Lovepedal - Purple Plexi 800 [goop-alarm]  [traced]

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

I really like the footswitch arrangement, with the latching relay and PIC controller. Extremely reliable, will sound good and might be fairly cheap. You can do all kinds of wacky stuff very easily and cheaply if you stick a PIC in there. The only pain is programming the PIC, but if he uses these in volume he can get them programmed by his distributor. VERY nice!!

I'd also defend his using SMD, much cheaper to get manufactured in volume as there are pick and place machines all over the place that can handle the parts. The only issue is if you can get the cap types (dielectric) you want for tone, and the supply of SMD caps is getting better all the time. It is a pain to modify one of these, but I can't imagine a pedal guy designing a pedal so it can be modified anyway. Good for him all around.

analogguru
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Post by analogguru »

I really like the footswitch arrangement, with the latching relay and PIC controller. Extremely reliable, will sound good and might be fairly cheap. You can do all kinds of wacky stuff very easily and cheaply if you stick a PIC in there. The only pain is programming the PIC, ....
Should be possible to do with standard c-mos chips too....
when I find some time I wil think about it.

analogguru
There´s a sucker born every minute - and too many of them end up in the bootweak pedal biz.

MKB
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Post by MKB »

analogguru wrote: Should be possible to do with standard c-mos chips too....
analogguru
Indeed it is possible, but takes far less parts count and space with a PIC. We use PIC's all the time at my work, they are making sense for simpler functions as the price goes down. PIC's are not good for DIY'ers as you have to have a programmer to load them, which can cost several hundred dollars. I haven't seen any cheap DIY programmers for 12C parts either.

sandmannn69
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Post by sandmannn69 »

Here's an update on the schematic submitted by Ghandi showing the 4 previously unknown cap values. I removed the parts and measured with a cap meter so they are accurate. The diodes are SMD version of BAT46 schottkys.
Attachments
PP800 clone.JPG

kantul
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Post by kantul »

schematic is correct?
4700pF =4,7n?
Thanks.

chris_d
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Post by chris_d »

Ah, Interesting. I thought this one sounded fairly decent in clips, and wondered what it was inside. I also am kind of partial to the sound that the Krank DM makes, so i guess it is not surprising that they both utilize a somewhat similar approach.

I really don't need another dirt pedal right now, but i think i will probably give this one a go anyhow at at some point.

Thanks for the information!

-chris

Ghandi
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Post by Ghandi »

alright sandman,
here we go again...
Lovepedal_Purple_Plexi_800.pdf
(239.55 KiB) Downloaded 1281 times
thanks very much sandman!
comes close to my values..
with a bigger tone cap and a smaller cap after the 4k7 resistor I also liked a 4u7 input cap!

that is on nice sounding one,
like it better than the box of rocks, BSIAB2 and the rust driver for that marshall like "grit"!
oh, and the responds to the volume and tone controls of the guitar is amazing!

Ghandi
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Post by Ghandi »

oh,
and sandman could you also please measure the resistor on this pic?
I'm not totally sure if I got it correct it's very difficult to tell from the pic...
q.jpg
and thanks again for your work! :applause:

sandmannn69
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Post by sandmannn69 »

Ghandi,

Kudos to you for coming up with the schematic so quick. And building one already, too!
The resistor is labeled 1741 which makes it a 1.74K ohm. Minotaur is putting together a strip board (vero) layout hopefully we'll see soon...thanks for your help!

Ghandi
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Post by Ghandi »

pleasure!
was very curious about this one!

It's was a very fast n' easy "freestyle" build on perfboard,
if I have access to a windows pc I'll make a pcb and perfboard layout.

and it seems that me eyes aren't that bad either! :wink:

minatour87
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Post by minatour87 »

:applause: after some revisions during slow times during the last couple of days,
here it is: although the reverse bias protection isn't on the vero board it is optional, some think that the voltage drop (and current limiting) and reverse bias function may influence the distortion of the 386. i have to go to the approval board of my wife to build this box....
peace minatour87
Attachments
PurplePexi800.pdf
(178.11 KiB) Downloaded 1155 times

Torchy

Post by Torchy »

Vero layout

Not yet built.

madbean

Post by madbean »

I'll have a PCB of this in a bit.

sandmannn69
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Post by sandmannn69 »

madbean wrote:I'll have a PCB of this in a bit.
Madbean,

Use these values. The vero layout values are incorrect, although the layout is very good.

C1 = 370pF
C2,C6 = 4700pF
D1,D2 = BAT46 schottky diodes

Ghandi
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Post by Ghandi »

@Torchy and minatour87

on your vero layouts the 47uF cap parallel to the 100nF from pin6 to ground is missing!

minatour87
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Post by minatour87 »

upgrading the vero board, plus schematic all in one.
Attachments
PurplePlexi800ver2.pdf
(173.86 KiB) Downloaded 1854 times

Torchy

Post by Torchy »

Ghandi wrote:@Torchy and minatour87

on your vero layouts the 47uF cap parallel to the 100nF from pin6 to ground is missing!
<Edit> Its in one schem but not the other. Updated.

Thats the trouble when a thread has more than one schematic attached.
Last edited by Torchy on 12 Oct 2008, 16:39, edited 2 times in total.

madbean

Post by madbean »

PCB is done...just checking it over.

madbean

Post by madbean »

Okay, not verified but it should be correct. Please have a look over. I don't really plan on building this one, but I'll revise it if there are mistakes. Print the PCB at DPI setting (which is 160dpi)
PurplePlexi_Layout.png
PurplePlexi_PCB.png

sandmannn69
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Post by sandmannn69 »

Welll, finally got around to putting together a clone of my PP800. Turned out pretty good, little edgier than the original probably due to the extra noise picked up by the leaded components vs. the originals SMD parts. I used a 390 pF in place of the 370 pF. FWIW, it's good enuff for me, I'm putting the original on EBay cause I need some parts to convert my EVjr to a Marshall 18Watt.
Thanks for everybody's help in puttin this clone together, it definitely works for a poor man's Marshall.
BTW, anybody got an Epiphone Valve Jr. that you would like to convert to a Marshall 18Watt LiteIIb for about $140, check out this website

http://guitaramplifierpcbs.com/liteiib.aspx

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