Earthquaker Devices Chrysalis Overdrive  [traced]

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

GUTS!

33za16f.jpg
2u6ig6b.jpg
Capacitors from left to right:

First Row:
.1uf
.022uf
100pf
.1uf

Second row:
.001uf
100uf
4.7uf
.0047uf
.1uf

Transistors:
MPSA18

The overdrive sounds great, reasonably priced, and well built. Would love to figure out what goes on in this one!
Last edited by culturejam on 05 Jul 2011, 12:58, edited 1 time in total.
Reason: Attached photos (so they don't go missing later)

jamiefbolton
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Post by jamiefbolton »

pics of the trace side?

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culturejam
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Post by culturejam »

I like that layout!

It *almost* has a Jack Deville quality to it. 8)

ieatyouforbreakfast
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Post by ieatyouforbreakfast »

I'll try and get some trace side pics around Wednesday. It's on my practice board right now but I should be free to take it off and open it up sometime later this week.

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JOHNO
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Post by JOHNO »

It's going to be difficult to see much with the pots soldered on like that, unless your prepared to remove them. You might be able to bend them slightly to expose the traces.
Thanks for the pic.

Lawnchair
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Post by Lawnchair »

Looks pretty straight forward. MPSA18's are a interesting choice for a overdrive.

ieatyouforbreakfast
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Post by ieatyouforbreakfast »

Lawnchair wrote:Looks pretty straight forward. MPSA18's are a interesting choice for a overdrive.

High gain transistors in an overdrive remind me of this.
I wouldn't say it's too far off from Martin's Folk Driver in basic design. It definitely does have that "chewy" discrete sound.

RnFR
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Post by RnFR »

the fact that the folk driver uses nfb as well as pfb makes it pretty unique. I wouldn't be surprised it was more along the lines of this-
http://www.freestompboxes.org/viewtopic.php?f=7&t=12875

most likely two BJT stages and assym clipping, or possibly with the clipping in between the stages by the way it looks laid out.
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Mich P
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Post by Mich P »

Any updates about this one ?
Thanks,
Mich P.

reaganomics
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Post by reaganomics »

so this was discontinued earlier this month. Maybe now's a good time to get a hold of this schematic?

black_out
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Post by black_out »

Any chance we can revive this one? Anyone out there that would care to trace the circuit? T'would be much appreciated.

Mich P
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Post by Mich P »

Still interested, if anyone ...
Mich P.

Mich P
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Post by Mich P »

Anyone ?
Thanks,
Mich P.

MoonWatcher
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Post by MoonWatcher »

Mich P wrote:Anyone ?
Thanks,
Mich P.
In absence of replies, why not at least look at what is indicated on the pcb? I don't see any resistors of value 2m2 (red/red/black/green), so it's probably not built up from either an Electra or the Folk Driver. The caps look like they'd all be similar in value, and there are enough to indicate that they are needed for something like a Big Muff-type of sustain control. The b100k seems to reinforce this. For something adjusting gain off the emitter, you'd see either a 1k or 2k pot, or maybe a 10k pot, biggest.

So probably most caps are value of 100n, maybe with 22n or so. There's a diff cap type next to the clipping diodes - probably parallel to it, and probably a value Earthquaker didn't stock in the Panasonic-types. So maybe has a value of 1n or 2n2 - again very common if taking clipping diodes to ground off the collector of q2.

50kb pot - probably tone control either of a Big Muff-type, or maybe just a variation of stupidly wonderful tone control.

Resistor values seem to be standard things with transistors used like with a Big Muff or LPB-1 - I think I see 100r's, 470k, maybe 220r and similar. Also 1k and such, unless I'm just not making out a 3rd or 4th band correctly...

Manfred
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Post by Manfred »

I bought a second hand one and traced it.
It was hard to trace the circuit because it is an multilayer PCB.
The ground connections and some others are on internal layers.
I traced the clipping diodes,a comparison of the reference diodes traces gives BAT48.
The the semiconductor analyzer read HFE=784@5Milliamps for Q1 and HFE=HFE=736@5Milliamps for Q2.
ChrysalisPCBComponentSide.jpg
ChrysalisPCBSolderSide1.jpg
ChrysalisPCBSolderSide2.jpg
EDQ_CrysalisComponetsArrangement.JPG
EQD_chrystalis.JPG
DiodeCompare.jpg
ChrysalisClippingDiodeTrace.jpg

Manfred
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Post by Manfred »

I designed a stripboard board for, but I haven't actually made use of it.
ChrysalisStripBoardComponents.jpg
ChrysalisStripBoardComponents.jpg (90.79 KiB) Viewed 1215 times
ChrysalisStripBoardSolder.jpg
ChrysalisStripBoardSolder.jpg (96.18 KiB) Viewed 1215 times
Print the PDF-files with the original size setting option.
chrsysalisSize.pdf
(62.56 KiB) Downloaded 46 times
chrsysalisComponets.pdf
(43.08 KiB) Downloaded 40 times
chrsysalisCuts.pdf
(23.93 KiB) Downloaded 47 times
Schematic with added potentiometer connection designations:
EQD_ChrystalisSchematic.JPG

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