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Re: Lovepedal - Purple Plexi 800 [goop-alarm]

Posted: 05 May 2012, 05:52
by ansil
also there is the arsehole way of saying gwt used to it. lol but also you can dowand use thw positive feedback trick. piss on my phone argh
nload the app notes

Re: Lovepedal - Purple Plexi 800 [goop-alarm]

Posted: 05 May 2012, 20:59
by ansil
terribly sorry for the above post my phone kept jumping around while i was typing well greasy hands can't always be good. what i was saying is download the app notes and look into the positive feedback helped me out quite a bit. other than that you can do a similar thing with the input stage as the ole rockman and utilize a fet as a gate based upon input decay. but really hand sorting them has been the best one for me. or build one from scratch ie all transistors.

Re: Lovepedal - Purple Plexi 800 [goop-alarm]

Posted: 28 Jun 2012, 10:40
by carpediemgr
i just measure the pot's ressistance when the pedal start to make the squeel , my multimeter show me in one of my builds 128 ohm and at another 48 so i placed in both pedals 150 ohms at the first and 50 ohm at the second at Gain pot pin 3 before to wire to the Pcb and the squeel stoped :) i do not think that i lost some gain or make the pedals work deferent , just this

Re: Lovepedal - Purple Plexi 800 [goop-alarm]

Posted: 28 Jun 2012, 10:53
by Troll_face
jymaze wrote:Hello all,

I had the same problem with hiss at max gain (cf Renegadrian).

Here is the solution I found: replace the 10 ohms resistor in series with the gain pot with a 22 ohms resistor (or put another 10 in series). It took care of it. If it is not enough, the value of the resistor can be pushed even higher until the problem disappears, the tone changes a little but nothing too bad, the value of the cap in series can then be adjusted to something else than 47u. In my case I settle for 20 ohms and 22u.

Then I decided to get rid of the gain pot alltogether since everyone has to admit is mostly useless. The amount of distortion is way easier to control with the guitar volume knob.

Now it is a great pedal with a convincing brown sound. And with only 2 pots, I have more room on the pedal for some nice graphics.
:applause: :D :D Thanks! This fixed the squealing problem perfectly. 40 ohms is what worked for me.

Re: Lovepedal - Purple Plexi 800 [goop-alarm]

Posted: 28 Jun 2012, 10:57
by carpediemgr
could someone advice how i could keep and prevent the MAX gain but make the pedal start from 0 gain setting from a lower amount of gain ?

thanks Mike

Re: Lovepedal - Purple Plexi 800 [goop-alarm]

Posted: 28 Jun 2012, 11:30
by ansil
If you are wanting more flexibility in the gain department. Try utilizing negative feedback. It would probably work better

Re: Lovepedal - Purple Plexi 800 [goop-alarm]

Posted: 28 Jun 2012, 11:44
by carpediemgr
ansil wrote:If you are wanting more flexibility in the gain department. Try utilizing negative feedback. It would probably work better
this mean to do what in the circuit , could you explain , if i use a 2k gain pot this will make any deference? or if i change the 470R ressistor to smaller or bigger this will make any deference too ?

thanks again Mike

Re: Lovepedal - Purple Plexi 800 [goop-alarm]

Posted: 28 Jun 2012, 23:24
by carpediemgr
could someone advice how i could keep and prevent the MAX gain but make the pedal start from 0 gain setting from a lower amount of gain ?

thanks Mike

Re: Lovepedal - Purple Plexi 800 [goop-alarm]

Posted: 19 Jun 2013, 06:17
by shiflet
Guys, a question, is there any way to control more the journey that has the Gain potentiometer? Maybe poniendole another resistor in parallel to lose more value and better control that way?

Re: Lovepedal - Purple Plexi 800 [goop-alarm]

Posted: 10 Oct 2013, 07:12
by soggybag
While reading this thread I noticed that people were saying the gain control only worked for the last 10% of the travel. Has anyone tried a reverse audio taper C1K pot?

Re: Lovepedal - Purple Plexi 800 [goop-alarm]

Posted: 13 Oct 2013, 07:28
by shiflet
soggybag wrote:While reading this thread I noticed that people were saying the gain control only worked for the last 10% of the travel. Has anyone tried a reverse audio taper C1K pot?
Yep

Re: Lovepedal - Purple Plexi 800 [goop-alarm]

Posted: 13 Oct 2013, 19:31
by ansil
I am Terribly sorry I didn't know I had a reply on this thread our I would have hollered sooner. Negative feedback is the process of feeding the out put back to the input o out of phase. So add a larger capacitorand a pot in series from output to negative input.

Re: Lovepedal - Purple Plexi 800 [goop-alarm]

Posted: 17 Jan 2014, 01:32
by Jayallen
Just built this pedal it sounds pretty good. One problem I have is after I play my guitar for a little while then stop the pedal will make some weird crackle sound like when you remove your guitar cord before shutting down your amp. All my cords are new. I re-soldered everything and I re-checked all my wiring. Thanks

Re: Lovepedal - Purple Plexi 800 [goop-alarm]

Posted: 17 Jan 2015, 17:47
by jalmonsalmon
Chiming in here with a question about adding a blend cap to this one.
Before I build this on strip, wondering if this is the proper way to add a blend cap and if the small and large cap values are good?
I know I will socket those and see what works but just asking anyway :hmmm:

Re: Lovepedal - Purple Plexi 800 [goop-alarm]

Posted: 17 Jan 2015, 19:08
by Ripdivot
jalmonsalmon wrote:Chiming in here with a question about adding a blend cap to this one.
Before I build this on strip, wondering if this is the proper way to add a blend cap and if the small and large cap values are good?
I know I will socket those and see what works but just asking anyway :hmmm:
That should work fine

Re: Lovepedal - Purple Plexi 800 [goop-alarm]

Posted: 04 May 2018, 19:36
by bc108
Bump! :)

Which is the 370p cap function here?
Thanks

Re: Lovepedal - Purple Plexi 800 [goop-alarm]

Posted: 05 May 2018, 08:54
by Manfred
bc108 wrote:Bump! :)

Which is the 370p cap function here?
Thanks
Here is the answer:
https://www.freestompboxes.org/viewtopic.ph ... 12#p270412

Re: Lovepedal - Purple Plexi 800 [goop-alarm]

Posted: 17 Apr 2019, 21:03
by lovetone
Has anyone got any info on the SE version that has the control from JTM45 to JCM800?

Re: Lovepedal - Purple Plexi 800 [goop-alarm]

Posted: 17 Jun 2020, 13:55
by tacianocanassa
Here is my layout for the Purple Plexi, pots should be soldered on the copper side of the pcb. It's written in portuguese but pretty straightforward.
Hope you like it. Layout verified!
https://mega.nz/file/WSIklKSa#_wCs2ORmA ... byLpn0MgwU