This boost has a fairly unique sound - I wanted something a bit more "small Fender" sounding than the Fetzer Valve and figured out that the 2 knob tone stack on the SF champ was what did the trick. This is a very ROG-ish design - note I don't even claim doing anything towards the design of this pedal. What I did is combine a ROG Fetzer Valve (btw read the updated article - it's great!) with the rest of one of my favorite amps - the AA764 champ - using the AA764's tone stack and passive component topology and got this great sounding circuit.
(http://mojotronics.com/images/vibinchamp/vibinchamp_2.JPG)
Here's the layout:
(http://mojotronics.com/images/vibinchamp/vibinchamp_lo_2.JPG)
Here's the PCB mask (you'll have to shrink this - note the 1" ruler)
(http://mojotronics.com/images/vibinchamp/vibinchamp_pcb_2.JPG)
How's it sound? Well, great - kind of sounds like you're playing through a champ if you set your amp's eq to be fairly flat with a clean sound - it has a lot of that small fender amp vibe to the sound; nice soft highs, with a bell like tone. What I really like is that since I finished this pedal and started using it (and I use it a lot) I don't feel the need to switch amps to use my Deluxe Reverb to get a Fender sound - this pedal pretty much does that better than anything else I have tried.
Notes:
0) Torchy suggested making R3=3k - I need to add that mod to the above schematic as it sounds better
1) Sw1 works like a boost to overdrive switch - it works well as either a mini-switch or a 2nd DPDT
2) As specified in the schematic, this has a very clean sound. If you crank the drive control past 50% and switch Sw1 to connect C5 to the source of JN2 you get a nice grind with humbuckers - see mods for use with single-coils
3) Mods I really like:
- If you want more of a "hot 12AX7" - or a Beefier Proph Tweed sound - use a J201 for JN2 and a 3K resistor for R1 - I also recommend this for use with vintage single coils
- If you really like the Fenderish "expander" aspect of this circuit's sound - use a 3K resistor for R1
- If you want the most authentic Champ sound - add some warmth by attaching a 220pF cap from Dr2 (the drive pot wiper) to ground
I put references to WILLING HEART MINISTRIES for anyone wanting to support the work of an artist named Kelly Willard. Kelly Willard's music is extremely inspirational, even for a rocker-Satch fan like me, and if this generates some support for her Christian ministry - I would be overjoyed. :icon_biggrin:
Well here's the sound clips for the Vibin' Champ (VC):
Note 1: I used Torchy's sugestion and made R1=R3=3k and 2 J201s - Sounds the best to me - THANKS!!!
Note 2: Its really hot here today - (no AC and I do these in my attic :icon_twisted:- 100+ degrees.. Yikes!) I did these clips quickly so I would not pass out - please excuse the roughness of the sound and playing...
Note 3: In the heat my S470 developed a buzz, so there is some buzz in the HB clips - it's my guitar/playing not the VC
Setup1: Ibanez S470 (w/Gibson Classic '57/'57+ pickups) -> VAMP (for small combo)->computer sound card
Clip 1: Clean Neck HB: VC set to Dr:30%, Tr:50%, B:50%, Vol:70% :I played using the neck HB pickup w/out the VC on for a D-G-D chord set then added it - so you hear the change when activated, then I played the same blues like stuff in all of these clips
http://www.mojotronics.com/images/vibinchamp/vc_4_clean_HB.mp3 (http://www.mojotronics.com/images/vibinchamp/vc_4_clean_HB.mp3)
Clip 2: Over-Drive Neck HB: VC set to Dr:70%, Tr:70%, B:60%, Vol:50% :I played using the neck HB pickup w/out the VC on for a D-G-D-am chord set then added it -
I play one lick, turn the vol back to 80% on the guitar, play just about the same lick, then turn it back up. The rest of the clip I try to show how the VC cleans up with pick attack when used as an overdrive
http://www.mojotronics.com/images/vibinchamp/vc_5_dirt_HB_N.mp3 (http://www.mojotronics.com/images/vibinchamp/vc_5_dirt_HB_N.mp3)
Clip 3: Over-Drive Bridge HB: VC set to Dr:70%, Tr:70%, B:60%, Vol:50% :I played using the bridge HB pickup w/out the VC on for a D-G-D chord set then added it... This clip I try to show how the VC has a bit of grit - as an overdrive - I should have turned the bass up a bit...
http://www.mojotronics.com/images/vibinchamp/vc_6_HB_BR_dirt.mp3 (http://www.mojotronics.com/images/vibinchamp/vc_6_HB_BR_dirt.mp3)
Setup2: Warmoth (Swamp Ash) strat (w/Fender Fat '50's pickups) -> VAMP (for small combo)->computer sound card
Clip 4: Squeeky Clean Strat Neck: VC set to Dr:30%, Tr:50%, B:50%, Vol:70% :I played using the neck pickup w/out the VC on for a D-G-D chord set then added it - so you hear the change when activated, then I played the same blues like stuff in all of these clips. In this clip I switch the VC in and out 3 times (the VC level is a bit louder - so you can hear it kick in) in the first 1/2 of the clip, then I use the Guitar's vol control and picking attack to control dynamics in order to demo the sensitivity
http://www.mojotronics.com/images/vibinchamp/vc_7_clran._strat.mp3 (http://www.mojotronics.com/images/vibinchamp/vc_7_clran._strat.mp3)
Clip 5: Over-Drive Neck Strat: VC set to Dr:70%, Tr:70%, B:60%, Vol:50% :I played using the neck pickup w/out the VC on for a D-G-D chord set then added it - so you hear the change when activated, then I played the same blues like stuff in all of these clips. In this clip I switch the VC in and out a few times (the VC level is a bit louder - so you can hear it kick in) in the first 1/2 of the clip, then I use the Guitar's vol control and picking attack to control dynamics in order to demo the sensitivity
http://www.mojotronics.com/images/vibinchamp/vc_7_dirt._strat.mp3 (http://www.mojotronics.com/images/vibinchamp/vc_7_dirt._strat.mp3)
You can here from this last clip that it does not have a lot of overdrive using vintage strat pickups - but with a FatBooster in front of the VC it sounds very much like a small Fender being over driven with a booster... I really like that sound myself.
very cool
Looks absolutely amazing! Any sound clips?
Quote from: gtrwrks on July 21, 2006, 09:27:57 AM
very cool
Thanks :icon_biggrin: - I certainly got a lot out of http://www.runoffgroove.com/fetzervalve.html (http://www.runoffgroove.com/fetzervalve.html) - which is an awesome writeup on doing something like this.
Quote from: call1800ksmyazz on July 21, 2006, 09:38:20 AM
Looks absolutely amazing! Any sound clips?
I will get some sound clips out. With R1=3k and using 2 J201 JFets the sound is very much like what I get out of a small fender - reminds me very much of my SF Deluxe Reverb w/EH12AX7 tubes.
With a 2N5457 for JN2 the FET the sound is much cleaner - in fact, with vintage single coils I just get a hint of overdrive with boost on using the 2N5457 and the sound is very chimey. With a J113 the sound is even more clean.... But I prefer the gain-ier sound of the J201 using a 3k source resistor (R1) for bump up Vgs so that the input does not start clipping just due to a low Vgs. With J201s the sound is still chimey - but has much more of a sound like if I put a Mullard 12AX7 in for V1 in my SF deluxe Reverb - it's darker and more harmonically richer (I know - that's a very subjective term) with plenty of overdrive. What I was shooting for with the J201 in JN2 is to get the sound of my Delluxe Reverb amp - which has a darker sound than most Fenders and starts to breakup at Vol set to 4 and I run it with bass=4 and treb=3.5...
Very Nice Mojotron.
I like it mucho!
Looks like MarkM may have a project for the weekend afterall......
Or should I dive back into my "projects I want to build" list that seems to get longer on a daily basis :icon_confused:
Thanks for sharing!
Looks great, but did you really have to include all of the religious banter? I have nothing against you being religious and do try to respect everybodies beliefs as I wish they do mine, but I find it quite irritating when people try to push their beliefs onto me, especially considering the fact that religion is such a personal thing. Sorry to turn this into a thread on ethics, but if I wanted to join your church, I would have already.
Cliff....
What do you mean 'all of the religious banter' ?
He had one comment / notice at the bottom of his very informative post.
As a Christian, I find it very offensive that we are suppose to keep ALL our
"religious' comments to ourselves and cant say a thing that might upset those
who dont share our beliefs.
Why dont you practice some of that 'tolerance' that I keep hearing people talk about.
It seems to me that 'free speech' and 'tolerance' are rights and practices that are reserved
for everyone else Except Christians.
I bet you (or anyone else) wouldnt have said a thing had he mentioned Islam or Budda.
As one who is guilty of trailing off topic..........
Mojo-
Looks nice. Thanks for the work. Way to give props to those who helped!!
Time to break out the breadboard ;)
Quote from: Cliff Schecht on July 21, 2006, 08:34:52 PM
Looks great, but did you really have to include all of the religious banter? I have nothing against you being religious and do try to respect everybodies beliefs as I wish they do mine, but I find it quite irritating when people try to push their beliefs onto me, especially considering the fact that religion is such a personal thing. Sorry to turn this into a thread on ethics, but if I wanted to join your church, I would have already.
welcome to the land of the First Amendment ...
Quote from: awilson40 on July 21, 2006, 10:09:25 PM
Cliff....
What do you mean 'all of the religious banter' ?
He had one comment / notice at the bottom of his very informative post.
As a Christian, I find it very offensive that we are suppose to keep ALL our
"religious' comments to ourselves and cant say a thing that might upset those
who dont share our beliefs.
Why dont you practice some of that 'tolerance' that I keep hearing people talk about.
It seems to me that 'free speech' and 'tolerance' are rights and practices that are reserved
for everyone else Except Christians.
I bet you (or anyone else) wouldnt have said a thing had he mentioned Islam or Budda.
Yeah it was a little hypocritical of me to go off like that, but I would have still made the point no matter what religion he was talking about. It just gets to me when people include unnecessary messages like that. I'm sure you guys would be just as irritated if I decided to include a passage about my schematic being only for those opposed to the ideas of unorganized religion. I guess his wording is what really threw me off though...
Quotefor the purpose of supporting those in the service to the Lord...
But again, let me apologize... I should be in support of anybody making an attempt to keep the DIY community alive.
Quote from: markm on July 21, 2006, 07:56:32 PM
Very Nice Mojotron.
I like it mucho!
...
Thanks for sharing!
Thanks Dude! I felt especially inspired to start writing up as many of these design ideas I have been playing with as I can - I owe a lot to others who have helped me. I meant to do this much earlier, but recently my day job got really busy there for a few months... I hope someone else likes this one as much as I do - I hope others can build this ok - you never know since you end up being sort of subjective after building a number of boards in the process of experimenting - but I'm pretty sure I got all the notes in there that someone else would need.
Quote from: Cliff Schecht on July 21, 2006, 08:34:52 PM
Looks great, but did you really have to include all of the religious banter? I have nothing against you being religious and do try to respect every bodies beliefs as I wish they do mine, but I find it quite irritating when people try to push their beliefs onto me, especially considering the fact that religion is such a personal thing. Sorry to turn this into a thread on ethics, but if I wanted to join your church, I would have already.
Thanks for expressing your irritation with how I did this. I do respect that, and I think I can understand where you're coming from; my intent with this was not to push religion as much as just share a cool circuit and point those who might want to - to volunteerly donate to one of several worthy causes in the process.
Quote from: Cliff Schecht on July 22, 2006, 04:56:05 AM
...I'm sure you guys would be just as irritated if I decided to include a passage about my schematic being only for those opposed to the ideas of unorganized religion. I guess his wording is what really threw me off though...
Quotefor the purpose of supporting those in the service to the Lord...
...
Ahh I see what you mean, I can see how that might have been misinturpreted.
I didn't mean this circuit is only for certaiin people - I intended quite the opposite: if anyone wants to post it anywhere, claim that they drew/designed it, make comercial pedals from it without compensating me... it that's all fine with me - what I really ment to say is "I would like to support the below ministry... please send a donation if you liked it"
Looks cool Mojo, It's very similar to a lot of my recent "Jfet excursions" so I probably wont
be making one of them.
Thanks for sharing though :D
Peace,
MM.
A friendly word-up Bro,
There is a time and a place for everything, I also am of the Christian persuasion ...BUT... I don't think anyone's religious disclaimers should accompany schematics here, it's not the appropriate place.
In fact it makes me NOT want to try a build, as placing stuff like that on your schem-o is subliminally making (folks) feel guilty if they build one, and like it.
Bringing people to the Lord is not about guilt, it's about forgiveness.
Lets PLEASE keep our religion out of this forum. There is another forum here called "The Lounge" where it would be much more appropriate to post (and invoke) invitations to support you favorite ministries, here we discuss electronics.
Totally agree with red house. Schematics in schematics place, religion in religion place. You don't sell Barbie on a tool store do you? I believe it's the same... (sorry if it sounded rude, trully not intended).
Well well, lets live that side apart, very nice of you posting schematics and everything! wouldnt be better if the pcb without components was in black? so it could ready for PNP or something similar?
Has anyone got a sound clip? would love to see how it sounds, and make a decission throught it!
Thanks!
Bye bye
Diego Andrés Cao
PS Excuse my english(sometimes it's hard to think in one language and express in other)
Quote from: QSQCaito on July 22, 2006, 12:00:41 PM
Excuse my english (sometimes it's hard to think in one language and express in other)
"Sometimes it's even harder to think in one language and express in the same" :icon_lol:
MM
Yikes... either way... great circuit... tweaking the Fetzer valve was something I have wanted to do but am not quite smart enough to do ...yet...
Thanks for the suggestions, I made a few updates and reposted the files.
I did not intend for anyone to feel guilty, or for anyone to support something they did not want to... I expressed this in a way that was inclined to be misunderstood - I think I have made it clearer now that this work is offered free without any obligation for any purpose - personal, commercial or other..... Have fun! There are a few more on the way.
Built this today and like the result - I used J201s (all I had) and 3k R3. Dials in quite a nice range and will definitely box this one up. Thanks for the schematic Mojotron :)
Oh, I have a vero layout if its ok to post it ?
Quote from: Torchy on July 22, 2006, 06:52:21 PM
...Oh, I have a vero layout if its ok to post it ?
That would be great Torchy - thanks much! Glad you liked the circuit. Let me know if you need a place to host it.
I think the J201's definitely give it a nice grind and higher drive levels - that's what I'm using right now. I'll try a 3k in R3, and see how that sounds. In my simulations of this circuit I settled on 1.2k to match the Fender circuit frequency responce with triode spice models, but in my sims I totally missed R10 and I just added R10 and simulated R3. R3 at 3k seems to keep JN1's Vg from dipping too low and on the bottom swing of the signal when the input signal is strong preventing premature clipping :icon_biggrin: - thanks for the suggestion I'll check this out and update the schematic.
Let me know if anyone would like the SuperSpice sim files.
Can't wait untill torchy posts the vero- I just got some vero in today and am ready to try my hand at building a vero project and this one looks like a great one to start.
Im at work today but I'll post the layout tonight ...
(http://i7.photobucket.com/albums/y278/veroboard/debug.gif)
The unlabelled resistor next to C4 is the status LED series resistor, to suit whichever LED you use.
Anybody see any errors ?
Quote from: Torchy on July 23, 2006, 04:19:38 PM
..
The unlabelled resistor next to C4 is the status LED series resistor, to suit whichever LED you use.
Anybody see any errors ?
That's great! Thanks.
Well here's the sound clips for the Vibin' Champ (VC):
Note 1: I used Torchy's sugestion and made R1=R3=3k and 2 J201s - Sounds the best to me - THANKS!!!
Note 2: Its really hot here today - (no AC and I do these in my attic :icon_twisted:- 100+ degrees.. Yikes!) I did these clips quickly so I would not pass out - please excuse the roughness of the sound and playing...
Note 3: In the heat my S470 developed a buzz, so there is some buzz in the HB clips - it's my guitar/playing not the VC
Setup1: Ibanez S470 (w/Gibson Classic '57/'57+ pickups) -> VAMP (for small combo)->computer sound card
Clip 1: Clean Neck HB: VC set to Dr:30%, Tr:50%, B:50%, Vol:70% :I played using the neck HB pickup w/out the VC on for a D-G-D chord set then added it - so you hear the change when activated, then I played the same blues like stuff in all of these clips
http://www.mojotronics.com/images/vibinchamp/vc_4_clean_HB.mp3 (http://www.mojotronics.com/images/vibinchamp/vc_4_clean_HB.mp3)
Clip 2: Over-Drive Neck HB: VC set to Dr:70%, Tr:70%, B:60%, Vol:50% :I played using the neck HB pickup w/out the VC on for a D-G-D-am chord set then added it -
I play one lick, turn the vol back to 80% on the guitar, play just about the same lick, then turn it back up. The rest of the clip I try to show how the VC cleans up with pick attack when used as an overdrive
http://www.mojotronics.com/images/vibinchamp/vc_5_dirt_HB_N.mp3 (http://www.mojotronics.com/images/vibinchamp/vc_5_dirt_HB_N.mp3)
Clip 3: Over-Drive Bridge HB: VC set to Dr:70%, Tr:70%, B:60%, Vol:50% :I played using the bridge HB pickup w/out the VC on for a D-G-D chord set then added it... This clip I try to show how the VC has a bit of grit - as an overdrive - I should have turned the bass up a bit...
http://www.mojotronics.com/images/vibinchamp/vc_6_HB_BR_dirt.mp3 (http://www.mojotronics.com/images/vibinchamp/vc_6_HB_BR_dirt.mp3)
Setup2: Warmoth (Swamp Ash) strat (w/Fender Fat '50's pickups) -> VAMP (for small combo)->computer sound card
Clip 4: Squeeky Clean Strat Neck: VC set to Dr:30%, Tr:50%, B:50%, Vol:70% :I played using the neck pickup w/out the VC on for a D-G-D chord set then added it - so you hear the change when activated, then I played the same blues like stuff in all of these clips. In this clip I switch the VC in and out 3 times (the VC level is a bit louder - so you can hear it kick in) in the first 1/2 of the clip, then I use the Guitar's vol control and picking attack to control dynamics in order to demo the sensitivity
http://www.mojotronics.com/images/vibinchamp/vc_7_clran._strat.mp3 (http://www.mojotronics.com/images/vibinchamp/vc_7_clran._strat.mp3)
Clip 5: Over-Drive Neck Strat: VC set to Dr:70%, Tr:70%, B:60%, Vol:50% :I played using the neck pickup w/out the VC on for a D-G-D chord set then added it - so you hear the change when activated, then I played the same blues like stuff in all of these clips. In this clip I switch the VC in and out a few times (the VC level is a bit louder - so you can hear it kick in) in the first 1/2 of the clip, then I use the Guitar's vol control and picking attack to control dynamics in order to demo the sensitivity
http://www.mojotronics.com/images/vibinchamp/vc_7_dirt._strat.mp3 (http://www.mojotronics.com/images/vibinchamp/vc_7_dirt._strat.mp3)
You can here from this last clip that it does not have a lot of overdrive using vintage strat pickups - but with a FatBooster in front of the VC it sounds very much like a small Fender being over driven with a booster... I really like that sound myself.
Ok dudes, It's HOT - I'm out of here - I need to go to the beach!! :icon_redface:
Thanks again everyone for the suggestions :icon_biggrin:
Great clips! Nice sounding little drive, as soon as I can get the parts together I think i'll build it. Great work!
Quote from: mojotron on July 22, 2006, 04:38:33 PM
Thanks for the suggestions, I made a few updates and reposted the files.
I did not intend for anyone to feel guilty, or for anyone to support something they did not want to... I expressed this in a way that was inclined to be misunderstood - I think I have made it clearer now that this work is offered free without any obligation for any purpose - personal, commercial or other..... Have fun! There are a few more on the way.
I guess you just didn't get it.
It's great that you reiterate and edited the disclaimer...but... the religous slant in your disclaimer is still there, doesn't belong in this forum, please post your invitations of support for your favorite ministries in the Lounge forum, leave the schematics/layouts
religion free is that asking too much?.
mojotron, thanks for the project, layout, soundclips and all your work. I was not bothered or offended at all.
Quote from: RedHouse on July 23, 2006, 09:29:23 PM
Quote from: mojotron on July 22, 2006, 04:38:33 PM
Thanks for the suggestions, I made a few updates and reposted the files.
I did not intend for anyone to feel guilty, or for anyone to support something they did not want to... I expressed this in a way that was inclined to be misunderstood - I think I have made it clearer now that this work is offered free without any obligation for any purpose - personal, commercial or other..... Have fun! There are a few more on the way.
I guess you just didn't get it.
It's great that you reiterate and edited the disclaimer...but... the religous slant in your disclaimer is still there, doesn't belong in this forum, please post your invitations of support for your favorite ministries in the Lounge forum, leave the schematics/layouts religion free is that asking too much?.
Yes
RedHouse: I'm not religious, but I think he can put whatever he wants on his schem. I'm just glad that he is willing to share something he has worked on- lots of guys won't share stuff for fear of it getting ripped off (talked about in the naming thread) Just my .02
Thanks Mojo for the project . Sounds like an interesting OD. I'll give it a try.
And, thanks also Torchy for the layout. Looks fairly easy to build.
I consider myself an atheist, but hey, mojo's contribution is great and we should show respect at the least, I don't have any problem with what he's trying to promote. Keep up the good job Mojo :icon_wink:
Quote from: RedHouse on July 23, 2006, 09:29:23 PM
Quote from: mojotron on July 22, 2006, 04:38:33 PM
Thanks for the suggestions, I made a few updates and reposted the files.
I did not intend for anyone to feel guilty, or for anyone to support something they did not want to... I expressed this in a way that was inclined to be misunderstood - I think I have made it clearer now that this work is offered free without any obligation for any purpose - personal, commercial or other..... Have fun! There are a few more on the way.
I guess you just didn't get it.
It's great that you reiterate and edited the disclaimer...but... the religous slant in your disclaimer is still there, doesn't belong in this forum, please post your invitations of support for your favorite ministries in the Lounge forum, leave the schematics/layouts religion free is that asking too much?.
This is is the problem with a country that enshrines free speech in it's constitution - pesky people that insist on exercising their constitutional rights!
Maybe you'd feel more comfortable living in a country where such freedoms don't exist?
Well seeing how he changed it without anybody asking, I must assume mojo is a reasonable man. I probably wouldn't have said anything if my day hadn't gone so bad. It's his right (and duty) as an American to express himself however he pleases. Censorship is a huge problem already in America.
Why can't we just "ignore" the religious slant and accept a very nice circuit, which has already been verified
and made into an easy vero layout, that we can all build and enjoy ?
I don't see any problem ( that's my own personal opinion )
It's like a "bad TV show" .... if you dont like it ..... then DONT watch it ! why "complain about it" ??
MM.
+1 Totally.
In Australia we call it whinging.
The man is dedicating his work to his beliefs and exercising his right to free speech whilst similtaneously NOT standing over anyone............so whats the problem? If your beliefs are different....just let it go.
Mate, that's a lovely contribution and I think 99.9% of the people here really appreciate your fine work.
Praise jebus, Allah akhbar, I am dedicating this post to Isis, thor and venus, the league against religious violence and Bob the satanist. They need a new spaceship to escape the madness. Also, please support your local athiests, they have the strength to face their eventual personal abyss.
Quote from: MartyMart on July 24, 2006, 06:32:18 AM
Why can't we just "ignore" the religious slant and accept a very nice circuit, which has already been verified
and made into an easy vero layout, that we can all build and enjoy ?
I don't see any problem ( that's my own personal opinion )
It's like a "bad TV show" .... if you dont like it ..... then DONT watch it ! why "complain about it" ??
MM.
I wasn't meaning to "
complain" about it, I was hoping we just wouldn't get started with religion in our stompbox forum, it's not the appropriate place. Having been hangin out here for about 5 years now I've been quite happy it (was) a non-political non-religous forum. Again, I'm a Christian too, don't have anything against that (obviously), and I'm all into American freedom (having been born here in the USA 47 years ago) it's just that there is a time and a place for everything, but I'll say no more of it so as not to cause any further waves..
Peace out.
No worries , I think this has ended well, with another cool circuit designed and ready to go :D
Peace ,
MM.
nice soundings!, but ive got one tiniy question.. can it be used as a preamp/booster, just to boost signal, no distortion, clena sound
thanks
bye bye
DAC
Quote from: QSQCaito on July 24, 2006, 02:12:46 PM
...
ive got one tiniy question.. can it be used as a preamp/booster, just to boost signal, no distortion, clena sound
...
Thanks.
Yes - IMHO, I think that this pedal is well suited as a preamp/booster if you want a Fendery sound - mostly becasue as an 'overdrive' it does not come close to the levels of gain you get from other devices that are called an 'overdrive'. What you hear on the clips is as much overdrive as it will muster by itself without putting a booster in front of it.
It does fendery clean sounds very well if you leave SW1 open - or if you don't use SW1 and use a 2n5457 for JN2.
Very cool! Im going to build this one then.. its excellent to have a switch to select, i love that..
Which are the mods that made it sound better, r1+r3=3k..something else??
and.. regarding the j201, i can't find that one, have you got any replacement??
and.. last question,
what are the trimpots for??
thanks a lot
bye bye
DAC
Quote from: QSQCaito on July 24, 2006, 04:12:42 PM
Very cool! Im going to build this one then.. its excellent to have a switch to select, i love that..
Ya - I like switches too - there is another mod where you can put a 1kB pot in series with Sw1 between the 2 V2 connections - this allows you to adjust the level of overdrive that kicks in - and if one makes Sw1 a stomp switch - that will allow for an adjustable "solo boost".... I'm not altogether crazy about an extra knob and stomp switch for this mod because the boost level is not that huge on this pedal - although it is very similar to the overall volume differenced with the 'boost' control on the Fulltone FD2.
Quote from: QSQCaito on July 24, 2006, 04:12:42 PM
Which are the mods that made it sound better, r1+r3=3k..something else??
Yes, use 3k resistors for R1 and R3. I will update the schematic to indicate this as soon as I can.
These resistor values are most important if you are using a JFET like the J201 - with a lot of gain. With the J113 and 2N5457 parts the values of R1/R3 did not seem to matter as long as they were between 1-3k.
Quote from: QSQCaito on July 24, 2006, 04:12:42 PM
and.. regarding the j201, i can't find that one, have you got any replacement??
J201 JFETs are kind of unique in that they offer a lot of gain, low Vp (~.75v which I think aids a most natural breakup of the signal when being overdriven) and make a bit more of a darker sound - and they are relatively common. In my experiments 2N5457 parts sounded nice too - but the 2nd stage (JN1) sounds much better with a J201
Quote from: QSQCaito on July 24, 2006, 04:12:42 PM
and.. last question,
what are the trimpots for??
...
I got this info from the fetzer valve article at runoffgroove.com (this is a great read as it distills the work of Dimitri Danyuk, and others I believe, into a 'what you need to know format' - thought out and presented from the perspective of building a stomp-box circuit)
You really want your drain voltage (Vd) set to:
Vd = .6 * Vcc + .7 * |Vp|
Which for a J201 in this circuit this would be:
Vd = .6 * 9v + .7 * .75 = 5.925
It is common to see trim pots used on JFET circuits like this as most people want to try lots of different parts as each part offers it's own bit of 'mojo' - plus no one really wants to stop and measure Vp on all of their JFET parts... it's just a convenience and worth a $1 - or two - to me.
Thanks a lot for this circuit. I appreciate all the work you had to make this effect became alive (and I'm sure it was lots of work). The soundclips sound great too. It's in my "to build" list.
I just can't get that j201 :(, the best thing would be to use 2 2N5457 right?? In that case, how would affect that the sound, less gain, cleaner, how, any clue?
Also in the case i use 2 2n5457, the trim pots should be the same value? to what voltage should i adjust them??
Thanks a lot
bye bye
DAC(Diego Andrés Cao)
That looks like a great little circuit. And for the record, you put what ever you want on your schems. They are your artwork and NOBODY I mean NOBODY has any right to criticize it.
Scott
Quote from: Marcos - Munky on July 25, 2006, 05:36:06 PM
Thanks a lot for this circuit. I appreciate all the work you had to make this effect became alive (and I'm sure it was lots of work). The soundclips sound great too. It's in my "to build" list.
Great Marcos - I am more than happy to contribute any way I can!
Quote from: QSQCaito on July 25, 2006, 08:58:33 PM
I just can't get that j201 :(, the best thing would be to use 2 2N5457 right?? In that case, how would affect that the sound, less gain, cleaner, how, any clue?
Also in the case i use 2 2n5457, the trim pots should be the same value? to what voltage should i adjust them??
Thanks a lot
bye bye
DAC(Diego Andrés Cao)
Hey DAC, with 2 2n5457 it will about 1/2 the gain and about 1/2 the breakup - so somewhere in between the clean vs. dirty sound clips I made if running at 9v. This would make a nice boost - it would be on the clean-ish side. You may want to control the high-end a bit too by putting a 220pF cap across the Drive (Dr) pot lugs - but that is totally a preference thing. The other thing I would do if using 2 2n5457 parts is to use 2 batteries or an 18v adaptor and run the circuit at 18v - I have not tried that, but it is what I would do if I did not have j201 parts - it may sound even better...
The easiest way to set the trimpots is to set R6 so that you get the most "crackle" volume, when you first adjust it, then adjust R7 for the most sound volume, then tweak R6 again for the most sound volume - I use this method a lot when I am swapping out parts and generally gets you close to the computed value of (Vd = .6 * Vcc + .7 * |Vp|) = .6(9)+.7(1.5) = 6.45v using 2n5447 parts assuming Vcc = 9v - double Vcc for 18v. It is safe to assume that JN1 and JN2 drain voltages (Vd) will be roughly the same - but because of R3 - JN1 will have a slightly higher Vd where JN1's Vd would be 6.45v + Vr3. The simplest thing is to 'tune' the trimmer pots by volume.
Quote from: burnt fingers on July 25, 2006, 11:57:01 PM
That looks like a great little circuit. And for the record, you put what ever you want on your schems. They are your artwork and NOBODY I mean NOBODY has any right to criticize it.
Scott
Thanks Scott - this approach is new so I anticipated some comments and I never expected complete acceptance of this method. It's great that everyone is so respectful here, even if people disagree with me - that's one of the things that makes this forum great. And, this gives me the right approach for me to release other designs.
Wow, thanks a lot for the help.
BTW i found an electronic shop faaar away that told me he had j201.. so im planning a big order.. to uild 5/6 pedales out of once..
byebye
DAC
Quote from: QSQCaito on July 29, 2006, 01:09:28 AM
Wow, thanks a lot for the help.
BTW i found an electronic shop faaar away that told me he had j201.. so im planning a big order.. to uild 5/6 pedales out of once..
byebye
DAC
If you are getting started, you might want to buy extras - like enough to build two times what you had planned. A few years ago I bought 10 times of everything I was building at the time. After a few buys like that I got to the point where, generally, I just need to buy a few unique parts here and there - like a D-FF IC - in order to build new stuff since then. I wish I had done that back in the '80's when there were no online parts dealers - it would have saved me a lot of trips to obscure places :icon_biggrin: