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bossarea
Forum Admin
United Kingdom
3652 Posts |
 Posted - 11/04/2008 : 20:09:44
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I posted a couple of internal pics of this thing in the internals thread.
I picked it apart because I wanted to backwards engineer it and put the parts into a DS-1 enclosure. I thought there would be just one big chip inside but this thing is completely analog. It's not cosm modelling like most emulator circuits.
It would be quite a job to figure out the circuit. It's a double sided PCB and the components are so small that it's hard to say if a part is a resistor or capasitor. Finding the value is going to be even harder. There's 4 transistors and 4 opamps. The opamps markings are
2100 J02 JRC
062 J06 JRC
7082 B801 JRC
BDU 7CK JDH5
The 2 first ones are probably JRC2100 and JRC062. I couldn't find any links for JRC7082 so I'm not sure if that's correct. The last one I have no idea about.
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Ollie
Gold Member
United Kingdom
729 Posts |
Posted - 11/04/2008 : 23:02:45
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Just out of curiosity, what model do you have?
I have the classic rock one, its sounds pretty wild at full gain, but sounds good with it backed off a bit, same with the tone. Sunshine of your love anyone? |
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bossarea
Forum Admin
United Kingdom
3652 Posts |
Posted - 11/04/2008 : 23:11:46
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| I got the AC-30. It's got less gain than a real AC-30 but it's got a very decent crunch rock sound. |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 11/05/2008 : 10:49:10
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Hi Bossarea & Guys
That's one really packed & compact PCB.
Was it difficult to take apart?
You said you had to pick it apart.
Are they expensive?
Thanks for uploading the pics,
I'll put it into the Index; We are now up to Page 11.
Bossarea, I just had another look at your pics, in the first one,
it looks like it has a surface mount coil on it, near the slide switch marked 220,
I wonder if this is part of a DC to DC inverter, to step up the 3V from the AA batteries?
It would make sense, unless they have the op-Amps running on a 1.5VDC split rail, or maybe they are using single rail op-amp?
If you look on what would be the underside of the coil, it has another IC near it, which could be a switching inverter.
The 5 pin IC with the leads all on one side.
Is that the chip with those unusual numbers?
Regards Dr. Bob |
Edited by - Dr. Bob on 11/05/2008 11:11:42 |
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bossarea
Forum Admin
United Kingdom
3652 Posts |
Posted - 11/05/2008 : 11:39:34
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It wasn't hard to take it apart but it was tricky to figure out how. It snaps together with a lock in each corner. I was scratching my head for a while until I managed to pry a screwdriver between the two halfes and the first plastic lock opened.
I paid �25 for it at Amazon. My only complaint with it so far is that it keeps falling out of my guitar (Telecaster with the jack socket underneath). I was also toying with the idea of building it into a guitar.
There is a coil on the PCB but I don't know what it's for. I'll take it apart again when I get home from work and see which IC is which. Might take another few pictures and maybe use the flash this time  |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 11/05/2008 : 15:17:44
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quote:
Originally posted by bossarea
[There is a coil on the PCB but I don't know what it's for. I'll take it apart again when I get home from work and see which IC is which. Might take another few pictures and maybe use the flash this time
Just looking for the coil on the pics... guess it needs that flash. A coil in a pedal is usually part of the analog/digital ground isolation, but it's all analog... Curious.
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 11/05/2008 : 15:52:53
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Hi Laurie
quote:
Just looking for the coil on the pics... guess it needs that flash. A coil in a pedal is usually part of the analog/digital ground isolation, but it's all analog... Curious.
Please read the Bule test in my above psot.
What do you think?
Do you think I might be right about the Switching DC to DC step up inverter?
The IC is typical of the ones I see in my daily travels.
Maybe this steps it up to around 9-10VDC, I guess we might ask Bossarea to take some measurements with his DVM.
I can't see them running the split rails on the opamps at 1.5VDC.
Regards Dr. Bob
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 11/05/2008 : 16:14:57
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quote:
Originally posted by Dr. Bob
Hi Laurie
quote:
Just looking for the coil on the pics... guess it needs that flash. A coil in a pedal is usually part of the analog/digital ground isolation, but it's all analog... Curious.
Please read the Bule test in my above psot.
What do you think?
Do you think I might be right about the Switching DC to DC step up inverter?
The IC is typical of the ones I see in my daily travels.
Maybe this steps it up to around 9-10VDC, I guess we might ask Bossarea to take some measurements with his DVM.
I can't see them running the split rails on the opamps at 1.5VDC.
Regards Dr. Bob
Ah... missed that. Yeah, that's what it probably is. |
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Vox Amplug
