Earthquaker Devices - Ghost Echo  [traced]

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Earthquaker Devices - Ghost Echo

Postby entropicp » 19 Dec 2009, 23:30

For anyone who may be interested, here is a gutshot of the Earthquaker Devices Ghost Echo reverb. Just got it today. It sounds nice and natural and I'm quite impressed overall. It can go from subtle to heavy feedbacking reverb if you max out the knobs. Also the build quality is very nice inside and the sparkle finish is quite good although the case is a Chinese 1590BB clone and the screw threads aren't the greatest.

It has a reverb brick on the underside of the PCB, which you can't see in the pictures. I'm guessing it's a Belton, but I'm not sure because I'm not really willing to take it apart to find out. Also the IC's are a TL074CN and a PT2899. Not sure how similar this is to the GGG/Hermida pedal or the Malekko Spring Chicken.
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Re: Earthquaker Devices Ghost Echo [guts]

Postby newly » 20 Dec 2009, 13:21

Spring Chicken is only 1 knobs and so to Hermida. Thier build are not much deviated from the datasheet circuit.
This one has added PT chips. I wonder what is it used for :scratch:
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Re: Earthquaker Devices Ghost Echo [guts]

Postby IvIark » 20 Dec 2009, 13:45

newly wrote:Spring Chicken is only 1 knobs and so to Hermida. Thier build are not much deviated from the datasheet circuit.
This one has added PT chips. I wonder what is it used for :scratch:

Does the attack control add a pre-delay to the reverb?
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Re: Earthquaker Devices Ghost Echo [guts]

Postby entropicp » 20 Dec 2009, 14:13

IvIark wrote:
newly wrote:Spring Chicken is only 1 knobs and so to Hermida. Thier build are not much deviated from the datasheet circuit.
This one has added PT chips. I wonder what is it used for :scratch:

Does the attack control add a pre-delay to the reverb?


Yeah, the attack knob does add pre-delay to the pick attack of the wet signal, which is what I'm guessing the PT2399 chip is there for (excuse the earlier typo). It also seems to have more of an ambient/roomy delay than the Spring Chicken/Hermda ones when you turn up the Depth control. If you have both the Depth and Dwell on high at the same time it starts self-oscillating and feedbacking a bit. I' wondering if the PT2399 is used to add additional delay to the brick on higher settings or just to set the attack knob.
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Re: Earthquaker Devices Ghost Echo [guts]

Postby madbean » 31 Dec 2009, 12:46

I'm interested in how they are utilizing the PT2399. I've worked through several designs with the Beton now, but I'm still looking to add more ideas. The design I was working on also used a TL074 and used the extra stage to dirty up the echo and feed it back into the input. Kinda 'meh'.

Anyway, if there's anyway you can get a shot of the other side that would be great. The pins on the Belton are very resilient and will desolder easily. If you don't wanna go through the trouble, I totally understand...no worries.

Thanks for the gut shot!
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Re: Earthquaker Devices Ghost Echo [guts]

Postby Lawnchair » 31 Dec 2009, 23:57

can it do a spring sim?
Last edited by Lawnchair on 01 Jan 2010, 00:03, edited 2 times in total.
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Re: Earthquaker Devices Ghost Echo [guts]

Postby entropicp » 01 Jan 2010, 13:40

madbean wrote:Anyway, if there's anyway you can get a shot of the other side that would be great. The pins on the Belton are very resilient and will desolder easily. If you don't wanna go through the trouble, I totally understand...no worries.


Sorry to be a tease, but I really don't want to take it apart. It cost £135, which is a lot of money for me and my soldering skills can be a bit rough at times so I don't want to risk ruining it. Also, the soldering and construction are very high quality and it would pain me to undo that.

Lawnchair wrote:can it do a spring sim?


Yeah it can do a fairly passable spring reverb on the lower settings. Check out these demos for a better idea:

http://www.earthquakerdevices.com/devices/ghostecho.htm
http://www.youtube.com/watch?v=mmTpSX2cd9o&feature=related

I have to admit that it sounded slightly more convincing on the demos than in person. I'm sure it is pretty similar to the Malekko or Hermida in its spring emulation. I'm using it as my amp reverb throuh the FX loop, since my amp doesn't have a built in reverb. The really interesting thing about this pedal for me is how much it responds to your picking dynamics. If you you pick really hard you get a slapback effect whereas if you pick softly you get more of a classic reverb sound.
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Re: Earthquaker Devices Ghost Echo [guts]

Postby RnFR » 18 Jan 2011, 13:45

I do like the idea of the belton and the 2399 together. it sounds like an excellent combo.
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Re: Earthquaker Devices Ghost Echo [guts]

Postby solder_blob » 18 Jan 2011, 17:08

With the PT2399, you can almost a get a decent reverb anyways. Maybe they're some how combined or something?
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Re: Earthquaker Devices Ghost Echo [guts]

Postby Hides-His-Eyes » 18 Jan 2011, 21:09

I wonder if some of the ouput of the reverb chip is sent back in before the pre-delay maybe?
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Re: Earthquaker Devices Ghost Echo [guts]

Postby Motter » 22 Jan 2013, 20:50

Took some photos of mine last night, and desoldered the reverb brick (boy was that a pain) to get some shots of the trace side. I'm working on my own trace, but I thought I'd put up the photos if anyone wants to beat me to it. Let me know if there are any close-ups or measurments you'd like. I'll try and read the cap values tonight, but they're so bunched together some of them might be really hard to see without desoldering

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Re: Earthquaker Devices Ghost Echo [guts]

Postby Motter » 23 Jan 2013, 17:46

I've been working on a trace, but it's proving to be rather difficult, because there are a number of traces hidden by caps and ICs on the component side and I've never worked on a circuit this complicated before. I think I can do it, but I might not have much to show until maybe this weekend or next week.
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Re: Earthquaker Devices Ghost Echo [guts]

Postby Motter » 25 Jan 2013, 23:42

Anyone want to take a look at this, and tell me if anything sticks out as blatantly incorrect?

see here for updated schem

Keep in mind this is the first time I've traced or drawn a circuit involving any sort of IC; 90% of my pedals are fuzzes. This one has 5 ICs, including 2 digital ones, so there may still be an error or two.

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Re: Earthquaker Devices Ghost Echo [guts]

Postby Motter » 26 Jan 2013, 02:19

LED is backwards :slap:
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Re: Earthquaker Devices Ghost Echo [guts]  [traced]

Postby Motter » 28 Jan 2013, 20:18

I have revised my schematic to:

-More accurately reflect the switching method used in the pedal

-Correct the LED orientation

-Fix the grounding scheme for the reverb IC. Pins 2 and 4 are internally connected, so pin 2 of the BTDR-2H and pin 2 of the 78L05 are not directly grounded, but grounded through pin 4 on the reverb IC. This was presumably a way to separate the digital ground of the brick from the analog ground of the rest of the circuit. Curiously, there is no separation of the digital and analog grounds on the PT2399, as pins 3 and 4 are soldered directly together on the trace side of the PCB. Also, the ground from pin 6 through the Attack pot (VR1) is decoupled from the 9V supply through a large electrolytic cap.

-I have double-checked every node in this schematic with my multimeter on the actual circuit board, so this schematic is as correct as I can make it. Let me know if you see any issues and I can triple check.

-If the mods can remove the attachment from my previous post, the schematic attached to this post is the revised schematic.

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Re: Earthquaker Devices Ghost Echo [guts]

Postby kodiakklub » 24 Mar 2013, 01:20

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VERIFIED!!

notes:
1.the reverb brick gets soldered on the bottom of the board once everything else is soldered on, which includes the lead for the LED+ pad
2. 2 jumpers: A1---->A2 and B1----->B2

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Re: Earthquaker Devices Ghost Echo [guts]

Postby Motter » 24 Mar 2013, 08:41

Does this fit in a 1590B? Any chance you have a spare board? I don't etch but I'd love to build one of these to compare to the store bought one. I haven't looked at your schematic too closely, but did you spot any errors in my trace?
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Re: Earthquaker Devices Ghost Echo [guts]

Postby kodiakklub » 24 Mar 2013, 18:47

you would have to lay the jacks out within a half millimeter of their lives to make it fit in a 125B. it would be incredibly tight.

im pretty sure i copied your schematic part for part. good work on tracing it. i dont have any spare boards. i etch them as i build them. it sounds very "spooky" for a reverb. its a little different but interesting and good.
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Re: Earthquaker Devices Ghost Echo [guts]

Postby destro » 05 Apr 2013, 21:14

Interesting that the new version has two voltage regulators, one for the brick, one for the pt2399.
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Re: Earthquaker Devices Ghost Echo [guts]

Postby nativetrash » 15 Apr 2013, 20:13

First time poster here - I just built this circuit w/ the PCB transfer & it sounds great except that it knocks my volume in half when I engage the effect. Any idea what could be causing that?
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