Chuck D'Aloia is a master teacher!

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Chuck D'Aloia doing his thing at the 2012 LA amp show

As you those that follow this blog now, I spend most of my spare time inhaling solder fumes working on my various amp and effects projects.  But once in awhile -- not as often as I should -- I get the urge to actually, you know, play some guitar.  The problem is, I'm just not all that good, and not particularly imaginative.  Like a lot of guys, I seem to have a hard time breaking out of familiar patterns and riffs. So it's a wonderful tonic when something comes along that can help you break out of a rut and introduce you to some new ideas.   This blog post is about one of those discoveries.   Chuck D'Aloia is a really great player -- I've long admired his playing, which I first came across when checking out various amplifier demos on the intertubes.  But, as it turns out, Chuck is a first rate teacher as well.   I highly recommend that you check out his "Blues with Brains" lesson series. Here's a little preview on YouTube, showing how to take on a basic blues progression with a little bit of a more interesting harmonic approach.   I bought the rest of the lessons, and it just gets better from there. It was money well spent.. Thanks Chuck!

Layout for circuit similar to 5F1 Champ

The Fender Champ is an iconic amplifier with roots going all the way back to 1948.   Noted for the simplicity of its circuit and controls (in many versions, just a simple volume knob), it's hard to imagine a simpler or lower-cost tube amplifier.  This perhaps explains why, over the years, many manufacturers have produced amplifiers with circuits that vary from that found in the Champ in only incidental ways, and why the circuit is of ongoing interest to DIY hobbyists.  Well, that and the great tube tone!   While a wide variety of Champ circuit variants have been produced by Fender, the 1958 Tweed-era 5F1 is perhaps the most enduring.  However, the layout employed in the 5F1 has a primitive ground scheme, and the amplifier is not particularly quiet.   I've been asked a few times how I would lay out such an amplifier with a more modern approach.  Note that while it employs a "bussed stars" approach, it has only *one* attachment point to the chassis for the audio circuit right at the input jack (although please note that any real-world circuit MUST also incorporate a completely sound safety earth connection from the third prong / ground of the mains power to the chassis).   The input and output jacks themselves should be insulated. The circuit shown here is fairly true to the original.  If I were to build one for myself, I would undoubtedly incorporate a few more changes to further modernize things to improve noise performance and reliability -- but purists would undoubtedly complain.  Please note that the suggested layout is a draught only, and should be thoroughly error-checked before using it as a launching pad.

Black Iris Toyota spot

Cam DiNunzio and the folks over at Black Iris have been busy lately!  If you've been following this blog, you know that Black Iris commissioned both the EQP-1A tube equalizer and the LA-2A optical compressor described at length in earlier posts here.  Cam has told me that these have been used in the recording of the music for quite a few television commercials that you may have seen over the last year or so. But my favourite is a jingle that that Black Iris did recently for the Saatchi & Saatchi Agency for their Toyota Prius "Hum" ads.  Cam used both the Wombat Amps EQP-1A and the LA-2A for tracking the acoustic guitar and the vocals, and evidently the agency "continuously commended the 'warm' and 'natural' sound of the recording".  Cool!  

This 30 second spot came out awhile ago, back in September I think:

However, I just became aware of this newer 60 second spot, which is what prompted me to post this today:

Quest Amp Demos

I've been quiet for awhile here, but there should be a flurry of posts coming in the next few weeks.   I've been working on-and-off on a solid-state studio equalizer project based on the EQ section from the the old-school Trident S-80.  This is based largely on circuit boards developed by PeterC over on group DIY.   According to current plans, the unit will be a quad channel EQ.

In the meantime, here are links to a couple of brief videos I recorded this summer before sending the Quest amplifier off to David Morin, the winner of the LLS amp Raffle.

First is a general demo of some of the clean sounds from the Quest amp.  In the end, I was quite happy with how sparkly the cleans can be.  There is a decent amount also of clean headroom, albeit less than would be expected in an amp with global negative feedback.  I had wanted also to record a demo of the overdrive channel, but the crappy camera mic just wasn't up to the job. Apologies for the rudimentary playing.

Next  is a demo of how the tremolo sounds, which I thought would be of interest, since the method by which the volume is modulated is, I think, somewhat novel (the transistor based LFO varies the current through a vactrol, which acts the series resistance in front of a virtual-earth mixer type tube stage, which, aside from the mixing function, is also configured to provide some additional gain for the reverb recovery.  As I mention at the end of the video, I think it worked out pretty well.

 Let me know what you think!

We have a winner!

The raffle for the Wombat Amps Quest amplifier was conducted today using the RandomPicker.com website.  You can see the details and the protocol that was used.

I'm excited to announce that David Morin of Monmouth, ME is the lucky winner!

Many thanks to everyone that so generously donated to support the Leukemia and Lymphoma Society and this project.  Special thanks are also in order to my collaborators from the Gothik Amps consortium that so graciously donated time and materials for the amp project.

This includes Ben Sykora of Sykora Custom Tube Amps, for his donation of a beautiful hand-built head cabinet, Mason Atom Wolak of TMI amplification, for the engraved faceplate, and Brian Schmittling of DirtyDawg Amps for the custom aluminum amp chassis.

In the end, we raised almost $3800 for cancer research, with donations coming from five countries (USA, Canada, Slovakia, Australia, and the United Kingdom) and three continents.

More soon.

Raffle amp is almost complete -- Drawing soon!

Hey everyone!  I know it has been quiet here, but this almost always means that I have been busy amp building instead of blogging.  Just to update everyone, on 3 June, I ran the San Diego half-marathon with the Leukemia and Lymphoma Society's "Team in Training".  Although I ended up dropping down from my originally planned full marathon to the half, and I didn't set any speed records this time, I'm proud to say that this was the sixth event I have completed with Team in Training as either a participant or as a fundraising mentor.  With over 2500 Team in Training participants at San Diego, it was a great experience, and at this one event alone the LLS raised over $7.3 million for cancer research.  To those of you that have donated, thank you very much -- you are making a real difference.   For those of you that have not yet donated and wish to get in on the amplifier raffle, the fundraising page is here.  Remember, each $25 donated counts as a ticket in the amp raffle!

Team Wombat celebrates! When anyone asks I tell them, "Yes, I *did* win, thank you for asking!"

So the run is over, and the fundraising will also soon be coming to an end.  With only a couple of days left before the amplifier raffle (the raffle is happening on this Sunday 24 June!), I wanted to post a few more more build pictures before the amplifier is totally completed.  Right now, virtually everything is done, except for tweaking the final wiring of the sockets and the pots, which I should be able to knock off on Saturday morning.  After that, we'll be ready for first fire-up and final tweaking.

The guts, awaiting final harnessing up.

Close-up of the solid-state tremolo board.  It's a good illustration of the hybrid turret and PCB approach I tried out for the first time with this amp.   The board with the green capacitors is actually a hand-fabricated PCB, while the surrounding main board is traditional turret board construction.  So far, I'm pretty happy with how this worked out.

Close up of the main board.  The TO-220 packages visible in the foreground are the ultra-low noise "Stealth" rectifier, and the STF3NK80Z MOSFET that at the heart of the capacitor multiplier on the screen supply.

Something else that I've tried that's slightly unusual on this amp is to have a dedicated turret board for all of the power tube associated circuitry. I got tired of the screen grid resistors vibrating around, and it just made sense for this layout.

Let's build an amp!! Rafle amp update

This afternoon, UPS delivered on my doorstep the beautiful cherry case constructed by Ben Sykora that he generously donated to support my amp raffle to benefit the Leukemia and Lymphoma Society.  Also arriving in the package was the awesome custom 12-gauge aluminum chassis donated by Brian Schmittling of DirtyDawg Amps, which is definitely the hobbyist's go-to place for guitar chassis.  So now all the boards are constructed, all the components are in-hand and we are now ready to enter the final assembly and wiring phase.  It won't be long now!

That said, I'm leaving for the race in San Diego this Friday, so it's time to admit that things have fallen a little bit behind schedule.  The original plan was to hold the amplifier raffle immediately following the race.  However, as it's clear now that the amp just won't be ready by then, I've decided to delay the amplifier raffle until Sunday, 24 June.  That's three weeks after the day of the race, which will give me time to fully complete the amplifier prior to the drawing.  I've also settled on a method to transparently and independently conduct the raffle. I will be using the services of the RandomPicker website.

Oh, and one final thing!  The amplifier has a name, courtesy of John Hannon over at AX84... henceforth it shall be known as the Wombat Amps "Quest"!