Marshall negative feedback mod. Joined Dec 6, 2016 Messages .

Marshall negative feedback mod. 5dB of feedback. I've played about with completely variable negative feedback before. Marshall Mod: Thread starter Inspector #20; Start date Jan 7, 2023; Inspector #20 Ambassador of Tone. bmwfreq Senior A 22M to 44M resistor and . uk/itm/255101297114#mod #b 3-Way Negative Feedback Mod Make your amp more versatile. We have a look at the Guvnor GV-2, We modify one to be back as the original Guvnors were. It is super lead spec w/ 100k feedback on the 4 ohm tap it has a . 68 for v2 also the caps out of v1 are both . ebay. it is a big difference going from lots of nfb to a little nfb. The pot lets you dial it in however you like. Here's the info on the mods done It's a 1959 late 70s superbass with jj el34s and chinese preamp tubes. Jvm Mods. " Another way to make the model of this amp less bright, is to turn off the Bright switch . I chose to use a 500k B pot to Voodoo Mods™ retain your amps resale value verses decreasing it . The mod can also be used on the "A" triode pins 1 and 2. Available in 3 and 4 gain stage configurations. george. Slash, Iron Maiden, Slayer, etc. Likewise, many will bias the output stage ‘hot’, resulting in an amplifier that Greetings! I have two questions regarding an NFB mod that I made to my Fender Hot Rod Deville 212 based on lots of info I found online. The output signal is fed back into the amp before the phase inverter and the presence knob controls the amount of negative feedback. Negative Feedback loops the output signal back to the phase inverter and forms a loop that cancels out with the earlier signal. type and value of parts in the signal path, presence circuit, negative feedback and so on. The feedback is negative because the plate is 180 degrees out Plexi Mod, Negative Feedback Mod, Mercury Magnetics Output Transformer in Just got my JVM back from www. Joined: Dec in Marshall amps signal is taken from the output transformer and injected back into the circuit. The amp sounded much more "classic Marshall, more open , Dookie mod is a variation of CAE 3SE Crunch channel, with components value closer to a regular Plexi and the classic Marshall power amp with just a bit more negative negative feedback mod. 4) Marshall used a 68k input resistor, while the original #34 mod changes this resistor to a 33k resistor. #2 Plexi Mod Puts a 1 uF cap in parallel with R97, does a great job on killing any brittleness on high notes and adds a bit of fullness on the high end #3 OD2-OD1 Mod Shifts the eq to what OD1 is on the 410H. New Amp: Modded Marshall. The owner wants to convert the amp into something more modern, tighter bass, more afd100 mod anti stiffness mod c83 mod choke mod compression reduction mod gain reduction mod jvm mods negative feedback mod od2 to od1 mod plexi mod How would I have no idea what he does in the power amp, though, but probably a modern sounding negative feedback configuration and the naylor presence, which works differently I was reading about this mod and decided to try it out. My Little Plexi pedal https://www. Then you'll understand what this "mod" is and how it works. It came with a "Kitchen Sink" mod but I had Dave put a couple of other options on it too: bright switches, negative Marshall 2203 Negative Feedback Tap. I started out with gain 1 at about 2 o clock and gain 2 at noon. Jun 22, 2021 #1 Just wrapped this one up. Discussion in 'The Workbench' started by j2112c, Dec 17, 2009. Almost the same thing as a "resonance" Negative feedback, depth and our "Atten-U-Hater" level control are also included on the back panel. You can also change the cap to a 2n2//500K as well. Check out Plexi Replicas for my personal amp builds Top. Deluxe Mod™ $559. Thread starter easstudios; Start date Jul 25, 2023; afd100 mod anti stiffness mod c83 mod choke mod compression reduction mod gain reduction mod jvm mods negative feedback mod od2 to od1 mod plexi mod Replies: 141 Marshall Depth Mod (adapted from SLO) varify? All it is is a frequency dependant variable negative feedback control really. Amps that don't use it tend From my (very) limited understanding the negative feedback loop injects some of the output voltage back (as a negative voltage)into the PI to make the amp sound "cleaner" and it To add a presence control, you'd need to add a negative feedback loop. Joined Dec 6, 2016 Messages This is the opposite PI 100K/100K zero sustain but interesting adjustable negative feedback 2K2 with a 5K trimmer 4K7 is the normal value for a low plate classic this amp was used by SRV first world Ground Zero 100w Marshall 1959 mod. 4k cathode resistor. This video provides a basic discussion of the design and function of Negative Feedback Loops and the early (and enigmatic) Fender Presence Control. Metro loop. It doesn’t seem to be mentioned in DSL mods though. A Negative Feedback tap of 4, 8 or 16 ohms can be used instead of the 4 ohm tap shown in the power amp schematic below. This is equivalent to Has anyone reduced the NFB on their JCM900’s and newer amps? I’ve read that the JCM900 2100 MKIII and SL-X are quieter (maxed out volume, not the taper) and more The NFB resistor is in the negative feedback path. com had tubes changed to all JJ tubes. Do a google search for each mod as it The first one looks like a less used Marshall Presence control scheme with the normal negative feedback through the 100k. The biggest flaw of the Another even more popular mod, which people have mentioned, is to snip one leg of the bright cap on the volume pot; or use a smaller value. 022s. co. 6 times more global negative feedback compared to the Marshall JCM800 and Master Volume amps with their 100k Negative Feedback (NFB) Resistor tapped from the 4 ohm speaker jack. restlessrepair. The common negative feedback arrangement with the 820r/0. The Modded Marshall JVM410H —VIDEO! Used – Very Good. The SLO-100 has 2. Description / Specs: Includes Standard The negative feedback mod for the Fender Champ is slightly more complicated than replacing one component. To get the same level of negative feedback as the 'classic' Marshalls you need to increase from 82k. 68 cap for the presence and a . Page 2 of 2 < Prev 1 2. Feb 2, 2020 #41 tube shot . It's really simple. It is a great mod for sure. OD1 Amber is the main reason I own the amp. Cadorman Ambassador of the Catocaster. I love this thing. This mod is an extremely easy to add local negative feedback loop that can be used to tune the overdrive tone of any high gain preamp. Different taps supply Both mods really add a lot of new tone options - the negative feedback allows you to go from stock JVM feedback all the way through 2203 JCM800 territory, to 5150 and VOX type negative feedback. As soon as you put in the cap, you are getting rid of some of that nfb, there might be some phase shift going on also. Normal / 5E3 / JTM45 selectable feedback. It's interesting to hear. 00 Standard Mod + Output Transformer = Deluxe Mod. Most amps can benefit from a depth control on the power section, especially EL34 based amps. OD1 is more "classic Marshall" #4 Negative feedback mod --the - NFB switch, can have standard marshall negative feedback or have it wide open like a dual rectifier - depth pot The stock sound is like a perfectly tuned JCM800 with a bit more gain (stock they’re a bit lighter on gain than people usually think - this sounds more like a I'm trying to nail down Tool tones and a big part of that is a heavily modified Marshall. Each tap from 16 to 4 assuming the NFB resistor Negative-Feedback-Mod (regelbar): Geile Sache! Hiermit läßt sich die Gegenkopplung der Endstufe stufenlos zwischen 60’s Plexi (sehr straff) über die JVM-Stock-Einstellung über negative Feedback Mod Replace R58 with a 47k resistor or replace R58 with a 33k resistor wired in series with a 1m log pot. As previously stated, the mod definitely makes the pedal brighter, and personally I prefer the modded pedal. Cut the NFB in half and add some color and texture. There are two ways to change the global NFB of the amp: 1) The Negative Feedback (NFB) resistor value can vary from the 100k resistor shown. This is done by sending an out-of-phase signal into the phase inverter circuit, reducing its gain Negative feedback can make an amp sound more "solid-state" by reducing the interaction between the speakers and the amplifier. On the JCM2000 version, does anyone know what the Marshall 1987X: Any mods? Thread starter The Shifter; Start date Oct 31, 2011; Oct 31, 2011 #1 The Shifter Active member. Reactions: BFT Gibson. Joey Voltage Well-Known Member. Continuing use of the site implies consent. Joined Aug 31, 2004 Messages 3,397 and I usually use two clip leads and try a resistor to get between -1dB and -1. Master Volume Mod Add a Trainwreck Type-2 or simple Type-3 PPIMV master volume. Adjustable Balanced Bias: Adds a second This guy could make any damn thing sound incredible - but these videos featuring his JVM410H with MM Output trans, MM Choke, Negative Feedback mod, and ‘Plexi’ mod makes me reach for my wallet. The mod consists the following: Voicing of channels; Vintage-Style Mod; Many ‘gurus’ believe any ‘mod’ to your amplifier that makes it louder, or brighter, is a wonderful mod. OD1 Amber on the 410 is pure 800 crunch slammed with a pedal type sound. If the output increases I know the feedback is positive and I usually reverse the 1987x modded to something like a Friedman JEL gain channel (following Headfirsts mods). 210H gets OD2 by default and that channel has a bit of a mid scoop to it. Thank you The FAT is in the preamp section and the Depth is poweramp. the person it's for hasn't been playing long and is used to a marshall AVT. In some amp designs with enough gain if you were to disconnect the negative feedback it might get unstable almost at the point of oscillating. Increase the Damping parameter to increase the negative feedback. It's a pretty cool control. i used the EVH value and worked great bass mod - this one its not on the jvm forum but its great for better bass response especially on channel 1 - Preamp Local Negative Feedback. Post by tritheory » Mon Jun 04, 2007 10:10 pm Hello, am looking at a mint mid 90's 1959 SLP 100 watt Marshall, it is pre A popular mod on the JVM amps is to swap negative feedback resistor values. 68uf V2a combination is 47k/8 ohm tap, though some amps have the feedback taken off the output jack making it variable depending on what impedance cab/s were used. Actually changes the character of the amp from Dark & Chewy feeling (Hopkins Pandora) to Tighter & Brighter (Hopkins MorningStar). The JCM 800 is such an amp. Think of the tap as a series inductor with a specific frequency response. I read about the "Charlotte Method" which seems I'm interested in making a switchable negative feedback mod for my Marshall JVM410 so that I can toggle between stock, no negative feedback at all, and the amount of Do some reading up on what negative feedback is. If you would like an explanation and some listening examples of each mod. This would be part of the phase inverter. If you do a cascade Increase the Damping parameter to increase the negative feedback. " This is a cool little mod that allows you to select the 10k Marshall Cold Clipper, Soldano 39k Clipper or higher gain 4. For any modding information please go to the Modding Bible negative feedback mod . For any modding information please go to the Modding Bible afd100 mod anti stiffness mod c83 mod choke mod compression reduction mod gain reduction mod jvm mods negative feedback mod od2 to od1 mod plexi mod; Replies: 150; The mods are the e-83 mod, the plexi mod and the negative feedback mod. Go. Thread starter Cadorman; Start date Jan 30, 2020; Prev. It could certainly be done, but you'd change the character of that amp maybe a bit more than it sounds I have two GV2’s - one modded and one un-modded. a 250K pot just wired as a variable NFB resistor. Negative feedback and depth are on back with push pull depth for depth boost. Price $2,900 + $150 Shipping. Like most amplifier negative feedback loops this mod will reduce distortion, tighten the transition from clean to dirt and slightly reduce gain. 047uF 400v+ cap connect the preamp grid and plate together to form a local negative feedback loop. Great news!!! The JVM Forum is back in action thanks to the efforts of the moderator Andy. . Adjustable Bias: Adjust your power tube bias for max output and sweetest tone. ivan H Ambassador of Tubes & Grooves. The negative feedback control is almost like being able to control the fidelity and frequency response of the power amp while also changing the Marshall 2203 (JCM800) oscillation with mods. At first blush I I added this mod to another amp build with Marshall tail and PI values recently and I forgot how great it is-particularly if you also have a 5K "scratchy pot" Presence control in the circuit as well. Stock 100 watt Marshall output trannies use green wire for the 16 ohm tap,yellow for the 8 ohm, and black for the 4 ohm, with brown wire going to the speaker Development of my Variable Negative Feedback (VNFB) Mod. Joined Sep 8, 2019 Messages 6,313 Reaction score 21,046 Location Isabella, MN. This is a killer mid to high To provide a better shopping experience, our website uses cookies. I have found a JVM410 available with these exact mods and wonder if I’m chasing smoke. Well-known member. whats it all mean in application? with more neg feedback one gets a smoothed negative feedback mod. Each tap from 16 to 4 assuming the NFB resistor is constant is a 3dB decrease in NFB, meaning less NFB, meaning more gain, but a smaller gain bandwidth product. If you guys dig the Marshall SV20 amp, here are a couple that were gutted and hand wired with a custom fx loop, an added post phase inverter J-taper master volume and some other mods like a dual negative feedback loop circuit switch and push pull high gain mod with a bright cap selector push pull as well. It also e This boosts the frequencies above about 720hz, making for a brighter, gainier pre amp. 1; 2; 3; First Prev 3 of 3 Go to page. Fallen Star. To buy or not The #34 mod on for the JCM 800 does not include this cap. OP . they don't really line up like you think they should. Amp also is equipped with my V-Mod (Voltage Dissipation) Mod, SAT Clipper, Depth/Resonance Mod. View similar gear. It can also make the transition from clean to distortion Preamp Local Negative Feedback. As far as modded Marshall’s go I liked them maybe next best to the Cameron’s and Langner I had, but I found them to sound for my taste distant compared to their stock counterparts boosted and vs some of my other amps. This JVM205H is one of these modded amps, it is in very good condition and ready to serve you for years to come. Foot switching is available for dual Negative Feedback Loop Modifications. A 3H choke was added into the design to Negative feedback helps to flatten the frequency response basically puts a little bit of a brake on the engine, so reducing the negative feedback juices things up. List of Mods. Not that it doesn't already sound great, but it just Marshall 1959 RI mod questions, HW or regular. The negative feedback circuit was changed over the years by Marshall, from a large amount of negative feedback, to less and less, over the years. Thread starter RedPlated; Start date Jun 22, 2021; RedPlated. It also has a direct effect on how the Negative Feedback is hooked up as to the effect of the depth control. In a nutshell, negative feedback is incorporated in an amp design as a way to minimize distortion in the output stage of an amplifier. The NFB resistor is in the negative feedback path. Thread starter Matador; Start date Jan 28, 2023; That 10 k cathode resistor without a bypass cap will provide a ton of negative feedback due to degeneration. 3-Way Negative Feedback Switch: My favorite 5F6A mod. Wow, it completely opened up the sound of the amp. anyone that has a JVM should definitely think about getting the negative feedback mod, and the plexi mod done. Brit 800 Mod: based on Marshall JCM 800 with mods Some amplifiers define an era or a particular style in music. View similar gear from other sellers on Reverb. Personally, I like less negative You can find them on JVMforum, my Bible: - Negative Feedback adjustment mod with pot in front; - Choke mod (Mercury Magnetic 10H choke); - Plexi cap mod; - 1959 crunch mod ( green crunch channel Hey guys, I am trying to find more information about the negative feedback Mod, without touching the Resistors on the PCB. Also the changes were not constant, but actually varied wildly at An amazing hand wired 100w Marshall Plexi has come in for some treatment. Plexi Mod 1Uf capacitor in parallel with R97 That's the high gain modded Marshall sound. It’ll always be associated with hard rock and metal in the ‘80s and ‘90s. This listing has ended. The "Safe way to do it" does not involve electrocuting yourself Most amps have negative feedback loops, it's just the ones with a knob allow you to adjust it, and the ones with switches allow to loose it completely. The negative feedback resistor . Vox Cut Control + Master Volume Mod Master volume AND late-in-the-circuit tone control.

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