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

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ansil
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Post 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

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ansil
Cap Cooler
Posts: 479
Joined: 03 Mar 2009, 22:49
my favorite amplifier

my hughes and kettner blue 30r

Completed builds

3 jcm 800 builds
4 vintage plexi builds
2 bogner ecstasy preamps [both for personal use]
10 marshall guvnor mods and builds
100 jungle kat boosts
too many penguin love's to count.
5 blues pearl purplexed
dozen tube screamer fulldrive whatever you call them variants

hell i can't type this long it will piss off people what can i say i have been doing mods on toyz appliances gear sex toyz computers and such for 27 years. i started when i was 6 taking stuff apart.

Location: cleveland tn
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Post 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.

carpediemgr
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Post 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

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Troll_face
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Post 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.

carpediemgr
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Post 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

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ansil
Cap Cooler
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Joined: 03 Mar 2009, 22:49
my favorite amplifier

my hughes and kettner blue 30r

Completed builds

3 jcm 800 builds
4 vintage plexi builds
2 bogner ecstasy preamps [both for personal use]
10 marshall guvnor mods and builds
100 jungle kat boosts
too many penguin love's to count.
5 blues pearl purplexed
dozen tube screamer fulldrive whatever you call them variants

hell i can't type this long it will piss off people what can i say i have been doing mods on toyz appliances gear sex toyz computers and such for 27 years. i started when i was 6 taking stuff apart.

Location: cleveland tn
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Post by ansil »

If you are wanting more flexibility in the gain department. Try utilizing negative feedback. It would probably work better

carpediemgr
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Post 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

carpediemgr
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my favorite amplifier: hiwatt

Post 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

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Post 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?

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Post 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?

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Post 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

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ansil
Cap Cooler
Posts: 479
Joined: 03 Mar 2009, 22:49
my favorite amplifier

my hughes and kettner blue 30r

Completed builds

3 jcm 800 builds
4 vintage plexi builds
2 bogner ecstasy preamps [both for personal use]
10 marshall guvnor mods and builds
100 jungle kat boosts
too many penguin love's to count.
5 blues pearl purplexed
dozen tube screamer fulldrive whatever you call them variants

hell i can't type this long it will piss off people what can i say i have been doing mods on toyz appliances gear sex toyz computers and such for 27 years. i started when i was 6 taking stuff apart.

Location: cleveland tn
Has thanked: 7 times
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Contact:

Post 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.

Jayallen
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Post 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

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Post 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:
Attachments
Schematic mod
Schematic mod

Ripdivot
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Post 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

bc108
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Post by bc108 »

Bump! :)

Which is the 370p cap function here?
Thanks

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Post 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

lovetone
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Post by lovetone »

Has anyone got any info on the SE version that has the control from JTM45 to JCM800?

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Post 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

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