/off/on switch. If not, use the on/on you've got and you'll have the two clipping options like the Landgraff/Clay Jones.

What size/color LEDs are you using? (Does this really make a difference, btw?)
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sidehatch » 18 Nov 2008, 03:34

Thanks for your reply.

Do you know where the wires would go on my new switch? its still has
6 lugs . I really need to be told what to do. Since I'd be giving up the clean boost I dont know how to compensate on the wiring.

I dont know anything about the leds. I just went to radioshanck and bought 2 5mm white leds and want to try them.

I'd like to try the switch I have tonight but I need someone to "hold my hand" !!
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sugarinthegourd » 18 Nov 2008, 03:49

You already said it yourself!

So I remove d3 and d4 and run a wire from each end of D3. One goes to 2 and the other goes to 5. Then I solder the removed diodes in parallel between 3&6 but make sure the diodes are facing oppisite directions. Do I have it right so far?

If so then I solder the new led's in parallel but again opposite in between 1 & 4. Is this right?


That's it, exactly.

Do you have a solder sucker or desoldering braid to get those diodes off the board cleanly?
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sidehatch » 18 Nov 2008, 04:30

Yes I do. Im going for it right now. I hope it works out ok!

Thanks!
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sidehatch » 18 Nov 2008, 08:30

It didnt work. I put it back and its dead

I've gone over evrything and I cant figure out whats wrong. The pedal does work but it has no gain and the gain knob doesn't work.

The worst part is that even though it is a cheap pedal I loved that one sound it has and I cant get it with any of my other OD's. To top it all off I did a swirly paint job on it the other day ala dragonfly and it looks incredible! Im bummed. :(
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby IvIark » 18 Nov 2008, 10:16

Can you post a close up pic of both sides of the board so we can see if anything obvious stands out
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sugarinthegourd » 18 Nov 2008, 13:44

Yeah, please post the biggest, closest-up macro pictures you can. If you don't know how to host pix, pm me and I will post them. We'll get it working!
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby nooneknows » 18 Nov 2008, 14:15

sidehatch wrote:Found scematic on here:
http://www.indyguitarist.com/schematics ... _schem.gif


the schematics isn't complete, it lacks the reference voltage for the opamp ins, maybe with some picture it could be possible to draw the right circuit.
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sugarinthegourd » 18 Nov 2008, 14:52

nooneknows wrote:
sidehatch wrote:Found scematic on here:
http://www.indyguitarist.com/schematics ... _schem.gif


the schematics isn't complete, it lacks the reference voltage for the opamp ins, maybe with some picture it could be possible to draw the right circuit.


Argh. I was afraid of that. It sounds like the modder may have an open circuit now somewhere around that 250k pot. But I don't know why, if he successfully replaced those 2 diodes. Without a good schem, though it's hard to say. I have one backordered from guitarcenter.com but I may try to drive over to the local place tonight and see if they have one -- I have like 5 mod/build projects underway and I need one more like a hole in the head, but such is this obsession...
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sugarinthegourd » 19 Nov 2008, 03:55

Got a Green Screamer tonight. Also got a few red LEDs: will use 5mms if they fit and 3mms if not, and a DPDT on/off/on switch from Rat Shack.

I want to try to understand this circuit better before I removed the diodes. Will see what I can figure out and hopefully post findings later the week.
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