2011 - Weber Z-Matcher

Weber Z-Matcher 50W version

I've had this red box for a few months now, and have used it exclusively with my Fender Princeton Reverb RI and Epiphone 12" cab, which resided in my isolation cab.

The Princeton is engineered for a nominal load of 8 Ohms, but the Epiphone cab is 16 ohms. Everything I've read about the subject is that the amp down't handle the higher load very well, and that it would be better to run two 8 om speakers in parralell(gets you 4 ohms), rather than an 8 and 16. It's all to do with math and ratio's and running mismatched loads is a no no. Sure it's going to get you a load of 6 ohms or so, but since one speaker has less resistance, most of the power will go through there and will naturally be louder than the other as a matter of course. Also this doesn't fit the ratio that the amp requires.
First I tried using a resistive dummy load to match everything up, but since a speaker doesn't have a fixed resistance (due to the combination of frequency and inductance of the voice coil), the results weren't exactly pleasing.

I'd read all about inductive loads being the way to go, and pretty much the only one that I could find with any reviews, was the one from Weber. The manufacturers of fine speakers for guitar amps.
After a lot of deliberation and indecision, I decided that having a variable inductive load would be the way to go. so I bought the 50w Z-Matcher.

The purchasing process is a little odd, it's all via email and can take some time to get your quote back, but the staff were helpful when arranging the postage. But the transaction itself was done via Paypal and they were happy to send it Via USPS when asked. Weber build all of their stuff to order, so there's a bit of a waiting period, but being in Australia, I've gotten used to waiting for my stuff to arrive. Hey, if I can't get what I want locally (or locally at a competitive rate), then I have to go offshore for the products I want/need.

They estimated up to six weeks for assembly, but it was at my door in less than a month (not bad in my opinion). Anyway, back to the box. It came in a simple postage container wrapped in paper and bubble wrap. It's quite a heavy unit, so I delayed taking it home for a few days.
There's no manual to speak of, but there's no need if you're familiar with the basics of speaker matching (all us amplified guitars and bassists should be!).

Front Panel:
amp in
amp impedance (2-16 ohms)
speaker impedance (2-16 ohms
speaker out

Rear Panel
Line Volume
Line out - Balance
Line out - unbalanced
Parallel Speaker out

It was put to work matching the Epiphone Cab in the isolation box.
The first test I ran it through was the line out. Honestly I wasn't really impressed. Clean guitar was fine, but overdriven just sounded fizzy (pretty much like any amp with line out ever).
But hey, I wasn't exactly expecting a miracle there.

The next test I did was mic (Shure SM57) up the speaker and A/B that with the line out. Guess what? The mic even carelessly placed, sounded a lot nicer than the line out. I left it like this for a few months, and just playing with it when I had a couple of spare hours. After a while I noticed a bit of a weird distortion when using reverb on the Princeton. Especially if I was driving the reverb hard. I figured it was either a dodgy cable or maybe a quirk of the speaker cab inside a fairly small volume of air (there's a lot going on in an iso cab with a large speaker. Standing waves and other funky things can send voltage back to the transformer of the amp if you're unlucky). Also my headphones are a little rattly in some frequencies.

Upon further investigation, it turned out not to be a problem with anything mentioned above, and I haven't got definitive proof yet, but I have a hypothesis which makes sense (need to find an engineer wiling to experiment).

I decided to test the whole rig outside of the cabinet and directly with my ears, reducing the variables where interference could occur(cab, mic, lead, mixer, earphones). First up, I tested the amp by itself on a rubber mat to damp vibrations into the floor. Aside from making the house rattle when it was barely past two on the dial, the amp sounded as it should with the reverb cranked).

The next thing I did was to put the Z-Matcher between the amp and it's stock 10" speaker and set for 8 ohms per side. The distortion came back. Next I plugged in the 16 ohm cab. Again, fine on straight guitar signal, weird distortion with reverb. Last up I placed the speakers in parallel. The 16 ohm cab directly into the amp, and the 8 ohm stock speaker via the Z-Matcher (the amp side of the Z-Matcher was set to 16 ohms in order to present and 8 ohm overall load to the amp). As I'd already had a suspicion that the distortion was happening inside the Z-Matcher, it was no surprise to find that I had the distortion coming through the 10" speaker and not the 12".

The Z-Matcher works flawlessly with any signal presented to it as long as there is no reverb in the mix.
What I think is happening is that there are weird things happening inside the inductors of the Z-Matcher, due to the complex reflections generated by the reverb.

Reverb adds to those complexities and since the coils of the Z-Matcher aren't on the move as they would be with a speaker/magnet combination, there is a bit of a inductive choke effect going on and the result is the distortion that I'm hearing. It's subtle and I don't think that it would matter much in a band setting. The sound does stand out for me now as I'm aware of it. But I don't think it's a deal breaker on the Z-Matcher. It's just a quirk of electromagnetism and I can live with it as the unit serves it's purpose.

Reader input

Ok, so I do the update thing whenever I get a new bit of gear or am reminiscing about the good old days, lamenting being a dunderhead or whatever.


But tell me dear reader, what would you like to see on these pages?
Sound files
Videos
More photo's
Tutorials

I've recently passed the 11,000 view mark, but I've only received a handful of comments.
So it seems that I'm either doing something right, or doing something wrong.

Come on kids.
Let me have it!

Repairs: Ibanez FL9 Flanger - Not quite!

Oh man. I went to play with it last night.
The LFO problem is back.

Oddly though, the ability to do a parked flange is pretty nifty.
Kinda like parking your wah, but with a time based effect instead!

Repairs: Ibanez FL9 Flanger

Since I don't get much time to play guitar these days and when I do, it's generally just guitar and amp. My FX don't get used too often, and the least often used of my FX would have to be my Ibanez FL9 Flanger. Generally I don't havemuch use for flanging effects. It's fun and all, but I prefer to use it sparingly. If I'm going to use a modulated effect, it's more likely that I'll use a phaser. Just personal preference.

Because of this, my FL9 sat in a drawer for the best part of a year. It's an old pedal (over 25 years) and the last time I went to use it, it just passed a clean tone. The pedal wasn't toally broken, the delay chip was still working as there as a bit of a flange sound when twiddling the controls. Upon opening it up, some of the jooints looked cold. So I proceeded to re-solder everything on the board. No go. It took a  while to track down the schematic (didn't end up using it), but I'd read a snippet from one forum about replacing old electrolytic caps, so i figured that i'd give it a try. I went over the board and documented everything electrolytic.

There were two caps near the middle of the board which weren't coloured blue like the rest (they were orange), so I decided to replace them first and give it a test (I'd seen a similar arrangement on a synth I'd built). My hunch was right, they were there to control the LFO rate. The LFO was working again, but the effect was very subtle. Not at all like I remembered.

Fortunately the board has three trim pots for adjusting various biases. Ignore the middle one, it's there to bias a transistor and the factory setting is just right to avoid unwanted and unpleasant clipping. The trim pot closes to the middle controls feedback and the one further away controls depth. With these two trim pots you can get the pedal to self oscillate. Particularly with the first one. It's not a sound I'd want all the time, so I've set it up to kick in at about 70% maximum on the front panel feedback knob. The mod is safe and easy to do. You won't even need to take the board out to do it. While increasing the feedback makes the flanger more prominent, it still falls short of being a true "jet" flanger. Still it is nice to have in the tool kit.

FL9 Service Manual Page 1

FL9 Service Manual Page 2 (Schematic)

FL9 Service Manual Page 3 (Trouble Shooting)

FL9 Service Manual Page 4 (PCB Layout) - LFO Caps Highlighted w/red box.

Re-Repair & sound sample.

Stereo Flying V Demo

I've not been up to much in the guitar realm of late.
Winter has not been favourable for working outside, mostly due to the lack of dry weather and daylight.

For this post I'm revisiting the Stereo Flying V mod from May 2011.

I did a rough demo a few weeks ago, but have only just got around to uploading it.
The recording was done straight into the desk, with a couple of amp plugins and some out of the box drum loops. Before the guitar signal hit the mixer it passed through a pair of Bad Monkeys with a cheap octave down pedal on the Mustang Bass pickup.

My guitar playing is far from perfect and the sound quality one I uploaded it has changed a bit, so your mileage may vary. Despite my shortcomings, I feel as though the sound clip demonstrates the mod effectively.

StereoFlyingV by TheAwesomePowerOfRockets

July 2011 Pedal Gallery

My neighbour told me that I've been neglecting the blog of late, so I've just taken a few happy snaps of the pedals that I keep under my desk. This is most of my current working collection. I've built loads more than I have here at the moment and have discovered Circuit Snippets to be a great collection of unusual circuits for processing audio. Whoever the guy is behind it, must be some kind of genius!

Not much has been going on, trying to get motivated to finish my pickup ring templates, and in turn finish modding my Les Paul.

Home made fuzz pedal - A blend of a failed Ampeg scrambler followed by two cascading Germanium Transistor boosters.

Fuzz face clone - Easy face with tone control - Substituted Soviet era transistors for recommended.

Psychtar - From circuit snippets.

DOD stereo chorus - With vibrato mod (my design).

Bronx Cheer - Another pedal from Circuit Snippets

Ibanez  DE7 - Cheap good sounding delay.

Zoom H4n - Not a pedal, but has loads of FX. Good as a Rocktron substitute.

Danelectro Cool Cat Chorus - 18v model. Yard sale bargain.

MXR Blue Box - Two octaves down with lots of fuzz - Great square wave tones.

Fuzz Face Clone - Another fuzz face clone - Soviet GT404 Germanium Transistors. Volume control only.

Belcat Tremolo - Nice cheap variable wave shape tremolo.

Boss SD-1 - Modded clipping stage - Can't remember which mod...

Digitech Bad Monkey - One has been modded to let more bass through - Can't remember the cap value, probably .1uf

Sovtek Big Muff Pie - Indie rock staple. Fuzz Fuzz Fuzz. Works best with low output pickups.

Sovtek Small Stone Phaser - Nice sounding phaser, but has a tendency to generate nasty clipping on the front end if modded to compensate for the volume drop.

Fulltone DejaVibe - Nice Univibe clone. A bit expensive, but worth checking out.

Jim Dunlop Octavio - Fuzz Octave - Unpredictable insane fuzz. Very pronounced octave effect. Sounds different on every guitar.

Legacy OC-100 - Boss OC-2 clone - Might be cheap, but it tracks as well as any pedal. Works great with my stereo flying v!

Enough talk - Action! Manito Flying V Stereo Mod

I finally got around to modding my bargain Flying V from last year. Inspired by a blog post on Tym Guitars website. The mod is pretty easy to do if you have the tools. I used me Dremel and Router attachment. First thing to do was place the pickup on the guitar and drill the holes for the screw adjustment. Next was to flip the pickup upside down and trace the outline with a sharpie. I had to eyeball the line to make sure that I didn't go over. For the most part I kept within the line and did the final filing and shaping by hand. The Mustang Bullet Bass pickup fits nice and tightly in the hole. Once that was ready, I needed to make space in the body. The manufacturer promised a solid mahogany body, it's low grade, but it looks pretty similar to the photos in my woodworking book.  

Routing out the hole was done with the neck in situ, I just made some rails out of ice-cream sticks and masking tape to allow the router edge to glide over the fretboard. A little bit of soldering and a re-string(the proper way) and it was all roses. The nut needed to be replaced and is close to finished, though I need to spend a bit more time on it to make it just right. Once it was strung up I fired up a few effects, with the mustang bass pickup feeding an octaver. 

 It needs a little noise suppression to kill the bleed over from the 5th string, but nothing to worry about in any real sense. A fun project, that I recommend to anyone brave enough to get into cutting scratch plate material.