Pre-Amp for 5E3

[Bufferz]

Hey guys,

This is my first build report.....I want to take this opportunity to say thank you to everyone who is part of this amazing sub communty of audio electronics nerds like myself - special thanks to Austiz Ziltz @ Coldcraft for his help on the deluxe version. 

I have been working on this for the past 7 months (I even shed blood for this thing - look under foiotswitch  )and am really happy with how it has turned out - it is a preamp pedal that I have designed to be paired with my fender tweed deluxe - as you can see I am also working on vox and marshall versions: the basic concept being that the circuit is designed to be paired with the specific corresponding amp - all of the design features (high pass filter value at input, transitor types / gain, diode types / orientation, notch filters, and looks of course) have been customed tuned to serve the respective amp archetype. I'm looking forward to finishing the other versions as well, luckily I have a friend who owns a recording studio so I have access to many different amps for testing










I also have created a "deluxe" version which has additional features like active Treb/Bass/Mids, an effects loop, and a 12AU7 clean blend. This one is designed as more of a add-on to the amp than a stomp box per-say, so the mode switch near the jacks switches from just a buffered signal with a variable high pass filter which is there tailored to suit single coils and humbuckers respectivly and then the active mode which incoportates the Gain/EQ/and Tube stages.

[micromegas]

hmmmm... all this seems interesting...

can't say anything about the sound of it and there's still not enough info to talk about the circuit design, but at least I can say those enclosures look georgeous

[Bufferz]

Thanks! I really want to get a video made to share.

As for circuit design the deluxe version has a Cornish style buffer with a high pass filter following it and a recovery stage. From there the signal is split with one side going to a gain stage and the active tone stack and the other side is tapped from the buffered signal and run it into a the 12Au7 stage. The two signals go into a summing opamp which works out nice as I am able to dial in some of the fat (not subjected to high pass filters) buffered tone with the very filtered low gain tones.

The std model is a transistor gain stage with a couple toggle operated notch filters and blend-able clipping and a then a MOSFET gain stage. The two can be used together or independently. I absolutely love it. So simple and yet intentional.

Here's some pics of the PCBs that I took when I was testing before they were boxed up

[jubal81]

Really interesting idea and some neat looking kit. Looking forward to hearing more about it. Thanks for sharing.

[Blues Healer]

interesting ... the pedal is almost more complicated than the amp!

[jtn191]

color me interested as well. I like the idea of not an amp in a pedal perse, but an add-on that adds to what an amp is missing/needs.

[micromegas]

interesting ... the pedal is almost more complicated than the amp!

+1

I really dig the idea of the separated (then mixed) paths. I suppose the kind of tube used in the buffered stage alters the tone in one on other way, am I right?

[Bufferz]

Ya it does alter it a little bit, I have a trimmer that I can set the level on the tube path prior to the summing amp so that it's mostly a clean tone rather than gritty, but sometimes gritty is fun as well. 5e3 does grit up quite well on its own.

And yes I think I have been guilty of over complicating this as it went in lol! I just kept thinking "wouldn't it be cool if it could also....."

[Bufferz]

I'm kinda embarrassed to post this but since some of you seem interested in the signal split....here is a schem for one of the versions of the deluxe version...sorry its very messy...

I ended up making a 2nd pcb for the tube circuit/buffer/fx loop rather than having it on one pcb...but this shows most of the circuit as one piece

[Blues Healer]

And yes I think I have been guilty of over complicating this as it went in lol! I just kept thinking "wouldn't it be cool if it could also....."

my comment was not really a criticism ... of course it's much easier to add features to a pedal than an amp ...
I've had my '56 Deluxe for over 20 years, so I'm pretty familiar with it ... and I learned that with amps, "simple is better" ... the tone control is amazing, if you get a chance to study the way it works ..
I think a 5E3 is also less gainy than people think, because it's so crunchy ... for instance, the 12AY7 in V1 is a low gain tube, compared to a 12AY7 ... but that, along with the cathode biasing, is part of what gives the amp its charm and character ... crunch, and lots of harmonics.