BBE - Green Screamer modification

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

Postby sugarinthegourd » 19 Nov 2008, 04:33

I may be wrong but looking at Wampler's schematic I'll bet there's a cap missing in parallel with the 2 diodes. This pedal seems to be a very slightly modified version of Orman's Son of a Screamer (as I think the Eternity is).

I've never drawn a schem before but may attempt it. Can anyone recommend any good freeware software? Eagle? ExpressPCB?

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

Postby sidehatch » 19 Nov 2008, 06:13

I took it by Keeleys' today. they are 10 mins from me and they can get it going and do all of those mods because its exactly what they do on the rat. They also showed me their boss sd1 mod where they use leds and a germanium diode . Im thinking about subbing it for one of the positions. What do you guys think?

Also, its costing me $50 which is more than I paid for it but I guess its better than me screwing it up even more. I have to buy a pro level soldering iron before I do anymore stuff like that. I couldn't get solder to stick to the back of some brand new cts pots in my guitar tonight . A 20 min job turned into 5 hours and a burned hand. Ijm a basket case and should probably stick to playing the guitar!
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sugarinthegourd » 20 Nov 2008, 06:14

Here's a tentative parts list:

VR1: A250K (Gain pot)
VR2: B10K (Tone pot)
VR3: A10K (Level pot)

D1: 1N4001? (black diode)
D3, D4: 1N914? 1n41148? (I assume D2 is the power LED)

R2, R3, R12: 10K 5% carbon film
R4: 3M 5% carbon film
R5, R11: 1K 5% carbon film
R6: 10M 5% carbon film
R7, R8: 1.15K 1% metal film
R9: 1K 5% carbon film
R10: 220 ohm 5% carbon film
R13: 6.31K 1% metal film

C1: 1000uF 25V electrolytic, polarized radial (Xiahui)
C2: 10uF 25V electrolytic, polarized radial (Xiahui)
C3,C5: 100 pF, ceramic
C4: .01uF 100V 5% (green)
C6: 0.1uF 100V 5% (green)
C7, C8: 220nF 63V (brown)
C9: 1uF 50V electrolytic, non-polarized radial

U1: TL072CP

Values above were read by eye. Not 100% sure about some of the mf resistors -- tomorrow I'll pull out the multimeter & try to check, though that doesn't always work when components are on-board.

I'm sure the Wampler schematic linked earlier has some things missing, besides the reference voltage section.
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby nooneknows » 20 Nov 2008, 08:00

please, any picture of the pedal inside?
thank you
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sugarinthegourd » 20 Nov 2008, 14:42

Yes, will take some nice big pics of both sides of the board tonight. Maybe you all can help me verify component values &c. I want to draw the schematic but I've never done that before & a little unsure of where to start -- I guess I'll start by drawing the ground, 9V and Vref lines, and then trace input to output, huh?
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sidehatch » 20 Nov 2008, 17:42

When I pick mine up from Keeley's this week I'll post some pics too so you guys can see what they did to it.

I listened to their sd1 and rat and on the rat they do stock,diode lift and clipping leds.

On the ds1 they do stock and clipping germanium dides.

They said they could do either one on my pedal. I said at least do stock and diode lift. He's
supposed to call me before they do the mod part after they get it going.

Should I do clipping leds or germanium transistors?

The GE sounded very fuzz like and Im thinking about having him do it just so I can take pics of whats going on and post on here.
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sugarinthegourd » 21 Nov 2008, 01:34

Here are some big pics of the board

http://farm4.static.flickr.com/3053/3047113280_7689b874e9_o.jpg
http://farm4.static.flickr.com/3269/3047113890_bf110c6f39_o.jpg
http://farm4.static.flickr.com/3271/3046280033_cddd89c127_o.jpg

You'll notice D3 & D4 are facing in the same direction but they're tied together in with a diagonal trac on the back of the board.
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sugarinthegourd » 21 Nov 2008, 06:34

Schematic & Finalized parts list -- UNVERIFIED

Image

VR1: A250K (Gain pot)
VR2: B10K (Tone pot)
VR3: A10K (Level pot)

D1: 1N4001? (black diode)
D3, D4: 1N914? 1N4148? (I assume D2 is the power LED)

R2, R3, R12: 10K 5% carbon film
R4: 1M 5% carbon film
R5, R11: 1K 5% carbon film
R6: 10M 5% carbon film
R7, R8: 2.15K 1% metal film
R9: 1K 5% carbon film
R10: 220 ohm 5% carbon film
R13: 6.81K 1% metal film

C1: 1000uF 25V electrolytic, polarized radial (Xiahui)
C2: 10uF 25V electrolytic, polarized radial (Xiahui)
C3,C5: 100 pF, ceramic
C4: .01uF 100V 5% (green)
C6: 0.1uF 100V 5% (green)
C7, C8: 220nF 63V (brown)
C9: 1uF 50V electrolytic, non-polarized radial

IC1: TL072CP
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sidehatch » 21 Nov 2008, 07:57

Keeley finished mine today and I'm going to pick it up tomorrow.

Now that you have it apart and a schematic what do you think about the parts quality?

Is it as good as eternity and such?
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby analogguru » 21 Nov 2008, 09:02

Before I would buy an Eternity, I would buy this.... and it is easy to mod.

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

Postby Torchy » 21 Nov 2008, 10:55

R4 is 1M not 3M ... check the board photo again.
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sugarinthegourd » 21 Nov 2008, 13:48

Torchy wrote:R4 is 1M not 3M ... check the board photo again.


Thanks! I thought 3M seemed weird. In real life the first band looks like orange, but you're right, in the pic it's more brown.

Thanks again!

If anyone would like to double-check my work, I'd really appreciate it. This is a well-made pedal with some extra room in the case -- at $50 I think it's a great platform for modding. I'm planning to do the GrandLaff LED thing and also add a switchable high pass cap to get some more bass.

Was looking at the AnalogMan "silver" TS mods -- anyone think it's worth "upgrading" the signal caps and changing the signal resistors to carbon comps in this thing?
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sugarinthegourd » 21 Nov 2008, 14:30

Now that you have it apart and a schematic what do you think about the parts quality?

Is it as good as eternity and such?


I think the parts look OK. I'm actually not wild about the sound (think I prefer Maxon OD808 but I don't have one here to compare) but then I'm not really a TS guy. I do have a Lovepedal Kanji which I like a lot. Part of my motivation here is to get this one sounding a bit like that so I can sell the overpriced thing. My main motivation is education though. Like I said, I'm not a TS guy but it seems like a good circuit to understand.
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sugarinthegourd » 22 Nov 2008, 05:54

OK, I did 2 mods on this pedal tonight:

1. Did the "Landgraff" mod the the OP had attempted. It worked fine. I removed both diodes and ran wires from one set of pads to a DPDT on/off/on with the pair of diodes (parallel, opposed) on one side and a pair of 5mm red LEDs in the same configuration on the other.

2. Removed the 0.1uf poly cap at C6 and ran wires to a DPDT on/on with the 0.1uf on one side of the switch and a 1.0uf np electrostatic on the other side. This lets the bass through pre-clipping and gets rid of the "mid hump". Credit goes to Jack Orman on this one.

Findings: mod 1 is cool -- I like the center clean boost option a lot but the LEDs didn't do much for me. The gain is quieter, and the clipping is softer with the stock cap at C6, BUT: when the other switch (the "fat bass" switch) is flipped, it becomes more of a bassy distortion pedal -- I like it much better this way, and in this configuration the LEDs have an entirely different effect: switching from the 914s to the LEDs in fat bass mode results in much louder, raunchier clipping. I'm guessing the forward voltage of the LEDs is higher than the 914s, but when they are passing current maybe their resistance is lower? Dunno, just a guess.

Anyway, had a lot of fun and this is a really versatile pedal now. Next, will probably switch out some signal components: poly and electrolytics to Panasonic and Xicon and carbon comp resistors, and socket the IC.

But first, sleep.
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sugarinthegourd » 22 Nov 2008, 21:01

OK, just played this thing some more. With the LEDS & the 1uf cap it kicks ass. Played it side by side with the Lovepedal Kanji, and while I wouldn't expect them to be identical, it gets a lot of the same sounds at different places on the knobs. The Kanji will be up for sale soon.

I think the 1uf cap goes a little too low, and the stock .1uf rolls off too much bass, so will probably try tweaking those two values a bit.

Just finished a BYOC wah that sounds killer & these two pedals together are magical.

Good times, good times...
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sidehatch » 23 Nov 2008, 01:08

I used mine on my gig last night with my Jazz group. I have an amp with a real dumble ODS channel that I use for most distorted solos but this pedal is very cool in its own right.

I bought it at GC for $50 even though I didn't really need it just because I didnt have a TS type pedal and I read nothing but glowing reviews.

From the moment I first turned it on I knew there was something special that none of my previous TS pedals had. Because I know Keeley so well I have had just about every pedal he mods and this one sounded every bit as good stock. With the mods its is insanely good.

I will get those pics taken and uploaded asap. Probably later tonight when my kid is in bed. They said one way is stock with some upgraded parts and the middle is a diode lift for clean boost/fat sounds and the 3 way is LEDS.

It is right between the two sounds to my ears. Its louder and not as gainy as stock but not as clean as the diode lift.

They said its basically the mod that they do to their rat pedal.

I wish I still had my sparkledrive pedal but I think in the LED mode this sounds pretty similar to their modded version as far as I can remember.

It has a socketed op amp that I did myself and I think it is a huge improvement alone. I have read so many great review about the tl 072 but I dont think it sounds that good in this pedal. A friend of mine bought the green screamer the same time I bought mine and I socketed the chip so I can switch them out in real time and we hooked his stock version up with mine on the same settings before the mods and both the JRC and TI 4558's sounded much better to both of us. Surprisingly, The JRC4558DD even sounded better than the TL072 iin that pedal but to my ears, the TI4558RC is the best. I tried 5532's and even the Burr Brown 4558 and they all sounded good to me with the original chip being in last place.

I know the TL072 has a faster slew rate and what knot but who cares about that if it doesn't sound the best? Isn't the TL 072 what Ibanez ships in the newer TS9's that everyone wants replaced with the old chip anyway?

I am curious exactly what keeley did to mine. I dont know what kind of leds etc were used. They also replaced those diodes that I pulled out. They were pretty mangled. I dont know if they used the exact part or just something close.

BTW: Who is the first guy to start using LED's in the circuit? I thought it was landgraff or Clay Jones but I remember at least 10 years ago going over Keeley's Trailer where it was just him in a bedroom modding pedals and he told me he was using assemetrical LED's on Boss and Ibanez pedals.
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sugarinthegourd » 30 Nov 2008, 15:47

sidehatch wrote:It has a socketed op amp that I did myself and I think it is a huge improvement alone. I have read so many great review about the tl 072 but I dont think it sounds that good in this pedal. A friend of mine bought the green screamer the same time I bought mine and I socketed the chip so I can switch them out in real time and we hooked his stock version up with mine on the same settings before the mods and both the JRC and TI 4558's sounded much better to both of us. Surprisingly, The JRC4558DD even sounded better than the TL072 iin that pedal but to my ears, the TI4558RC is the best. I tried 5532's and even the Burr Brown 4558 and they all sounded good to me with the original chip being in last place.


I am going to put a socket in mine and try rolling opamps -- just curious if you tried a Burr Brown OPA2134. I'm going to try it when I have some time to open the thing up again. Will let you know what I find.
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Re: BBE green screamer. Bought it to mod. toggle LDO CJOD

Postby sidehatch » 30 Nov 2008, 18:55

Sorry I forgot to do photos. I'll do it as soon as I'm done here.

I do have the burr brown op amp I can try but I have it in one of my delay's instead of the 5593? I think thats it. It is much much quieter in my delay than than the stock chip.

I didnt like the burr brown op- amp in other OD's I tried it in like the barber direct drive , Keeley tube screamers and the zen drive.

Who knows though it may be great in this.

I thought the TI sounds better than the JRC in this. Better may not be the word but it does seem richer or more colorful.

Its really strange because I have always gone for the JRC in the past. I got a bunch of op amps from keeley who is just a few mins away from me and I think this is the first time I went for the TI chip.

I'd like to try the old TI4558 too because I think this is a new one.
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BBE green screamer: more drive?Add GE diodes for Zen tone?

Postby sidehatch » 04 Dec 2008, 20:56

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!
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Re: BBE - Green Screamer modification

Postby sidehatch » 09 Dec 2008, 07:09

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!
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