Edit March 9:
Had some question about how to wire the footswitches. Here's how I'd wire them:
The LED for the channel switch doesn't have to be bi-color, but in my mind it seems like a good thing utilize instead of have a normal LED being on for one channel and off for the other.
Edit Nov. 28, 2018:
Had 2 pads for the Drive footswitch mislabeled. Fixed now and good to go. Schematic for reference (note the pot lug numbering in the schematic does not follow the normal numbering convention used on this site).
Edit Nov. 28, 2018:
Had 2 pads for the Drive footswitch mislabeled. Fixed now and good to go. Schematic for reference (note the pot lug numbering in the schematic does not follow the normal numbering convention used on this site).
Can the LF347 be subbed with a TL series quad op-amp (TL064,TL074,TL084)?
ReplyDeleteI would think so, but I haven't compared the datasheets.
DeleteA TL074 has less power supply current requirement.... other than that they appear directly compatible.
DeleteIsn't the ac tone just a few component swaps? I'm sure I've seen a layout somewhere online that does both.
ReplyDeleteHow should we wire up the LEDs and the DPDT footswitches? I suppose the positive lead from the LED itself should go to FSw5. But should the LED+ from the board go to FSw4 or FSw6? Thanks! I want to verify this in the next couple days.
ReplyDelete
Deletethe connection of the dpdt is here...
http://www.taydakits.com/instructions/plexitone/pages/enclosure-and-wiring--6
You can do it that way, though this layout was designed to use the buffered bypass like the original (In/Out pads going to the In/Out jacks). I'll post an diagram of how I'd wire the switches.
DeleteIt could help me with the wiring I did it exactly as indicated but it does not give me clean signal it only works when activating the drive the Chanel switch does not change the channel
Deletehi
Deletei have the same problem … did you resolve It ??? i have 2 or 3 hours to find the problem but all is ok i dont understand
Did you solve the problem? I think i have the same
DeleteWhat a great project!
ReplyDeleteIs much to ask some advice of what I have to avoid if I would like to feed directly with 18v or 9v?
I have some not verified clue reading the schematic I found around the web..
Thanks David!
The effect is designed to run with a bi-polar supply, so you have to use either a transformer like in the original, or the charge pump like I used in this layout. To run it without the charge pump would require some redesign of the circuit and a whole new layout.
DeleteWow i just found this site googling around for some schematics. Awesome job!
ReplyDeleteIs the schematic used for this Plexitone exactly the same as the original except the charge pump? Cos i'm looking for something as close as possible to the original one, and on other sites they applied some mods, like 4 clipping leds instead of 3 and other modifications.
Yes, this follows the original Plexitone aside from the power section. Early versions of the Plexitone seem to have had a few differences as shown in this schematic:
Deletehttp://4.bp.blogspot.com/-ier5Qk_vR-U/Tx1MsJ0sKoI/AAAAAAAAAro/1KKJZX2vyy4/s1600/Plexitone_rev3.gif
So, not really mods as much as what Carl Martin originally used.
Hey guys! I already finished and it works very good! VERIFIED!
ReplyDeleteTake notes:
*I just jumpered the Drive Footswitch 1-2, and the 3 I leave empty (no connect)
*I made True Bypass, as showed on the Tayda page.
*I used TL074 for the Quad Op amp, it works fine. I must try with LF347.
* For every diode in the Power Supply stage I used 1N4007.
Greetings for Corrientes, Argentina!
Héctor.. gracias por tus consejos.
DeleteIvan de Mza :-)
Conseguiste LT1054? tengo el LF374N, pero no consigo el otro.
Así es, lo compré en Axis. Aunque tampoco te hagas tanto drama, podes armar un doblador de voltaje con un LM555
DeleteGenial...lo voy a buscar ahí.
DeleteSi, lo estuve pensando, mucho más accesible aparte.
I'm ever using TL074 too but LF347 for this fx is the best for me
DeleteHey Héctor, if you are doing this True Bypass, you gotta remember it's an original buffered effect. So, i'd suggest you to increase the output resistor (the 22k one on the lug 2 of Level) to something like 220k. If you don't, your 12:00 volume will be WAY louder than the dry signal. Raising it to 220k, your 12:00 knob position is almost the same volume as the dry signal! (;
DeleteWait, can i use 16v Capacitors or should i use 25/50v cause of the 18v pump charge?
ReplyDeleteDefinitely higher rated ones. I would recommend 50v caps as I've seen 25v ones blow on 18v supply.
DeleteThanks for your answer! I was in doubt about the power supply. You said original uses 12V, but then a transformer to turn 12V to 18V, right?
ReplyDeleteAnyway, i'm out of 100uF's 50v atm, i'll get tomorrow by the morning. But i'm using 2 10uF 25v and 1 63v. I think i'll just buy everything new @ 50v just for security (:
ReplyDeleteMine didnt work. Its squelling and whinning. The sound is good before entering tone pot, and lost there. And i think the crunch and gain pots wired backward also. Any comment guys?
ReplyDeleteHi, can you help me please?
ReplyDeleteI have no bypass sound, the bufered bypass does not act or the boost, can it be because I am using a MAX1044CP for the pump?
The rest if it works well, it has good sound in drive and select and in this mode if the boost works perfectly
I thank you in advance, greetings
dis you solve it i have the same problem
DeleteWhat diodes are D1-D3?
ReplyDeleteI mean in PCB
Delete5mm red LEDs
DeleteVery nice sound!I realized this true-bypass mod, but i have a big problem of popping at engaging boost. There anyone can help me solve this? Do you have a dpdt connection diagramm? thank you
ReplyDeletehello, did you solve boost pumping ?
Deleteno, unfortunately .. I don't want to risk damaging that .. at the moment, i'm boosting with an external pedal.
DeleteHello evrybody,
ReplyDeletenobody have a link to buy the "LT1054"
Please … cant find it
Hello evrybody,
ReplyDeletenobody have a link to buy the "LT1054"
Please … cant find it
Sorry I'm not unkwnow I'M Francky !!
ReplyDeleteHi very body !
ReplyDeletePlease what kinds of DPDT are they ? Momentary or locked ?
Thx
Franck
Latching DPDTs
Delete:) ... thanks for your very fast answer..
ReplyDeleteHow are the IN and OUT jacks connected?
ReplyDeleteWorks great but for me all pot are reversed and a Strange thing i have no sound in bypass mode ! just work when i engage the drive !! it's not very clear but normaly in/out on pcb are in/out jack ?
ReplyDeleteHello DAvid, what about the big pumping when boost swicht is engaged ?
ReplyDeleteAny idea ? cant touch my money for that …. ;)
Did you try adding pulldown resistors?
Deleteno, because i dont know exactly where i have to put it . :)
DeleteI found this for boost switch popping problem: "The pop when switching in the boost is probably because unless you use a make before break switch there's a brief period when the connection is broken and the opamp has nothing in its feedback loop. I would rewire it so lug 1 of the boost pot connects to pin 8 of the opamp, and put the switch so it shorts out lugs 2 and 3 of the pot. That will switch the boost on and off without breaking the feedback loop."
ReplyDeleteI tried it and it works! Popping problem disappeared!;)
I've just built this, great sound and nice job to put in a 1590BB, the stomp are quite close but still usable. There's a mistake I believe, the crunch, higain, Tone and boost are reversed. I've built twice, and verified this. In the following schematic the lug orientation is more clear (it's without drive fw). https://www.diystompboxes.com/smfforum/index.php?topic=111395.0
ReplyDeleteLug 2-3 should be shorted and connected to the neg input of the op amps (pin 2-6-9 in this layout), otherwise the controls act reverse.
A solution without modifying the layout is mount the pots reversed, with the potz back against the solder side of pcb (back isolation needed, I use felt pad for chairs), changing the drill layout and jack layout, i did so. The Level pot orientation is correct, if all the other will be reversed is better use a solder lug potz or cut the through hole angled lugs and connect it with cables.
Also boost popping issue solved, like suggested by Ian Rider, just need to short/bridge lug 2 and 3 of boost switch, with the potz correctly soldered (potz lug 1 to boost fw3 lug). The hard pop disappear and boost works great.
Last, the boost pot is 500kB, not 50kB, but due to the excessive amount of db is better to try smaller potz, such as 250-100 kB, have enough volume.
See this topic https://www.freestompboxes.org/viewtopic.php?f=7&t=1113&p=265933&hilit=carl+martin#p265933 for more info.
About mods, I think i'll build also a simplified version, without boost and true bypass, to fit in a 1590BB vertical with 2 stomps (drive and channel). Thanks again David for all your job, it helps me to learn a lots about effects electronics.
Awesome pedal, I had one I bought based on the boneyard project I think, but I didn´t like it much, it sounded harsh and has too much low end in the hig gain channel.
ReplyDeleteThis one sounds just great.
As Lorenzo said BOOST CRUNCH HI GAIN and TONE pot are reversed. I managed to change the wiring without installing the pot over the soldering. TI left the Tone pot just like that, reversed, I´d call bass and that´s it; does not bother me much.
For the BOOST pot I used the 50k , havn´t tried a bigger value, I think its totally usable like that.
I have a minor problem, when bypassed, or with only the boost activated, there´s some of the distortion passing through, at a verylow volume, but it´s there in the background, any ideas what could it be? also a get a bump when activated the drive.
by the way, are you sure thw gain pots is not wired backward? I think lug 2-3 should be joined together, not lug 1-2, is it?
ReplyDeleteWhich diode should I take instead of 4742? I guess it´s a silizium? I´ve 1N4001, 1N4148, 1N914 at home as well as some germanium and zener diodes.
ReplyDeleteThx
That's a 12v zener to protect the charge pump. If you're careful and only run it with a 9v supply you can leave it out.
Deletei hv a question, what the polarity on the led diode on pcb ?, sorry for my poor english, thanks in advance
ReplyDeleteNegative leg is the upper side for D1 and D3, lower side for D2.
DeleteOkk, Thanks
DeleteI need help with this layout. Instead 5817 i used 5819, Vcc on LF347 is +10V and -2V, when i swapped diodes to 1n400x it was even lower. I powered it with 9V battery. When i unplug lf347 from stand the voltage raise to -12V and + 14V. Idk what do next,drive doesn't work, hi gain just fart with bass. Please help me.
ReplyDeleteHi everyone,
ReplyDeleteI'd like to swap the tone control with a 3 bands Marshall tonestack.
Any idea about what I have to do with the tone pot (replace with a fixed resistor or let its place open) and where I have to place the tonestack?
Thanks!