Greetings
I'm an electronics student and I have built 2 tube-amps in the past. I like building guitar amps from scratch with its cabinets and everything. I also tried to make an SS amp but the tone wasn't good at all. However I used a few ss pedals and amps which sounded pretty well like behringer od100, marshall mg series. In my ss amp design I used the schematics of a ts-9 combined with a flat response power amp that only produced a nice sound with a GT8 :p .
I know that there is a good preamp circuit out there that can produce can give a nice overdrive/distortion sound (marshall mgs are fine imo, they use leds for clipping), but the problem is I cant find any schematics for such an amp. I tried the TS-9 circuit and it sounded bad (uses diodes for clipping), I traced the circuit of my friends bc-rich bcl12 amp which also sounds terrible. I couldnt get a hold on to a simple marshall (mg10, mg15) Least i could find was 50dfx which is hard to trace with all the effects and such.
I will really appriciate if you can provide me the schematic of a mg10 or 15 cd or any other analog circuit (behringer od100 has digital effects I believe :/ ) that can provide me with a nice fat overdrive/distortion sound for heavy metal, similar to Iron Maiden tones.
Thank you
Hi weatherlght
Build the Marshall Lead12 preamp (I think the model is 5005); it's very good and simple.
Like this? http://www.drtube.com/schematics/marshall/3005.gif
thank you for the info :) however i need to add a few things to this.
-a diode clipping distortion pre-amp (i'm not sure whether the preamp will give distortion without the diodes or the leds),
-a switch to bypass the clipping stage for clean tones
-a headphones output (i believe i can add this to the end of the preamp as an *pre-out jack, then include an *po-in jack and make a simple effects loop. but some amps add that at the end of power amp using some attenuation circuit to lower down the headphones signal voltage :s, i need a simple schematic for it)
-a simple mixer to the power amp input (or preamp clean stage input) just like in marshall mgs, so i can hear the song as i play
I would suggest looking for a separate circuit for the headphone out. Also, if you don't do some sort of speaker cab simulation for the headphone out, the sound of a high gain preamp will sound like complete crap. You might check out the condor project on runoffgroove.com. Also, while many of the circuits on ROG might not be suitable for metal, you might like the Thor. You should probably also build a separate good clean preamp for clean tones and switch between the two rather than one that tries to do both. I designed a simple expandable mixer circuit, though I hesitate to post it as I've only tested the design in simulation, and I'm sure there are some good proven designs. btw, it's cool to see another Electronics student on the site. I'm slowly working on an EE degree myself, and taking electronic classes is what got me interested in amp building, which got me back into playing guitar.
I forgot how to play the guitar actually due to dealing with all these amps and tubes as well as the school :( I checked the link you gave me and found some nice schematics, 5010, 5203 and 5213a. 5203 and 5213 have the leds i need for the fat od/ds sound i believe. I just need to figure out a way to simply those circuits as much as I can. Perhaps throw out the fet switches and all those low output impedence emitter follower transistors. Just put a 2 way switch to bypass the ds preamp and directly connect the input to clean preamp. Add a simple 2nd input before the power amp for cd input, and use that circuit of 5010 for the headphone output. I will use simple a tda2051 circuit running at 25-30w instead of the transistor power amp stage of 5010 though. If i can get my hands on a marshall mg10-15, i'll try to implement the fdd as well.
I'll also add a simple pre-out - pwr-in effects loop stuff. Do i really need a emitter follower before the pre-out jack ?
I haven't checked out all those, but I would definately leave in the emitter follower buffer stages. Removing those might have a bad effect on your tone. You could certainly build your circuit of choice on a solderless breadboard and experiment.
update, still need an mg10-15 schematic please :)
so, do you know dr boogie?? it's a mesa boogie jfet emultator, and it's excelent if you're searching a metal suond like high gain distortion... http://gaussmarkov.net/layouts/drboo/drboo-schem.png ... ;D
I recently built a Dr. Boogey using the info from Gauss Markov's site. It pretty much rocks. However, I think the bass response is a little lacking. I really like Mensur's adaptation of this circuit. See http://www.ssguitar.com/index.php?topic=991.0 . His sound clips are F#*$ing awesome. He's using an 18V supply and lower gain FET's. He also adds a source follower buffer after the tone stack, which allows for low impedance output. The Gauss Markov version has a scaled down version of the tone stack for low output impedance. While I do not have a build of Mensur's version to compare it to, I imaging the Source Follower buffer is a much better solution.
--EDIT--
Oops, he's using a 24V supply.
Quote from: rowdy_riemer on January 22, 2010, 03:25:41 PM
I recently built a Dr. Boogey using the info from Gauss Markov's site. It pretty much rocks. However, I think the bass response is a little lacking. I really like Mensur's adaptation of this circuit. See http://www.ssguitar.com/index.php?topic=991.0 . His sound clips are F#*$ing awesome. He's using an 18V supply and lower gain FET's. He also adds a source follower buffer after the tone stack, which allows for low impedance output. The Gauss Markov version has a scaled down version of the tone stack for low output impedance. While I do not have a build of Mensur's version to compare it to, I imaging the Source Follower buffer is a much better solution.
--EDIT--
Oops, he's using a 24V supply.
what's???? dr.boogie is rock?? no no, i don't think... listen it http://www.youtube.com/watch?v=FU8G_6XMISc&feature=related what jfets did you use??
By saying the Dr. Boogey rocks, I was saying it sounds really good. ;) I used j201's. If I did it over again, I might use an MPF102 for Q5.
Quote from: rowdy_riemer on January 24, 2010, 12:02:35 PM
By saying the Dr. Boogey rocks, I was saying it sounds really good. ;) I used j201's. If I did it over again, I might use an MPF102 for Q5.
mmm.... ???... j201s are high gain jfet, i don't think that if you'll use MPF102 ,gain will not increase...
have you ever tryed to built "krank distortus maximus? it's high gain distortion with 3 bands equalizer
,try to check out and listen sample on youtube.... I recently built and i really like that!
I'll check out the ""krank distortus maximus". Keep in mind that Q5 is setup as a source follower. There will be a voltage gain of a little less than 1 regardless of the FET used. However, I think you will have more current gain(lower output impedance) with the MPF102. Also, Vth(cutoff voltage) is lower for the J201. Some may disagree, but I think FET's in a source follower configuration should have as high a Vth as practical and as high a Idss as practical. Look on page 208 of Teemuk's book to see what he says about J201s in a source follower configuration.
Thank you for the schematic :) This is something that i will definately built. Still i'll also want to build a classic mg10-15 preamp and combine these 2 along with a tda2050 30w poweramp in a 2 channel nice sounding combo amp :)
Hi rowdy
QuoteSome may disagree, but I think FET's in a source follower configuration should have as high a Vth as practical and as high a Idss as practical.
Well, I *do* agree. ;)
In fact, I always buy Fets in lots of 100 or more and nmeasure them all.
The ones with Vp (pinch-off) from 1.3 to 1.9V are labelled "preamp"; the ones around 2.5V "general purpose" and those above 3.5V "switching/compression/source follower"
Here it is. MG15 CDR.
IMO, Distortion Channel is good for metal (and nothing else, actually). Clean channel is awfully dull.
Thanks alot :)
That MG15 pre-amp looks similar to the Guv'nor pedal also produced by Marshall. Guess the sound could be similar. But a believe there are two important differences that could make the distortion sound different;
- Guv'nor uses two red LEDs to produce (symmetrical) clipping, with one green an one red LED, which the MG15 pre-amp uses, the clipping should be asymmetrical if I get this right?
- Instead of connecting the diodes to the ground like the Guv'nor, the diodes is at the feedback (not sure about the thermology here so feel free to correct me if I'm wrong) of the op-amp. This usually produce a softer clipping than putting them between the signal and ground. But the MJ4558 use in the MG15 is described as an "high gain op-amp" in the data-sheet (Guv'nor uses the old familiar TL072). So I don't know, I guess it can clip quite hard anyway.
I'm also looking for a good metal pre-amp and this one really looks interesting. One that sounds like the ProCo Rat (best metal distortion ever IMO) would probably be better, but maybe this one can work.
In practical use RC4558 and TL072 sound the same, with the 072 being *slightly* brighter.
The Rat is excellent if plugged into a good guitar amp, preferably a good "metal" tube one.
On its own , driving straight a chip amp or into an effects loop the sound is, well, "raw", maybe suitable for Punk.
I'm seriously considering to build the MG15 pre-amp, using the schematic attached schematic. There is some things I need to know before a start however. Two questions that might be obvious, but I want to for sure.
- The reverb circuit and jackets after the pre-amp made me a bit confused. However I'm only going to build the pre-amp, and then use it to drive a lm3886 chip. So I'm not really sure exactly what part of the schematic that includes this one. I've marked part what I think could work as a pre-amp if built at the attached schematic, but maybe I've missed something (except the PSU).
- Some pots wasn't marked at the schematic. This wasn't very hard to figure out, but if someone else could look at too it would be nice.
I could not find the 2n5484 mosfets shown at the schematic :( I found a few bf256 which are a replacement for 2n5485 and 2n5486 i believe. Will they work fine for a nice metal distortion sound? Or they will ruin it? What transistor would be best for this DR.Boogy preamp?
I wouldn't worry too much about the substitution. Just make sure that the cut off voltage and Idss for the bf256 are about the same as the 2n5486. Keep in mind that even JFET's with the same part number will vary quite a bit. For the Dr. Boogey, get some j201's if you're using a 9v supply voltage. For Q5 (gauss markov schematic) you might use a MPF102. If doing the mensur version which uses a much higher supply voltage, use 2n5457's or something like that. You might use transistor sockets to try different FETs. I wish I did. Also, checkout J M Fahey's post above. He's got a pretty good idea. The measured characteristics of an individual JFET are more important than the part number printed on it.
hi everybody!
im new here, just wondering cause i cant access Davelectro schem for the marshall
i need this really bad and it would e a real help if anybody could provide one
cheers
Hi dorothy, here it is.
http://uploading.com/files/e71e9a78/Marshall%2BMG15CDR.pdf/
A Distortius Maximus clone might be pretty good for metal, too.
My vote also goes for Dr.Boogey. :D
I haven't tried Mensur's version, but even the standard Gaussmarkov version sounds great to me :tu:
Although it is more common to build it as a "distortion stompbox", I actually did it as a preamp for my practice solid-state amp (TDA2003). If you want to hear it: I made a short sound sample (http://www.box.net/shared/nr08r4ul8c) with all knobs at 12 o'clock = 50%. I used a 2n5457 for input transistor (Q1) and for buffer (Q5), the other three are J201.
You can clearly (pun intended) hear that even with gain at 50%, it is distorted as hell (a bit too much for my taste) ;D
I usually use it with lower gain and somewhat more scooped eq, and It sounds realy great (I use Ibanez with dimarzios, and Marshall 1960AV cab)
Very good, congratulations.