Fender 5e3 and a 5f6a preamp pedals

[bsas]

Hi guys,

I am thinking about building two small boxes that are basically a Fender 5e3 and a 5f6a preamps.

I was wondering if it is possible to do them in a "pedal" format (even better if we can do it using DC plugs like normal pedals do), probably doing some high voltage conversion internally for the heaters...

How hard do you think is to do that?

Thanks!

[Travis]

With the 5e3 pretty much all of the nice clipping happens in the 6V6s. Building the preamp alone wouldn’t sound like a 5e3

The 5f6a would make a more sense if you change V1 to a 12ax7 like the JTM45 to get more clipping from the preamp alone. It’s still not the same as the whole amp, but the 5f6a preamp can stand alone better than the 5e3

Heaters don’t run on high voltage nor would a charge pump have nearly enough current. If you have any specific questions fire away but sorry I can’t design the project for you.

I will suggest this.. there was a project available from grind customs called the STM800 which you could use to do a 5f6a preamp although you probably actually want the JTM45 preamp

[bsas]

Sure, I wasn't asking anyone to design the project for me. I just wanted some good starting references and advises, which is exactly what you gave me. Thanks! :D

[balazs.bencs]

Since I built a JTM45 clone (the old version with KT66 tubes), let me share experiences: it is mostly a clean amp, a real winner for pedals. It does not have a ton of gain, only when you crank everything to ten. I played an EL34 50W lead plexi too, for me that is very different. I'd say the power amp section is a pretty important section to get the plexi sound.

If you want a really similar sound, for me the ZVex Distortron is the pedal that gets that sort of sound.
I built one for a friend of mine and turned a Fender Twin into almost a JTM45 :) (we played it side by side)

[Travis]

Yeah I agree that these amps are all about power tube distortion. And frankly it’s ALL important. In a DIY pedal for example many people will tell you the DC filter cap value doesn’t matter much just use 47uf-220uf or something

In a 5e3 if you change the filter caps from 16uf to 22uf you will make the bass response different. If you used a solid state rectifier it would be even more different. If you start changing voltages, component values, tube types, tube brands, etc it will all have a noticeable effect. The speaker type, cabinet, EVERYTHING comes into play, to the extent where just the positioning of the wires inside the amp can be the difference between a great sounding amp and a pile of junk

So when I suggest the 5f6a or JTM45 preamp I am definitely not saying that will achieve the complete sound, but it will be closer than many projects.

Suggesting something like the Distorton, Professor Tweed, Formula No. 5, etc makes a lot of sense because it is a much easier project that actually may come closer to the desired sound in the long run. I was going to suggest that in my first reply, but the way I kept wording it made me feel like I’d come across as rude, so I tried to keep it short haha

[bsas]

Cool! Thanks guys, I will take a better look on the JTM45 preamp circuit :D