tag:blogger.com,1999:blog-6847048658257278783.post110823513990547018..comments2024-03-27T15:26:01.893+00:00Comments on Guitar FX Layouts: Marshall 3005 PreampIvIarkhttp://www.blogger.com/profile/08416945174853142251noreply@blogger.comBlogger75125tag:blogger.com,1999:blog-6847048658257278783.post-47992101226670092082022-03-16T14:41:10.027+00:002022-03-16T14:41:10.027+00:00PS: I think I'll just use +/-9v
from an NE555...PS: I think I'll just use +/-9v <br />from an NE555 voltage inverter (Mirosol design): https://tagboardeffects.blogspot.com/2013/02/ne555-voltage-inverter.htmlj-peehttps://www.blogger.com/profile/06075769174607916244noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-91582500611114194092022-03-16T14:28:31.318+00:002022-03-16T14:28:31.318+00:00wow, great contribution, thanks a lot!!wow, great contribution, thanks a lot!!j-peehttps://www.blogger.com/profile/06075769174607916244noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-32703162415206305322021-11-27T18:30:59.130+00:002021-11-27T18:30:59.130+00:00i was wrong. tiny little speck of crud between the...i was wrong. tiny little speck of crud between the very edge of the two rails between pins 1 and 3 of the gain control...literally off the edge of the board!<br />all fixed. other than pins 1 and three of the gain pot being backwards, Alltrax74's layout is perfect and sounds great. i DID have to add a small cap from pin 2 of the 1458 to ground to knock out a microphonic whine.... hey, it happens with high gain and flying leads sometimes... but it sounds great, tone stack works perfectly too.<br />nice layout!pinksterhttps://www.blogger.com/profile/13385798043782856976noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-66769047117807984532021-11-27T02:31:23.972+00:002021-11-27T02:31:23.972+00:00hey alltrax, yeah, i think there may be a problem ...hey alltrax, yeah, i think there may be a problem with your layout. its definitely not working right, the one from here sounds completely different. i'm gonna go thru it and see if i can figure out the problem. seriously lacking balls, and seems like something's shorted somewhere that shouldn't be... good news to come soon, hopefullypinksterhttps://www.blogger.com/profile/13385798043782856976noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-63805724903565476402021-11-19T16:17:35.107+00:002021-11-19T16:17:35.107+00:00won't fire that way. needs a bipolar supply.won't fire that way. needs a bipolar supply.pinksterhttps://www.blogger.com/profile/13385798043782856976noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-32035621597876111452021-11-19T16:16:50.170+00:002021-11-19T16:16:50.170+00:00gotta be a bjt kinda opamp in these. anything with...gotta be a bjt kinda opamp in these. anything with a fet will sound like shit, hissy and too brite. there's a reason the guv'nor specc'd 1458's. less noise, warmer tone. jfets only really sound like tubes clean to my ear, when they distort, they distort hard and crackly and harsh.<br />pinksterhttps://www.blogger.com/profile/13385798043782856976noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-43507094781835315902021-11-19T16:14:51.464+00:002021-11-19T16:14:51.464+00:00you can fix that squeel. small cap from pin 2 to g...you can fix that squeel. small cap from pin 2 to ground. pinksterhttps://www.blogger.com/profile/13385798043782856976noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-22064405476060546342021-11-19T16:13:58.278+00:002021-11-19T16:13:58.278+00:00sounds fine into an amp toosounds fine into an amp toopinksterhttps://www.blogger.com/profile/13385798043782856976noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-23948848803613363732021-11-19T16:10:33.262+00:002021-11-19T16:10:33.262+00:00gain 1 and 3 seem to be labeled backwards.
if it o...gain 1 and 3 seem to be labeled backwards.<br />if it oscillates at full gain, add a small cap between pin 2 of the chip and ground... 470p to 2.2nf. go with the smallest one you can. if it's still oscillating, a small resistance in line between pin 2 of the gain and ground can do wonders, too. mine wants to see 660r there... i bet 666r would be perfect ;) but closest value i had was 680r so i went with that.<br />25k and 5k pots were used.<br />i own a lead 12, and most of the solid state marshalls from this series of amps, and this little sucker nails it.<br />thanks as always! peace out!<br />pinkjimiphotonpinksterhttps://www.blogger.com/profile/13385798043782856976noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-22293297987192239612021-09-18T00:44:00.405+01:002021-09-18T00:44:00.405+01:00yes you can. the actual unit runs the ic chip 5vol...yes you can. the actual unit runs the ic chip 5volts positive at pin 8, and 5 volts negative at pin 4. 9 volts is more than close enough for rock and roll.pinksterhttps://www.blogger.com/profile/13385798043782856976noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-23116850031215788782021-09-18T00:42:57.762+01:002021-09-18T00:42:57.762+01:00hey guys, not to bump a zombie, but i just restore...hey guys, not to bump a zombie, but i just restored one of these 12 watt marshalls. it IS running about 20 volts for the rails, BUT the actual chip itself in the preamp? 5 volts to pin 8, -4 volts to pin 4. so the whole thing will run on 9 volts, you don't need a separate transformer. if you do something like this:<br /><br />https://www.bristolwatch.com/ele/img/bipolar2.gif<br /><br />you should be fine running this at 9 volts. all ya need is two caps and two diodes to generate +/- 5 volts like on the original unit. save the extra bucks for more parts, or a phat sack or a couple pints ;)<br />pinksterhttps://www.blogger.com/profile/13385798043782856976noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-7682558387941365292021-06-06T21:12:25.647+01:002021-06-06T21:12:25.647+01:00Is there a way I can convert the Lead 12 preamp to...Is there a way I can convert the Lead 12 preamp to work with 9V asymmetrical supply? I was wondering if I could use the virtual ground method like most IC based pedals, but I'm not sure what components from the Lead 12 should connect to Vbias. ThanksBiriguiboushttps://www.blogger.com/profile/16192547217234304041noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-5342240053458422872021-01-23T17:42:32.528+00:002021-01-23T17:42:32.528+00:00I made this, but the mid pot dont work...I made this, but the mid pot dont work...GuitarMasterhttps://www.blogger.com/profile/14788315223114268126noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-52666649781539851302020-09-10T10:41:19.115+01:002020-09-10T10:41:19.115+01:00YesYesAlltrax74https://www.blogger.com/profile/13079701857494829507noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-13371065153254766292020-09-10T01:53:07.042+01:002020-09-10T01:53:07.042+01:00Does the IC 1458 refers to LM1458? Thank youDoes the IC 1458 refers to LM1458? Thank youPercy Hornickelhttps://www.blogger.com/profile/10941035617287446189noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-85716322505569195442020-09-10T01:51:51.060+01:002020-09-10T01:51:51.060+01:00This comment has been removed by the author.Percy Hornickelhttps://www.blogger.com/profile/10941035617287446189noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-38480489030670795002020-06-27T01:51:51.773+01:002020-06-27T01:51:51.773+01:00Hey, Zach, how I can transfer this layout for perf...Hey, Zach, how I can transfer this layout for perfboard? Can you help me? Thx!GuitarMasterhttps://www.blogger.com/profile/14788315223114268126noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-61050357686959588552020-06-26T19:46:43.187+01:002020-06-26T19:46:43.187+01:00Hola gran trabajo.
En el enunciado del esquema Dic...Hola gran trabajo.<br />En el enunciado del esquema Dice: 10 Cuts, 3 Jumpers, Me habré vuelto loco loco mirando pero solo veo dos.<br /><br />Gain funciona al revés de lo que se espera.<br /><br />Observado el esquema (https://drtube.com/schematics/marshall/3005.gif)<br />No es que solo Gain2 vaya a masa si no que Gain3 también, no acabo de entender el esquema, esta conexión, parece acabar en una flecha ¿cómo lo interpretamos, que se desconecta cuando el jack se introduce en LOW? ¿Hace lo mismo al conectar HIGH? ¿Es un circuito antiPop que solo tiene sentido cuando no hay jacks puestos?<br /><br />Hello great work.<br />In the statement of the scheme It says: 10 Cuts, 3 Jumpers, I will have gone crazy crazy looking but I only see two.<br /><br />Gain works the opposite of what is expected.<br /><br />Observed outline (https://drtube.com/schematics/marshall/3005.gif)<br />It is not that only Gain2 goes to ground but rather that Gain3 also, I do not just understand the scheme, this connection seems to end in an arrow in the ring of the jack, how do we interpret it, which disconnects when the jack is inserted in LOW? Does the following arrow say the same when connecting HIGH? Is it an antiPop circuit that only makes sense when there are no jacks in?<br />I have already done the pedal but I have things that I would like to understand. Thank you<br />Paco de Torreshttps://www.blogger.com/profile/04970210642948399147noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-16432954041666575182020-04-15T19:14:03.553+01:002020-04-15T19:14:03.553+01:00Thanks! Great sound!
My project
https://youtu.be/n...Thanks! Great sound!<br />My project<br />https://youtu.be/nn92ruizjKc<br /> Andyhttps://www.blogger.com/profile/18428117698602506968noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-18607468914298923192020-04-03T08:54:13.047+01:002020-04-03T08:54:13.047+01:00I would also like to design the 3005 power amp, bu...I would also like to design the 3005 power amp, but I wanted to know what software you used? thanks<br />Anonymoushttps://www.blogger.com/profile/01048923634696932458noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-4347283424765768692020-02-10T23:58:07.728+00:002020-02-10T23:58:07.728+00:00proper chip for this circuit is a 1458, that's...proper chip for this circuit is a 1458, that's what the guv'nor used, good enough for me. that chip in this circuit really shines. looses some glass, but gains a lot of tone.pinksterhttps://www.blogger.com/profile/13385798043782856976noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-54362666622230519512019-08-23T18:49:15.581+01:002019-08-23T18:49:15.581+01:00I had one of these in high school I couldn't g...I had one of these in high school I couldn't get it to sound good but it was the 90s and curt cabang made all guitars sound crappy for a while. Anonymoushttps://www.blogger.com/profile/12596138111993645594noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-86653103834047230332019-07-23T23:21:22.887+01:002019-07-23T23:21:22.887+01:00No hay por que Zach...No hay por que Zach...Cristianhttps://www.blogger.com/profile/11202200801546721547noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-62386519774829975262019-07-15T21:00:40.871+01:002019-07-15T21:00:40.871+01:00I modified this circuit a bit to get it where I wa...I modified this circuit a bit to get it where I wanted it for a guitar/bass amp head build I am working on. <br /><br />First I replaced the op amp with a NE5532, this reduced much of the "fizz" you hear on lower gain settings with many SS amps. Second I replaced the 2.2uF cap with a 1uF film box type capacitor for a less mushy tone and more clarity at high gain settings. <br /><br />To make it useful as a bass amp I took the 0.01uF cap off the gain pot and set it up on a switch so that it can be bypassed with a wire. I also added a 0.1uF input cap on the low gain channel. In addition to this I replaced the tonestack with that of the Bassman 5F6-A circuit.<br /><br />With these mods I get rich cleans, nice bluesy overdrive, and when dimed it screams like a plexi. Great circuit with a lot of modification potential.<br /><br />AlexKuhnhttps://www.blogger.com/profile/03361988304120368924noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-23669036190519374302019-07-05T21:06:08.526+01:002019-07-05T21:06:08.526+01:00Great layout, Zach. I just finished a build with a...Great layout, Zach. I just finished a build with a few slight tweaks:<br /><br />* In my build, I needed to swap the Gain 3 and Gain 1 leads to work as expected.<br />* Swapped the 60k R3 for a 68k (I think there's some confusion on this point above; the layout still shows 60k).<br />* Tweaked the tonestack for tighter bass and more mids.<br /><br />I used a 16vAC / 2amp supply, and split accordingly. The power section is an LM1875T straight from the datasheet and into an 8ohm 1x12 cab. So, it's around 10-12W of output. Plenty freaking loud and sounds great :) <br /><br />Ricky Sheaveshttps://www.blogger.com/profile/14164211187482248362noreply@blogger.com