Tuesday, September 3, 2019

A Busy Start to Fall

The fall of 2019 is shaping up to be busy, now that the studio space is done and word is getting out. I tracked and mixed six songs for a new band featuring Jake Levee of Canadian Rifle, who is among the first punks I met after moving to Chicago 23 years ago. Even though he is playing bass in this band (whose name is in the process of being changed) he brought over this Music Man HD130 which I sold to him circa 2007 and has been his main amp in Canadian Rifle ever since. It has gotten some serious road wear since Jake took over ownership, and has had the transformers and speakers replaced along with a number of other repairs. Every time I see the Rifle play I get a twinge of regret for selling it - it always sounds amazing and held up the bargain for the recording. 
Apart from great songs, good vibes and excellent playing, Jake and Kate would like to remind us all of what is really important for a successful recording session:
In the next month I will be recording the new hardcore band Dog Flashback, and working on a new record for Primitive Teeth. I also have several projects in the works that are still being finalized. That's a lot of bags of chips in my future.

Friday, August 30, 2019

Ibanez Echo Shifter Review/repair

While on tour in 2018, I thought my delay pedal (DOD Rubberneck) was broken so I went to a local music store to see if there was an inexpensive replacement. They had one of these Ibanez Echo Shifters available, and it wasn't too pricey so I picked it up. It lacks a lot of the features of the Rubberneck, but I considered them nice to have and not necessary (tone on repeats, modulation speed, the pitch shift/rubberneck function). I really like the temporary feedback feature on the Rubberneck, and while there's not a stomp switch dedicated to it on the Echo Shifter, it does have a toggle switch to activate additional gain in the delay feedback to create self-oscillation.

I swapped the Echo Shifter in to my pedal board, and we had a little rehearsal the day before our first show. Everything went nicely, the sound of the Echo Shifter was right in line for what I want in an analog delay. However, at the show that night, the slider for echo time snapped off, like three songs into the set. I am not a wild man onstage, and I would expect a little more from the slider given that the rest of the construction on this pedal is nice and solid. I finished out the tour with the pedal - I pretty much left the delay time setting in the same place anyway - and came to appreciate its sound.

Some other review notes: For my taste the modulation depth control has too much range. I really don't know who uses delays with pitch sweeps of almost an octave on the repeats, but someone must because you can go there with this pedal. Another thing, it would be lovely to have a tails option when going into bypass - I really like that about the Rubberneck as well. Last, I am a fan of stomp switches that have a positive click when you engage them. This wouldn't be practical on the tap tempo switch, but I would prefer it on the bypass switch. It's a small thing though.

After coming home from tour, I discovered that the Rubberneck was just fine after all, luckily. The issue was actually with how I had set up my power supply. Lesson learned - when going overseas invest in a pedalboard supply that accepts dual voltage input so that you don't have to use a stepup converter. The one I was using introduced a lot of noise into the line voltage and I think that was messing with the digital circuitry of the Rubberneck somehow. Interestingly, other digital or hybrid pedals on my board, like my Strymon Blue Sky and DLS Rotosim, were not similarly affected.

On to repairing the Echo Shifter. There are a number of people who have posted repairs to these, including this nice post with info on the replacement of the slider control. I didn't want to just do that- after all it broke almost immediately and I knew it would happen again. Also, I don't generally need or want to change the delay time on the fly, so the ability to push the slider with my foot wasn't a concern. I decided to try to shoehorn in a standard rotary potentiometer as a fix.

First step- disassemble the pedal and remove the broken component. This is a little time consuming due to how the pedal is designed. It's not as easy as pulling apart an MXR or even a Boss style pedal. Lots of loose parts to keep track of.
Here's the circuit board with the slider removed and three flying leads attached to the now vacant pin locations. The pot is a 16mm Alpha, 10K linear. This one came from Tayda Electronics (I like this place for DIY project parts, a lot easier to browse than Mouser or DigiKey) and it has a plastic cover on the body. The part is a very tight fit and there are only a couple of places along the footprint of the old slider that will work, since the 16mm pot is wider than the slider and all those DIP chips come right up to it. I wound up having to cut off the plastic cover from the pot, and since it looked like it would potentially contact traces or solder pads on the board I put a single layer of electrical tape on the bottom. Alternatively, I could have sourced a square format pot like the factory-installed ones elsewhere on the board which should fit pretty much anywhere along the slider's footprint, but I already had the 16mm pot in hand and it wasn't too difficult.
I drilled the top panel for the pot shaft. As I said above, this hole has to line up with pretty much the only place on the circuit board where there's enough space to squeeze in the pot body. A 9/32 or 5/16 hole should do it. Since you're drilling on top of an existing slot, a drill press is a nice to have. If I didn't have a drill press, I would probably have done this with a rat tail file, or a grinding stone in a Dremel tool. In a handheld drill, the bit would just "walk" along the slot and not make a nice clean hole.
Here it is all put together. I had an old skirted knob in my spare parts stash that looked appropriate on the pedal even though it isn't an exact match (and MXR/Rickenbacker style knobs like these are easy to come by if you really need it to look the same). Someday, I will make a modification that will allow the oscillation to be engaged by either the toggle switch, or an external momentary stomp switch, to make it function more like my Rubberneck.

Thursday, August 29, 2019

Archive Project: Condenada Demo

This tape is one of the first things I ever recorded for a band I wasn't in. Circa 2004 or 2005, I was working a student job in grad school, doing production setups and sound board operating for events in a large campus auditorium. Condenada was new on the scene and I was a huge fan from the get go. I had just acquired my first digital interface (a Presonus Firepod) and was eager to try it out. My boss let me use the facility on a dark day to do the recording. The band set up on stage at the auditorium, and we quickly discovered we had to close the main stage curtains because without them, the reverberance of the hall was way too intense.

This tape is very rare, since shortly after it came out the band decided to re-record these songs for a new demo, as they felt these performances were slower than their evolving sound was going. That aside, this tape contains early versions of a bunch of tunes that would become classics and part of their live set throughout the life of the band.

Two classic Condenada songs, circa 2007:

Friday, June 28, 2019

SPX90 Repair

This repair would probably have taken someone who knows what they're doing about 5 minutes... it took me significantly longer than that. 

Many years ago, I got this Yamaha SPX90 as a throw-in when I bought my Tascam 246 Tape machine. It hasn't gotten that much use over the years - occasionally I would use it on the effects send of my headphone mixer to give singers a little reverb in their headphones, but that was about it. It always worked when I needed it to, until recently when I plugged it in and got nothing, no lights on the front panel at all.

I opened it up, put a voltmeter on the power supply rails and could see that it was not outputting any of the required voltages. The internal fuse was fine, though. This has a switch-mode power supply which is not a design I've ever worked on or troubleshot before. So, I did a little research first (this article by Scott Dorsey, in particular, was helpful) and then started hunting down sources of the issue.

The first thing I looked at was Q1, which is the main high current switching transistor that feeds the main transformer. I pulled it out and sure enough, it was shorted. This is a 2SC2555, which are no longer made but I found some NOS ones on ebay. Once those showed up, I put one in, and still nothing. At this point, I knew I should really get systematic and check everything in the circuit. I started with the other transistors, and discovered that Q2 was also kaput. This is a 2SD1207, also obsolete. I checked all the diodes, there are quite a few, and all those checked OK. Then I started looking at passive components. I discovered that R2, which directly follows the bridge rectifier and feeds the entire circuit, was failed open. So that would explain a significant reason that the supply wasn't working.

I decided that if I was going to be replacing a bunch of parts I should do the large filter capacitor, so I put together a Mouser order with the power resistor and the capacitor, and a substitute for Q2 that I thought was reasonable - not a pinout match but similar specs, or so I thought.

When all that stuff arrived, I loaded them into the board and applied power. The switching circuit fired up, but before I could even verify voltages, most of the electrolytic caps on the low voltage side of the supply let out their magic smoke. I guess my slick substitute transistor was not a great idea. I was really careful to modify it for the correct B-C-E arrangement, but I think there was some other specification that I overlooked that was causing trouble. Not something I am experienced enough to diagnose.

Once all the low voltage caps were removed, I made yet another order to get the replacements (even ones that hadn't popped). I sprang for low ESR Panasonics, since I read this is a good idea.

Here is the PS board waiting for its new capacitors and the replacement Q2 that I got off ebay - correct part this time.
Here is the board with all the components installed and back in the chassis. That long metal bar that connects the power switch to the front panel is a real pain, since it requires the removal of the front panel to get the PS board in and out. I assume it's set up this way to keep the mains voltage wiring segregated to the back corner of the chassis and away from the audio signals. I tested the supply voltages with the headers disconnected, and all the rails looked good!

It's alive! Now I can make all my cool lo-fi 80s gated reverb drum sounds that this thing has in its presets. Next time I have to mess with a switching power supply, I will hopefully not make so many mistakes. Overall, this probably cost me $25 or so in parts and shipping. Part of that is the sellers of these obsolete transistors make you buy more than 1.

When I got the SPX90, I also got  a lot of documentation. In addition to the manual, I also got these:
The one on the left has some pretty funny stuff in it. Here are my two faves:

Saturday, June 22, 2019

Archive Project: Heated Demo

I played drums in Heated for a while - the band was moderately active but never managed to find its groove with regular shows. We did this demo tape in the spring of '17, and also recorded a lot more songs for an LP a year later that remain unreleased, and to my knowledge never even finished getting mixed. The demo recording was another practice space affair, on the third floor at Superior Street. It's hard to track a band when you're also playing drums.

Friday, June 21, 2019

Archive Project: Distract/Warrior Tribes Split CS

This tape feels like a marker of a specific heyday in Chicago DIY. Both bands were doing tons of fun shows and the project of putting them on the same tape made perfect sense. We did this in one day in 2013 at my place, with one setup for both bands (there might have been some switching of guitar amps, but that's about it).

Archive Project: Kontaminat Demo

I am not sure if this 2011 recording ever had a proper physical release. I can't find a copy in my collection. This was a great band and revisiting this recording, I think it does a good job of capturing their sound and energy. Also, someone (not sure who) mastered this before they put it online and it definitely improved things.

A Busy Start to Fall

The fall of 2019 is shaping up to be busy, now that the studio space is done and word is getting out. I tracked and mixed six songs for a ne...