tag:blogger.com,1999:blog-6847048658257278783.post378578639265802897..comments2024-03-29T01:36:12.851+00:00Comments on Guitar FX Layouts: Xotic EP Booster - Briggs ModdedIvIarkhttp://www.blogger.com/profile/08416945174853142251noreply@blogger.comBlogger54125tag:blogger.com,1999:blog-6847048658257278783.post-34399078537876630312020-10-10T00:27:03.843+01:002020-10-10T00:27:03.843+01:00My bad. I had the top of the first 10u going to th...My bad. I had the top of the first 10u going to the top row rather than pin 2. Makes sense.Old and Ignored https://www.blogger.com/profile/06772581922016192424noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-35244243562599961232020-10-09T23:46:18.047+01:002020-10-09T23:46:18.047+01:00Well, this thread is 8 years old, but I’ll ask any...Well, this thread is 8 years old, but I’ll ask anyway. I’m not getting 18v anywhere either, however, the only charge pump I had around was a 1044. Is this the problem?Old and Ignored https://www.blogger.com/profile/06772581922016192424noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-6985187638767584072020-04-04T01:35:40.585+01:002020-04-04T01:35:40.585+01:00It could be done but it wouldn't just be a cas...It could be done but it wouldn't just be a case of tweaking resistor values, the scheme would have to be adapted to accommodate bipolar transistors instead of JFETs. <br /><br />Probably one to experiment with for a tweaker with a breadboard.IvIarkhttps://www.blogger.com/profile/08416945174853142251noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-44665346745947068362020-04-03T19:52:42.977+01:002020-04-03T19:52:42.977+01:00Hi everyone, would it be possible to replace the s...Hi everyone, would it be possible to replace the silicon transistors with some germanium ones ? I know that germanium to silicon is feasible by tweaking a resistor, but I don't know how it works from silicon to germanium (kinda new to all this...). Thanks !dullmanhttps://www.blogger.com/profile/00250072289503487886noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-85735514545700138782017-03-15T15:27:12.941+00:002017-03-15T15:27:12.941+00:00I've just finished for someone, my second EP B...I've just finished for someone, my second EP Booster, but this time, this Briggs Modded one. I took the liberty to mod it a liiiiittle bit more! A very nice booster now, with tons of output, and a usable 3 way bass switch!<br /><br />Basically, you replace the 47nf input cap with a 3 way dpdt on off on, in the middle you put a 470 PF cap, on one side a 561 pf one, and on the other the stock 47n; You replace the 3k3 and 4k7 for the two 2n5457 resistors, with 1K and 1K. Perfect! <br /><br />Here is my build:<br /><br />http://hgecontraptions.blogspot.com/2017/03/ep-booster-modded-version-very-good.html<br />HGE Contraptionshttps://www.blogger.com/profile/13124050879741157587noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-58760236674610128992017-03-15T15:26:15.902+00:002017-03-15T15:26:15.902+00:00This comment has been removed by the author.HGE Contraptionshttps://www.blogger.com/profile/13124050879741157587noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-81158208656127189902015-05-24T00:36:22.686+01:002015-05-24T00:36:22.686+01:00as long as the charge pump ic is a 7660s you'r...as long as the charge pump ic is a 7660s you're good, do not use one that is just a plain 7660. also, while i haven't built this, i can tell you that if it's verified it should be good to you, and have no issues if built correctly.Zachhttps://www.blogger.com/profile/00044917566185720896noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-10466185288169748812015-05-23T12:37:16.155+01:002015-05-23T12:37:16.155+01:00Hey all
Two questions:
Are you guys substituting ...Hey all<br /><br />Two questions:<br />Are you guys substituting ICL7660SCPA for the IC7660SCPA (note the added "L")? Or using a different IC?<br />Also, reading above it seems people have had issues with the Briggs mod.... has anyone had success with the Briggs as it's drawn above? Or should I stick with the original EP-B?<br /><br />ThanksUnknownhttps://www.blogger.com/profile/10575020640579289439noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-19870907805022949822014-06-27T17:54:18.655+01:002014-06-27T17:54:18.655+01:00Hey Mark, first of all, I'd like to thank you ...Hey Mark, first of all, I'd like to thank you for making this layout (and a ton of others). I've built a decent amount of pedals based on your layouts, and I just wanted to let you know that your work is appreciated. Now, onto the bad news. I don't think my build is working properly. I mean, it works, but it doesn't have as much volume on tap as I thought it would. I think that the charge pump might be the problem. It seems like the effect is only getting 9v instead of 18v. You can hear a high pitched whine whenever the effect is engaged. It's not very loud, but it's there. I had a Klone a while ago that did that too, but I'm pretty sure that it was getting 18v because it had a massive amount of headroom, so maybe that's just the nature of the beast with charge pumps? I replaced the charge pump in that one and I think it reduced the noise a little bit, but it was still there. Anyways, the op-amp is extremely hot to the touch when the pedal is on. Is it possible that the op-amp is bad? I'm pretty sure I ordered it from Tayda, and I've had pots and switches from them fail on me before, so I wouldn't be surprised. Any help is greatly appreciated. Thanks!JoeSuthershttps://www.blogger.com/profile/12430467368922784534noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-61503570650022347372014-05-12T15:54:42.828+01:002014-05-12T15:54:42.828+01:00I know this is a late reply, but take a look at ma...I know this is a late reply, but take a look at madbeans fatpants. From what I understand it has many similaries to the ep-pre.Adamhttps://www.blogger.com/profile/14896415346359192288noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-84153359063606715392014-04-24T21:50:55.685+01:002014-04-24T21:50:55.685+01:00Thanks for taking the time to reply lvlark; really...Thanks for taking the time to reply lvlark; really appreciate it :)Nanananah Giroudhttps://www.blogger.com/profile/01025015230195350528noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-65958702889397959112014-04-24T21:28:38.168+01:002014-04-24T21:28:38.168+01:00You're ok for the top right hand cap, but I wo...You're ok for the top right hand cap, but I wouldn't risk it with the bottom one. It will work without them both though so you can still test the effect is working. They are both filter caps and so are there to help prevent noise, but if it isn't noisy you may not even need them, plenty of effects don't have them anyway, and supplies normally have one built in anyway.<br /><br />The 16V rated caps will still be useful for future builds, because I often have a 100u in 9V pedals which they are perfect for.IvIarkhttps://www.blogger.com/profile/08416945174853142251noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-30643257800733872102014-04-24T21:01:50.445+01:002014-04-24T21:01:50.445+01:00Hi all,
Love the site! Just ordered the bits I ne...Hi all,<br /><br />Love the site! Just ordered the bits I needed for this and got 16v rated 100uF caps sent to me instead of 35v ones. Can anyone with more knowledge than me tell me if that's gonna be an issue for this build? I know it runs on 18v but not sure how to tell whether these specific caps will be exposed to that voltage. Thanks in advance for your help!Nanananah Giroudhttps://www.blogger.com/profile/01025015230195350528noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-33647424015477346752014-04-03T15:19:45.297+01:002014-04-03T15:19:45.297+01:00If you are losing all the high frequencies, i'...If you are losing all the high frequencies, i'm quite certain that you have an error in your build.<br />+mmirosolhttps://www.blogger.com/profile/02400327798106357876noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-21703835176644380032014-04-03T05:20:48.402+01:002014-04-03T05:20:48.402+01:00Built this pedal and here is my impression:
I am ...Built this pedal and here is my impression:<br /><br />I am disappoint.<br /><br />The treble completely disappears. The layout *requires* a trimpot for the jfet. I used a 100k trimpot for mine. I also tried j201 jfet so along with the suggested ones and nothing. IMHO this pedal isn't very good at what it does at all. I am going to give the CAE line driver or the tc spark booster a shot instead. Don't waste your time with this one.Sensei Timhttps://www.blogger.com/profile/04338775054703359643noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-41025541601979181632013-10-24T18:35:13.758+01:002013-10-24T18:35:13.758+01:00So can anyone recommend this highly enough to let ...So can anyone recommend this highly enough to let go of the Madbean Fat Pants 2012 version?Doron Barnesshttps://www.blogger.com/profile/11002512823760367163noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-6285544974181679532013-03-10T12:33:28.184+00:002013-03-10T12:33:28.184+00:00There is a radical solution for fixing this, I bui...There is a radical solution for fixing this, I built the non modified version and it is brilliant! What a charmer :)Anonymoushttps://www.blogger.com/profile/06398692084354522702noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-28489927244310581902013-03-10T12:28:31.124+00:002013-03-10T12:28:31.124+00:00There is a radical solution for fixing this, I bui...There is a radical solution for fixing this, I built the non modified version and it is brilliant! What a charmer :)Anonymoushttps://www.blogger.com/profile/06398692084354522702noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-49395671452834917422013-03-09T12:32:21.223+00:002013-03-09T12:32:21.223+00:00Hi all, any ideas how to get back the treble in th...Hi all, any ideas how to get back the treble in this circuit? It's sooooo bassy. <br />On another note, I biased the q1 drain to 5.8v using a 100k trim pot. Ended up around 65k dial up. Listening through the amp, it sounded the loudest at that point. I don't know if this is good or bad but it sounds right. If I could only put some treble back.....<br />Cheers for any help.Anonymoushttps://www.blogger.com/profile/06398692084354522702noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-17792456846854094652012-10-12T06:50:49.585+01:002012-10-12T06:50:49.585+01:00I hear you Mark! I shall stop tinkering with this ...I hear you Mark! I shall stop tinkering with this now, put the old 8k2 back in and call it a day.<br />My constant nagging about this stems more from scientific interest i think. I wanted to fully understand how this thing works, ya know?<br />And you explained that well!<br />Thank you very much again! :-)=shaggadelikhttps://www.blogger.com/profile/09782281953333076813noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-78688902419642621502012-10-10T17:12:14.086+01:002012-10-10T17:12:14.086+01:00As the ratio between the drain and source resistor...As the ratio between the drain and source resistors changes, so does the bias point, gain and output impedance, so you could use a trimmer in either spot to perform the task. Some people swear that one way is better than the other but to me as long as it works I don't have the enthusiasm to look into it much more deeply. Any advantage one may have over the other isn't too important to me as long as the pedal still sounds good.<br /><br />I don't know for sure, but maybe drain trimmers are used more frequently by manufacturers simply because the drain resistor is usually larger and the source relatively low, and 20K, 50K, 100K trimmers are more readily available than 330 ohm, 470 ohm or 1K. But whatever the reason I think it preferable to do the layouts as it was done in the original pedal and not think too much about it :o)IvIarkhttps://www.blogger.com/profile/08416945174853142251noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-25593947285959709432012-10-10T16:27:58.274+01:002012-10-10T16:27:58.274+01:00Reading up on the issue of "JFET biasing"...Reading up on the issue of "JFET biasing", the most often mentioned method is using a "source resistor to bias a JFET"? So the source resistor should be variable, not the drain's? I am officially confused now... ;-)=shaggadelikhttps://www.blogger.com/profile/09782281953333076813noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-52291893205873978312012-10-10T16:18:12.039+01:002012-10-10T16:18:12.039+01:00Still thinking about this: do i really measure the...Still thinking about this: do i really measure the bias of a JFET between drain and ground? <br />And: maybe the 5.5V "sweet spot" bias is only valid when using 9V power? Might it need to be doubled in this case (18V circuit), so being around 11V should be the "sweet spot"?shaggadelikhttps://www.blogger.com/profile/09782281953333076813noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-23911044283075247012012-09-24T06:47:19.294+01:002012-09-24T06:47:19.294+01:00This is the part of Fred's blog post that i...This is the part of Fred's blog post that i'm referring to:<br />"[EDIT2] - ... I'd also recommend one other small change - replace the drain resistor on the first FET with a 10k trim pot then use it to dial in a 5.5v bias on the Jfet's drain to make sure you've got it in the "sweet spot". Just thought I'd add that ;-)"shaggadelikhttps://www.blogger.com/profile/09782281953333076813noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-89308679432940041392012-09-23T16:39:53.855+01:002012-09-23T16:39:53.855+01:00I'll have a word with Fred and see what he say...I'll have a word with Fred and see what he says, but in my mind Q2 will always be around 17.5V from a 9V supply, that can't change, and I can't see how an 8K2 resistor could taje 17.5V down to 5.5V if that has been mentioned, I'd expect you to need a much bigger resistor.IvIarkhttps://www.blogger.com/profile/08416945174853142251noreply@blogger.com