The Fenton Project III

Here's the populated board with all flying leads attached looking for a home. The circuitry for each stage follows in order and parallels the tube placement so there will be a minimum of crossing wires and nothing is close that can't run together.

In the interest of a neat layout nearly everything mounts to the board. The tone control network will mount on the back of the pots, very simple and neat and the signal from the tone and volume will run directly to the next tube stage through a shielded lead.

Grounds for the preamp section are all grouped and run together to the common buss at the main filter / decoupling cap.

Next we get the chassis drilled, hardware mounted and start with the off-board wiring.

The Fenton Project II

I'm playing catch up a little here, so this comes right on the heels of the first post of the series.

Parts have arrived, the first to come in are the very solid looking ClassicTone transformers from Magnetic Components.


They are shown here with the chassis from Dirty Dawg Amps. Just for scale, that chassis is 17 inches wide and over 2-1/2 inches deep. These are chunky. The photo does not do justice to the finish and workmanship of the chassis. Brian does great quality, fast work at a very reasonable price. That's a theme throughout this project; we are looking for above average components at a reasonable price and combining them with a good layout and workmanship for a superior amp.

The next step is combining these parts into something like a guitar amp. For the layout process I like to have parts in hand and work out the plan on paper. I know a lot of people depend on computer assistance for this phase of the job, but I just feel more comfortable holding and measuring a part as I decide where it goes.

I'll confess, this is the slowest phase of any project for me. I tend to chew on these things forever until I'm sure that everything has been considered and all of the inevitable compromises are balanced appropriately.



After a few more sketches and some trial and error fitting I had a board and control panel layout and was ready to stake down some turrets.


Now, we're getting somewhere.

In the next post we'll have the board populated and be positioning things on the chassis. Then things get marked and the chassis goes under the drill press.

The Fenton Project

This is an interesting project. Commissioned by a fellow TGP'er, I am building an amp inspired by the Fenton 110. This is a variant on the classic 2xEL84 theme. Everybody and his kid brother has a Marshall 18W alike or Vox AC15-ish amp - this was different enough to be interesting and right in line with my experience with EL84 practice.

I had never heard of this company before - NB, this is not the vintage Fenton Weill - rather a small and now defunct builder. My client had tried this amp for a time and liked it, and now wanted one for himself but has been unable to find one.



A couple of things stand out about this design, and there are a few changes in store. Since we aren't going to be using the low gain input jack, that component will be omitted, which should make for better reliability (I've worked on a lot of JCM 800s with the complaint of "lo gain input works, hi gain doesn't). We're also making a change to the power supply. Our build will use some extremely beefy AC15 type iron from Magnetic Components. This means a 6CA4 rectifier tube instead of the 5Y3. The original used a Fender Deluxe Reverb type output tranny so this should be a good bit more solid.

The client has a very nice 1x12 cab that was previously occupied by a heavily modded Epiphone Valve Jr that the new amp will be designed to go into.



Updates to follow shortly.

I'm Back

After a long time away, I am back and blogging again.

Just to kick things off, here's an interesting failure mode that came into my day job:



It's actually easier to plug that power cord into the XLR than into the power inlet jack where it belongs. Sometimes in a design you have to consider possibilities that seem impossible.

First Look Ronsonic Diesel Driver

Here's the big, bad buffer. The Ronsonic Diesel Driver. Plug 9 - 18VDC into the jack at the top and your guitar into the jack you see on the side there.

The input impedance is matched to that of classic guitar amps. This will not load down your guitar. It also won't give it that unpleasant brittle, glassy top end that some buffers with extremely high input impedances do.

The goal here was transparency, as if nothing was added to your guitar and nothing taken away.

Then you go around to this side:

The top jack goes out to your tuner. It has its own buffer so nothing that happens there can affect your signal. Some tuners are infamous tone-hogs that will kill signal even off on a side chain. That won't happen here.

The next jack is the Send to your pedal board. This is buffered with a state-of-the-art opamp that can drive any load that will be encountered in the wild. Prototypes were built with more usual opamps that sounded good but didn't have these spec's, now we are way ahead of the bunch with great sound and impeccable technical spec's.

The third jack down is the Return from your board.

The bottom jack goes to your amp. Again this is seriously buffered and fully capable of driving huge runs of cable without signal loss. For large stages and ever more common isolation boxes this will get your signal to the amp intact and sounding great.

The switch can either bypass your pedalboard or work as a mute, silencing everything except the tuner out. Choose this option when you order. It can be changed with a simple soldered in jumper by any reasonably competent tech should you change your mind later. If you prefer, a user selectable jumper can be added at a slight extra charge. We don't recommend this as this should be a more or less permanent decision and even with the gold plated connectors we prefer the reliability of soldered connections.

Legends are hand marked on the bottom since we don't anticipate this being plugged and unplugged a lot. Mostly this will get installed on the board and forgotten except to step on it when it's time to tune. You can order top markings if you prefer in legible technician hand lettering.

We are taking orders now, no payment until we are ready to ship in 2-4 weeks. Price is $129 plus $8 flat rate shipping in the USofA.

Please email if you are interested in getting a free test run with the prototype.

Hero / Guru Pedal

Just got some photos in of a current Hero/Guru dual pedal.

Pretty huh?

Here's the gut shot. Because it should be pretty on the inside too.

Time for an Update.

Wow, way overdue for an update. The big action around here is still the development of the Diesel Driver Buffer. That's right my obsessive compulsive pursuit of the ultimate guitar buffer pedal/system continues. Prototypes have been built and electronically they are almost there. I'm still auditioning driver IC's, it works well and sounds excellent with a very common type, but I'm still looking for a high performance driver that is as smooth and uncolored.

One Diesel Driver has made it into a customer's hands and is now in service after being auditioned against a CAE buffer.

The first prototype circuit boards answered all the questions they were supposed to. Now I've ordered samples of what I hope and expect will be the final design. I'm hoping to have a Tour Box going out before Halloween. So if you're interested in trying this bad boy out, hit the email button and let me know.

Other business proceeds apace. Still doing repairs and finding time to play guitar again.

Stay well and healthy. Be back with more soon.