New at runoffgroove.com: Eighteen

[B Tremblay]

Eighteen is a FET emulation of the Marshall 18W combos. Check it out!

Article, schematic, and perfboard layout: http://runoffgroove.com/eighteen.html

[Peter Snowberg]

Do you guys ever sleep???

Great work!

Take care,
-Peter

[B Tremblay]

Do you guys ever sleep???

Of course, but we sleep in shifts so one of us is at the breadboard at all times.

[BDuguay]

Say fellas,
Please 'splain these emulation circuits your coming up with.  A ferinstance; how, or do, they differ from a standard (if there is such a thing) issue gain/boost/distortion pedal.
I'm very curious and have become increasingly interested in trying to build a couple of them. I encourage you to brag/boast away.
Thanks!
B.

[Jim Jones]

At first I thought this was going to be a FET sim of an old Alice Cooper song.  

Jim

[Alpha579]

How would you do a push-pull output stage?

[B Tremblay]

Well, there's no difference between our emulator circuits and a "regular" distortion pedal - at least in terms of usage.

The main difference for me has been the quality of the overdrive.  I've been consistently impressed with the character of the distortion produced by these emulations.  It seems so much more natural and transparent than designs that rely on diode clipping.  I actually found our Supro emulator to be better sounding than my actual amp at times!

All we're doing is taking a tube amp schematic and replacing the tubes with FETs.  There's some filtering that we add to simulate the speaker response, but they're nearly identical otherwise.

[Brian Marshall]

Output inverted?

[Gary]

How would you do a push-pull output stage?

Use the full phase inverter stage.  You can figure out how it goes from there.

[petemoore]

Like dogs, distortion circuits have alot in common, all dogs should have two eyes, all distortions should have clipping.
 Also like dogs,  distortion circuits are quite distinguishable diferences in their outward appearances [schematics] , and what they can be trained to do well.
 I like just looking at a schematic and trying to figure out what it might sound like, I can usually spot a distortion, figureing out just what it can do requires building and getting to 'know' it.
 Sometimes, they can be your instant best friend, other times they pee all over your intentions for them.
 I find these Jfet simulations to be quite good sounding, I know I like test selected Jfets, even though they may hit a more limited parameter of various tones compared to say a double OA clipper, they hit that specefic sound, which can be very dynamic, and do multiple tricks within it's realm.
 I think the builds sound real good, for tube amp type tones, mild distortions, heavy distortions, excellent harmonic content accentuations and note bloom, 'TS killer' sounds, ability to alter into distortion and retain good amounts of original timbre, all these characteristics I like.
 I would like to see...what you think about the possiblities of a Dual Rectifier emulation...I suspect that there is an interaction between the output section and speakers that is a big part of the Mod Metal, D, or T, Rectifier  type crunch...I've never looked at a Rectifier schematic, but I'm sure there's some interesting voicing going on, how much of that crunch could be contained in a circuit board is quandry-ous, and like all circuit chains, dependant on what's before and after it.
 Gotta love them Jfet smoothie Transistors.
 Only ones I've tried are the MPF102, and the J201's, both of which I like and are different.

[Marcos - Munky]

Another one!!! Wow, Runoffgroove is working hard in the lats days.

[Lonestarjohnny]

Mr B, you gonaa be putting a soundclip up on the Eighteen?
I got my Fet's in this mornig, I'll be try'in out the Professor Tweed in a short,
JD

[Gringo]

I only have two hands, guys!!! :shock:

[Ben N]

At first I thought this was going to be a FET sim of an old Alice Cooper song.  

Jim

LOL!  That'll be the "JFET Baby's In Black".

Ben

[Ben N]

Runoffgroovy Guys (and Doug H):

Since everyone seems to think they can just post requests for these emulations, and you guys seems willing to actually do them all, I'll put my own $.02 in:  Howzabout a JFET Sansamp GT2 kind of thing, that switches around a few components--a bias resistor here, a source cap there--to produce a variety of good JFET emulations in a single enclosure.  'Cause otherwise, our pedalboards are gonna get really full!

I know it's a tall order, but WTH--you guys know no fear (and are also apparently in no need of a day job)!

Ben

[javacody]

ASK AND YE SHALL RECEIVE!

Thanks Brian and Gary! I can't wait to solder this puppy up. Have you guys tried running it after a Fuzz Face to see if you get that infamous Hendrix Marshally-Fuzz tone?

[B Tremblay]

Thanks to everyone for their enthusiastic response!  We're glad to be able to share the fun with all of you.

While it seems like we're taking requests, the 18W emulation was developed a couple weeks back.  We've been knocking them out pretty quickly (a testament to the general ease of converting the schematics rather than our genius), but wanted to stagger their release so each circuit could have its well-deserved time to shine.

I haven't tried it with a Fuzz Face yet, but hope to when I get a chance to record some clips.

As I've mentioned in other threads related to our recent work, we're hoping that others will follow our lead and find a cool amp to emulate with FETs.  We'll help as much as we can!

[javacody]

Hey guys, did you hear that? They're taking requests. Woo hoo! Ok, I want a 5150 WITH reverb. When will it be ready? After that, I want a Roland Jazz Chorus WITH chorus.  Will that be ready in two days? Hmm, after that? I want you guys to make a pedal that makes me sound like Django Rheinhardt when it's mini toggle is one way and Elmore James when its the other. I'll expect all three pedals in a week. Ok?    After that, I want a speaker sim that I can switch from Fender 8, 10, 12, and Celestion 12. I also want it to emulate anywhere from 1 to 8 speakers. It needs to have less than 8 parts. After that....

[bobbletrox]

Damn, I gotta get me some J201s.

[petemoore]

WARNING,,,long post...may wander slightly, or take some cypherin' to 'get'. ...ends with: So Many Variables.        
 All kinds of stuff you can do with Fet's.
 Who's to say the exact schematic is the answer.
 I would imagine they'd have to be modified a litte from the actual amp schematic?
 Combining circuit segments, or hybrid-ing, has always been done for well liked cirtuit sections.
 Just looking at a Modern Heavy Metal Amp, that uses tubes to get there, for the most part would be interesting to look at, speculate on, and possibly dinker with.
 Having never developed tube schematic reading comprehension skills, I'm limited to reading transistor schematics, [I understand they are very similar, but like Fet's DSG Vs Si with the EBC, with tubes having plates grids and cathodes, whichever is which...I need to get a power supply going so I can build a Tuber, once I did that, and debugged/tweeked it, I'd probly have it...I'll cross that bridge someday].
 So for now it's too cool for me that these guys are de-coding them for me.
 The Jfet builds Ive done so far seem really well behaved, bias is N/P [it helps to have some extra Jfets], Great tones, work well with others, etc. sound great.
 One of my favorite combinations would be a mid OD tone, that when coupled with another circuit that: goes into hard distortion with alot of harmonics...would be cool. The way I'm doing this: going from point A [OD] to point B [lead DIST}, is tuning so one side of the switch gets a perfect point A [mild boost to OD], by means of say a booster + [X], then arriving at point B [the other side of a stompswitch where you'd put a bypass jumper]...A Fuzzy DIST.
 Having one that stays on, then the other one added...like dividing a schematic say bypassing a stage...I think that's an area Ppl would like to see revealed more, that way you're getting more out of your circuits and batterie per hour of use, and tends to keep noise down, and makes for a smaller amount of enclosure, pots, parts, etc...by dividing stages that work well together as opposed to switching to the 'other side', which has all the above stated drawbacks, and others.
 Having two tastes that taste great together...[and one or both of them taste great alone].
 Drawbacks include...complicated switching on the schematic and off the board, wires become more confusing [color coding helps this] and harder to keep neat.
 Pretty much I already have been doing this, with good results, One fave is a Jfet gainer, followed by a nice OD. If there were a source for favorite combos...that would be cool.  
 Some circuits obviously dont 'like each other,  filtering highs, and setting gains becomes increasingly complex..tha's why the latest one's of mine have idle circuits alot of the time...I'll take one 'fave'...a BP'd [bypassable] Phase 90, then the 'on' Minibooster, then the *SD-1 or Hot Silicon*...this eats batteries, sounds very good for Boost, OD, And Heavy Fuzz..cuts back on jacks, batteries, etc. works fantastic, but took alot of tweeking...getting high gains from multi-build circuit requires testing, doctoring the filtering and voicing etc...and the 'dis is: fixed chain selection, which really isn't a disadvantage in the sense you get used to playing these sounds as 'standards'...I'm always switching Pedals up and around...dialing...dialing...       dialing...finding something really cool...I now know some cool combo's...I'm sure you do too.
 Did so and so use two effects at one time? Do you know the mods to the first Booster Stage that were used?...lol...It really takes alot of experimenting, a good ear, and road testing...[big sounding tube amp helps IMO]...whoops...politically incorrect...so many darn variables...
 No really I've been testing these pedals on:
 Old Twin [didn't like anything but the phaze 90..it's bass input tube suspect]
 Mesa Boogie Mk 3 [or 4?..I need to ask Bill..]..totally Somokes...noisy, not exactly smooth, lotsa knobs so disregard any actual comments about tone...wayy tooo many knobs for any definitive tone to be relayed through typeing IMO]
 Fender [some Hot Si]  one ten inch transistor amp, much superior to use the distortion in the amp, otherwise yer jess talkin' out of control or noise or not so good...boost doesn't improve the already voiced sounds...other's MUST have gotten better results trying them more than I did...liked the phazers...
 Marshall ValveState 60: as far as pedals are concerned, this amp, like the Si Fender amp, liked the phazer. Has a nice built in Fuzz tone also.
 Dyna ST 70 loves pedals...all pedals just about
 Marshall MkII 50w: Well it's my favorite owned amp...rediculous...likes most pedals, gets very aggrexxive comparitively, pedals work great on this one. It is Sensative/Critical about voicing.
 So there you have it, I reported wide variances in pedal performances testing them in different amps. I never push them on amps that don't like it...I just try some settings and if it really just sounds like crud o' I switch them off, or pull and bag them...amp owners seem often to expect these pedals to perform fantastically, as I tell them they do or can do [I gotta be more careful there..what I claim] through their amp, and they simply will not...it takes just a bit of explaining...and removing pedals from the effects chain and bagging them. I mean to tell you turned Wayy Down..and through certain amps either sounded really horrid, lost to noise, or inferior to the internal distortion voiced for the amp and speaker..."hard to beat them transistor amps distortion sounds" I heard...course 'he' [quoted] does not know what the difference is, having never heard these pedals through one of my tube amps.
 I can see where someone just likes their ez to tweek, light to carry, loud little tranny amps...they sound just fine IMO, and the limitations can be a good thing...
 A popular trend these days is to have a transistor amp, turn it Wayyy down on stage, and play the entire night at that setting...it can be set to sound musical.
 I prefer tube dynamics, wide variety of tones...if I'm watching a band for many minutes, I get quickly tiresome of the same sounding guitars, and start thinking of Zep Or Tool, Phish, JH, and other's records that encompass a widely variable pallete of bright. dull, shimmery, Heavily Distorted, Echoed, Modulated etc. sounds. TA is just my cup of tea.
 Funny, at the recent jam parties, where testing Pete's pedals was to be one of the highlights, it gets hard to convince Ppl that these pedals can do totally amazing things...that they are probably quite familiar with, to the guitar sound...the host didn't know he wasn't complimenting my booster, or OD, or anything except the Phazer...I'd pulled the POS sounding devices and packed them away very early...leaving only my multi floor panel Model, with the phazer only on...lol...I 'd to correct him as he begain talking them up toward the end... :oops: ..I just like to have fun at the party, anyones welcome to try them out unless they sound like a POS...then they get packed !!!
 That overdriven, hissy because everything is 'double done', nasty overdriven input tones...I ain't into none of it....but that S out like yesterday...you don't get any more !!!
 Wandering post enough for you readers?  :evil:  I warned you this time...lol