The Story behind the Richard Fortus R4 Single Lead Amp


New member
From June 5th

The Story behind the Richard Fortus ‘R4 Single’ Amp – As many have asked I thought I would share this story here so everyone could read it. The ‘R4 Single’ is a unique & unusual design offering a great deal of different tones. Going back several years this amp initially started out as a clone of Mick Mars’ #1 recording amp, which Richard purchased from Mick. This amp was initially Modded by Jose A however it’s not the usual Mods Jose was most known for, it was less gainy & more organic sounding.

I first met Richard & Jason Baskin (Guitar Tech) on the 2007 Winter Namm Show Floor in Anaheim CA. We spoke at length about the amp & that he had several companies try to clone it. Shortly there after Richard sent the amp to us along with a pallet of Marshalls he purchased that were all manufactured in the same year. The original amp had been on the road & had not been properly serviced since Jose Modded it so the first order of business was to bring give it some well deserved TCL. It’s my understanding that this amp was used on all the Motley Crue albums, which in my very humble opinion it was best captured on the album ‘Dr Feelgood’ by producer Bob Rock & engineer Randy Staub.

I blue printed the amp from top to bottom, made detailed schematics, bill of materials along with detailed videos & photos. I then performed the necessary maintenance, cleaned up solder connections as necessary, performed a CapJob, Retubed, Biased, etc & then made a 2nd set of schematics, videos & photos to compare against one another. There’s a variety of reasons for this but we’ll save that for a more technical review in the future.

I then set out going through the pallet of Marshalls to find the closest related donor to create a clone. Unfortunately the lam thickness on every Output, Power & Choke Transformer were different. Additionally none of the primary impedances were the same on the Output Transformers & every Power Transformer provided different B+ voltages loaded & unloaded. IE: in short, not one was the same & none matched the original amp (more on that later).

Richard & I talked & felt that in order to replicate the tone & feel of the original we would have to design-&-build a Custom Amp from the ground up. I removed the transformer set, measured & documented everything. I then had had our good friends at Mercury Magnetics spin up a set. I then laid out a hand-wired circuit board & delved into building the amp using one of our Voodoo ‘V-Rock’ hand-wired chassis’.

Once completed we then sent that amp to Richard along with a Custom IEC Power Cable (more on that later), which he then began using with GnR. As a side bar, this is the same amp Richard used on several album sessions, GnR tours as well as the ‘Chinese Democracy’ album, The Dead Daises album & tours, in addition to the Rhianna & Thin Lizzy tours Richard performed on.

Improvements – GnR were in rehearsals for the up coming ‘Not In This Lifetime’ Reunion Tour & the amp was (improperly) diagnosed with a shorted Output Transformer so Richard sent the amp to us to go through. The OT tested out fine & I found a shorted 1ohm resistor to ground off from the cathode of the power tube as a one of the EL34 power tubes had shorted. This was fortuitous as this was the first time I was able to spend some quality time with the amp since we had first built it.

Having watched Richard play guitar up close several times & knowing what his ears like to hear as well as what his hands like to feel, I made some additional tweaks to the circuit in the midrange, I also gave it what I like to call an ‘easier-to-play’ feel & it was also time to replace the Filter Caps. I performed a CapJob with some amended values, Retubed the amp & placed it on our proprietary Break-In Rig & shipped it out to the rehearsal facility. We were also working on the ‘R4 Single’ Signature Series at the same time.

R4 Production Model – Richard reported back that he loved the improved sound & feel on the R4 prototype so I implemented those changes into the production model along with some additional versatility. I should note I am not a fan of versatility if it compromises the tone or feel of the amp.

From a technical point of view the design has (3) Gain controls though you only see (2) on the front panel. It has an incredible 3-dimensional girth & width on the low end which is different than any other amp I’ve ever worked on. While you can get convincing plexi style tones, the R4 is by no means a ‘plexi-clone’. Richard & I also wanted to design in some versatility that the prior versions did not have. IE: Each Gain control has its own (3) Position ‘Bright’ Switch, which effects gain, low end as well as feel & over all Brightness.

Effects Loop – The original amp did not have a ‘Buffered’ Effects Loop & for 50% of most players a Buffered Loop is a must. I’ve worked on countless Effect Loop designs but to my ears & hands they tend to alter the tone & feel of the amp when you turn the loop on & off. These days Loops are usually a solid state design, which of course helps reduce cost & there’s nothing wrong with that. To my hands & ears I still prefer a Tube so we went with our own Tube Buffered Loop, which works equally well with both pedals & rack gear. It’s incredibly transparent & also ‘feels’ the same whether it’s in or out of the circuit.

Over all, the R4 literally sounds-&-feels like an ‘old’ amp but is also remarkably flexible. The sound & character of each guitar comes through as well as the most subtle nuances. It also works amazingly well with a variety of guitars such as Scala’s, Trusarts ,Gretch’s, Strat’s, Tele’s, Semi-Hollow Bodies, Les Paul’s, & more, all of which Richard uses in the live GnR shows.

Richard’s words speak far louder than mine but in my humble opinion I truly believe we have not only captured the spirit the original amp but we were able to raise the bar in order to offer a high end product with zero compromise. You can get Richard’s studio tones & live tones as well as Mick’s - but equally important, you can find your own voice as well.

We also have a new website that is nearly complete, which will be dedicated to the products & will contain far more photos, descriptions, updated pricing & more. I hope each & every one of you has an amazing day & do a kindness for someone along the way today – Trace Davis, President / Founder