Basic Audio - Scarab Deluxe  [traced]

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
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Cub
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Post by Cub »

Hello lads,

Just came across a clip of this and I like what I hear. It's silicon and Bender-ish and that's about all I could find. Enclosed are two gut shots, sadly without visible what transistors are used and no shots of the trace side.

[youtube]https://www.youtube.com/watch?v=J70JpHVrVbg&hd=1[/youtube] you can see more gut shots at 1:34-1:45 and 2:23-2:31 min

with several gut shots. The most important one (the PCB) is in view from 1:40-1:58 min.

Does anybody have more information ?

Thank you ! :thumbsup

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Post by rbstep »

Try--basicaudio.net----for more info and prices....

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Barcode
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Post by Barcode »

rbstep wrote:Try--basicaudio.net----for more info and prices....
John Lyons (Basic Audio) is a member here. Just PM him, I don't think he's all that secretive...

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Post by Cub »

Barcode wrote:John Lyons (Basic Audio) is a member here. Just PM him, I don't think he's all that secretive...
Thank you, I had no idea he was a member here ! I dropped him a PM, I hope I will get a reply.

Until then, here's a link to one of the coolest pedal demonstrations ever to hit YouTube:
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Post by Cub »

Cub wrote:
Barcode wrote:John Lyons (Basic Audio) is a member here. Just PM him, I don't think he's all that secretive...
Thank you, I had no idea he was a member here ! I dropped him a PM, I hope I will get a reply.
No reply from John yet, but I've done a little digging and I think there might be a possibility that he got the inspiration for his Scarab and Scarab Deluxe from pedals with schematics similar to the ones posted in the Silicon Tone Bender thread:
viewtopic.php?f=13&t=7767

What do you lads think ?
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Post by bigmufffuzzwizz »

That pedal demo is really awesome! So many classic fuzz tones are being achieved. I've seen some other demos of his Scarab and I remember being quite impressed. After hearing those original demos I decided I needed to build myself a silicon tone bender fuzz (not interested in germanium at the moment) similar to John Lyons. I'd say the link John posted on the first page is a good place to start. The schem mictester posted is pretty much identical.
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Post by ~arph »

Let's start.. here are the component values:

Image

I've looked at three or four different gut shots for the values. (EDIT: To clarify: There are two places where to resistors are the same value left and right from the text.. This is the case with the 10k above the 100n? in the center and the 110R at the bottom center )

The values in white are educated guesses.

Most of them come from the tonebender schems on the web.
The 10n comes from the Hot Silicon. The FAT pot blends between the 10u and the 10n.
The tone cap values come from the Hot Silicon too (or mictesters :lol: )
Transistors probably 2N5089 or 2N5088, diode 1N400? something.

The bias pot biases Q3 as mentioned on Johns website. So it leads me to believe Q2 and Q3 are not on the same collector resistor.

Now we need a prelliminary schematic.
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Post by ~arph »

Ok, here is what I came up with. Please let me know what you think. This is after all a guess.

Image

There are still some values missing/wrong
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Post by bigmufffuzzwizz »

Nice one arph! That looks pretty close to what I was thinking, just a few changed values. Is there a reason you switched the order of the 2K2/8.2n side of the tone pot?
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Post by ~arph »

The order of those two does not matter to the sound. They were ordered that way on the schematic I used to create the one above. If you look at the gutshots it appears that they are the other way around so they should be switched. I was too lazy to do that... as it is not 100% accurate yet anyway.
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Post by roseblood11 »

I'd really like to know if that schematic is correct...
John, will you enlighten us?

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Post by John Lyons »

Fairly close.
Remove R9
Remove the 750 in series with +9v
Put 1k in series with the Bias Pot (25K)
R5 is 1k
C4 is 100uf
FAT is 100k
1K off FUZZ pot is 750 ohms
C7 is .1
Q3 emitter goes to .1 then to the high side of the tone pot.
Split off the same .1 is 10k to the low side of the pot and
a .1 to 2k2 to ground. (Low pass only, shelved at that)

I started with the Hot Silicon as a base. Mic Testers schematic (which is the same) :scratch:
was not on line at that time (for a few years actually)

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Post by iq01221 »

I'm not a fuzz pedals lover, but this one!! :thumbsup And I really enjoy the demos!!

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Post by roseblood11 »

Many thanks, John!!! :popcorn:
I haven't built a fuzz over the last two years, because I've got more than enough, but I'll dfinitely build this...

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Post by storyboardist »

So would this schematic be correct?

Image

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Post by roseblood11 »

No, if I get it right:
John Lyons wrote:Q3 emitter goes to .1 then to the high side of the tone pot.
Split off the same .1 is 10k to the low side of the pot and
a .1 to 2k2 to ground. (Low pass only, shelved at that)

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Post by storyboardist »

Yeah, that part confused me. But his description of the tone circuit made me think he may have meant Q4? :?
roseblood11 wrote:No, if I get it right:
John Lyons wrote:Q3 emitter goes to .1 then to the high side of the tone pot.
Split off the same .1 is 10k to the low side of the pot and
a .1 to 2k2 to ground. (Low pass only, shelved at that)

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Post by IvIark »

storyboardist wrote:Yeah, that part confused me. But his description of the tone circuit made me think he may have meant Q4? :?
Yes that's the way I interpreted it too. But John said the 100n goes to the high side and then a 10K down to the low side which to me sounds like the 100n from the emitter goes to the 10K/100n junction rather than as it is in the updated schematic going to the low side of the pot.
John Lyons wrote:Q3 emitter goes to .1 then to the high side of the tone pot.
Split off the same .1 is 10k to the low side of the pot and
a .1 to 2k2 to ground. (Low pass only, shelved at that)
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Post by storyboardist »

Ah, so like this:

Image

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Post by IvIark »

storyboardist wrote:Ah, so like this:

[ Image ]
Yes that looks like the way John described it, or at least that's how I understood it.
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