bonnie & jason

New guitar stuff –> DIY 2×12 cabinet

I was in a band in high school. Sort of. We played a set at prom… or was it homecoming? In any case, I was able to fake rhythm guitar by leveraging my violin skills. And I had this killer fluorescent yellow guitar. Looked exactly like this:

It was pretty bad actually. Didn’t hold tune well, had some buzzing, and the action was way too high. But there was no internet back then and I didn’t know what I was missing. Fast forward more years than I would care to admit and the guitar and my Peavey amp were just collecting dust so they were sold.

Fast forward to a month ago and I picked up this Epiphone Les Paul Traditional Pro guitar on CL along with a Mustang I practice amp:

Been learning a ton on the interwebs although I have a looong way to go.

Fast forward a few weeks (last fast forward, I promise) and as I’m often inclined to do, I found a way to turn another hobby into a DIY endeavor. So I built my own amp cabinet.

Step 1 – Decide what the guts were going to be:

Got these 12″ drivers from parts-express on factory buyout for cheap:

Step 2 – Decide on cabinet design:
Got some solid red oak and red oak plywood from Home Depot:

Decided to try dovetail joints for the first time:

And grooves for the front and rear panels hidden by the dovetail fingers:

Step 3: Assembly
The joints were super tight so glue up went well for this first one:

The subsequent simultaneous glue up with the front/rear/top was not so easy. Tight joints are great, but so many pieces going together all at once made things a bit difficult. Success nevertheless:

Here’s the front with the drivers installed:

And the rear with just the first driver installed:

And the whole shebang finished with some hand rubbed polyurethane with the new Mustang V v.2 amp to drive it:

Sounds great! It has so much volume potential. I’ll have to improve my skills so I can get a gig just to have an excuse to bring the rig with me to really test it’s potential. In the meantime, the amp does a nice job of getting the sound I want even at modest volumes.

Last thing to do is to install the grill cloth frame.

EDIT: 5/14/13
Grill cloth done:

Very happy with it. I ended up double layering and just gluing the cloth to inside edges of a wooden 1/2″x1″ frame. I used a line of binder clips to hold it in place while it dried (one side at a time). Worked brilliantly despite putting quite a bit of tension on the grill cloth. And I was able to size everything correctly to simply press fit into the cabinet frame. This may be the first time where measure twice cut once actually worked for me! There is some give in the cloth that gave me a little wiggle room though so that helped.

I’m still on the lookout for a logo of some kind. I may buy one of those woodburning brands to generically label all my projects since they tend to all have wood in them somewhere. But a chrome logo of some sort on the grill cloth seems to be a good fit for a project like this. Ebay has some letters that I sort of like but some don’t have the (+) sign for 1+2. And I don’t think I want oneplustwo since most of the letters are about an inch tall and wide. A bit overwhelming for the simplicity of the overall project. I’ll keep looking though.

Nelson Pass Aleph X clone build log

This is the biggest amp build so far and I doubt I will ever build anything bigger. Again, I went with a clone from the father-figure of DIY amps, Nelson Pass. Again, I got lots of help from the diyaudio.com community. And also got a ton of help from this particular website.

I won’t bore you with the details. If you’re interested in the nitty gritty, read through the diyaudio thread. Instead, here are a few photos from the build.

That is a lot of heat sinks and a lot of power transformer. Being class A comes at a cost.

These are the power supply boards half populated with big capacitors. Almost 300,000uF of capacitance could hurt you. A lot.

These are the boards for one channel. The main board and the daughter boards that parallel the MOSFETs to handle the extra power.

Here’s the basic layout on the heat sinks:

Bottom view showing the 1/4″ aluminum tie pieces:

I mounted the PSU board on one of the heat sinks:

Here they are completed and in testing position:

Like I said, they’re big. I think 20″ deep, 14″ wide, and probably about 50 lbs each. I’ll put them on a scale to find out for sure, but they’re really heavy.

Still breaking in, but so far, they sound really good. And act as space heaters as well.

More speakers!? A high-end two-way bookshelf

I wanted to try a speaker with super high-end drivers so I found some used for a pretty good deal and also found a pair of cabinets that someone didn’t want anymore. As such, I was able to go high-end without a high-end price. Brand new, the drivers and crossover plus a from scratch cabinet would have easily exceeded $1000. As is, I spent about half that.

Here is the cabinet that I started with:

And I turned them into these:

I still have quite a big of material left over of course, but it was nice to be able to spend zero dollars on the cabinet and just a few bucks on some rattle can satin spray paint.

The crossover is a Madisound design that came with the drivers (The Scan Speak 5″ Revelator and D6600 tweeter). They turned out fine… but I’m not convinced the price premium is worth it. I haven’t done a lot of listening yet so I might change my mind, but I doubt it. Even if I can hear a difference compared to my various Dayton speakers, for sure it will not be very significant.

My dorky bench equipment

Finally had a chance to put the bench test equipment together. Oscilloscope, two DMMs and two power supplies.

And the DMMs are well calibrated. So it seems.

Nelson Pass F5 Class A Stereo Amplifier

Another project in the books. This one is my first class A power amplifier build. The circuit itself is actually relatively simple. And the casework wasn’t bad either truth be told. But I’m getting ahead of myself.

The design is from one of the godfathers of the DIY HIFI community, Nelson Pass. He runs a DIY website as well as a commercial and a sort of hybrid enterprise that sells retail items but also provides schematics and articles so the enterprising DIY’er can “roll his own.” He’s also active on the diyaudio.com site and chimes in from time to time.

The specific design I chose is the F5. It’s a push-pull Class A amplifier, utilizing JFETs and MOSFETs in a very simple two stage complementary circuit. It spits out about 180W (most of it in heat) and is one of the more popular designs from Mr. Pass.

For my build, I sourced the PCB from tech-diy.com and most of the little bits from mouser. The heat sinks were from antek and the rest of the chassis was made up of scraps actually. I had spare 1/4″ aluminum for the bottom, African mahogany for the front panel, plywood for the rear, and plexiglass (from an old document holder) for the top. I did buy some 1/4-20 bolts and some new RCA jacks and speaker posts. But all in all, I think I only spent about $300 all told. Some have been known to spend that much just on the front plate!

In any case, pictures are where the fun is so here you go.

The trafo, rectifiers, and first pair of caps that make up the separate PSU enclosure. I used a 4-pole Neurtrik Speak-On connector for V+/G/V-/earth ground:

Here’s the enclosure for the PSU. Made from more scraps:

Here are the amp PCBs coming to together mounted on the heat sinks:

Here’s the view of the front/bottom with the mahogany and aluminum holding the heat sinks together:

And of the rear/bottom:

In mockup mode:

The beginnings of milling the rear:

All put together with the plexiglass top:

Shot of the front with the powdercoated aluminum letters I splurged on:

Stacked on the PSU:

It sounds great and doubles as a space heater! I got it biased up to about 580mV and the DC offset is essentially zero on both channels.

Some sketches I made on the plane on the way home from a business trip:

RS 150 DIY Bookshelf Speaker Build

I can’t seem to stay focused these days… building speakers, amps, and a buffer all at the same time. Anywho… here’s a post for the latest item. A pair of CJDs rs150 TM bookshelf speakers. I need a pair of smaller speakers for the bedroom. They’ll probably be driven from a chip amp (that I’ve actually completed already) using my iphone as a source.

I got the tweeters used and the woofers aren’t that much to begin with so I just bought them.

I made the cabinet with simple birch plywood all leftover from other projects with mitered and biscuited corners. The front corners will be about a 3/8″ bevel as a design feature (I’m a sucker for the laminate look for some reason) with a basic hand rubbed tung oil finish to match many of my other builds.

The sides and back glued up:

Crossovers installed with foam and just waiting for the front baffles:

The problem with not having perfectly square cuts and positioned biscuits:

Testing out the first speaker:

Their current resting place book-ending my headphone amp and the chipamp.

So far, I’ve been very happy with them. They need a little breaking in and they don’t sound nearly as good as the full size designs, but they’re very good for what they are.

The next project will be the opposite end of the spectrum… very large with dual woofers, dual mid-ranges, and my first build with a ribbon tweeter. And of course, I still need to finish the other amps and buffer projects!

Subwoofer Build – 12″ Dayton Audio RSS315HF

A few pics of the subwoofer I just finished. It’s based on the Zaph Audio design found on his site’s archives. The difference is I didn’t incorporate the dedicated subwoofer amp since I decided to use an old integrated amp I had lying around. Also, I used plywood construction with mitered joints all around. This was the first time I tried mitered joints on a large piece. I tried the tape and plastic wrap method as seen below:

Also, I added a bit more bracing to the inside since plywood isn’t quite as dead a material as MDF:

A little sanding and a little tung oil later:

And done:

The thing weighs a ton… the driver itself weighs 25 lbs, mostly from the magnet but also from the beefy cast aluminum frame.

Pretty happy with it considering everything was scrap materials except for the driver and the stainless screws I used. The same setup from parts-express.com is almost $600. I paid $100 for the driver from a fellow DIY’er. Yay DIY!

Sunflower speakers archive

Archiving the sunflower speakers page here:

For my third pair of DIY speakers (I know… running out of rooms to put speakers in), I decided to try a new style with an open baffle design. The open baffle designs that get most of the press are Linkwitz’s Orions and John Krekovsky’s NaOs but those use really expensive drivers with active electronics requiring multiple channels of amplification. So instead, I’m using one of Paul Carmody’s designs that he has dubbed the Sunflower XT.

It uses dayton reference drivers which are great performers at a good price. I used a few from this lineup for the ZDT 3.5 speakers from the last project as well. Also, it uses a Vifa XT tweeter which is a driver used in many high end designs that is generally accepted as an excellent tweeter with low distortion and great dynamics. Whatever that means.

In any case, here are a few pictures of the speaker in progress.

March 13, 2011

The baffles:

The rears with the cutout and recess for the port:

A little photoshop on what will be the side panels (maple birch ply):

The “box” part glued up:

View of the bracing and foam on the inside:

Side panels cut and just positioned to see what it will look like:

Next step is to do some sanding and bondo-ing before figuring out how to assemble the pieces together and paint. Speaking of which, I think the “box” part is just going to be black. Either a spray textured black or a brushed/rolled on enamel flat black. The plywood sides are going to just have a few coats of a simple tung oil rub. That’s the plan right now anyway. More to come.

March 27, 2011
A few updates:

The “translam” top piece (still needs to be trimmed and sanded)

It will look something like this:

Also, here’s what I think the crossover box top will be:

It’s a remnant piece of hardwood (not sure what species) that I book-ended and sort of-kind of biscuited together with my table saw and a piece of MDF.

It will look something like this (carrying through the translam concept):

Got some glue/water sealing done today also.

March 29, 2011

March 31, 2011
Got some painting done:

April 5, 2011:
Drivers installed and crossovers partially complete:

April 9, 2011
Got the crossovers done an everything wired up.

Hello again

Wow, has it been nearly two months since the last post?! Oops… been crazy busy recently.

Ok, let’s get caught up.

Lots of park days! These are from the Westlake Park in Daly City where I USED to play tennis all the time.

After the farmers market, a walk in the mall:

Cheeky monkey: (on a side note, Amanda is likely going to grow up with the nick name Chi-chi. It started out with us calling her Mon-chi-chi after the cartoon character of the early 80′s but it seems to have stuck. Alissa and Ashley also call her Chi-chi more often than not.)

Chunky monkey: (another side note… Ashley is still a good eater.)

Happy Chinese New Year:

One of Bonnie’s dinner ideas:

…with dessert:

Going or a walk… and digging for gold:

Off to the park again:

Yay park!

Denim is in:

Alissa took these:

Abigail’s fifth birthday party:

Finally, another set of speakers in progress:

Playhouse progress

The playhouse is nearly done… here are some in process pics:

Me and my helper finishing the framework:

Alissa with Uncles Alan and Calvin enjoying the half finished playhouse. The wall sheating is up and the roof is mostly shingled:

Fully shingled and mostly painted:

Now I just have to finish the doors and windows along with the trim. Alissa wants green windows and a purple door.